952d affi" } COMMITTEE PRINT
WEATHER MODIFICATION: PROGRAMS, PROBLEMS, POLICY, AND POTENTIAL
Prepared at the Keqtiest of Hon. Howard W. Cannon, Chairman COMMITTEE ON COMMERCE, SCIENCE, AND TRANSPORTATION UNITED STATES SENATE
Printed for the use of the Committee on Commerce, Science, and Transportation
r
95S Congress I COMMITTEE PRINT
2d Session J
WEATHER MODIFICATION:
PROGRAMS, PROBLEMS, POLICY, AND POTENTIAL
Prepared at the Request of
Hox. Howard W. Cannon, Chairman
COMMITTEE ON COMMERCE, SCIENCE, AND TRANSPORTATION UNITED STATES SENATE
MAY 1978
Printed for the use of the Committee on Commerce, Science, and Transportation
U.S. government printing office
34-857 WASHINGTON : 1978
COMMITTEE ON COMMERCE, SCIENCE, AND TRANSPORTATION
HOWARD W. CANNON, Nevada, Chairman
WARREN G. MAGNUSON, Washington RUSSELL B. LONG, Louisiana ERNEST F. HOLLINGS, South Carolina DANIEL K. INOUYE, Hawaii ADLAI E. STEVENSON, Illinois WENDELL H. FORD, Kentucky JOHN A. DURKIN, New Hampshire EDWARD ZORINSKY, Nebraska DONALD W. RIEGLE, Jr., Michigan
Aubrey L. Sarvis, Staff Director and Chief Counsel
Edwin K. Hall, General Counsel Malcolm M. B. Sterrett, Minority Staff Director
JAMES B. PEARSON, Kansas ROBERT P. GRIFFIN, Michigan TED STEVENS, Alaska BARRY GOLDWATER, Arizona BOB PACKWOOD, Oregon HARRISON H. SCHMITT, New Mexico JOHN C. DANFORTH, Missouri
LETTER OF TRANSMITTAL
U.S. Senate,
Committee on Commerce, Science, and Transportation,
November 15, 1978. To the members of the Committee on Commerce. Science, and Transportation, U.S. Senate:
I am pleased to transmit herewith for your information and use the following report on "Weather Modification: Programs, Problems, Policy, and Potential."
The report was prepared at my request by the Congressional Re- search Service under the direction of Dr. Robert Morrison, Specialist in Earth Sciences, Science Policy Research Division. We thank Dr. Morrison and the others involved in the study for their extremely thorough and scholarly report. Substantial material on almost all areas of weather modification are included and the report will provide the committee with an excellent reference source for future delibera- tions on the subject.
The completion of the report is particularly timely due to the up- coming recommendations expected from the Weather Modification Advisory Board and the Department of Commerce (as directed by Public Law 94-490) on the future Federal role in weather modification.
James B. Pearson, Ranking minority member.
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LETTER REQUESTING STUDY
U.S. Senate,
Committee on Commerce, Science, and Transportation,
Washington, D.C., July 30, 1976.
Dr. Norman A. Beckman,
Acting Director, Congressional Research Service, Library of Congress, W ashington, D.C.
Dear Dr. Beckman: Weather modification, although a relatively young science, has over the years stimulated great interest within the scientific, commercial, governmental, and agricultural communities. Such responses are readily understandable. Weather-related disasters and hazards affect virtually all Americans and annually cause untold human suffering and loss of life and result in billions of dollars of eco- nomic loss to crops and other property. While weather modification projects have been operational for nearly 25 years and have been shown to have significant potential for preventing, diverting, moderat- ing, or ameliorating the adverse effects of such weather related disas- ters and hazards, I am greatly concerned regarding the lack of a coordinated Federal weather modification policy and a coordinated and comprehensive program for weather modification research and development. This fact is all the more disturbing in view of the mani- fest needs, and benefits, social and economic, that can be associated with weather modification activities. These deficiencies in our Federal orga- nizational structure have resulted in a less than optimal return on our investments in weather modification activities and a failure, with few exceptions, to recognize that much additional research and develop- ment needs to be carried out before weather modification becomes a truly operational tool.
Reports and studies conducted by such diverse organizations as the National Academy of Sciences, the National Advisory Committee on Oceans and Atmosphere, the General Accounting Office, and the Domestic Council have highlighted the lack of a comprehensive Federal weather modification policy and research and development program. Hearings that I chaired in February of this year reinforced my con- cerns regarding the wisdom of our continued failure to implement a national policy on this very important issue.
I am therefore requesting the Congressional Research Service to prepare a comprehensive report on weather modification. This report should include a review of the history and existing status of weather modification knowledge and technology; the legislative history of existing and proposed domestic legislation concerning weather mod- ification; socio-economic and legal problems presented by weather modification activities; a review and analysis of the existing local, State, Federal, and international weather modification organizational
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structure: international implications of weather modification activi- ties: and a review and discussion of alternative U.S. and international weather modification policies and research and development programs.
If you have any questions with respect to this request, please contact Mr. Gerry J. Kovach, Minority Staff Counsel of the Senate Commerce Committee. He has discussed this study with Mr. Robert E. Morrison and Mr. John Justus of the Science Policy Division, Congressional Research Service.
Very truly yours,
James B. Pearsox,
U.S. Senator.
LETTER OF SUBMITTAL
The Library of Congress, congressional research service,
Washington, D.C., June 19, 1978.
Hon. James B. Pearson,
Committee on Commerce, Science, and Transportation, U.S. Senate, Washington, D.C.
Dear Senator Pearson: The enclosed report, entitled "Weather Modification: Programs, Problems, Policy, and Potential," has been prepared by the Congressional Research Service in response to your request.
The study reviews the history, technology, activities, and a number of special aspects of the field of weather modification. Activities discussed are those of the Federal, State, and local governments, of private organizations, and of foreign nations. Consideration is given to international, legal, economic, and ecological aspects. There are also an introductory chapter which includes a summary of issues, a chapter discussing inadvertent weather and climate modification, and a chapter summarizing recommendations from major Federal policy studies.
The study has been coordinated by Dr. Robert E. Morrison, Special- ist in Earth Sciences, Science Policy Research Division, who also prepared chapters 1, 2, 3, 5, 7, 8, and 9 as well as the Summary and Conclusions. Mr. John R. Justus, Analyst in Earth Sciences, and Dr. James E. Mielke, Analyst in Marine and Earth Sciences, both of the Science Policy Research Division, contributed chapters 4 and 6, respectively. Chapter 10 was prepared by Mrs. Lois B. McHugh, Foreign Affairs Analyst, Foreign Affairs and National Defense Di- vision. Chapter 11 was written jointly by Mrs. Nancy Lee Jones, Legislative Attorney, and Mr. Daniel Hill Zaf ren, Specialist in Ameri- can Public Law, both of the American Law Division. Dr. Warren Viessman, Jr., Senior Specialist in Engineering and Public Works, contributed chapter 12; and Mr. William C. JolW, Analyst in En- vironmental Policy, Environment and Natural Resources Division, was responsible for chapter 13. In addition, appendixes C, F, Q, and R were assembled by Mrs. McHugh ; appendixes D and S were prepared by Mrs. Jones; and information in the remaining appendixes was collected by Dr. Morrison.
I trust that this report will serve the needs of the Committee on Commerce, Science, and Transportation as well as those of other committees and individual Members of Congress who are concerned with weather modification. On behalf of the Congressional Research Service, I wish to express my appreciation for the opportunity to undertake this timely and worthwhile assignment. Sincerely,
Gilbert Gtjde,
Director.
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Digitized by the Internet Archive in 2013
http://archive.org/details/weatificatOOunit
CONTENTS
Page
Letter of transmittal in
Letter requesting study v
Letter of submittal vn
Summary and conclusions xix
Chapter 1
Introduction and summary of issues 1
Perspective 1
Situation 1
Advantages 3
Timeliness 5
Definitions and scope of report 7
Summary of issues in planned weather modification 9
Technological problems and issues 9
Governmental issues 12
The role of the Federal Government 12
Roles of State and local governments 14
Legal issues 15
Private rights in the clouds 15
Liability for weather modification 16
Interstate legal issues 17
International legal issues 17
Economic issues 18
Issues complicating economic analyses of weather modifica- tion 18
Weather modification and conflicting interests 19
Social issues 19
Social factors 20
Need for public education on weather modification 21
Decisionmaking 22
International issues 23
Ecological issues 24
Chapter 2
History of weather modification 25
Introduction 25
History of weather modification prior to 1946 26
Prescientific period 26
Early scientific period 27
Development of scientific fundamentals 32
Early cloud-seeding experiments 34
Weather modification since 1946 35
Chronology 35
Langmuir, Schaefer, and Vonnegut 37
Research projects since 1947 39
Project Cirrus 39
The Weather Bureau cloud phvsics project 41
The U.S. experiments of 1953-54 42
Arizona Mountain cumulus experiments 44
Project Whitetop 44
Climax experiments 45
Lightning suppression experiments 46
Fog dispersal research 46
Hurricane modification. 46
Hail suppression 46
Foreign weather modification research 47
Commercial operations 48
History of Federal activities, committees, policy studies, and
reports 53
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X
Chapter 3
Page
Technology of planned weather modification 55
Introduction 55
Assessment of the status of weather modification technology 56
Classification of weather modification technologies 61
Principles and status of weather modification technologies 62
Precipitation augmentation 64
Cumulus clouds 66
Cumulus modification experiments 67
Effectiveness of precipitation enhancement research and
operations 69
Results achieved through cumulus modification 70
Recent advances in cumulus cloud modification 71
Orographic clouds and precipitation 71
Orographic precipitation modification 75
Orographic seeding experiments and seedability criteria 77
Operational orographic seeding projects 81
Results achieved through orographic precipitation modifi- cation 82
Hail suppression 84
The hail problem 84
Modification of hail 86
Hail seeding technologies 87
Evaluation of hail suppression technology 88
Surveys of hail suppression effectiveness 89
Conclusions from the TASH study 91
Dissipation of fog and stratus clouds 92
Cold fog modification 93
Warm fog modification 93
Lightning suppression 96
Lightning modification 98
Evaluation of lightning suppression technology 99
Modification of severe storms 101
Hurricanes 101
Generation and characteristics of hurricanes 104
Modification of hurricanes 108
Tornadoes 112
Modification of tornadoes 113
Technical problem areas in planned weather modification 115
Seeding technology 115
Evaluation of weather modification projects 118
Extended area effects of weather modification 124
Approaches to weather modification other than seeding 129
Research needs for the development of planned weather modification- 131
General considerations 131
Recommendations from the 1973 National Academv of Sciences
study i 134
Recommendations of the Advanced Planning Group of NOAA__. 136
Summary of Federal research needs expressed by State officials. 138 Research recommendations of the AMS Committee on Weather
Modification 139
Research recommendations related to extended area and time
effects 143
Chapter 4
Inadvertent weather and climate modification 145
Introduction 145
Terminology 145
Climate 145
Climatic fluctuation and climatic change 146
Weather 146
Weather modification 146
Climate modification 146
Planned climate modification 147
Inadvertent climate modification 148
XI
Page
Background 149
Historical perspective 149
Understanding the causes of climatic change and variability 151
The concept of climatic change and variability 152
When and how do climatic changes occur 154
The facts about inadvertent weather and climate modification 156
Airborne particulate matter and atmospheric turbidity 156
Do more particles mean a warming or cooling? 157
Sources of atmospheric particulates: Natural vs. manmade.. 158
Atmospheric processes affected by particulates 159
The La Porte weather anomaly: Urban climate modification. 162
Carbon dioxide and water vapor 164
Increases in atmospheric carbon dioxide concentration:
What the record indicates 164
Predicting future atmospheric carbon dioxide levels 166
Sources and sinks for carbon dioxide 168
Atmospheric effects of increased carbon dioxide levels 169
Implications of increasing atmospheric carbon dioxide con- centrations 169
Implications of a climatic warming 170
Carbon dioxide and future climate: The real climate vs.
"model climate" 171
Ozone depletion 172
Concerns regarding ozone destruction 172
Action by the Government on the regulation of fluorocar-
bons 175
Climatic effects of ozone depletion 176
Waste heat 177
The urban "Heat Island" 177
Albedo 179
Large-scale irrigation 180
Recapitulation 181
Issues in inadvertent weather and climate modification 184
Climatic barriers to long-term energy growth 184
Thoughts and reflections — Can we contemplate a fossil-fuel-free
world? 185
Research needs and deficiencies 186
Chapter 5
Federal activities in weather modification 193
Overview of Federal activities..-- '— — 193
Legislative and congressional activities 194
Federal legislation on weather modification 194
Summary 194
The Advisory Committee on Weather Control 195
Direction to the National Science Foundation 196
Reporting of weather modification activities to the Federal
Government 197
The National Weather Modification Policy Act of 1976 198
Congressional direction to the Bureau of Reclamation 201
Proposed Federal legislation on weather modification 203
Summary 203
Legislation proposed in the 94th Congress and the 95th
Congress, 1st sessions 205
Other congressional activities 207
Resolutions on weather modification 207
Hearings 208
Studies and reports by congressional support agencies 209
Activities of the executive branch 209
Introduction 209
Institutional structure of the Federal weather modification
program 210
Current status of Federal organization for weather modifica- tion 210
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3?a?e
Federal structure; 1946-57 214
Federal structure; 1958-68 215
Federal structure; 1968-77 216
Future Federal organization for weather modification 216
Coordination and advisory mechanisms for Federal weather
modification programs 221
Introduction 221
The Interdepartmental Committee for Atmospheric Sciences
(ICAS) 222
The National Academv of Sciences/Committee on At- mospheric Sciences (N AS/CAS) 226
The National Advisory Committee on Oceans and Atmos- phere (NACOA) 227
Other coordination and advisory mechanisms 228
Weather Modification Advisory Board 231
Weather modification activities reporting program 232
Background and regulations 232
Reporting of Federal activities 233
Summary reports on U.S. weather modification activities 233
Federal studies and reports on weather modification 234
Introduction 234
Studies of the early 1950's 235
Advisory Committee on Weather Control 236
National Academy of Sciences studies 237
Studies bv the Interdepartmental Committee for Atmos- pheric Sciences (ICAS) 238
Domestic Council study 239
Policy and planning reports produced by Federal agencies 239
Federal programs in weather modification 241
Introduction and funding summaries 241
Department of the Interior 246
Introduction 246
Project Skywater; general discussion 247
The Colorado River Basin Pilot Project (CRBPP) 254
The High Plains Cooperative Program (HIPLFX) 258
The Sierra Cooperative Pilot Project (SCPP) 263
Drought mitigation assistance 266
National Science Foundation 267
Introduction and general 267
Weather hazard mitigation 274
Weather modification technology development 282
Inadvertent weather modification 283
Societal utilization activities 287
Agricultural weather modification 288
Department of Commerce 290
Introduction and general discussion 290
The Florida Area Cumulus Experiment (FACE) 292
Project Stormfurv 296
Research Facilities Center (RFC) 300
Global Monitoring for Climatic Change (GMCC) 301
Lightning suppression 302
Modification of extratropical severe storms 302
Department of Defense 303
Introduction 303
Air Force fog dispersal operations 303
Army research and development 304
Navy research and development 304
Air Force research and development 305
Overseas operations 307
Department of Transportation 308
Department of Agriculture 309
Department of Energy 310
XIII
Chapter 6
Review of recommendations for a national program in weather modifica- Page
tion 313
Introduction ^Jy
Summaries of major weather modification reports 314
Final report of the Advisory Committee on Weather Control — 314 Weather and climate modification: Report of the Special Com- mission on Weather Modification 315
Weather and climate modification: Problems and prospects 317
A recommended national program in weather modification 318
A national program for accelerating progress in weather modifica- tion 320
Weather and climate modification: Problems and progress 321
Annual reports to the President and Congress by NACOA 323
Need for a national weather modification research program 324
The Federal role in weather modification 325
Trends and analysis 326
Chapter 7
State and local activities in weather modification 331
Overview of State weather modification activities 331
Introduction 331
North American Interstate Weather Modification Council 333
Survey and summary of State interests and activities in weather
modification 340
State contacts for information on weather modification activities. 343
Non-Federal U.S. weather modification activities 343
Analysis of calendar year 1975 projects 344
Preliminary analysis of projects for calendar years 1976-77_ 347 General discussion of local and regional weather modification policy
activities „ 348
Weather modification activities within particular States 351
California 352
State weather modification law and regulations 352
Weather modification projects 353
State-sponsored emergency projects 356
Illinois 358
Illinois weather modification law and its administration 358
Operational projects 359
Research activities 360
Kansas 361
Kansas Weather Modification Act 361
Research activities 362
Operational activities 364
Emergenc}- Drought Act of 1977 364
North Dakota 365
Weather modification law and administration of regulations- 365
Authority and organization for local projects 370
North Dakota operational projects in 1975 and 1976 371
South Dakota 376
Utah 381
Washington 382
Chapter 8
Private activities in weather modification 385
Introduction 385
Commercial weather modifiers 386
Scope and significance of contract activities 386
Summary of contract services 386
Evaluation and research by commercial firms 388
Participation in Federal research programs 389
Weather modification organizations 389
Professional organizations 389
Weather Modification Association 390
American Meteorological Society 395
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Page
Opposition to weather modification 399
General discussion 399
Opposition to the seeding project above Hungry Horse Dam. 399
Tri-State Natural Weather Association 400
Citizens for the Preservation of Natural Resources 402
Chapter 9
Foreign'activities in weather modification 405
Introduction 405
World Meteorological Organization register of weather modification
projects 408
Description of weather modification activities in some foreign nations. 412
The Union of Soviet Socialist Republics 412
Overview of projects in the U.S.S.R 412
Summary of weather modification and related atmospheric
research in the U.S.S.R 413
Israel 415
Australia 416
Canada 418
Mexico 419
People's Republic of China 420
Kenya 421
Republic of South Africa 422
Rhodesia 423
India 423
The Swiss hail experiment 424
Chapter 10
International aspects of weather modification 427
Introduction 427
Convention on the prohibition of military or any other hostile use of
environmental modification techniques 429
Development of the treaty 429
Criticism of the convention 431
Activities since the United Nations approval of the convention.. 432 Activities of the World Meteorological Organization in weather
modification 433
Precipitation enhancement program (PEP) 434
Other WMO activities in weather modification 436
Registration and reporting of weather modification projects. 436
WMO conferences on weather modification 436
Typhoon and serious storm modification 437
Global atmospheric research programme 437
Legal aspects of weather modification 437
United Nations Conference on the Human Environment 438
Declaration of the United Nations Conference on the Human
Environment 438
Action Plan for the Human Environment 438
Earthwatch Program 439
Study of Man's Impact on Climate 439
Other international activities 440
United States/Canadian agreement 440
North American Interstate Weather Modification Council 440
Congressional activities 441
Weather modification as a weapon of war 441
Senate Resolution 71, prohibiting environmental modification
as a weapon of war 441
Congressional activities related to hostile use of weather
modification, 1974-76 442
Other Congressional actions relating to weather modification 443
Senate Concurrent Resolution 67 — U.S. participation in the
world weather program 443
National Weather Modification Policy Act of 1976 444
Senate Resolution 49 444
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Page
U.S. foreign policy 444
Various executive branch proposals 445
National Advisory Committee on Oceans and Atmosphere 447
Activities in 1977 448
Chapter 11
Legal aspects of weather modification 449
Domestic 449
Private rights in the clouds 449
Liability for weather modification 453
Defenses which may be raised against claims of liability 456
Interstate allocation of atmospheric water 457
Methods of controlling weather modification 459
Congressional authority under the Constitution to regulate or
license weather modification activities 461
Federalism 461
The commerce clause 461
The commerce clause generally 462
The commerce clause and the regulation of navigable
waters 463
Limitations on the commerce power 464
Fiscal powers 465
War powers 466
Property power 466
Treaty power 467
Conclusion 467
International 468
Certain hostile uses of weather modification are prohibited 471
Nations are responsible for environmental conduct which causes
injury or damage in or to other nations 471
Nations are liable for injuries sustained by aliens within their territory caused by tortuous conduct in violation of inter- national law 472
Nations or their citizens may be liable for injury and damage they caused to citizens of another nation occurring in that
nation 472
Chapter 12
Economic aspects of weather modification 475
Introduction 475
Economic setting 476
Economic aspects of weather modification procedures 477
Fog dispersal 477
Precipitation augmentation 478
Orographic cloud seeding 478
Convective cloud seeding 478
Precipitation augmentation and energy considerations 479
Hail suppression 480
Lightning suppression and reduction in storm damage 480
Analytic methods for economic analysis 481
Case studies of the economics of weather modification 482
Hungry Horse Area, Montana 482
Connecticut River basin 483
State of Illinois 483
Nine-county Southeastern Crop Reporting District, South Dakota, 483
Colorado River 484
Conclusions 486
Chapter 13
Ecological effects of weather modification 487
Introduction 487
Modification of weather and climate 487
Ecology and ecological systems — 487
Knowledge of ecological implications of applied weather modifi- cation technologies 488
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Page
Important variables 490
Temporal considerations 491
Season of modification effort 491
Duration of effort: Short- v. long-term 491
Regularity of modification effort 491
Ecosystem type 492
Aquatic v. terrestrial systems 492
Cultivated v. natural systems 492
Arid v. humid systems 492
Cumulative and synergistic effects 492
Effects of silver iodide* 493
Deliberate weather modification 496
Precipitation enhancement 496
Increased rainfall 496
Snowpack augmentation 497
Severe storm abatement 498
Fog dispersal 499
Hail suppression 499
Alteration or arrest of lightning discharges 499
Inadvertent weather modification 499
Extra-area effects 499
Long-term, climatic, and global implications 500
Summary and conclusions 501
Appendixes
A. Statement on weather modification in Congressional Record of
June 17, 1975, by Congressman Gilbert Gude, containing White
House statement on Federal weather modification policy 503
B. Department of Defense statement on position on weather modification. 509
C. Text of United Nations Convention on the prohibition of military
or any other hostile use of environmental modification techniques 510
D. State statutes concerning weather modification 514
Arizona 515
California 516
Colorado 520
Connecticut 528
Florida 529
Hawaii 531
Idaho 531
Illinois 533
Iowa 541
Kansas 543
Louisiana 549
Minnesota 550
Montana 554
Nebraska 557
Nevada 565
New Hampshire 571
New Mexico 571
New York 573
North Dakota 573
Oklahoma 584
Oregon 59 1
Pennsylvania 599
South* Dakota 604
Texas 600
Utah 612
Washington 613
West Virginia 618
Wisconsin 622
Wyoming 622
E. List of State contacts for further information on weather modification
activities within the States 625
F. Agreement on exchange of information on weather modification
between the United States of America and Canada 627
XVII
G. Weather modification activities in the United States during calendar Pa?e
year 1975 630
H. Selected bibliography of publications in weather modification 641
I. Public laws dealing specifically with weather modification 640
J. Summary of language in congressional documents supporting public
works appropriations for the Bureau of Reclamation's atmospheric
water resources program 655
K. Membership and charter of the U.S. Department of Commerce
Weather Modification Advisory Board 660
L. Rules and regulations and required forms for submitting information on weather modification activities to the National Oceanic and Atmospheric Administration, U.S. Department of Commerce, in
accordance with requirements of Public Law 92-205 662
M. Selected State rules and regulations for the administration of State
weather modification statutes 676
Illinois 676
Kansas 6 S3
North Dakota 691
Utah 707
Washington 712
N. Documents of the Weather Modification Association 717
O. Policy statement of the American Meteorological Society on purposeful
and inadvertent modification of weather and climate 722
P. Reporting agencies of member countries and questionnaire circulated to receive weather modification information from members of the
World Meteorological Organization 724
Q. Report of the World Meteorological Organization/ United Nations Environment programme informal meeting on legal aspects of
weather modification 727
R. Text of Senate Resolution 71; considered, amended, and agreed to
July 11, 1973 734
S. Reported cases on weather modification 740
T. Glossary of selected terms in weather modification 741
34-857—79 2
SUMMARY AND CONCLUSIONS
Weather modification is generally considered to be the deliberate effort to improve atmospheric conditions for beneficial human pur- poses— to augment water supplies through enhanced precipitation or to reduce economic losses, property damages, and deaths through mitigation of adverse effects of hail, lightning, fog, and severe storms. Not all weather modification activities, however, have been or can be designed to benefit everyone, and some intentional operations have been used, or are perceived to have been used, as a weapon of war to impede the mobility or tactical readiness of an enemy. Further- more, environmental change is also effected unintentionally and with- out any purpose at all, as man inadvertently modifies the weather and climate, whether for better or worse scientists are not certain, through activities such as clearing large tracts of land, building urban areas, and combustion of fossil fuels.
Historically, there have been attempts, often nonscientific or pseudo- scientific at best, to change the weather for man's benefit. Until the 20th century, however, the scientific basis for such activities was meager, with most of our current understanding of cloud physics and precipitation processes beginning to unfold during the 1930's. The modern period in weather modification is about three decades old, dat- ing from events in 1946, when Schaefer and Langmuir of the General Electric Co. demonstrated that a cloud of supercooled water droplets could be transformed into ice crystals when seeded with dry ice. Soon afterward it was discovered that fine particles of pure silver iodide, with crystal structure similar to that of ice, were effective artificial ice nuclei, and that seeding clouds with such particles could produce ice crystals at temperatures just below freezing. Silver iodide remains the most often used material in modern "cloud seeding."
By the 1950's, many experimental and operational weather modifi- cation projects were underway; however, these early attempts to augment precipitation or to alter severe storm effects were often in- conclusive or ineffective, owing to improper experimental design, lack of evaluation schemes, and the primitive state of the technology. Through research programs over the past two decades, including laboratory studies and field experiments, understanding of atmos- pheric processes essential to improved weather modification tech- nology has been advanced. Sophisticated evaluation schemes have been developed, using elaborate statistical tools; there has also been im- provement in measuring instruments and weather radar systems ; and simulation of weather processes using numerical models and high speed computers has provided further insights. Meanwhile, commer- cial weather modifiers, whose number decreased dramatically along with the total area of the United States covered by their operations after the initial surge of the 1950 era, have grown in respectability and competence, and their operations have incorporated improvements as they benefited from their accumulated experience and from the re-
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suits of research projects. Since such operations are designed for prac- tical results, such as increased precipitation or reduced hail, however, the sophisticated evaluation procedures now used in most research projects are most often not used, so that the effectiveness of the opera- tions is frequently difficult to assess.
Weather modification is at best an emerging technology. Progress in development of the technology over the past 30 years has been slow, although there has been an increased awareness of the complex nature of atmospheric processes and a steady improvement in basic under- standing of those processes which underlie attempts at deliberate modi- fication of weather phenomena. Though most cloud-seeding practices are based on a common theory and form the basis for a number of seed- ing objectives, there are really a series of weather modification technologies, each tailored to altering a particular atmospheric pheno- menon and each having reached a different state of development and operational usefulness. For example, cold fog clearing is now consid- ered to be operational, while, at the other extreme, the abatement of severe storms such as hurricanes remains in the initial research phase. Development progress for each of these technologies appears to be much less a function of research effort expended than a dependence on the fundamental atmospheric processes and the ease by which they can be altered. There continues to be obvious need for further research and development to refine those few techniques for which there has been some success and to advance technology where progress has been slow or at a virtual standstill.
The following summary provides a reasonably accurate assessment of the current status of weather modification technology :
1. The only routine operational projects are for clearing cold fog. Research on warm fog has yielded some useful knowledge and good models, but the resulting technologies are so costly that they are usable mainly for military purposes and very busy airports.
2. Several longrunning efforts to increase winter snowpack by seed- ing clouds in the mountains suggest that precipitation can be increased by some 15 percent over what would have happened "naturally."
3. A decade and a half of experience with seeding winter clouds on the U.S. west coast and in Israel, and summer clouds in Florida, also suggest a 10- to 15-percent increase over "natural" rainfall. Hypotheses and techniques from the work in one area are not directly transferable to other areas, but will be helpful in designing comparable experiments with broadly similar cloud systems.
4. Numerous efforts to increase rain by seeding summer clouds in the central and western parts of the United States have left many questions unanswered. A major experiment to try to answer them — for the High Plains area — is now in its early stages.
5. It is scientifically possible to open holes in wintertime cloud layers by seeding them. Increasing sunshine and decreasing energy consmp- tion may be especially relevant in the northeastern quadrant of the United States.
0. Some $10 million is spent by private and local public sponsors for cloud-seeding efforts, but these projects arc not designed as scientific experiments and it is difficult to say for sure that operational cloud seeding causes the claimed results.
XXI
7. Knowledge about hurricanes is improving with good models of their behavior. But the experience in modifying that behavior is primi- tive so far. It is inherently difficult to find enough test cases, especially since experimentation on typhoons in the Western Pacific has been blocked for the time being by international political objections.
8. Although the Soviets and some U.S. private operators claim some success in suppressing hail by seeding clouds, our understanding of the physical processes that create hail is still weak. The one major U.S. held experiment increased our understanding of severe storms, but otherwise proved mostly the dimensions of what we do not yet know.
9. There have been many efforts to suppress lightning by seeding thunderstorms. Our knowledge of the processes involved is fair, but the technology is still far from demonstrated, and the U.S. Forest Service has recently abandoned further lightning experiments.1
Modification processes may also be initiated or triggered inadvert- ently rather than purposefully, and the possibility exists that society may be changing the climate through its own actions by pushing on ceitain leverage points. Inadvertently, man is already causing measur- able variations on the local scale. Artificial climatic effects have been observed and documented on local and regional scales, particularly in and downwind of heavily populated industrial areas where waste heat, particulate pollution and altered ground surface characteristics are primarily responsible for the perceived climate modification. The cli- mate in and near large cities, for example, is warmer, the daily range of temperature is less, and annual precipitation is greater than if the cities had neA^er been built. Although not verifiable at present, the time may not be far off when human activities will result in measurable large-scale changes in weather and climate of more than passing sig- nificance. It is important to appreciate the fact that the role of man at this global level is still controversial, and existing models of the gen- eral circulation are not yet capable of testing the effects in a conclusive manner.
Nevertheless, a growing fraction of current evidence does point to the possibility of unprecedented impact on the global climate by hu- man activities, albeit the effects may be occurring below the threshold where they could be statistically detected relative to the record of nat- ural fluctuations and. therefore, could be almost imperceptible amid the ubiquitous variability of climate. But while the degree of influence on world climate may as yet be too small to detect against the back- ground of natural variations and although mathematical models of climatic change are still imperfect, significant global effects in the future are inferred if the rates of growth of industry and population persist.
For over 30 years both legislative and executive branches of the Federal Government have been involved in a number of aspects of weather modification. Since 1947 about 110 weather modification bills pertaining to research support, operations, grants, policy studies, regu- lations, liabilities, activity reporting, establishment of panels and com- mittees, and international concerns have been introduced in the Con-
1 Weather Modification Advisory Board. "A U.S. Policy to Enhance the Atmospheric Environment," Oct. 21, 1977. In testimony by Harlan Cleveland. Weather modification. Hearing before the Subcommittee on the Environment and the Atmosphere, Committee on Science and Technology. U.S. House of Representatives. 93th Cong., 1st sess., Oct. 26, 1977, Washington, U.S. Government Printing Office, 1977. pp. 28-30.
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gress. Resolutions, mostly concerned with using weather modification ns a weapon and promotion of a United Nations treaty banning such activities, have also been introduced in both houses of the Congress ; one such resolution was passed by the Senate.
Six public laws specifically dealing with weather modification have been enacted since 1953, and others have included provisions which are in some way relevant to weather modification. Federal weather modi- fication legislation has dealt primarily with three aspects — research program authorization and direction, collection and reporting of in- formation on weather modification activities, and the commissioning of major policy studies. In addition to direction through authorizing legislation, the Congress initiated one major Federal research pro- gram through a write-in to an appropriations bill; this program regularly receives support through additional appropriations beyond recommended OMB funding levels.
There are two Federal laws currently in effect which are specifically concerned with weather modification. Public Law 92-205, of Decem- ber 18, 1971, and its amendments requires the reporting of all non- Federal activities to the Secretary of Commerce and publication "from time to time" of summaries of such activities by the Secretary of Commerce.2 The National Weather Modification Policy Act of 1976 (Public Law 94-490), enacted October 13, 1976, directed the Secretary of Commerce to conduct a major study on weather modification and to submit a report containing a recommended Federal policy and Fed- eral research program on wTeather modification. The Secretary ap- pointed a non-Government Weather Modification Advisory Board to conduct the mandated study, the report on which is to be submitted to the Secretary for her review and comment and subsequent trans- mittal to the President and the Congress during 1978. It is expected that, following receipt of the aforementioned report, the Congress will consider legislation on Federal weather modification policy, presuma- bly during the 96th Congress.
Congressional interest in weather modification has also been mani- fested in a number of hearings on various bills, in oversight hearings on pertinent ongoing Federal agency programs, in consideration of some 22 resolutions having to do with weather modification, and in commissioning studies on the subject by congressional support agencies.
The principal involvement in weather modification of the Federal Government has been through the research and development programs of the several Federal departments and agencies. Although Federal research programs can be traced from at least the period of World War II, the programs of most agencies other than the Defense Depart- ment were not begun until the 1950's and 1960's. These research and development programs have been sponsored at various times by at least eight departments and independent agencies — including the De- partments of Agriculture, Commerce, Defense, Energy, Interior, and Transportation, the National Aeronautics and Space Administration (NASA), and the National Science Foundation (NSF). In fiscal year
2 Although Federal agencies were excluded from the requirements of this not. upon Tnutu.il agreement, the agencies also submit information on their weather mollification projects to tlie Secretary of Commerce, so that there is a single repository for information on nil weather modification activities conducted within the United States.
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1978 six agency programs were reported, those of Transportation and NASA having been phased out, while that of Agriculture was severely curtailed.
Total funding for Federal weather modification research in fiscal year 1978 is estimated at about $17 million, a decline from the highest funding level of $20 million reached in fiscal year 1976. The largest programs are those of the Departments of Interior and Commerce and of the NSF. The NSF has supported weather modification research over a broad spectrum for two decades, although its fiscal year 1978 funding was reduced by more than 50 percent, and it is not clear that more than the very basic atmospheric science supportive of weather modification will be sponsored hereafter by the Foundation.
The present structure of Federal organization for weather modifi- cation research activities is characterized essentially by the mission- oriented approach, whereby each of the agencies conducts its own program in accordance with broad agency goals or under specific direc- tions from the Congress or the Executive. Programs have been loosely coordinated through various independent arrangements and/or advi- sory panels and particularly through the Interdepartmental Commit- tee for Atmospheric Sciences (ICAS). The ICAS, established in 1959 by the former Federal Council for Science and Technology, provides advice on matters related to atmospheric science in general and has also been the principal coordinating mechanism for Federal research in weather modification.
In 1958 the National Science Foundation was designated lead agency for Federal weather modification research by Public Law 85-510, a role which it maintained until 1968, when Public Law 90-407 removed this responsibility from NSF. No further action was taken to name a lead agency, although there have been numerous recommendations to designate such a lead agency, and several bills introduced in the Con- gress would have named either the Department of the Interior or the Department of Commerce in that role. During the 10-year period from 1958 to 1968 the NSF promoted a vigorous research program through grants to various research organizations, established an Advisory Panel for Weather Modification, and published a series of 10 annual reports on weather modification activities in the United States. Since 1968 there has been a lapse in Federal weather modification policy and in the Federal structure for research programs, although, after a hiatus of over 3 years, the responsibility for collecting and disseminat- ing information on weather modification activities was assigned to the Commerce Department in 1971. An important consideration of any future weather modification legislation will probably be the organiza- tional structure of the Federal research program and that for admin- istration of other related functions which may be the responsibility of the Federal Government. Options include a continuation of the present mission-oriented approach with coordination through the ICAS or a similar interagency body, redesignation of a lead agency with some autonomy remaining with the several agencies, or creation of a single agency with control of all funding and all research responsibilities. The latter could be an independent agency or part of a larger depart- ment ; it would presumably also administer other aspects of Federal weather modification responsibilities, such as reporting of activities,
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regulation and licensing, and monitoring and evaluation of operations, if a n}' or all of these functions should become or continue to be services performed at the Federal level.
In addition to specific research programs sponsored bv Federal agen- cies, there are other functions related to weather modification which are performed in several places in the executive branch. Various Fed- eral advisory panels and committees and their staffs — established to conduct in-depth studies and prepare comprehensive reports, to pro- vide advice and recommendations, or to coordinate Federal weather modification programs — have been housed and supported within exec- utive departments, agencies, or offices. The program whereby Federal and non-Federal U.S. weather modification activities are reported to the Government is administered by the National Oceanic and Atmos- pheric Administration (NOAA) within the Commerce Department. The State Department negotiates agreements with other nations which might be affected by U.S. experiments and has arranged for Federal agencies and other U.S. investigators to participate in international meteorological projects, including those in weather modification. In the United Nations, the United States has been active in promoting the adoption of a treaty banning weather modification as a military weapon.
In accordance with the mandates of several public laws or self-ini- tiated bv the agencies or interagency committees, the executive branch of the Federal Government has undertaken a number of major weather modification policy studies over the past 25 years. Each of the com- pleted major studies was followed by a report which included findings and recommendations. The most recent study is the one noted earlier that is being conducted by the Weather Modification Advisory Board on behalf of the Secretarv of Commerce, pursuant to requirements of the National Weather Modification Policy Act of 1976. Nearly all previous studies emphasized the needs for designation of a lead agency, increased basic meteorological research, increased funding, improve- ment of support and cooperation from agencies, and consideration of legal, socioeconomic, environmental, and international aspects. Other recommendations have included improvement of program evaluation, studv of inadvertent effects, increased regulation of activities, and a number of specific research projects. Although some of the recom- mended activities have been undertaken, many have not resulted in specific actions to date. Almost invariably it was pointed out in the studies that considerable progress would result from increased fund- ing. Although funding for weather modification research has increased over t he past 20 years, most funding recommendations have been for considerably higher levels than those provided. Since fiscal year 1976, the total Federal research funding for weather modification research hn=. in fact, decreased.
Most States in the Nation have some official interest in weather modification ; 29 of them have some form of law which relates to such activities, usually concerned with various facets of regulation or con- trol of operations within the Slate and sometimes pertaining to au- thorization for funding research and/or operations at the State or local level. A State's weather modification law usually reflects its gen- eral policy toward weather modification; some State laws tend to en-
XXV
courage development and use of the technology, while others dis- courage such activities.
The current legal regime regulating weather modification has been developed by the States rather than the Federal Government, except in the areas of research support, commissioning studies, and requiring reporting of activities. The various regulatory and management func- tions which the States perform include: (1) issuance, renewal, sus- pension, and revocation of licenses and permits; (2) monitoring and collecting of information on activities through requirements to main- tain records, submission of periodic activity reports, and inspection of premises and equipment; (3) funding and managing of State or locally organized operational and/or research programs ; (4) evalua- tion and advisory services to locally organized public and private op- erational programs within the State; and (5) miscellaneous admin- istrative activities, including the organization and operation of State agencies and boards which are charged with carrying out statutory responsibilities. Administration of the regulatory and managerial re- sponsibilities pertaining to weather modification within the States is accomplished through an assortment of institutional structures, in- cluding departments of water or natural resources, commissions, and special governing or advisory groups. Often there is a combination of two or more of these agencies or groups in a State, separating func- tions of pure administration from those of appeals, permitting, or ad- visory services.
Involvement in weather modification operational and research pro- grams varies from State to State. Some support research only, while others fund and operate both research and operational programs. In some cases funding only is provided to localities, usually at the county level, where operational programs have been established. The recent 1976-77 drought led some Western States to initiate emergency cloud- seeding programs as one means of augmenting diminishing water sup- plies. Research conducted by atmospheric and other scientists at State universities or other research agencies may be supported in part with State funds but is often funded by one of the major Federal weather modification programs, such as that of the Bureau of Reclamation or the National Science Foundation. In a few cases. States contribute funds to a Federal research project which is conducted jointly with the States and partly within their borders.
In 1975, 1976, and 1977, respectively, there were 58, 61, and 88 non- federally supported weather modification projects, nearly all opera- tional, conducted throughout the United States. These projects were sponsored by community associations, airlines, utilities, private in- terests, municipal districts, cities, and States. Eighty-five percent of all projects in the United States during 1975 were carried out west of Kansas City, with the largest number in California. In that State there were 11 proipets in each of the vears 1975 and 1976, and 20 projects during 1977. The majority of these operational projects were designed to increase precipitation; others were intended for sup- pression of hail or dispersal of fogs, the latter principally at airports.
In most instances, the principal beneficiaries of weather modification are the local or regional users, who include farmers and ranchers, weather-related industries, municipalities, airports, and utilities —
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those individuals and groups whose economic well-being and whose lives and property are directly subject to adverse consequences of drought or other severe weather. It is at the local level where the need to engage in weather modification is most keenly perceived and also where possible negative effects from such activities are most apparent to some sectors of the population. It follows that both the greatest sup- port and the strongest opposition to weather modification projects are focussed at the local level. The popularity of a particular project and the degree of controversy surrounding it are frequently determined by the extent to which local citizens and local organizations have had a voice in the control or funding of the project. At the local level, deci- sions to implement or to withdraw from a project can most often be made with minimum social stress. Indeed, studies have shown that most people are of the opinion that local residents or local government offi- cials should make decisions on whether or not to use weather modifica- tion technology in a given situation.
Many of the operational weather modification services provided for private groups and governmental bodies within the States are carried out under contract by commercial firms who have developed expertise in a broad range of capabilities or who specialize in particular services essential to both operational or research projects. Contracts may cover only one season of the year, but a number of them are renewed an- nually, with target areas ranging from a few hundred to a few thou- sand square miles. In 197G, 6 of the 10 major companies having substantial numbers of contracts received about $2.7 million for op- erations in the United States, and a few of these companies also had contracts overseas. Owing to increased demand for emergency pro- grams during the recent drought, it is estimated that 1977 contracts totaled about $3.5 million.
The initial role of the private weather modification operators was to sustain activities during the early years, when there was often heated scientific controversy with other meteorologists over the efficacy of cloud seeding. Later, their operations provided a valuable data base which permitted the early evaluation of seeding efforts and estimates of potential prospects for the technology, meanwhile growing in com- petence and public respect. Today, more often than not, they work hand in hand with researchers and, in fact, they often participate in research projects, contributing much of their knowhow acquired through their unique experiences.
Important among private institutions concerned with weather modi- fication are the professional organizations of which research and op- erational weather modifiers and other interested meteorologists are members. These include the American Meteorological Society, the Weather Modifical ion Association, and the Irrigation and Drainage Division of the American Society of Civil Engineers. Through the meetings and publications of these organizations the scientific, tech- nical, and legal problems and findings on weather modification are aired and discussed. These groups also address other matters such as statements of weather modification policy, opinions on pending legis- lation, social implieations. and professional standards and certifica- tion. Tn addition, the North American Interstate Weather Modifica- tion Council is an organizai ion whose membership consists of govern-
XXVII
ments of U.S. States and Canadian Provinces and the Government of Mexico, which serves as a forum for interstate coordination and ex- change of information on weather modification.
Weather modification is often controversial, and both formal and informal opposition groups have been organized in various sections of the country. Reasons for such opposition are varied and are based on both real and perceived adverse consequences from weather modifi- cation. Sometimes with little or no rational basis there are charges by these groups that otherwise unexplained and usually unpleasant weather- related events are linked to cloud seeding. There are also cases where some farmers are economically disadvantaged through receiving more, or less than optimum rainfall for their particular crops, when artificial inducement of such conditions may have indeed been planned to benefit those growing different crops with different moisture re- quirements. Opposition groups are often formed to protect the legiti- mate rights of farmers under such circumstances.
While the United States is the apparent leader in weather modifi- cation research and operations, other countries have also been active. Information on foreign weather modification activities is not uni- formly documented and is not always available. In an attempt to assemble uniform weather modification activities information of its member nations, the World Meteorological Organization (WMO) in 1975 instigated a system of reporting and of maintaining a register on such activities. Under this arrangement 25 nations reported weather modification projects during 1976, and 16 countries provided similar information in 1975. The largest weather modification effort outside the United States is in the Soviet Union, where there are both a con- tinuing research program and an expanding operational program. The latter is primarily a program designed to reduce crop damage from hail, the largest such effort in the world, covering about 5 million hectares (15 million acres) in 1976. Other countries with weather modi- fication programs of some note include Canada, Israel, Mexico, and the People's Republic of China. Projects in Rhodesia and the Republic of South Africa are not reported through the WMO register since these countries are not WMO member nations.
Recent years have seen increased international awareness of the potential benefits and possible risks of weather modification technology and increased international efforts to control such activities. The major efforts of the international community in this area are to encourage and maintain the high level of cooperation which currently exists in weather prediction and research and to insure that man's new abilities will be used for peaceful purposes. There has been exchange of ideas on weather modification through international conferences and through more informal exchanges of scientists and research documents. As with many scientific disciplines, however, the problems arising from use of and experiments with weather modification are not just scientific in nature, but are political problems as well.
In addition to the problems of potential damage to countries through commercial or experimental weather modification activities, another growing area of concern is that weather modification will be used for hostile purposes and that the future will bring weather warfare be- tween nations. The United States has already been involved in one
XXVIII
such instance during the Vietnam war when attempts were made to impede traffic by increasing rainfall during the monsoon season. In the future, even the perception that weather modification techniques are available or in use could lead to an increase in international tensions. Natural drought in a region, or any other natural disaster will be suspect or blamed on an enemy.
In light of these problems the international community has made scattered attempts both to further the study of weather and its modifi- cation and to insure the peaceful use of this new technology. One such attempt was the development of the Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Modification Techniques, which was adopted by the General Assembly of the United Nations and opened for signature on May 18. 19TT, at which time it was signed by the United States and 33 other nations (though it has not yet been submitted to the U.S. Senate for ratification) . Another exam- ple of promotion of peaceful use of weather modification is the Pre- cipitation Enhancement Program, sponsored by the WMQ, whose aim is to plan, set up, and carry out an international, scientifically con- trolled precipitation experiment in a semiarid region of the world under conditions where the chances are optimal for increasing pre- cipitation in sufficient amounts to produce economic benefits.
The United Nations Conference on the Human Environment, held in June 1972 in Stockholm, has been the pivotal point in much recent international environmental activity. It too has been an important catalyst in international activities relating to weather modification through portions of its "Declaration," its "Action Plan for the Human Environment," its "Earthwatch Program," and its "Study of Man's Impact on Climate."
Legal issues in weather modification are complex and unsettled. They can be considered in at least four broad categories : private rights in the clouds, liability for weather modification, interstate legal issues, and international legal issues. Since the body of law on weather modi- fication is slight, existing case law offers few guidelines to determine these issues. Regarding the issue of private rights in the clouds, there is no general statutory determination of ownership of atmospheric water, so it is often necessary to use analogies to some general common law doctrines pertaining to water distribution, although each such doctrine has its own disadvantages when applied to weather modifica- tion. Some State laws reserve ownership or right to use atmospheric water to the State.
Issues of liability for damage may arise when drought, flooding, or other severe weal her phenomena occur following attempts to modify the weather. Such issues include causation, nuisance, strict liability, trespass, negligence, and charges of pollution of the air and water through introduction of artificial nucleants. Statutes of 10 States dis- cuss weather modification liability: however, there is much variation among the specific provisions of the laws in those States. Before a case can be made for liability based on causation, it must be pro\en that the adverse weather conditions were indeed induced by the wen: r modifier; but, in fact, no one lias ever been able to establish causation of damages through such activities in view of the scientific uncer- tainties of weather modification.
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Significant issues may arise when weather modification activities conducted in one State affect another State as well. There may be, for example, the claim that seeding in one State has removed from the clouds water that should have fallen in an adjacent State or that excessive flooding resulted from cloud seeding in a State upwind. Operation of cloud-seeding equipment near the border of one State may also violate local or State regulations or prohibitions of such operations in that State. There have been some attempts to resolve these and other issues through specific legislation in some States and through informal bilateral agreements. While no formal compacts currently exist, some compacts allocating waters in interstate streams may be applicable.
Because atmospheric processes operate independent of national borders, weather modification is inherently of international concern, and. international legal issues have similarities to domestic interstate activities and dangers. Whereas domestic weather modification law is confused and unsettled, international law in this area is barely in the formative stage. In time, ramifications of weather modification may lead to major international controversy.
Whereas the potential for long-term economic gains through weather modification cannot be denied, current economic analyses are tenuous in view of present uncertainty of the technology and the complex nature of attendant legal and economic problems. Economic evaluation of weather modification activities has therefore been limited to special, localized cases, such as the dispersal of cold fog at airports, where benefit-cost ratios greater than 5 to 1 have been realized through sav- ings in delayed or diverted traffic. It has also been estimated, on the basis of a 15-percent increase in snowpack through seeding orographic clouds, that about 2 million additional acre-feet of water per year could be produced in the Colorado River Basin, at a cost of about $1.50 per acre-foot.
Costs of most weather modification operations are generally small in relation to other costs in agriculture, for example, and are normally l>elieved to be only a fraction of the benefits which could be achieved from successful operations. However, if all the benefits and all the costs are considered, benefit-cost ratios may be diminished. While direct co«ts and benefits from weather modification are reasonably apparent, in- direct costs and benefits are elusive and require further study of sociological, legal, and ecological implications.
There are numerous cases of both real and perceived economic losses which one or more sectors of the public may suffer while another group is seeking economic advantage through some form of weather modification. Overall benefits from weather modification are accord- ingly reduced when net gains are determined from such instances of mixed economic advantages and disadvantages. In fact, when mecha- nisms are established for compensating those who have suffered losses resultinof from weather modification, benefits to those groups seeking economic gain through such projects will probably be accordingly reduced.
Economically significant weather modification activities will have an eventual ecological effect, though appearance of that effect may be hidden or delayed by system resilience and/or confused by system
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complexity. Prediction of ecological effects may never be possible with any precision; however, the greater the precision with which the weather modifier can predict results of his activities, the more pre- cisely can the ecologist predict ecological effects. Such effects will rarely be sudden or catastrophic, but will result from moderate weather-related shifts in rates of reproduction, growth, and mortality of plants and animals. Adjustments of plant and animal communities will thus occur more slowly in regions of highly variable weather than in those with more uniform conditions which are slowly changing with some regularity over time. Deliberate weather modification, such as precipitation augmentation, is likely to have a greater ecological im- pact in semi-arid regions than in humid ones.
Widespread cloud seeding, using silver iodide, could result in esti- mated local, temporary increases in silver concentrations in precipita- tion approaching those in natural waters, but exchange rates would be an order of magnitude lower than the natural exchange rates. Ex- change rates will likely be many orders of magnitude less than those rates at which plants and soils are adversely affected.
Conclusions
1. Weather modification is an emerging technology ; there is a wide spectrum of capabilities to modify various weather phenomena, rang- ing from the operational readiness of cold fog dispersal to little prog- ress beyond initial research in the case of modifying severe storms such as hurricanes.
2. Along with cold fog dispersal, the only other weather modifica- tion capability showing near readiness for application is the aug- mentation of winter snowpack through seeding mountain cloud sys- tems. A probable increase of about 15 percent is indicated by a number of experiments and longrunning operational seeding projects in the western United States.
3. Most scientists and weather modification operators agree that there is continued need for a wide range of research and development activity both to refine weather modification techniques where there has been some success and to advance capabilities in modifying other weather phenomena where there has been much less or little progress.
4. Current Federal policy for weather modification research and development follows the mission-oriented approach, where each agency charged with responsibility for dealing with a particular national problem is given latitude to seek the best approach or solution to the problem; this approach or solution may involve weather modification.
5. The structure of Federal organization for weather modification reflects the mission-oriented approach which is characteristic of the current Federal policy, the programs loosely coordinated through ad- visory groups and the Interdepartmental Committee for Atmospheric Sciences.
0. The interest of the Congress in weather modification has been shown by the introduction of 110 bills related to the subject since 1017 — 0 of which have become public law — and the consideration of 22 resolutions on weather modification, one of which was passed by the Senate.
7. A number of major weather modification policy studies have been directed by public law or initiated within the executive branch over
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the past 25 years ; most of these studies recommended designation of a lead agency, increased basic meteorological research, increased fund- ing, improvement of support and cooperation from agencies, and con- sideration of legal, socioeconomic, environmental, and international aspects. Although some recommended actions have been undertaken, others have not seen specific action to date.
8. While major policy studies have recommended increased funding for Federal weather modification, research and development and fund- ing has generally increased over the past 20 years, recommended levels have been consistently higher than those provided, and funding has actually decreased since fiscal year 1976.
9. With enactment of the National Weather Modification Policy Act of 1976 and completion of the major policy study mandated by that act, there is a fresh opportunity for the Congress to assess the potential usefulness and problems in application of weather modifica- tion technology and to establish a new Federal policy for weather modification research and operations.
10. The principal role in regulating weather modification and in supporting operational programs has been taken by the States, while the role of the Federal Government has been support of research and development programs.
11. The majority of the States (29) have some form of law which relates to weather modification, and the general policy of a State toward weather modification is usually reflected in the weather modi- fication law of that State ; laws of some States tend to encourage devel- opment and use of the technology, while others discourage such activities.
12. The majority of operational weather modification projects in the United States (58 of a total of 72, or 80 percent in calendar year 1975) are conducted west of Kansas City, and the largest number of projects has been in California (20 during 1977) ; most operational projects are intended to increase precipitation, while others are designed to suppress hail or disperse fog.
13. Both the greatest support and the strongest opposition to weather modification projects are focused at the local level, where the economic and personal interests of local organizations and individuals are most directly affected; it follows that there is also the least social stress when decisions to apply or withhold weather modification are made at the local level.
14. Commercial weather modification operators have substained ac- tivities since the early days, after which some operations fell into disrepute, providing a valuable data base for evaluation of long-term projects and developing expertise over a broad range of capabilities: most have incorporated improvements into their technology as they have benefited from accumulated experience and from research results.
15. While the United States is the apparent leader in overall research and operational weather modification activities, there have been ap- proximately 20 foreign countries in which activities are conducted an- nually (25 countries reported such projects for 1976 through the register of the World Meteorological Organization) ; the largest for- eign program is that of the Soviet Union, whose operational hail suppression program covered about 15 million acres in 1976, the largest such effort in the world.
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16. The international community has attempted to further the study o f weather modification and insure its peaceful use through the recent development of a Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Techniques (adopted by the U.N. General Assembly and opened for signature in May 1977) and through sponsorship by the World Meteorological Organization of an international precipitation enhancement program.
17. Legal issues in weather modification are complex and unsettled; they include resolution of problems of ownership of atmospheric water, issues of liability, conflicting statutes and regulations of respective
e laws, and the need to develop a regime of relevant international
law.
18. Although the long-term potential for economic gains through weather modification cannot be denied, attempts to quantify benefits mnd costs from such activities will in most cases be difficult to undertake on a practical basis until the technology is more highly developed and control systems are perfected to permit reliable predictions of outcomes.
19. Economically significant wreather modification will always have an eventual ecological effect, though appearance of the effect may be delayed or hidden by system resilience and/or confounded by system complexity ; the more precisely the weather modifier can specify effects lie will produce, the more precise can be the ecologist's prediction of likely ecological effects.
20. Modification processes may also be initiated or triggered inad- vertently rather than purposefully ; man is already causing measurable variations unintentionally on the local scale, and artificial climate effects have been observed on local and regional scales. Although not veri fiable at present, the time may not be remote when human activities will result in measurable large-scale changes in weather and climate of more than passing significance.
CHAPTER 1
INTRODUCTION AND SUMMARY OF ISSUES
(I?y Robert E. Morrison, Specialist in Earth Sciences, Science Policy Research Division, Congressional Research Service)
Perspective
uIt is entirely possible, were he wise enough, that man could produce favorable effects, perhaps of enonnous practical significance, trans- forming his environment to render it more salutary for his purposes. This is certainly a matter which should be studied assiduously and explored vigorously. The first steps are clear. In order to control meteorological matters at all we nee d to understand them better than we now do. When we understand fully ice can at least predict weather with assurance for reasonable intervals in the future.
''With modem analytical devices, with a team of sound background and high skills, it is possible today to do a piece of work in this field which will render immediate benefits, and carry us for toward a more thorough understanding of ultimate possibilities. By all means let us get at it."
— Vanne var Bush 1
SITUATION
Two decades after completion of a major study and report on weather modification by the Advisory Committee on Weather Control and after the assertions quoted above, many would agree that some of the more fundamental questions about understanding and using weather modification remain unsolved. There is a great difference of opinion, however, on the state of technology in this field. According to Grant, "Some believe that weather modification is now ready for widespread application. In strong contrast, others hold that applica- tion of the technology may never be possible or practical on any substantial scale." 2 It has been demonstrated that at least some atmos- pheric phenomena can be modified with some degree of predictable success, as a consequence of seeding supercooled clouds with artificial ice nuclei, and there is some promise that the present technology will be expanded to include a greater scope of weather modification capa- bilities. Nevertheless, a systematic approach and reasonable progress in development of weather modification technology have been impeded by a number of problems.
Changnon asserts that a continuing and overriding problem restrict- ing progress has been the attempt to apply an ill-defined technology to increase rain or suppress hail without an adequate scientific under-
1 From statement of Dec. 2, 1957, quoted in final report of the Advisory Committee on Weather Control, Washington, D.C., U.S. Government Printing Office. 1958. vol. I. p. 1.
2 Grant, Lewis O., "Scientific and Other Uncertainties of Weather Modification. In William A. Thomas (editor), Legal and Scientific Uncertainties of Weather Modification. Proceedings of a symposium convened at Duke University. Mar. 11-3 2. 1976, by the National Conference of Lawyers and Scientists, Durham, N.C., Duke University Press, 1977, p. 7.
(1)
34-857—79 3
2
standing and predictable outcome.3 Experimentation has been poorly conducted, intermittent, or too short ; and "results have not been inte- grated with those of other projects so as to develop a continuing thread of improving knowledge." 4
In response to the query as to why progress in weather modification lias been so slow, Fleagle identifies three broad, general impediments. "First, the physical processes associated with clouds have turned out to be especially complex and difficult * * *. A second possibility may be that the atmosphere is inherently stable, so that within broad limits, no matter what we do to increase precipitation, the results are likely to be small and roughly the same * * *. A third reason * * * is that progress has been hamstrung by fragmentation of resources, by submarginal funding, ineffective planning and coordination, and a general lack of administrative toughness and fiscal stability." 5
Droessler points out the need to "formulate a comprehensive national weather modification policy which has the broad support of the scien- tific community, the general public, private industry, and the Govern- ment," contending that "the greatest deterrent in getting on with the task of preparing a satisfactory national policy is the lack of a con- sensus about the national goals for weather modification." 6
Although operational readiness varies from one form of weather modification to another, as a result of the degree of understanding and the complexity of decisionmaking in given situations, the prospects for successful weather modification are sufficiently promising that at- tempts to develop effective applications will continue. This was one of the major areas of co?isensus at a recent symposium on the uncertainties of weather modification :
There will be increased attempts to modify weather, both because people tend to do what is technically possible and because the anticipated benefits of precipi- tation augmentation, hail or lightning suppression, hurricane diversion, and other activities often exceed the associated costs.7
With the inevitable increases in weather modification capabilities and the increasing application of these capabilities, the development of a technology that is socially useful must be insured through a careful analysis of attendant benefits and disbenefits. According to Fleagle. et al.. deliberate efforts to modify the weather have thus far had only marginal societal impacts; however, as future activities expand, "they will probably be accompanied by secondary effects which in many instances cannot be anticipated in detail * * *." Consequently, "rational policy decisions are urgently needed to insure that activities are di- rected toward socially useful goals." 8
The lack of a capability to deal with impending societal problems
8 Changnori, Stanley A.. Jr.. "The Federal Role In Weather Modification." bgckgrbund paper prepared for use by the U.S. Department of Commerce Weather Modification Advi- sory Board. Mar. !). 3 077, p. 5.
' Ibid., pp. ">-G.
s Fleagle. Robert O.. "An Analysis of Federal Policies in Weather Modification.'' back- ground paper prepared for use by the U.S. Department of Commerce Weather Modification Adv:s< rv Hoard. Mar. 1<»77. pp. 17-18.
« Droessler, Farl (».. "Weather Modification" (Federal Policies. Funding From AIT Sources Interagency Coordination), background paper prepared for use of the U.S. Depart- ment of Commerce Weather Modification Advisory Board, Mar. l. l!>77. p. 10
7 Thomas. William A. (editor). "Legal and Scientific Uncertainties of Weather Modifie-i- tion," proceedings of a Symposium convened at Duke University. Mar 11-12. 1970, by the Vf»'onal Conference of Lawyers and Scientists. Durham, N.C., Dnke Universitv Pres., 1077, p. vl.
Flt*agie. Robert r> • -lames A. Crutchfteld, Ralph W. Johnson, and Mohamed F. AbdO, "Weather Modification in the PUbllC Interest." Seattle, American Meteorological Society
and the University of Washington Press, i<>73. p. 3, 31-32.
3
and emerging management issues in weather modification has been aphoristically summed up in the following statement by Crutchfield:
Weather modification is in the throes of a serious schizoid process The slow and sober business of piecing together the scientific knowledge of weather proc- esses developing the capacity to model the complex systems involved, and assess- ing systematically the results of modification efforts has led to responsible opti- mism about the future of these new technologies. On the other hand, the social technology" of evaluation, choice, and execution has lagged badly. Ihe present de- cisionmaking apparatus appears woefully inadequate to the extraordinarily ^diffi- cult task of fitting weather modification into man s pattern of life m optimal fashion There are' too many game plans, too many coaches, and a disconcerting proclivity for running hard before deciding which goal line to aim for— or, indeed, which field to play on. ,J . . . _ .
Mounting evidence indicates that weather modification of several types is, or may soon become technically feasible. That some groups will derive economic or other social benefits from such technology is a spur to action. But a whole thunderhead of critical questions looms on the horizon waiting to be resolved before any valid decisions can be made about the scale, composition, location, and management of possible operations.9
ADVANTAGES
In a study for the Interdepartmental Committee for Atmospheric Sciences, Homer E. Newell highlighted the potential benefits of inten- tional weather modification :
The Earth's weather has a profound influence on agriculture, forestry, water resources, industry, commerce, transportation, construction, field operations, commercial fishing, and many other human activities. Adverse effects of weather on man's activities and the Earth's resources are extremely costly, amounting to billions of dollars per year, sometimes causing irreparable damage as when human lives are lost in severe storms. There is, therefore, great motivation to develop effective countermeasures against the destructive effects of weather, and, conversely, to enhance the beneficial aspects. The financial and other ben- efits to human welfare of being able to modify weather to augment water supplies, reduce lightning, suppress hail, mitigate tornadoes, and inhibit the full development of hurricanes would be very great.10
More recently. Louis J. Battan gave the following two reasons, with graphic examples, for wanting to change the weather :
First, violent weather kills a great many people and does enormous property damage. A single hurricane that struck East Pakistan in Novemlier 1970 killed more than 250,000 people in a single day. Hurricane Camille hit the United States in 1969 and did approximately $1.5 billion worth of damage. An outbreak of tornadoes in the Chicago area on Palm Sunday of 1965 killed about 250 people, and the tornadoes of April 1974 did likewise. Storms kill people and damage property, and it is reasonable to ask whether it is necessary for us to accept this type of geophysical destruction. I say, "No, it is not — it should be possible to do something."
Second, weather modification involves, and in some respects might control, the production of those elements we need to survive. Water and food are cur- rently in short supply in many areas, and these shortages almost certainly will be more severe in the future. We can develop new strains of wheat and rye and corn and soybeans and rice, but all is for naught if the weather fails to coop- erate. If the monsoons do not deliver on schedule in India, residents of that country starve in large numbers. And if the drought that people have been predicting for the last several years does spread over the Great Plains, there will be starvation around the world on a scale never before experienced.
Weather is the one uncontrollable factor in the whole business of agriculture. Hail, strong winds, and floods are the scourges of agriculture, and we should not have to continue to remain helpless in the face of them. It may be impossible
9 Crntehfielri. James A.. "Social CVoice and Weather Modification : Concepts and Measure- ment of Impact." In W. R. Derrick Sewell (editor). Modifying the Weather: a Social Assessment, Victoria, British Columbia. University of Victoria. 1978. p. 1S7.
10 Newell. Homer E., "A Recommended National Program in Weather Modification." Fed- eral Council for Science and Technology, Interdepartmental Committee for Atmospheric Sciences, ICAS report No. 10a, Washington, D.C., November 1966, p. 1.
4
for us to develop the kind of technology we would like to have for modification of weather, but to assume failure in such an important endeavor is a course not to be followed by wise men.11
Specific statistics on annual losses of life and economic losses from property damages resulting from weather-related disasters in the United States are shown in table 1, which wras developed in a recent study by the Domestic Council.12 In the table, for comparison, are the fiscal year 1975 expenditures by the Federal Government in weather modification research, according to the several categories of weather phenomena to be modified. Although it is clear that weather disasters can be mitigated only partially through weather modifica- tion, even if the technology were fully developed, the potential value, economic and otherwise, should be obvious. The following quotation from a Federal report written over a decade ago summarizes the full potential of benefits to mankind which might be realized through use of this technology :
With advances in his civilization, man has learned how to increase the fruit of the natural environment to insure a livelihood. * * * it is fortunate that growing knowledge of the natural world has given him an increasing awareness of the changes that are occurring in his environment and a' so hopefully some means for deliberate modification of these trends. An appraisal of the prospects for deliberate weather and climate modification can be directed toward the ultimate goal of bringing use of the environment into closer harmony with its capacities and with the purposes of man — whether this be for food production, relief from floods, assuring the continuance of biologic species, stopping pollu- tion, or for purely esthetic reasons.13
TABLE 1. — ANNUAL PROPERTY DAMAGE AND LOSS OF LIFE FROM WEATHER-RELATED DISASTERS AND HAZARDS IN THE UNITED STATES AND FISCAL YEAR 1975 FEDERAL WEATHER MODIFICATION RESEARCH FUNDING (FROM DOMESTIC COUNCIL REPORT, 1975)
Property Modification damage1 research
Weather hazard Loss of life1 (billions) (millions)
Hurricanes 2 30 2 $rj. 8 3 $o. 8
Tornadoes . 2140 2.4 4 1.0
Hail 5.8 3.9
Lightning « 110 .1 .4
Fog M.000 7.5 1.3
Floods 6 240 8 2.3
Frost (agriculture) 7 1. 1
Drought 7.7 93.4
Total 1,520 6.7 10.8
1 Sources: "Assessment of Research on Natural Hazards," Gilbert F. White and J. Eugene Haas, the MIT Press, Cam- bridge, Mass., 1975, pp 68, 286, 305, 374; "The Federal Plan for Meteorological Services and Supporting Research, Fiscal Year 1976," U.S. Department of Commerce, National Oceanic and Atmospheiic Administration (NOAA), Washington, D.C., April 1975, p 9; "Weatheiwise," February 1971, 1972, 1973, 1974, 1975, American Meteorological Society, Boston, Mass.; "Summary Report on Weather Modification, Fiscal Years 1969, 1970, 1971," U.S. Department of Commerce, NOAA, Wash- ington, D.C., May 1973, pp 72, 81; "Estimating Crop Losses Due to Hail — Wot king Data for County Estimates," U.S. De- partment of Agriculture, Economic Research Service, September 1974; "Natural Disasters: Some Empirical and Economic Considerations," G. Thomas Sav, National Bureau of Standards, Washington, D.C., February 1974, p 19; Traffic Safety magazine, National Safety Council, February 1974.
2 1970-74 average.
3 These funds do not include capital investment in research aircraft and instrumentation primarily for hurricane modi- fication, which in fiscal year 1975 amounted to $9,200,000.
4 These funds support theoretical research on modification of extratropical cloud systems and their attendant severe storms such as thunderstorms and tornadoes.
5 1973.
« 1950-72 average.
7 Average.
1 1965-69 average.
9 These funds support precipitation augmentation research, much of which may not have direct application to drought alleviation.
11 Battan, Louis J.. "The Scientific Uncertainties: a Scientisl Responds." in William A. Thomas (editor), "Legal and Scientific Uncertainties of Weather Modification." proceed- ings of a symposium Convened at Duke University, .Mar. 11-12, 197©, by C e National Con- ference of Lawyers and Scientists. Durham. N.C., Duke University Press. 1!)77. p. 20.
12 U.S Domestic Council. Environmental Resources Committee, Subcommittee on Climate Change. "The Federal Rofe in Weather Modification," December i(->~r», p. 2.
u» Special Commission on Weather Modification. "Weather and Climate Modification," National Science Foundation. NSF 6G-3, Washington, D.C., Dec. 20, 1965, p. 7.
5
TIMELINESS
The modern period in weather modification is about three decades old, dating from events in 1946, when Schaefer and Langmuir demon- strated that a cloud of supercooled water droplets could be transformed into ice crystals when seeded with dry ice. Activities and interests among scientists, the commercial cloud seeders, and Government spon- sors and policymakers have exhibited a nearly 10-year cyclic behavior over the ensuing years. Each of the three decades since the late 1940's has seen an initial burst of enthusiasm and activity in weather modi- fication experiments and/or operations; a midcourse period of con- troversy, reservations, and retrenchment; and a final period of capability assessment and policy examination, with the issuance of major Federal reports with comprehensive recommendations on a future course.
The first such period ended with the publication of the final report of the Advisory Committee on Weather Control in 1957.14 In 1959, Dr. Robert Brode, then Associate Director of the National Science Foundation, summarized the significance of that study in a 1959 congressional hearing :
For 4 years the Advisory Committee studied and evaluated public and private cloud-seeding experiments and encouraged programs aimed at developing both physical and statistical evaluation methods. The final report of the com- mittee * * * for the first time placed before the American public a body of available facts and a variety of views on the status of the science of cloud physics and the techniques and practices of cloud seeding and weather modifica- tion.15
The year 1966 was replete with Government weather modification studies, major ones conducted by the National Academy of Sciences, the Special Commission on Weather Modification of the National Science Foundation, the Interdepartmental Committee for Atmos- pheric Sciences, and the Legislative Reference Service of the Library of Congress. During that year, or thereabouts, planning reports were also produced by most of the Federal agencies with major weather modification programs. The significance of that year of reevaluatiori and the timeliness for congressional policy action were expressed by Hartman in his report to the Congress :
It is especially important that a comprehensive review of weather modification be undertaken by the Congress at this time, for a combination of circumstances prevails that may not be duplicated for many years. For the first time since 1957 there now exists, in two reports prepared concurrently by the National Academy of Sciences and a Special Commission on Weather Modification, created by the National Science Foundation, a definitive appraisal of the entire scope of this subject, the broad sweep of unsolved problems that are included, and critical areas of public policy that require attention. There are currently before the Congress several bills which address, for the first time since enactment of Public Law 85-510. the question of the formal assignment of Federal authority to undertake weather modification programs. And there is increasing demand throughout the country for the benefits that weather modification may bring.16
14 F^tablishment of the Advisory Committee on Weather Control by the Congress and its actJ^ties are discussed in following chapters on the history of weather modification and on Federal activities, chs. 2 and 5, respectively. Recommendations of the final report are summarized in ch. 6. Other renorts mentioned in the following paragraphs in this section are also discussed and referenced in chs. 5 and 6. ■ \ - ..
15 U.S. Congress. House of Representatives. Committee on Science and Astronautics. "Weather Modification." Hearing. Sfith Cong.. 1st sess., Feb. 16, 1959. Washington, JJ.L., U.S. Government Printing OfhYp 19^9. p 3. .t _ _
16 Hartman, Lawton M. "Weather Modification and Control.' Library of Comrress, Legislative Reference Service. Apr. 27. 1966. Issued as a committee print by the Senate Committee on Commerce. 89th Cone.. 2d sess., Senate Rept. No. 1139, Washington,
U.S. Government Printing Office, 1966, p. 1.
6
Toward the close of the third decade, a number of policy studies and reports appeared, starting in 1973 with a second major study by the National Academy of Sciences, and including others by the U.S. Gen- eral Accounting Office and by the U.S. Domestic Council. The major study of this period was commissioned by the Congress when it enacted Public Law 94-490, the National Weather Modification Policy Act of 1976, in October of 1976. By that law the Secretary of Commerce was directed to conduct a study and to recommend the Federal policy and a Federal research program in weather modification. That study was conducted on behalf of the Secretary of Commerce by a Weather Modi- fication Advisory Board, appointed by the Secretary, and the required report will be transmitted to the Congress during 1978. The importance of that act and its mandated study was assessed by Dr. Robert M. White, former Administrator of the National Oceanic and Atmos- pheric Administration (NOAA), the Commerce Department agency with administrative responsibilities and research programs in weather modification :
The National Weather Modification Policy Act of 197C> * * * will influence X( )AA to some degree during the next year, and its effect may have a large impact on the agency and the Nation in future years. The comprehensive study of and report on weather modification that will result from our implementation of this act will provide guidance and recommendations to the President and the Congress in the areas of policy, research, and utilization of this technology. We look to this study and report as an opportunity to help set the future course of a controversial science and technology with enormous potential for henefit to the Nation.17
Thus, conditions once more are ripe and the stage has been set, as in 1957 and again in 1966, for the Congress to act in establishing a defini- tive Federal weather modification policy, one appropriate at least for the next decade and perhaps even longer. Among other considerations, such a policy would define the total role of the Federal Government, including its management structure, its responsibilities for research and development and for support operations, its authorities for regu- lation and licensing, its obligation to develop international cooperation in research and peaceful applications, and its function in the general promotion of purposeful weather modification as an economically vi- able and socially accepted technology. On the other hand, other factors, such as constraints arising from public concern over spending, may inhibit the development of such policy.
While some would argue that there exists no Federal policy, at least one White House official, in response to a letter to the President, made a statement of weather modification policy in 1975:
A considerable amount of careful thought and study has been devoted to the subject of weather modification and what the Federal role and. in particular, the role of various agencies should he in (his area. As a result of this study, we have developed a general strategy for addressing weather modification efforts which we believe provides for an appropriate level of coordination.
We believe that the agency which is charged with the responsibility for dealing with a particular national problem should Ite given the latitude to seek the best approach or solution to the problem. In some instances this may involve a form of weather modification, while in other instances other approaches may be more appropriate.
While we would certainly agree that some level of coordination of weather modification research efforts is logical, we do not believe that a program under
w CJ.S. Congress, Souse of Representatives, Committee on Science and Technology. Sub*
committi d the EBaTlronmeal snd the Atmosphere. "Briefing «"i the National Oceanic and
Atmospheric Administration." Hearings. 9.1th Cong., 1st sess., May 17. 18, 1977. Washing- Jon. I'.S. Government Printing Ollice, 1977. i». 4-i5.
7
the direction of any one single agency's leadership is either necessary or desirable. We have found from our study that the types of scientific research conducted by agencies are substantially different in approach, techniques, and type of equip- ment employed, depending on the particular weather phenomena being addressed. Each type of weather modification requires a different form of program manage- ment and there are few common threads which run along all programs.13
Presumably, there will be a resurgence of congressional interest in weather modification policy during the first session of the 96th Con- gress, when the aforementioned report from the Secretary of Commerce has been reviewed and considered. In view of the recom- mendations in numerous recent studies and the opinions of the Weather Modification Advisory Board (the group of experts preparing the re- port for the Secretary of Commerce) , it seems unlikely that any action by the Congress would perpetuate the policy expounded in the White House letter quoted above.
It is expected that this present report, intended as an overall review of the subject of weather modification, will be valuable and timely dur- ing the anticipated congressional deliberations.
DEFINITIONS AND SCOPE OF REPORT
In the broadest sense, weather modification refers to changes in weather phenomena brought on purposefully or accidentally through human activity. Weather effects stimulated unintentionally — such as urban influences on rainfall or fogs produced by industrial com- plexes— constitute what is usually termed inadvertent weather modifi- cation. On the other hand, alterations to the weather which are induced consciously or intentionally are called planned or advertent weather modification. Such activities are intended to influence single weather events and to occur over relatively short time spans, ranging from a few hours in the case of clearing airport fog or seeding a thunderstorm to perhaps a few days when attempts are made to re- duce the severity of hurricane winds. Weather modification experi- ments or operations can be initiated or stopped rather promptly, and changes resulting from such activities are transient and generally reversible within a matter of hours.
Climate modification, by contrast, encompasses changes of long-time climatic variables, usually affecting larger areas and with some degree of permanence, at least in the short term. Climatic changes are also brought about by human intervention, and they might result from either unintentional or planned activities. There are numerous ex- amples of possible inadvertent climate modification; however, at- tempts to alter climate purposefully are only speculative. The con- cepts of inadvertent weather and climate modification are defined more extensively and discussed fully in chapter 4 of this report.
The primary emphasis of this report is on intentional or planned modification of weather events in the short term for the general bene- fit of people, usually in a restricted locality and for a specific time. Such benefit may accrue through increased agricultural productiv-
18 Ross, Norman E., Jr., letter of June 5, 1975. to Congressman Gilbert Gude. This letter was the official White House response to a letter of April 25. 1975. from Congressmen Giule and Donald M. Fraser and Senator Claiborne Pell, addressed to the President, urging that a coordinated Federal program be initiated in the peaceful uses of weather modifica- tion. The letter to the President, the replv from Mr. Ross, and comments by Congressman Gude appeared in the Congressional Record for June 17. 1975, pp. 19201-19203. (This statement from the Congressional Record appears in app. A.)
s
ity or other advantages accompanying augmentation of precipitation or they may result from mitigation of effects of severe weather with attendant decreases in losses of life or property. There are broader implications as well, such as the general improvement of weather for the betterment of man's physical environment for aesthetic and cul- tural reasons as well as economic ones. The following recent definition sums up succinctly all of these purposes :
Weather modification is the deliherate and mindful effort by men and women to enhance the atmospheric environment, to aim the weather at human purposes.1"
The specific kinds of planned weather modification usually consid- ered, and those which are discussed, in turn, in some detail in chapter 3, are the following:
Precipitation enhancement.
Hail suppression.
Fog dissipation.
Lightning suppression.
Mitigation of effects of severe storms. Planned weather modification is usually considered in the context of its net benefits to society at large. Nevertheless, it should be recog- nized that, in particular instances, benefits to some segment of the population may be accompanied by unintended injuries and costs, which may be real or perceived, to other segments. There is yet an- other aspect of advertent weather modification, which has engendered much controversy, both in the United States and internationally, not designed for the benefit of those directly affected — the use of weather modification for hostile purposes such as a weapon of war. This aspect is not a major consideration in this report, although there is some discussion in chapters 5 and 10 of congressional concern about such use of the technology, and in chapter 10 there is also a review of recent efforts by the United Nations to develop a treaty barring hostile use of weather modification.20
Following this introductory chapter, witli its summary of issues, the second chapter sets the historical perspective for weather modi- fication, concentrating primarily on activities in the United States to about the year 1970, The third chapter attempts to review the scien- tific background, the status of technology, and selected technical prob- lems areas in planned weather modification; while chapter 4 contains a discussion of weather and climate changes induced inadvertently by man's activities or by natural phenomena.
The weather modification activities of the Federal Government — those of the Congress and the administrative and program activities of the executive branch agencies — are encompassed in chapter 5 ; and the findings and recommendations of major policy studies, conducted by or on behalf of the Federal Government, are summarized in chap- ter 6. The seventh, eighth, and ninth chapters are concerned with weather modification activities at the level of State and local govern- ments, by private organizations, and in foreign countries, respectively.
111 Wc.it :'<m- Modification Advisory Hoard, "A TVS Policy to Enhance the Atmospheric Environment," Oct. 21, 1!>77. A discussion paper, included with testimony of Harlan Cleve- land, Chairman of the Advisory Hoard, in a congressional hearing: U.S. Congress. House of Representatives. Committee on Science and Technology. Subcommittee on the Environ- ment and the Atmosphere. Weather Modification. !).".th Cong., 1st sess., Oct. 2(5, 1J>77, Washington, D.C., U.S. Government Printing Office, H»77. p. 25.
211 Copies of the current official position of the I'.S. Department of Defense on weather modification and of the draft TT.\ convention prohibiting hostile use of environmental modification, respectively, are found in apps. B and C.
9
The increasingly important international problems related to weath- er modification are addressed in chapter 10, while both domestic and international legal aspects are discussed in chapter 11. Chapters 12 and 13, respectively, contain discussions on economic and ecological aspects of this emerging technology.
The 20 appendixes to the report provide materials that are both sup- plementary to textual discussions in the 13 chapters and intended to be valuable sources of reference data. In particular, attention is called to appendix D, which contains excerpts dealing with weather modification from the statutes of the 29 States in which such activities are in some way addressed by State law, and to appendix E, which provides the names and affiliations of individuals within the 50 States who are cognizant of weather modification activities and interests with- in the respective States. The reader is referred to the table of contents for the subjects of the remaining appendixes.
Summary or Issues in Planned Weather Modification
"The issues we now face in weather modification have roots in the science and technology of the subject, but no less importantly in the politics of Government agencies and congressional committees and in public attitudes which grow out of a variety of historical, economic, and sociological factors." 21 In this section there will be an identifica- tion of critical issues which have limited development of weather modification and which influence the ability to direct weather modifi- cation in a socially responsible manner. The categories of issues do not necessarily correspond with the subjects of succeeding chapters dealing with various aspects of weather modification ; rather, they are organized to focus on those specific areas of the subject where there has been and there are likely to be problems and controversies which impede the development and application of this technology.
The following sections examine technological, governmental, legal, economic, social, international, and ecological issues. Since the primary concern of this report is with the intentional, planned use of weather modification for beneficial purposes, the issues summarized are those involved with the development and use of this advertent technology. Issues and recommendations for further research in the area of inad- vertent weather modification are included in chapter 4, in which that general subject is fully discussed.
TECHNOLOGICAL PROBLEMS AND ISSUES
In a recent discussion paper, the Weather Modification Advisory Board summarized the state of weather modification by concluding that "no one knows how to modify the weather very well, or on a very large scale, or in many atmospheric conditions at all. The first require- ment of a national policv is to learn more about the atmosphere it- self." 22 Representative of the state of weather modification science
21Fleagle. Crutchfield, Johnson, and Abdo, "Weather Modification in the Public Inter- est," 1973, p. 15. . . . .
22 Weather Modification Advisory Board. "A U.S. Policy To Enhance the Atmospheric Environment." Oct. 21, 1977. This discussion paper was included with the testimony ot Mr. Harlan Cleveland, Chairman of the Advisory Board, in a recent congressional hearing : U.S. Congress, House of Representatives, Committee on Science and Technology, Subcom- mittee on the Environment and the Atmosphere. "Weather Modification. 9oth Cong., 1st sess. Oct. 26, 1977, Washington, D.C., U.S. Govt. Print. Off., 1977, p. 25.
10
and technology is the following commentary on the state of under- standing in the case of precipitation enhancement, or rainmaking as it is popularly called :
Today, despite the fact that modern techniques aimed at artificial stimulation of rain rest upon sound physical principles, progress is still fairly slow. The application of these principles is complicated by the overwhelming complexity of atmosheric phenomena. It is the same dilemna that meteorologists face when they attempt to predict weather. In both cases, predicting the evolution of atmospheric processes is limited by insufficient knowledge of the effects produced by the fairly well-known interactive mechanisms governing atmospheric phenom- ena. Moreover, the temporal and spatial variability of atmospheric phenomena presents an additional difficulty. Since any effects that are produced by artificial intervention are always imposed upon already active natural processes, assess- ment of the consequences becomes even more difficult.23
Grant recognizes the current progress and the magnitude of remain- ing problems when he says that :
Important^and steady advances have been made in developing technology for applied weather modification, but complexity of the problems and lack of adequate research resources and commitment retard progress. Advances have been made in training the needed specialists, in describing the natural and treated cloud systems, and in developing methodology and tools for the necessary research. Nevertheless, further efforts are required.24
Though it can be argued that progress in the development of weather modification has been retarded by lack of commitment, ineffective planning, and inadequate funding, there are specific scientific and tech- nical problems and issues needing resolution which can be identified beyond these management problems and the basic scientific problem quoted above with respect to working with the atmosphere. Particular technical problems and issues at various levels which continue to affect both research and operational activities are listed below :
1. There is substantial diversity of opinion, even among informed scientists, on the present state of technology for specific types of weather modification and their readiness for application and with regard to weather modification in general.-5
%2. There are many who view weather modification only as a drought- relief measure, expecting water deficits to be quickly replenished through its emergency use; however, during such periods weather modification is limited by less frequent opportunities ; it should, in- stead, be developed and promoted for its year-round use along with other water management tools.-0
3. The design and analysis of weather modification experiments is intimately related to the meteorological prediction problem, which needs further research, since the evaluation of any attempt to modify the atmosphere depends on a comparison between some weather pa- rameter and an estimate of what would have happened naturally.
4. Many of the problems which restrict Understanding and predic- tion of weather modification phenomena stem from imprecise knowl- edge of fundamental cloud processes; the level of research in funda-
2:1 Dennis, Arnett S., and A. Ge^in. "Recommendations for Future Research in Weatlier Modification," U.S. Department <»i" Commerce, National Oceanic and Atmospheric Admin- istration, Environmental Research Laboratories. Boulder, Colo.. November 1077. p. VI.
-"Grant. "Scientific and Other Uncertainties of Weather .Modification," 1977. p. 17.
88 Sec table 2, ch. D. ">!>.
-• Silverman. Bernard A., "What Do We Need In Weather Modification?" In preprints of the Sixth Conference on Planned and Inadvertent Weather .Modification, Oct. lO-l.'i, 1077, Champaign, 111., Boston, American Meteorological Society, 1977, p. 308.
II
mental cloud physics and cloud modeling has not kept pace with weather modification activity.27
5. Progress in the area of weather modification evaluation meth- odology has been slow, owing to the complexity of verification prob- lems and to inadequate understanding of cloud physics and dynamics.
6. Most operational weather modification projects, usually for the sake of economy or in the anticipation of achieving results faster and in greater abundance, fail to include a satisfactory means for project evaluation.
7. There are difficulties inherent in the design and evaluation of any experiment or operation which is established to test the efficacy of any weather modification technique, and such design requires the inclusion of proper statistical methods.
8. In view of the highly varying background of natural weather phenomena, statistical evaluation of seeding requires a sufficiently long experimental period: many research projects just barely fail to achieve significance and credibility because of early termination; thus, there is a need for longer commitment for such projects, perhaps 5 to 10 years, to insure that meaningful results can be obtained.2S
9. There is a need to develop an ability to predict possible adverse weather effects which might accompany modification of specific weather phenomena : for example, the extent to which hail suppression or diminishing hurricane winds might also reduce beneficial precipi- tation, or the possibility of increasing hailfall or incidence of light- ning from efforts to stimulate rainfall from cumulus clouds.29
10. The translation of cloud-seeding technologies demonstrated in one area to another geographical area has been less than satisfactory; this has been especially so in the case of convective cloud systems, whose differences are complex and subtle and whose classification is complicated and sometimes inconsistent.
11. There is increasing evidence that attempts to modify clouds in a prescribed target area have also induced changes outside the target area, resulting in the so-called downwind or extended area effect : reasons for this phenomenon and means for reducing negative results need investigation.
1*2. There is the possibility that cloud seeding in a given area and during a given time period has led to residual or extended time effects on weather phenomena in the target area beyond those planned from the initial seeding.
13. The conduct of independent cloud-seeding operations in adjacent locations or in the neighborhood of weather modification experiments may cause contamination of the atmosphere so that experimental results or estimates of operational success are biased.
14. There have been and continue to be conflicting claims as to the reliability with which one can conduct cloud-seeding operations so that the seeding agent is transported properly from the dispensing device to the clouds or portions of the clouds one seeks to modify.
27 Hosier. C. L.. "Overt Weather Modification.*' Reviews of Geophysics and Space Phys- ics, vol. 12. Xo. 3, August 1974, p. 526.
28 Simpson. Joanne, "What Weather Modification Needs." In preprints of the Sixth Conference on Planned and Inadvertent Weather Modification. Oct. 10-13, 1977. Cham- paign. 111.. Boston. American Meteorological Society. 1977, p. 306.
29 Hosier, "Overt Weather Modification,'- 1974, p. 325.
12
15. There is need to develop, improve, and evaluate new and cur- rently used cloud-seeding materials and to improve systems for deliv- ery of these materials into the clouds.
16. There is need to improve the capability to measure concentra- tions of background freezing nuclei and their increase through seed- ing; there is poor agreement between measurements made with various ice nucleus counters, and there is uncertainty that cloud chamber measurements are applicable to real clouds.30
IT. In order to estimate amounts of fallen precipitation in weather modification events, a combination of weather radar and raingage network are often used; results from such measurement systems have often been unsatisfactory owing to the quality of the radar and its calibration, and to uncertainties of the radar-raingage intercalibration.
18. There is continuing need for research in establishing seedability criteria ; that is, definition of physical cloud conditions when seeding will be effective in increasing precipitation or in bringing about some other desired weather change.
10. Mathematical models used to describe cloud processes or account for interaction of cloud systems and larger scale weather systems greatly oversimplify the real atmosphere; therefore, model research must be coupled with field research.31
GOVERNMENTAL ISSUES
The basic problem which encompasses all governmental weather modification issues revolves about the question of the respective roles, if any, of the Federal, State, and local governments. Resolution of this fundamental question puts into perspective the specific issues of where m the several governmental levels, and to what extent, should goals be set, policy established, research and/or operations supported, activities regulated, and disputes settled. Part of this basic question includes the role of the international community, considered in another section on. international issues;32 the transnational character of weather modi- fication may one day dictate the principal role to international orga- nizations.
Role of the Federal Government
Because weather modification cannot be restricted by State bound- aries and because the Federal Government has responsibilities for re- source development and for reduction of losses from natural hazards, few would argue that the Federal Government ought not to have some interest and some purpose in development and possible use of weather modification technolo<rv. The following broad and specific issues on the role of the Federal Government in weather modification are among those which may be considered in developing a Federal policy:
1. Should a maior policy analysis be conducted in an attempt to re- late weather modification to the Xatioivs broad goals; that is, improv- ing human health and the qualit v of life, maintaining national security, providing sufficient energy supplies, enhancing environmental quality, and the production of food and fiber? Barbara Farhar suggests that such a study has not been, but ought to be. undertaken.33
™ Fbld.
m Fleagle et al., "Weather Modification in tUo Public interest." 197^. n St.
n= Sop n. 2&
"Farhar, Barbara C. "The Societal Imidieations of Weather Modification: a TCeview of issues Toward m National Policy.*' Background paper prepared f«r the U.S. Department of Commerce Weather ModinVatlonAdvisory Hoard, Mar. 1, 1977, p. 2.
13
2. Should the Federal Government commit itself to planned weather modification as one of several priority national goals ? It can be argued that such commitment is important since Federal program support and political attitudes have an important overall influence on the develop - ment and the eventual acceptance and application of this technology.
3. Is there a need to reexamine, define, and facilitate a well-balanced, coordinated, and adequately funded Federal research and development program in weather modification ? Many argue that the current Fed- eral research program is fragmented and that the level of funding is subcritical.
4. Is there a suitable Federal role in weather modification activities beyond that of research and development — such as project evaluation and demonstration and operational programs? If such programs are advisable, how can they be identified, justified, and established ?
5. Should the practice of providing Federal grants or operational services by Federal agencies to States for weather modification in times of emergency be reexamined, and should procedures for providing such grants and services be formalized ? It has been suggested that such as- sistance in the past has been haphazard and has been provided after it was too late to be of any practical benefit.
6. Should the organizational structure of the Federal Government for weather modification be reexamined and reorganized ? If so, what is the optimum agency structure for conducting the Federal research program and other functions deemed to be appropriate for the Federal Government?
7. TThat is the role of the Federal Government, if any, in regulation of weather modification activities, including licensing, permitting, notification, inspection, and reporting? If such a role is to be modified or expanded, how should existing Federal laws and/or regulations be modified ?
8. If all or any of the regulatory functions are deemed to be more ap- propriate for the States than for the Federal Government, should the Federal Government consider mandating minimum standards and some uniformity among State laws and regulations?
9. Should the Federal Government attempt to develop a means ade- quate for governing the issues of atmospheric water rights between States, on Federal lands, and between the United States and neighbor- ing countries ?
10. Where federally sponsored research or possible operational weather modification projects occupy the same locale as local or State projects, with the possibility of interproject contamination, should a policy on project priorities be examined and established?
11. Should the Federal Government develop a policy with regard to the military use of weather modification and the active pursuit of international agreements for the peaceful uses of weather modifica- tion? This has been identified as perhaps one of the most important areas of Federal concern.34
12. Is there a need to examine and define the Federal responsibility for disseminating information about the current state of weather modication technology and about Federal policy, including the capa- bility for providing technical assistance to the States and to others?
fS*Farhar Barbara C. "What r>o°s Weatber Modification Need"- In preprints of the Sixth Conference on Planned and Inadvertent Weather Modification, Oct. 10-13, 1977, Champaign. 111., Boston, American Meteorological Society, 1977, p. 299.
14
13. Should there be a continuing review of weather modification technology capabilities so that Federal policy can be informed regard- ing the readiness of technologies for export to foreign nations, with provision of technical assistance where and when it seems feasible? 35
14. How does the principle of cooperative federalism apply to weather modification research projects and possible operations carried out within the States ? Should planning of projects with field activities in particular States be done in consultation with the States, and should cooperation with the States through joint funding and research efforts be encouraged ?
15. What should be the role of the single Federal agency whose activities are most likely to be affected significantly by weather modi- fication technology and whose organization is best able to provide advisory services to the States— the U.S. Department of Agriculture? Among the several agencies involved in weather modification, the Department of Agriculture has demonstrated least official interest and lias not provided appreciable support to development of the technology.36
Roles of State and local go vernments
State and local 37 governments are in man}' ways closer to the public than the Federal Government — often as a result of more direct contact and personal acquaintance with officials and through greater actual or perceived control by the voters. Consequently, a number of weather modification functions, for both reasons of practical effi- ciency and social acceptance, may be better reserved for State and/or local implementation. Since weather phenomena and weather modifica- tion operations cannot be restricted by State boundaries or by bound- aries within States, however, many functions cannot be carried out in isolation. Moreover, because of the economy in conducting research nnd development on a common basis — and perhaps performing other functions as well — through a single governmental entity, such as an agency or agencies of the Federal Government, it may be neither feasible nor wise for State governments (even less for local jurisdic- tions) to carry out all activities.
Thus, there are activities which might best be reserved for the States (and possibly for local jurisdictions within States), and those which more properly belong to the Federal Government. In the previous l ist of issues on the role of the Federal Government, there was allusion to a number of functions which might, wholly or in part, be the re- sponsibility of either Federal or State governments; most of these will not be repeated here. Issues and problems concerned primarily with State and local government functions are listed below:
1. State weather modification laws. Where they exist, are nonuni- form in their requirements and specifications for licensing, permitting, inspection, reporting, liabilities, and penalties for violations. More- over, some State laws and policies favor weather modification, while ot hers oppose 1 he technology.
2. Authorities for funding operational and research projects with- in States and local jurisdictions within States, through public funds
[bid.
:" Changnon, "The Federal Role in Weather Modification." |p. 11.
37 ,fLocal" bere refers broadly to any jurisdiction below the State level : it could laelucto cities, townships, counties, groups of counties, water districts, or any other organized area Operating under public authority.
15
or through special tax assessments, vary widely and, except in a few States, do not exist.
3. Decisionmaking procedures for public officials appear to be often lacking; these could be established and clarified, especially as the pos- sibility of more widespread application of weather modification tech- nology approaches.
4. Many public officials, usually not trained in scientific and en- gineering skills, often do not understand weather modification tech- nology, its benefits, and its potential negative consequences. Some training of such officials could contribute to their making wise de- cisions on the use of the technology, even without complete informa- tion on which to base such decisions.
5. Many weather modification decisions have had strong political overtones, with some legislators and other public officials expressing their views or casting their votes allegedly on the basis of political expediency rather than on the basis of present or potential societal benefits.
6. State and local authorities may need to provide for the education of the general public on the rudiments of weather modification, on its economic benefits and disbenefits. and on other societal aspects.
7. To keep communication channels open, mechanisms such as pub- lic hearings could be established to receive comments, criticisms, and general public sentiments on weather modification projects from in- dividual citizens and from various interest groups.
8. Criteria and mechanisms have not been established for compen- sating those individuals or groups within States who might be eco- nomically injured from weather modification operations.
9. Questions of water rights within States, as well as between States, have not been addressed and/or resolved in a uniform manner.
LEGAL ISSUES
Legal issues in weather modification are complex and unsettled. They can be discussed in at least four broad categories :
1. Private rights in the clouds ;
2. Liability for weather modification ;
3. Interstate legal issues ; and
4. International legal issues,38
The body of law on weather modification is slight, and existing case law offers few guidelines to determine these issues. It is often neces- sary, therefore, to analogize weather modification issues to more set- tled areas of law such as those pertaining to water distribution.
Private rights in the clouds
The following issues regarding private rights in the clouds may be asked :
Are there any private rights in the clouds or in the water which may be acquired from them ?
Does a landowner have any particular rights in atmospheric water ?
Does a weather modifier have rights in atmospheric water \
^Questions on regulation or control of weather modification activities through licensing and permitting, while of a basic legal nature, are related to important administrative func- tions and are dealt with under issues concerned with Federal and State activities.
1(3
Some State statutes reserve the ownership or right to use atmospheric water to the State.39
There is no general statutory determination of ownership of atmos- pheric water and there is no well-developed body of case law. Conse- quently, analogies to the following general common law doctrines may be helpful, but each has its own disadvantages when applied to weather modification :
1. The doctrine of natural rights, basically a protection of the land- owner's right to use his land in its natural condition (i.e., precipita- tion is essential to use of the land as are air, sunlight, and the soil itself).
2. The ad coelum doctrine which states that whoever owns the land ought also to own all the space above it to an indefinite extent.
3. The doctrine of riparian rights, by which the one owning land which abuts a watercourse may make reasonable use of the writer, sub- ject to similar rights of others whose lands abut the watercourse.
4. The doctrine of appropriation, which gives priority of right based on actual use of the water.
5. The two main doctrines of ownership in the case of oil and gas (considered, like water, to be "fugitive and migratory" substances) ; that is, (a) the non-ownership theory, by which no one owns the oil and gas until it is produced and anyone may capture them if able to do so; and (b) the ownership-in-place theory, by which the landowner has the same interest in oil and gas as in solid minerals contained in his land.
6. The concept of "developed water," that is, water that would not be available or would be lost were it not for man's improvements.
7. The concept of "imported water," that is, water brought from one watershed to another.
Liability for weather modification
Issues of liability for damage may arise when drought, flooding, or other severe weather phenomena occur following attempts to modify the weather. Such issues include causation as well as nuisance, strict liability, trespass, and negligence. Other issues which could arise relate to pollution of the air or water through introduction of artificial nu- cleants such as silver iodide, into the environment. While statutes of 10 States discuss weather modification liability, there is much varia- tion among the specific provisions of the laws in those States.40
Before any case can be made for weather modification liability based upon causation it must be proven that the adverse weather con- ditions were indeed brought about by the weather modifier, a very heavy burden of proof for the plaintiff. In fact, the scientific uncer- tainties of weather modi Heal ion are such that no one has ever been able to establish causation of damage through these activities. As weal her modification technology is improved, however, the specter of a host of liability issues is expected to emerge as evidence for causation becomes more plausible.
While the general defense of the weather modifier against liability charges is that causation has not been established, he may also use as further defense the arguments based upon immunity, privilege, con- sent , and waste.
• Sec p. 4.">o, ch. 1 1. and app. n.
M Sec discussion p. 453 in ch. 11 and app. D.
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Interstate legal issues
When weather modification activities conducted in one State affect another State as well, significant issues may arise. The following- problem categories are examples of some generally unresolved inter- state issues in weather modification :
1. There may be the claim that cloud seeding in one State has removed from the clouds water which should have fallen in a second State or that excessive flooding in a neighboring State has resulted from seed- ing in a State upwind.
2. Operation of cloud-seeding equipment near the border in one State may violate local or State ordinances which restrict or prohibit weather modification in an adjacent State, or such operations may conflict with regulations for licensing or permitting of activities within the bor- dering State.
Some States have attempted to resolve these issues through specific legislation and through informal bilateral agreements.41 Another ap- proach would be through interstate compact, though such compacts re- quire the consent of Congress. No compacts specifically concerned with weather modification currently exist, though some existing compacts allocating waters in interstate streams may be applicable to weather modification.
International legal issues
Because atmospheric processes operate independent of national borders, weather modification is inherently of international concern. International legal issues have similarities to domestic interstate activi- ties and dangers. The following serious international questions, which have arisen in conjunction with a developing capability to modify the weather, have been identified by Orfield : 42
Do countries have the right to take unilateral action in all weather modification activities?
What liability might a country incur for its weather modifica- tion operations which [might] destroy life and property in a foreign State?
On what theory could and should that State base its claim ? The primary international legal issue regarding weather modifica- tion is that of liability for transnational injury or damage, which could conceivably result from any of the following situations :
(1) injury or damage in another nation caused by weather modification activities executed within the United States;
(2) injury or damage in another nation caused by weather modification activities executed in that nation or a third nation by the United States or a citizen of the United States ;
(3) injury or damage in another nation caused by weather modification activities executed in an area not subject to the juris- diction of any nation (e.g., over the high seas), by the United States or a citizen thereof ; and
(4) injury or damage to an alien or an alien's property within the United States caused by weather modification activities exe- cuted within the United States.
41 See discussion p. 457 in ch. 11 and app. D.
42 Orfield, Michael B.. "Weather Genesis and Weather Neutralization: a New Approach to Weather Modification," California Western International Law Journal, vol. 6, no. 2, spring 1976, p. 414.
34-S57— 79 4
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Whereas domestic weather modification law is confused and unset- tled, international law in this area is barely in the formative stage. In time, ramifications of weather modification may lead to major interna- tionl controversy.43
ECONOMIC ISSUES
The potential for long-term economic gains through weather modi- fication cannot be denied ; however, current, economic analyses are tenu- ous in view of present uncertainty of the technology and the complex nature of attendant legal and economic problems. Meaningful economic evaluation of weather modification activities is thus limited to special, localized cases, such as the dispersal of cold fog at airports, where bene- fit-cost ratios greater than 5 to 1 have been realized through savings in delayed or diverted traffic. Various estimated costs for increased pre- cipitation through cloud seeding range from $1.50 to $2.50 per acre- foot in the western United States.
fsy/es complicating economic analyses of weather modification
Costs of most weather modification operations are usually relatively small and are normally believed to be only a fraction of the benefits obtained through such operations. However, if all the benefits and all the costs are considered, benefit-cost ratios may be diminished. While direct costs and benefits from weather modification are reasonably obvious, indirect costs and benefits are elusive and require further study of sociological, legal, and ecological implications.
In analyzing benefit-cost ratios, some of the following considerations need to be examined :
Weather modification benefits must be considered in terms of the costs for achieving the same objectives as increased precipita- tion, e.g., through importation of water, modified use of agricul- tural chemicals, or introduction of improved plant strains.
Costs for weather modification operations are so low in compari- son with other agricultural investments that farmers may gamble in spending the 5 to 20 cents per acre for operations designed to increase rainfall or suppress hail in order to increase yield per acre, even though the results of the weather modification opera- tions may be doubtful.
Atmospheric conditions associated with prolonged droughts are not conducive to success in increasing precipitation; however, under these conditions, it is likely that increased expenditures may be made for operations which offer little hope of economic return.
Increased precipitation, obtained through a weather modifica- tion program sponsored and funded by a group of farmers', can also benefit other farmers who have not shared in the costs; thus, the benefit-cost ratio to those participating in the program is higher than it need be if all share in its costs.
As weather modification technology develops and programs be- come more1 sophisticated', increased costs for equipment and labor will increase direct costs to clients: indirect costs resulting from increased State license and permit fees and liability insurance for operators will probably also be passed on to the customer.
I: s»'c ch. 10 on International aspects and i>. 4<;s. ch. 11; on International legal aspects of wpa i her modification.
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The sophistication of future programs will likely incur addi- tional costs for design, evaluation, and program information ac- tivities, along with supporting meteorological prediction services; these costs will be paid from public funds or by private clients, in either case reducing the overall benefit-cost ratios.
Ultimate costs for compensation to those incurring disbenefits from weather modification operations will offset overall benefits and thus reduce bene fit -cost ratios.
Weather modification and conflicting interests
There are numerous cases of both real and perceived economic losses which one or more sectors of the public may suff er while another group is seeking economic advantage through some form of weather modi- fication. Overall benefits from weather modification are accordingly reduced when net gains are computed from such instances of mixed economic advantages and disadvantages. Benefits to the parties seek- ing economic gain through weather modification will be directly re- duced at such time when mechanisms are established for compensating those who have suffered losses. The following are some examples of such conflicting situations :
Successful suppression of hail may be valuable in reducing crop damage for orchardists while other agricultural crops may suffer f rom decrease of rain concomitant with the hail decrease.
Additional rainy days may be of considerable value to farmers during their growing season but may be detrimental to the finan- cial success of outdoor recreational enterprises.
Increased snowpack from orographic cloud seeding may be beneficial to agricultural and hydroelectric power interests but increases the costs for maintaining free passage over highways and railroads in mountainous areas.
Successful abatement of winds from severe storms, such as those of hurricanes, may result in decreased precipitation necessary for agriculture in nearby coastal regions or may redistribute the ad- verse storm effects, so that one coastal area is benefitted at the ex- pense of others.
SOCIAL ISSUES
It has been said that "weather modification is a means toward so- cially desired ends, not an end in itself. It is one potential tool in a set of possible societal adjustments to the vagaries of the weather. Iden- tifying when, where, and how to use this tool, once it is scientifically established, is the primary need in weather modification." 44 It is likely that, in the final analysis, the ultimate decisions on whether weather modification should and will be used in any given instance or will be adopted more generally as national or State programs depends on social acceptance of this tool, no matter how well the tool itself has been perfected. That this is increasingly the case has been Suggested by numerous examples in recent years. Recently Silverman said :
Weather modification, whether it he research or operations, will not progress wisely, or perhaps at all, unless it is considered in a context that includes everyone
M Fnrhar. Barbara C. "What Does Weather Modification Need ?" In preprints of the Sixth Conference on rianr.pd and Inadvertent Weather Modification. October 10-13, 1977. Cham- paign* 111. Boston. American Meteorological Society, 1977. p. 296.
20
that may be affected. We must develop and provide a new image of weather modification.45
Regardless of net economic benefits, a program is hard to justify when it produces obvious social losses as well as gains.
Research in the social science of weather modification has not kept pace with the development of the technology, slow as that has been. In time, this failure may be a serious constraint on further develop- ment and on its ultimate application. In the past, organized opposition has been very effective in retarding research experiments and in cur- tailing operational cloud-seeding programs. Thus, there is need for an expanded effort in understanding public behavior toward weather modification and for developing educational programs and effective decisionmaking processes to insure intelligent public involvement in eventual application of the technology.
Social issues discussed in this section are those which relate to public behavior and public response to weather modification, while societal issues are generally considered to include economic, legal, and other nontechnical issues as Veil as the social ones. These other aspects of societal issues were discussed in preceding sections. In the subsections to follow there are summaries of social implications of weather modifi- cation, the need for public education, and the problem of decisionmaking.
Social factors
It has been said that social factors are perhaps the most elusive and difficult weather modification externalities to evaluate since such fac- tors impinge on the vast and complex area of human values and at- titudes.46 Fleagle, et al., identified the following important social implications of weather modification, which would presumably be taken into account in formulation of policies : 47
1. The individuals and groups to be affected, positively or negatively, by tlie project must be defined. An operation beneficial to one party may actually barm another. Or an aggrieved party may hold the operation responsible * * ::: for damage * * * which might occur at the same time or following the modification.
2. The impact of a contemplated weather modification effort on the genera! well-being of society and the environment as a whole must be evaluated. Con- sideration should be given to conservationists, outdoor societies, and other citizens and groups representing various interests who presently tend to ques- tion any policies aimed at changes in the physical environment. It is reasonable and prudent to assume that, as weather modification operations expand, question- ing and opposition by the public will become more vocal.
3. Consideration must be given to the general mode of human behavior in response to innovation. There are cases where local residents, perceiving a cause and effect relationship between economic losses from severe weather and nearby weather modification operations, have continued to protest, and even to threaten violence, after all operations bave been suspended.
4. The uniqueness and complexity of certain weather modification operations must be acknowledged, and special attention should be given to their social and legal implications. The cases of hurricanes and tornadoes are especially perti- nent. Alteration of a few degrees in the path of a hurricane may result in its missing a certain area * * * and ravaging * * * instead, a different one. The decision on whether such an operation is justified can reasonably be made only at the highest level, and would need to be based on the substantial scientific finding thai the anticipated damages would be loss than those originally predicted h td the hurricane been allowed to follow its course.
1 b Silverman, Bernard A. "What Do We Need in Weather Modification?" In preprints of tli<' Sixth Conference on Planned and [nadvertenl Weather Modification, October 10—13, litTT. Champaign, ill.. Boston, American Meteorological Society. u»77. p. 310.
ia Flengle, Crutchfleld, Johnson, and Abdo. "Weather Modification in the Public Interest." 1074. p. :',7-38.
*• Ibid., p. 38-40.
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5. Attention must be given to alternatives in considering a given weather modification proposal. The public may prefer some other solution to an attempt at weather tampering which may be regarded as predictable and risky. Further- more, alternative policies may tend to be comfortable extensions of existing policies, or improvements on them, thus avoiding the public suspicion of inno- vation. In an area such as weather modification, where so many uncertainties exist, and where the determination or assigning of liability and responsibility are far from having been perfected, public opposition will surely be aroused. Any alternative plan or combination of plans will have its own social effects, however, and it is the overall impact of an alternative plan and the adverse effects of not carrying out such a plan which, in the final analysis, should guide decisions on alternative action.
6. Finally, it is important to recognize that the benefits from a weather modi- fication program may depend upon the ability and readiness of individuals to change their modes of activity. The history of agricultural extension work in the United States suggests that this can be done successfully, but only with some time lag, and at a substantial cost. Social research studies suggest that public perception of flood, earthquake, and storm hazards is astonishingly casual.
Need for public education on weather modification
The previous listing of social implications of weather modification was significantly replete with issues derived from basic human atti- tudes. To a large extent these attitudes have their origin in lack of in- formation, misconceptions, and even concerted efforts to misinform by organized groups which are antagonistic to weather modification. As capabilities to modify weather expand and applications are more wide- spread, it would seem probable that this information gap would also widen if there are no explicit attempts to remedy the situation. "At the very least," according to Fleagle, et al., "a large-scale continuing pro- gram of education (and perhaps some compulsion) will be required if the potential social gains from weather modification are to be realized in fact," 48 Whether such educational programs are mounted by the States or by some agency of the Federal Government is an issue of jurisdiction and would likely depend on whether the Federal Govern- ment or the States has eventual responsibility for management of op- erational weather modification programs. Information might also be provided privately by consumer groups, professional organizations, the Aveather modification industry, or the media.
It is likely that educational programs would be most effective if a variety of practical approaches are employed, including use of the news media, publication of pamphlets at a semitechnical level, semi- nars and hearings, and even formal classes. Probably the latter cate- gories would be most appropriate for civic groups, Government offi- cials, businessmen, or other interests who are likely to be directly affected by contemplated operations.
The following list of situations are examples of public lack of under- standing which could, at least in part, be remedied through proper educational approaches :
There is much apprehension over claims of potential d^rger of a long-lasting nature on climate, which could supposedly result from both inadvertent and planned modification of the weather, with little insight to distinguish between the causes and the scales of the effects.
There have been extravagant claims, propagated through ig- norance or by deliberate distortion by antagonistic groups, about
48 Ibid., p. 40.
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the damaging effects of cloud seeding on ecological systems, human lien 1th. and air and water quality.
The controversies between opposing groups of scientists on the efficacy of weather modification technologies and between scien- tists and commercial operators on the readiness of these technolo- gies for application has engendered a mood of skepticism and even mistrust of weather modification on the part of a public which is largely uninformed on technical matters.
The public has often been misinformed by popular news media, whose reporters seek to exploit the spectacular in popular weather modification "stories" and who, themselves usually uninformed in technical aspects of the subject, tend to oversimplify and distort the facts associated with a rather complex science and technology.
There has been an organized effort on the part of groups opposed to weather modification to mount an educational program which runs counter to the objectives of informing the public about the potential benefits of a socially acceptable technology of weather modification.
Portions of the public have acquired a negative impression that meteorologists and Government officials concerned with weather modification are irresponsible as a result of past use. or perceived present and future use. of the technology as a weapon of war.
Lack of information to the public has sometimes resulted in citizen anger when it is discovered that a seeding project has been going on in their area for some time without their having been informed of it.
Decisionmaking
"The nature of wenther processes and the current knowledge about them require that most human decisions as to weather modification must be made in the face of uncertainty. This imposes special re- straints on public agencies and it increases the difficulty of predict- ing how individual farmers, manufacturers, and others who are directly affected by weather would respond to changes in leather Characteristics.5' 49 The situation since 1965 when this statement was made has changed little with resrard to predictability of weather processes and their modification. There has also been little progress toward developing decisionmaking processes which can be applied, should the need arise, on whether or not weather modification should be emploved.
A number of studies on social attitudes indicate that the preference of most cit izens is that decisionmaking in such areas as use or restraint from use of weather modification should be at the local level. owim>- to the feeling that citizens' rights and property are best protected when decisions are made bv officials over whom they have the most direct; control. Farhar savs that evidence suggests that one important condition for public acceptance of weather modification technology is public involvement in the decision process, especially in civic derisions.™ Procedures must then be developed for enabling {peal
49 Special Commission on Wcnther Modification. "Weather and Climate Modification." NRF or, irto.~. p uc.
» F.-irlisir. Bar nun) P. "The Pnldie Derides Al<ont Weather Modification."' Environment
and Behavior, vol. 9. No. September 1 077. p. .".07.
23
officials, probably not technically trained, to make such decisions intelligently. Such decisions must be based both on information received from Federal or State teclmical advisers and on the opinions of local citizens and interest groups.
INTERNATIONAL ISSUES
International agreements regarding weather modification experi- ments and operations have been very limited. There exists a United States-Canada agreement, which requires consultation and notifica- tion of the other country when there is the possibility that weather modification activities of one country could affect areas across the border.51 Earlier understandings were reached between the United States and Canada concerning experiments over the Great Lakes and with the IJnited Kingdom in connection with hurricane modification research in the Atlantic.52 Recent attempts to reach agreement with the Governments of Japan and the People's Republic of China for U.S. experiments in the Far East on modification of typhoons were unsuccessful, though such research was encouraged by the Philip- pines. There is current intention to reach an agreement with Mexico on hurricane research in the eastern Pacific off that nation's coast.
During 1976, 25 nations reported to the World Meteorological Orga- nization that they had conducted weather modification activities.53 There have been two principal international activities, dealing with somewhat different aspects of weather modification, in recent years. One of these is the preparation and design of a cooperative experi- ment under the auspices of the World Meteorological Organization, called the Precipitation Enhancement Experiment (PEP) ; while the other is the development of a convention by the United Nations on the prohibition of hostile use of environmental modification.54
The following international considerations on research and opera- tional weather modification activities can be identified :
1. There is a common perception of a need to insure that the current high level of cooperation which exists in the international community with regard to more general meteorological research and weather re- porting will be extended to development and peaceful uses of planned weather modification.
2. There is now no body of international law which can be applied to the potentially serious international questions of weather modification, such as liability or ownership of atmospheric water resources.55
3. Past use by the United States, and speculated current or future use by various countries, of weather modification as a weapon have raised suspicions as to the possible intent in developing advertent weather modification technology.
4. There have been charges that weather modification research activi- ties were used to divert severe weather conditions away from the
r,t The United States-Canada agreement on weather modification is reproduced in nop. F.
52 Taubenfeld, Howard J., "National Weather Modification Policy Act of 1976 ; Interna- tional Agreements." Background paper for use of the U.S. Department of Commerce Weather Modification Advisory Board, March 1977, p. 13.
53 See table 1, ch. 9, p. 409.
54 These activities and other international aspects of weather modification are discussed in ch. 10.
55 See previous section on legal issues, p. 17.
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United States at the expense of other countries or that such activities have resulted in damage to the environment in those countries.56
5. As in domestic research projects, there are allegations of insuffi- cient funding over periods of time too short to achieve significant results in the case of internationally sponsored experiments; in par- ticular, many scientists feel that a means should be devised to insure that the planned Precipitation Enhancement Project (PEP) receives adequate continuous support.
6. Other nations should be consulted with regard to any planned weather modification activities by the United States which might con- ceivably affect, or be perceived to affect, those countries.
ECOLOGICAL ISSUES
The body of research on ecological effects of weather modification is limited but significantly greater than it was a decade ago. It is still true that much remains unknown about ecological effects of changes to weather and climate.
Economically significant weather modification will always have an eventual ecological effect, although appearance of that effect may be hidden or delayed by system resilience and/or confused by system complexity. It may never be possible to predict well the ecological effects of weather modification; however, the more precisely the weather modifier can specify the effects his activities will produce in terms of average percentage change in precipitation (or other vari- ables), expected seasonal distribution of the induced change, expected year-to-year distribution of the change, and changes in relative form of precipitation, the more precise can be the ecologist's prediction of possible ecological effects.
Ecological effects will result from moderate weather-related shifts in rates of reproduction, growth, and mortality of plants and animals; they will rarely be sudden or catastrophic. Accordingly, weather modi- fied ions which occur with regularly over time are the ones to which biological communities will react. Adjustments of plant and animal communities will usually occur more slowly in regions of highly vari- able weather than in those with more uniform conditions. Deliberate weather modification is likely to have greater ecological impact in semiarid systems and less impact in humid ones. Since precipitation augmentation, for example, would have the greatest potential for eco- nomic value and is, therefore, likely to have its greatest potential ap- plication in such areas, the ecological impacts in transition areas will be of particular concern.
Although widespread cloud seeding could result in local, temporary increases in concentrations of silver (from the most commonly used seeding agent, silver iodide), approaching the natural quantities in surface waters, the exchange rates would probably be an order of magnitude Lower than the natural rates. Even in localized areas of precipital ion management, it appears I hat exchange rates will be many orders of magnitude smaller than those adversely affecting plants and soils. Further research is required, however, especially as other poten- tial seeding agents are introduced.
m por example tbere were charges that attempts to mitigate severe effects of Hurricane Fifl in 15>75 caused devastat ion to Honduras. :i charge which the United Nt;ites officially denied, since no hurricanes had been seeded under Project Stormfury since 1971.
CHAPTER 2
HISTORY OF WEATHER MODIFICATION
(By Robert E. Morrison, Specialist in Earth Sciences, Science Policy Research Division, Congressional Research Service)
Introduction
The history of the desire to control the weather can be traced to antiquity. Throughout the ages man has sought to alleviate droughts or to allay other severe weather conditions which have adversely affected him by means of magic, supplication, pseudoscientific procedures such as creating noises, and the more on less scientifically based techniques of recent times.
The expansion in research and operational weather modification projects has increased dramatically since World War II; nevertheless, activities predating this period are of interest and have also provided the roots for many of the developments of the "modern" period. In a 1966 reprt for the Congress on weather modification, Lawton Hart- man stated three reasons why a review of the history of the subject can be valuable: (1) Weather modification is considerably older than is commonly recognized, and failure to consider this fact can lead to a distorted view of current problems and progress. (2) Weather modi- fication has not developed as an isolated and independent field of re- search, but for over a century has been parallel to and related to progress in understanding weather processes generally. (3) Earlier experiences in weather modification may not have been very different from contemporary experiences in such matters as experimental de- sign, evaluation of results, partially successful projects, and efforts to base experiments on established scientific principles.1
Hartman found that the history of weather modification can be conveniently divided into five partially overlapping periods.2 He refers to these as (1) a prescientific period (prior to about 1839); (2) an early scientific period (extending approximately from 1839 through 1891) ; (3) a period during which elements of the scientific framework were established (from about 1875 to 1933) ; (4) the period of the early cloud-seeding experiments (1921 to 1946) ; and (5) the modern period, beginning with the work of Langmuir, Schaefer, and Vonne- gut (since 1946). This same organization is adopted in discussions below ; however, the four earlier periods are collected into one section, while the more significant history of the extensive activities of the post-1946 period are treated separately.
1 Hartman, Lawton M., "History of Weather Modification. " In U.S. Congress, Senate Committee on Commerce "Weather Modification and Control." Washington. D.C U.S. Government Printing Oflice, 1966 (89th Cong., 2d sess.. Senate Rept. No. 1139: prepared by the Legislative Reference Service, the Library of Congress, at the request of Warren G. Maemn«on) , p. 11.
2 Ibid.
(25)
26
History or Weather Modification Prior to 1946
PRESCIENTIFIC PERIOD
From ancient times through the early 19th century, and even since, there have been reported observations which led many to believe that rainfall could be induced from such phenomena as great noises and extensive fires. Plutarch is reported to have stated, "It is a matter of current observation that extraordinary rains pretty generally fall after great battles/' 3 Following the invention of gunpowder, the fre- quency of such claims and the conviction of those espousing this hypothesis increased greatly. Many cases were cited where rain fell shortly after large battles, A practical use of this phenomenon was re- ported to have occurred in the memoirs of Benvenuto Cellini when, in 1539 on the occasion of a procession in Rome, he averted an impending rainstorm by firing artillery in the direction of the clouds, "which had already begun to drop their moisture." 4
William Humphreys jDOsed a plausible explanation for the appar- ently high correlation between such weather events and preceding battles. He noted that plans were usually made and battles fought in good weather, so that after the battle in the temperate regions of Europe or North America, rain will often occur in accordance with the natural 3- to 5-day periodicity for such events.5 Even in modern times there was the conviction that local and global weather had been adversely affected after the explosion of the first nuclear weapons and the various subsequent tests in the Pacific and elsewhere.0 Despite statements of the U.S. Weather Bureau and others pointing out the fallacious reasoning, such notions became widespread and persistent.7
In addition to these somewhat rational though unscientific obser- vations, many of which were accompanied by testimony of reliable witnesses, there had been, and there still exist in some primitive cul- tures, superstitions and magical practices that accompany weather phenomena and attempts to induce changes to the weather. Daniel Halacy relates a number of such superstitiouslike procedures which have been invoked in attempts to bring rain to crops during a drought or to change the1 weather in some other way so as to be of particular benefit to man : 8
Primitive rainmakers would often use various intuitive gestures, such as sprinkling water on the soil that they wanted the heavens to douse, Mowing mouthfuls of water into the air like rain or mist, hammering on drums to inu- la re thunder, or throwing firebrands into the air to simulate lightning.
Women would carry water at night to the field and pour it out to coax the skies to do likewise.
American Indians blew water from special pipes in imitation of the rainfall.
It was believed that frogs came down in the rain because many were seen following rain : therefore, frogs were hung from trees so that the heavens would pour down rain upon them.
Sometimes children were buried up to their necks in the parched ground and then cried for rain, their tears providing the imitative magic.
Ward, R. !>«• <\. "Artificial Rain : a Review of the Subject to the Close of lSSft." Amor- lean Meteorological Journal; vol. s. May 1891-Aprtl *S92, p. 484. * Ibid., n. 408.
s Humphreys. William -1 . "Rain Making and Other Weather Vagaries." Baltimore, The Williams and Wilkins Co.. 11*20. p. 31,
"Byers, Horace i:.. 'History of Weather Modification." In Wilnot N. Hess (editor), "Weather and Climate Modification," New York. Wiley, 1!)74, p. 4. ~ T'.id
« Halacy, Daniel S., Jr., "The Weather Changers," New York. Harper & Row. 1908. pp.
27
In China, huge paper dragons were part of religious festivals to bring rain; if- drought persisted, the dragon was angrily torn to bits.
North American Indians roasted young women from enemy tribes over a slow fire, then killed them with arrows before eating their hearts and burying their remains in the fields they wanted irrigated with rainfall.
Scottish witches conjured up the wind by beating a stone three times with a rag dipped in water, among intonations like those of characters in a Shake- spearean play.
New Guinea natives used wind stones upon which they tapped with a stick, the force of the blow bringing anything from a zephyr to a hurricane.
Pregnant women in Greenland were thought to be able to go outdoors, take a breath, and exhale it indoors to calm a storm.
In Scandinavian countries witches sold knotted bits of string and cloth which, supposedly, contained the wind ; untying one knot at sea would produce a mod- erate wind, two a gale, and three a violent storm.
Australian bushmen thought that they could delay the Sun by putting a clod of dirt in the fork of a tree at just the height of the Sun, or hasten its departure by blowing sand after it.
Bells have been thought to prevent hail, lightning, and windstorms, and some- times they are still rung today for this purpose.
EARLY SCIENTIFIC PERIOD
James P. Espy was a 19th century American meteorologist known especially for his development of a theon^ of storms based on convec- tion. Recognizing that a necessary condition for rainfall is the formation of clouds by condensation of water vapor from rising air, Espy considered that rain could well be induced artificially when air is forced to rise as a result of great fires, reviving a belief of the pre- .scientific era but using scientific rationale. In the National Gazette in Philadelphia of April 5, 1839, he said :
From principles here established by experiment, and afterward confirmed by observation, it follows, that if a large body of air is made to ascend in a column, a large cloud will be generated and that that cloud will contain in itself a self- sustaining power, which may move from the place over which it was formed, and cause the air over which it passes, to rise up into it, and thus form more cloud and rain, until the rain may become more general.8
If these principles are just, when the air is in a favorable state, the bursting out of a volcano ought to produce rain ; and such is known to be the fact ; and I have abundant documents in my possession to prove it.
So, under very favorable conditions, the bursting out of great fires ought to produce rain ; and I have many facts in my possession rendering it highly probable, if not certain, that great rains have sometimes been produced by great fires.10
Later in the same article Espy stated that :
From these remarkable facts above, I think it will be acknowledged that there is some connection between great fires and rains other than mere coincidence. But now. when it is demonstrated by the most decisive evidence, the evidence of experiment, that air, in ascending into the atmosphere in a column, as it must do over a great fire, will cool by diminished pressure, so much that it will begin to condense its vapor into cloud.11
Espy postulated three mechanisms which could prevent great fires from providing rain at all times when they occur: (1) If there is a current of air at some height, it sweeps away the uprushing current of air; (2) the dew-point may be too low to produce rain at all: and (3) there may be an upper stratum of air so light that the rising
9 Espy. Tames P.. "Artificial Rains." National Gazette. Philadelphia. Apr. 5, lSf!9. Re- printed in James P. Espy, "Philosophy of Storms," Boston. Little & Brown. 1841. pd. 493-494.
10 Ibid., p. 494.
11 Ibid., p. 496.
28
column may not be able to rise far enough into it to cause rain.12 He proposed an experiment in which he would set fire to a "large mass of combustibles," which would be ready for the right circumstances and at a time of drought. He added : "Soon after the fire commences, I will expect to see clouds begin to form * * *. I will expect to see this cloud rapidly increase in size, if its top is not swept off by a current of air at a considerable distance abov^e the Earth, until it becomes so lofty as to rain.'- 13
For over a decade Espy served as an adviser to the Congress on meteorological problems. He proposed in 1850 what is perhaps the first Fedora! project for large-scale weather modification. His plan included amassing large quantities of timber in the Western States along a 600- to 700-mile north-south line, to be set on fire simultaneously at regular T-day intervals. He believed that this fire could have started a "rain of great length" traveling toward the East, not breaking up until reaching "far over the Atlantic Ocean; that it will rain over the whole country east^of the place of beginning." The cost of this experiment would "not amount to half a cent a year to each individual in the United States." 14 Congress did not endorse the proposal for reasons which are unknown: however. Fleagle speculates that perhaps this failure was due to the fact that Congress had not yet accustomed itself to appropriating funds for scientific enterprises.15
There was continuing controversy over whether or not fire could cause increased rainfall. In an article which appeared in Nature in 1871, J. K. Laughton stated that, "The idea that large fires do, in some way, bring on rain, is very old; but it was, I believe, for the first time stated as a fact and explained on scientific grounds by the late Pro- fessor Espy." 10 Laughton cited instances where burning brush in hot, dry weather did not result in any rainfall, and he concluded that :
Large fires, explosions, battles, and earthquakes do tend to cause atmospheric disturbance, and especially to induce a fall of rain ; but that for the tendency to produce effect, it is necessary that other conditions should be suitable. With regard to storms said to have been caused by some of these agencies, the evidence is still more unsatisfactory ; and, in our present ignorance of the cause of storms generally, is quite insufficient to compel us to attribute any one particular gale, extending probably over a wide area, to some very limited and comparatively insignificant disturbance.17
The 1871 Chicago fire also aroused interest, many believing that the fire was stopped by the rainfall which it had initiated. Ward cites a telegram of the time sent to London which read :
This fire was chiefly checked on the third or fourth day by the heavy and con- tinuous downpour of rain, which it is conjectured is partly due to the great atmos- pheric disturbances which such an extensive lire would cause, especially wben we are told that the season just previous to the outbreak of the fire had been par- ticularly dry."
u Ibid.
1 ■ I 'id., p. 400.
« Espy, James P., "Second Reporl on Meteorology to the Secretary of the Navy." U.S. Senate. Executive Doctlmetats; No. 89, vol. 11, ."{1st Cong., 1st Bess. Washington, Wm. M Belt 1850. p. 20.
us Fleagle. Robert O.. "Background and Present status of Weather Modification." In Robert (i. Flea pie (editor). "Weather Modification: Science and Public Policy." University of w ah inert on Press, Seattle 1968, p. 7.
"' Lautrhton. J K., "Can Weather lie Influenced bv Artificial Means?" Nature, Feb. 10. 1871 i. :•(»(;
17 Ibid., p. 307.
« Reported in Ward. "Artificial Rain : a Review of the Subject to the Close of 1889," 1*02. pp. 480-400.
29
On the other hand, Prof. I. A. Lapham, speaking of the Chicago fire, contradicted the previous account, saying :
During all this time — 24 hours of conflagration — no rain was seen to fall, nor did any rain fall until 4 o'clock the next morning ; and this was not a very con- siderable downpour, but only a gentle rain, that extended over a large district of country, differing in no respect from the usual rains. It was not until 4 days afterward that anything like a heavy rain occurred. It is, therefore, quite certain that this case cannot be referred to as an example of the production of rain by a great fire.19
Lapham goes on to say that, "The case neither confirms nor dis- proves the Espian theory, and we may still believe the well-authenti- cated cases where, under favorable circumstances of very moist air and absence of wind, rain has been produced by very large fires." 20
Prof. John Trowbridge of Harvard reported in 1872 on his experi- ments in which he investigated the influence of flares on atmospheric electricity. Noting that the normal atmospheric state is positive and that clearing weather is often preceded by a change from negative to positive charge, he suggested that perhaps large fires may influence the production of rain by changing the electrical state of the atmosphere, since, in his tests, his flame tended "to reduce the positive charge of electricity which generally characterizes the air of fine weather." 21 He concluded by saying: "The state of our knowledge, however, in regard to the part that electricity plays in atmospheric changes is very meager. The question of the truth of the popular belief that great fires are fol- lowed by rain still remains unanswered." 22
Meanwhile, H. C. Russel, president of the Royal Society of South Wales and government astronomer, attempted to dispel the ideas that both cannonading and great fires could be used to produce rain. He hypothesized that, if fire were to have such an effect, rain should arrive within 48 hours following the fire. Reviewing the records of 42 large fires (including two explosions) covering a 21-year period, Russel concluded that there was not one instance in which rain followed within 48 hours as an evident consequence of the fire. He further cal- culated that to get increased rainfall of 60 percent over a land surface of 52,000 square feet at Sidney would require 9 million tons of coal per day, in an effort to show what magnitude of energy expenditure was necessary and how futile such an attempt would be.23
Toward the latter part of the 19th century there were a number of ideas and devices invented for producing rain artificially. In 1880 David Ruggles of Virginia patented what he said was "a new and use- ful mode of producing rain or precipitating rainfalls from rainclouds, for the purpose of sustaining vegetation and for sanitary purposes." His plan included a scheme by which balloons carrying explosives were sent up into the air, the explosives to be detonated in the upper air "by electric currents." 24
19 Lanham, I. A.. "The Great Fires of 1871 in the Northwest." The Journal of the Frank- lin Institute, vol. 64, No. 1. July 1872, pp. 46-47.
20 IMd., p. 47.
21 Trowlirirtge, John, "Great Fires and Rain-storms." The Popular Science Monthly, vol. 2, December 1872. p. 211.
22 Tbid.
23 Report of an address bv H. C. Russel was given in Science, vol. 3, No. 55, Feb. 22. 1884, pp. 229-230.
24 "New Method of Precipitating Rain Falls," Scientific American, vol. 43, Aug. 14. 1S80, p. 106.
30
G. H. Bell suggested a rainmaking device, consisting of a hollow tower 1.500 feet high, through which air was to be blown into the atmosphere, the volume of the up-rushing air to be increased through use of a s}^stem of tubes around the tower. The inventer consider that the same system could be used to prevent rain, by reversing the blower so that the descending air might "annihilate" the clouds.25
Still other schemes and contrivances were proposed and patented. J. B. Atwater was granted a patent in 1887 for a scheme to dissipate tornadoes by detonating an explosive charge in their centers, and an- other was granted to Louis Gathman in 1891 for seeding clouds for rain by exploding a shell containing "liquid carbonic acid gas" at cloud height,20 the latter concept antedating by over 50 years the more recent carbon dioxide seeding projects.
There continued to be adherents to the idea that explosions could cause rainfall. This belief was reinforced by "evidence" of such a con- nection in a book by Edward Powers, called "War and the Weather," published in 1871 and 1890 editions, in which the author recounted the instances in which rain followed battles, mostly from North America and Europe during the 19th century.27
Powers was convinced that :
The idea that rain can be produced by human agency, though sufficiently startling, is not one which, in this age of progress, ought to be considered as impossible of practical realization. Aside from its connection with the supersti- tions of certain savage tribes, it is an opinion of comparatively recent origin, and is one which cannot be regarded as belonging, in any degree, to a certain class of notions which prevail among the unthinking; * * * on the contrary, it is one which is confined principally to those who are accustomed to draw conclusions only from adequate premises, and * * * founded on facts which have come under their own observation.28
In tones somewhat reminding us of those urging a greater Federal research effort in recent years, Powers proposed that experiments be undertaken for economic benefit :
Judging from the letters which I have received since commencing in 1870 an attempt to bring forward the subject of rains produced by cannon tiring. I believe that the country would regard with interest some experiments in the matter, and would not begrudge the expense, even if they should prove unsuccessful in leading to a practical use of the principle under discussion. In some matters connected wTith science, the Government has justly considered that an expenditure of public funds was calculated to be of public benefit: but where, in anything of tiie kind it. has ever undertaken, has there been so promising a field for such actions as here?20
Powers, upon examining the records of many battles, said :
Let us proceed to facts — facts not one of which, perhaps, would be of a in- significance if it stood alone and unsupported by the others; but which, taken in the aggregate, furnish the strongest evidence that heavy artillery firing has an influence on the weather and tends to bring rain. 11
Perhaps influenced by the arguments of Powers and others, in 1890 the U.S. Congress had become so much interested in and gained
Another Ka in Controller." Scientific American, vol. 4:{. Aug, 21. 1SSO. p 11M.
26 Harrington, Mark W.. "Weather-making, Ancient and Modern," Smithsonian Institu- tion Annual Report, to July 1894, pp. 249 1270.
-'■ I'owers. IMward. "War and the Weather." Delavan. Wis.. 10. Powers. 1890, revised edition, 202 pp. (An earlier edition was published in Chicago in 1871. Incidentally, the plates for the first edition were deal roved in the Chicago lire, and I'owers did not have an opportunity to complete his revision until 1890. )
-* Ihid.. p. 5.
■ Ihid.. p. 143.
* Ihid., p. 11.
31
such faith in the possibility of weather modification that funds we re appropriated to support experiments to be carried out under the auspices of the Forestry Division of the U.S. Department of Agriculture. The initial $2?0p0 appropriated was increased first to $7,000, and finally to $10,000. in the first federally sponsored weather modification project. Of the total appropriated. $9,000 was to be spent on held experiments. Gen. Robert St. George Dyrenforth was selected by the Department of Agriculture to direct these tests, hav- ing earlier conducted tests near Utiea, X.Y., and Washington, D.C.. using balloons and rockets carrying explosives. The principal ex- periments were executed near Midland, Tex., using a variety of ex- plosive devices, detonated singly and in volleys, both on the ground and in the air.31
According to an interesting account by Samuel Hopkins Adam-. Dyrenforth arrived in Texas on a hot day in August 1891 with a company of 80 workers, including "* * * chemists, weather observers, balloon operators, electricians, kitefiiers, gunners, minelayers, sap- pers, engineers, and laborers * * * together with some disinterested scientists, who were to serve as reporters." 32 Adams discusses the ap- paratus which Dyrenforth took with him :
The expedition's equipment was impressive. There were 68 balloons of from 10 to 12 feet in diameter, and one of 20 feet — all to be hlled with an explosive mixture of hydrogen and oxygen. There were also sixty 6-inch mortars, made of pipe, and several tons of rackarock (a terrifying blend of potassium chlorate and nitro- benzol that, was the general's favorite "explodent" >, dynamite, and blasting powder. Finally, there were the makings of a hundred kites, to be assembled on the scene, and sent up with sticks of dynamite lashed to them. The congressional $9,000 fell considerably short of sufficing for so elaborate an outfit, but expectant Texans chipped in with liberal contributions and the railroads helped out by sup- plying free transportation.1"
Dyrenforth carried out five series of trials during 1891 and 1892 : one period of sustained cannonading coincided with a heavy down- pour, and the apparent connection provided support to the credi- bility of many people, who accepted the hypotheses as confirmed. Dyrenforth gave optimistic and promising reports of his results: however, meterologists and other scientists were critical of his work. It does not appear that the Forestry Division was fervently ad- vocating the research program for which it had responsibility. In 1891, Bernhard E. Fernow, Chief of the Division of Forestry, re- ported to the Secretary of Agriculture his sentiments regarding the experiments which were to be conducted in the coming summer, with a caution reminiscent of the concerns of many meterologists of the 1970°s :
The theories in regard to the causes of storms, and especially their local and temporal distribution, are still incomplete and unsatisfactory. It can by no means be claimed that we know all the causes, much less their precise action in precipi- tation. It would, therefore, be presumptuous to deny any possible effects of ex- plosions ; but so far as we now understand the forces and methods in precipitating rain, there seems to be no reasonable ground for the expectation that they will be effective. We may say, then, that at this stage of meteorological knowledge we are not justified in expecting any results from trials as proposed for the predtre- tion of artificial rainfall, and that it were better to increase this knowledge first
31 Fleagle. "Background and Present Status of Weather Modification." 1968, pp. 7-8.
32 Adams. Samuel Hopkins. The New Yorker. Oct. 9, 1952, pp. 93-100. *> Ibid., i«. !.'4.
32
by simple laboratory investigations and experiments preliminary to experiment on a larger scale.34
In 1893, the Secretary of Agriculture asked for no more public funds for support of this project.35
Fleagle tells about the use of 36 "hail cannons" by Albert Stiger, a town burgomaster, on the hills surrounding his district in Austria in 1896:
Tbe hail cannon consisted of a vertically pointing three-centimeter mortar above which was suspended the smokestack of a steam locomotive. This device not only produced an appalling sound, but also created a smoke ring a meter or more in diameter which ascended at about one hundred feet per second and produced a singing note lasting about ten seconds. Initial successes were impres- sive, and the hail cannon was widely and rapidly copied throughout central Europe. Accidental injuries and deaths were numerous, and in 1902 an inter ua- tional conference was called by the Austrian government to assess the effects of the hail cannon. The conference proposed two tests, one in Austria and one in Italy, the results of which thoroughly discredited the device.36
Though unsuccessful, the work of Dyrenforth and others had in- spired belief in the possibilities of drought alleviation such that a number of unscrupulous "rainmakers" were able to capitalize on the situation. Halacy gives an account of a famous rainmaker of the early 20th century, Charles Warren Hatfield, who operated for about 10 years in the western United States. With a 25-foot platform and a secret device for dispensing chemicals, he claimed to create rain over extensive areas. In 1916. Hatfield contracted with the city of San Diego to alleviate drought conditions and was to be paid $1,000 for each inch of rain produced. When 20 inches of rain coincidentally fell nearby, the resulting floods destroyed a dam, killed 17 people, and produced millions of dollars damage. Hatfield, faced with a choice of assuming financial responsibility for the lawsuits or leaving the city without pay, chose the latter.37
One of Hatfield's accomplices was a colorful racetrack reporter from Xew York, who met and joined Hatfield in California in 1912, named James Stuart Aloysius MacDonald, alias Colonel Stingo, "the Honest Rainmaker." Over his half -century career as a writer, mostly for var- ious horseracing journals. MacDonald reportedly involved himself in various schemes for quick profit, including weather changing projects on both the west and east coasts. Contracts with clients were drawn up with terms for remuneration that resembled very much the language of success or failure at the racetrack. By his own admission, Mac- Donald based his odds for success on past weather data for a given area, which he obtained from records of the U.S. Weather Bureau or the Xew York Public Library.88 MacDonald, or Colonel Stingo, was the inspiration for a Broadway play called "The Rainmaker" which opened in 1954.
DEVELOPMENT OF SCIENTIFIC FUNDAMENTALS
Espy's L839 proposal for an experiment on the production of con- vection currents and water vapor condensation at high altitudes was
■A Fernow, Rernhard E.. in report to Jeremiah McClain Rusk. Secretary of Agriculture, 1891, an reported in Ward, "Artificial Rain ; a Review of the Subject to the Close of 1889." 1882. p. 492.
• livers. "History of Weather .Modification." 1 1*74. p. 5. 38 Fleajcle. "Rackpronnd and Present Status of Weather Modification," 1968, p. 9. :t7 Halacy, "The Weather Changers," 1968, pp. 68 69. 38 Liebling, A. J., "Profiles," The New Yorker, Sept. 20, 1902, pp. 43-71.
33
based on sound physical principles. Since knowledge of atmospheric processes was expanding and unfolding rapidly at the time, Hartman reminds us that the limited usefulness of Espy's weather modification concepts should not be ascribed to faulty logic, but rather to the primi- tive understanding at the time of the complex processes in precipita- tion, many of which are still not understood satisfactorily.39
The understanding which meteorologists have today about precipi- tation has been learned slowly and sometimes painfull}^, and, while many of the discoveries haA'e resulted from 20th century research, some important findings of the latter part of the 19th century are fundamental to these processes. Important results were discovered in 1875 by Coulier in France on foreign contaminant particles in the normal atmosphere, and quantitative measurements of the concentra- tions of these particles were achieved by Aitken in 1879. These events established a basis for explaining the fundamental possibility for occurrence of precipitation. Earlier, it had been learned that high supersaturations were required for the formation of water droplets.40 Aitken was the first to imply that there are two types of nuclei, those with an affinity for water vapor (hygroscopic particles) and nuclei that require some degree of supersaturation in order to serve as con- densation centers. The Swedish chemist-meteorologists of the 1920's developed a theory of condensation on hygroscopic nuclei and showed the importance of sea-salt particles. In the 1930's in Germany and the United Kingdom, a series of measurements were conducted on the numbers and sizes of condensation nuclei by Landsberg, Judge, and Wright. Data from measurements near Frankfurt, augmented sub- sequently by results from other parts of the world, have been adopted as the standard of reference for condensation nuclei worldwide.41
At the beginning of the 1930's important aspects of cloud phys' were not yet understood. In particular, the importance of thp ic,ri phu to precipitation was not yet clarified, though, ever since the turn of the century meteorologists were aware that water droplets were abun- dantly present in clouds whose temperatures were well below the freez- ing point. Little was known about the microphysics of nucleation of ice crystals in clouds ; however, it had been noted that rains fell only after visible glaeiation of the upper parts of the clouds. Understanding of these processes was essential before scientific seeding of clouds for weather modification could be pursued rationally. In 1933 Tor Berg-er- on presented and promulgated his now famous theory on the initiation of precipitation in clouds containing a mixture of liquid and ice. W. Findeisen expanded on Bergeron's ideas and published a clearer statement of the theory in 1938 ; consequently, the concept is generally known as the Bergeron-Findeisen theory.42 in his investigation of the formation of ice crystals, Findeisen was of the opinion that they crys- talled directly from the vapor (that is, by sublimation) rather than freezing from droplets. He also conjectured that quartz crystals might be the nuclei responsible for this process and even foresaw that the mechanism might be initiated artificially by introducing suitable nuclei.43
33 Hartman, "Weather Modification and Control," 1966, p. 13.
40 Ibid.
41 Bvers. "History of Weather Modification," 1974, p. 7.
42 Ibid., p. 8.
*» Ibid., pp. 8-9.
34-857—79 5
34
Findeisen stated emphatically that rain of any importance must originate in the form of snow or hail, though Bergeron had admitted the occurrence of warm rain in the tropics. Though many meteorolo- gists doubted that the ice crystal process was an absolute requirement for rain, they had been unable to collect evidence from aircraft obser- vations. In Germany aerological evidence was obtained on the growth of rain drops by the collision-coalescence process in "warm" clouds, but the papers on this work were published in 1940, and World War II restricted communication of the results to meteorologists world- wide. Meanwhile in the United States, papers were published on the theory of the warm rain process. In 1938, Houghton showed that pre- cipitation could be started by either the Bergeron process or by the collision-coalescence process. He noted that drops could be formed by condensation on "giant" hygroscopic nuclei present in the air and that growth of droplets to raindrop size was possible through collision. G. C Simpson elucidated further on condensation and precipitation processes in 1941, disagreeing with Findeiseivs rejection of "warm" rain formation by the collision-coalescence process.44
EARLY CLOUD-SEEDIXG EXPERIMENTS
Starting about 1920 and continuing for about two decades until the outbreak of World War II, there were a number of experiments and operations intended to produce rain or modify the weather in some other way. Although some of these activities were pusued in a scientific manner, others were less so and were directed at producing immediate results; all of these projects lacked the benefit of the funda- mental knowledge of precipitation processes that was to be gained later during this same period, the discoveries of which are discussed in the preceding subsection. Various schemes during this period in- cluded the dispensing of materials such as dust, electrified sand, dry ice, liquid air, and various chemicals, and even the old idea that explo- sions can bring rain. Field tests were conducted in the United States, Germany, the Netherlands^ and the Soviet Union.
Byers tells .about the experimental work of Dr. E. Leon Chaffee, professor of physics at Harvard, who became interested in the possi- bility of making cloud particles coalesce by sprinkling electrically charged sand over the clouds :
Dr. Chaffee became enthusiastic about the idea and developed in his laboratory a nozzle tor charging sand and dispersing it from an airplane. The nozzle could deliver sand grains having surface gradients of the order of 1.000 V/ein. Flight experiments were carried out in August and Seprcmber of 1024 at Aberdeen, Md.. with an airplane scattering the sand particles in the clear air above clouds having tops at n.ooo to 10,000 feet. Dr. Chaffee reported "success*' in the reverse sense, in that several clouds were observed to dissipate after treatment. The tests were well publicized in newspapers and scientific news journals, and this author, then a freshman at the University of California, recalls that his physics pro- fessors were enthusiastic about the idea. Chaffee's results probably would not endure the type of statistical scrutiny to which experiments of this kind are subject today.43
Chaffee considered several trials successful, since clouds were dis- sipated after being sprayed with the charged sand. It has been pointed
" Ibid . p. 9. « Ibid., p. 5.
35
out, however, in view of the much greater experience in recent years, that scientists must be extremely cautious in ascribing success in such experiments, when the evidence is based largely on visual obser- vations.4'1
In the Netherlands, August Veraart successfully produced rain by seeding clouds with dry ice from a small aircraft in 1930. This was 16 years before the work at General Electric in the United States, when clouds were also seeded with dry ice, initiating the modern period in the history of weather modification. Since Veraart probably did not understand the mechanism involved in the precipitation process which he triggered, ho did not realize that the dry ice was effective in develop- ment of ice crystals by cooling supercooled clouds, and his success was likely only a coincidence. Byers observes that Veraart's vague con- cepts on changing the thermal structure of clouds, modifying tem- perature inversions, and creating electrical effects were not accepted, however, by the scientific community.47 He claimed to be a true rain- maker and made wide, sweeping claims of his successes. He died in 19o*2, a year before Bergeron's theory appeared, not aware of the theo- retical basis for his work.48
Partly successful experiments on the dissipation of fog were con- ducted by the Massachusetts Institute of Technology in the 1930s, under the direction of Henry G. Houghton. At an airfield near Round Hill, Mass., fog was cleared using sprays of water-absorbing solutions, particularly calcium chloride, as well as fine particles of dry hygro- scopic material. Results of these experiments, which predated some of the present-day foo- dispersal attempts bv some 30 vears, were reported in 1938. 19
Weather Modification Sixce 1946
CHRONOLOGY
The following chronology of "critical events" relating to weather modification policy, compiled by Fleagle. unfolds only some of the major events and activity periods which have occurred since the his- toric discoveries of 1946 : 50
1946 : Schaefer demonstrated seeding: with dry ice.
1947 : Vonnegut demonstrated seeding with silver iodide.
1947-55 : Irving Langmuir advertised weather modifieaton widely and aggres- sively.
1947- 53: General Electric field experiments ("Cirrus") extended evidence that clouds can he deliherately modified, but failed to demonstrate large effects.
1948- 50: Weather Bureau Cloud Physics Project on cumulus and stratiform clouds resulted in conservative estimate of effects.
1948-52 : Commercial operations grew to cover 10 percent of United States.
1950: Report of Panel on Meteorology of Defense Department's Research and Development Board (Haurwitz, Chairman) was adverse to Langmuir's claims.
1953: Public Law 83-256 established President's Advisory Committee on Weather Control.
45 McDonald. James E.. "An Historical Note on an Early Cloud-Modification Experiment. Bulletin of the American Meteorological Society, vol. 42. No. 3, March 1961, p. 19o.
47 Byers. "History of Weather Modification." 1947. p. 6.
48 Hartman. "Weather Modification and Control." 1966. p. 15. , , „
» Houghton. Henrr G.. and W. H. Radford. "On the Local Dissipation of Natural bog. Papers in Physical Oceanography and Meteorology. Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, vol. 6, No. 3. Cambridge and Woods Hole, Mass., October 1938, 63 pp. , „ - .. „ „ .
50 Fleagle. Robert G . "An Analysis of Federal Policies in \\ eather Modification. Back- ground paper prepared for use by the U.S. Department of Commerce Weather Modification Advisory Board. Seattle. Wash., March 1977. pp. 3-5.
36
1953-54: "Petterssen" Advisory Committee organized field tests on storm sys- tems, convective clouds, and cold and warm fog (supported by the Office of Naval Research, the Air Force, the Army Signal Corps, and the Weather Bureau). These statistically controlled experiments yielded results which have been substantially unchanged in subsequent tests.
1957: Report of Advisory Committee (Orville, Chairman) concluded that tests showed 15 percent increase in orographic winter precipitation.
1957 : Major cut in research support across the board by Defense Department sends major perturbation through research structure.
195S: Public Law 85-510 assigned lead agency responsibility to the National Science Foundation (NSF).
1959: Commercial operations had diminished to cover about one percent of the United States.
1961 : First hurricane seeding under Project Stormfury.
1961 : Bureau of Reclamation authorized by Congress to conduct research in weather modification.
1961 : RAND report on weather modification emphasized complexity of atmos- pheric processes and interrelation of modification and prediction.
1962-70: Randomized field experiments established magnitude of orographic effects.
1964: Preliminary report of National Academy of Sciences/Committee on Atmospheric Sciences (NAS/CAS) roused anger of private operators and stimu- lated the evaluation of operational data.
1964-present : Department of the Interior pushed the case for operational seed- ing to augment water supplies.
1966: NAS/CAS report 1S50 laid the basis for expanded Federal programs.
1966 : Report of NSF Special Commission on Weather Modification and an NSF symposium called attention to social, economic, and legal aspects.
1966: Interdepartmental Committee for Atmospheric Sciences (ICAS) report f Newell, Chairman) proposed expanded Federal support to $90 million by 1970.
1966- 68 : Efforts of the Departments of Commerce and Interior to gain lead agency status were unsuccessful.
1967: ICAS recommended that Commerce be designated as lead agency. 1967: S. 2916, assigning lead agency responsibility to the Department of Com- merce : passed the Senate but did not become law.
1967- 72 : Military operational programs conducted in Vietnam. 1968: Public Law 90-407 removed the NSF mandate as lead agency. 1968 : Detrimental effects of acid rain reported from Sweden.
1969: Public Law 91-190 (National Environmental Policy Act) required im- pact statements.
1970; Massachusetts Institute of Technology Study of Critical Environmental Problems called attention to inadvertent effects on climate.
1970 : Stratospheric contamination by SST's suggested.
1971 : Departments of Commerce and Interior carried out operational programs in Oklahoma and Florida.
1971 : Public Law 92-205 required filing of reports of non-Federal weather modification activities with the Department of Commerce.
1971 : International Study of Man's Impact on Climate raised this issue to inter- national level.
1971 : NAS/CAS report on priorities for the 1970's emphasized need for atten- tion to management and policy problems of weather modification.
1971: Federal Council for Science and Technology approved seven national projects under various lead agencies.
1971-72: First technological assessments of weather modification projects are favorable to operational programs.
1971-74 : Climate impact assessment program ( CTAP) of Department of Trans- portation indicates potentially serious consequences of large SST fleet but sug- gests ways to ameliorate the problem.
1972: Failure of Soviet wheat crop and drought in Sahel emphasized critical need for understanding climate and the value of effective weather modification.
1973: Weather modification budget reduced by impoundment from $25.4 million to $20.2 million.
1973 : Five national projects deferred or terminated.
1973: NAS/CAS report on weather and climate modification confirmed earlier conclusions and recommended lead agency status for NOAA.
37
1974 : Stratospheric contamination by freon reported.
1974 : Domestic Council organized panels in climate change and weather modification.
1974 : General Accounting Office report on weather modification criticized weather modification program and pointed to need for lead agency.
1974 : Defense Department released information on operations in Vietnam.
1974 : The United States and the U.S.S.R. agreed to a joint statement intended "to overcome the dangers of the use of environmental modification techniques for military purposes."
1975 : World Meteorological Organization Executive Committee proposed cumu- lus experiment perhaps in Africa or Iran.
1975 : Department of Transportation CIAP report indicated that a fleet of 500 SST's would deplete ozone significantly, but suggested that cleaner engines could be developed.
1976: Chinese disapproval resulted in abandoning plans for Stormfury in the western Pacific.
1976 : Hearings held on three weather modification bills by Senate Commerce Committee.
1976: The National Weather Modification Policy Act of 1976 (Public Law 94- 859) enacted requiring study of weather modification.
1977 : Exceptionally dry winter in the west stimulates State operational pro- grams intended to increase mountain snowpack.
Since the completion of Fleagle's list above in March 1977, at least three other activities of equivalent significance ought to be noted :
1977 : The U.S. Department of Commerce Weather Modification Advisory Board established in April 1977 and initiated a major study on a recommended national policy and Federal program of research in weather modification, in accordance with requirements to be fulfilled by the Secretary of Commerce under Public Law 94-490, the National Weather Modification Policy Act of 1976.
1977 : The United Nations General Assembly approved a treaty banning environ- mental modification activities for hostile purposes on May 18, 1977 ; and the treaty opened for signature by the member nations.
1978 : The Report of the Commerce Department's Weather Modification Advi- sory Board transmitted through the Secretary of Commerce to the Congress.
The history of the modern period of weather modification which follows is essentially that of the two decades following the monumental discoveries of 1946. An excellent account of the history of weather modification, which emphasizes this period, has been prepared by Byers.51 This work has been very helpful in some of the material to follow and is referenced frequently. The late 1960's and the 1970's are so recent that events during this period are discussed in various sections of the report as ongoing activities or events leading to current activities in weather modification research programs, operations, and policy decisions rather than in this chapter as an integral part of an updated history of the subject.
LAXGMUIR, SCIIAEFER, AND VOXXEGUT
The modern era of scientific weather modification begaai in 1946, when a group of scientists at the General Electric Co. demonstrated that, through "seeding," a cloud of supercooled water droplets could be transformed into ice crystals and precipitation could be induced. These were not traditional meteorologists, though their leader. Dr. Irving Langmuir, was a famous physicist and Nobel laureate. He and his assistant, Vincent J. Schaefer, had been working for 3 years on cloud physics research, however, in which they were studying particle sizes, precipitation static, and icing. Their field research was carried on
Byers, "History of Weather Modification," 1974, pp. 3-44.
38
at the summit of Mt. Washington., X.H.. where they observed super- cooled clouds which often turned into snowstorms.52
In an attempt to simulate field conditions. Schaefer contrived a laboratory setup using a home freezer lined with black velvet, with a light mounted so as to illuminate ice crystals that might happen to form in the box. Breathing into the box, whose temperature was about — 23° C, produced fog but no ice crystals, even when various sub- stances— including sand, volcanic dust, sulfur, graphite, talc, and salt — were dropped in as possible sublimation nuclei.53 On July 12. 19-16, Schaefer wanted to lower the freezer temperature somewhat, so he inserted a large piece of dry ice. and. in an instant, the air was full of millions of ice crystals. He discovered that even the tiniest piece of dry ice produced the same etfect. In fact, dry ice had no direct effect on the supercooled cloud; producing an air temperature below - 39° C was critical.54
In his paper on the laboratory experiments, published in the No- vember 15, 1946. issues of^Sciencev Schaefer stated :
It is planned to attempt in the near future a large-scale conversion of super- cooled clouds in the atmosphere to ice crystal clouds, by scattering small frag- ments of dry ice into the cloud from a plane. It is believed that such an opera- tion is practical and economically feasible and that extensive cloud systems can be modified in this way.53
Two days before the paper appeared, on Xovember 13, 1946, Schaefer made his historic flight, accomplishing man's first scientific seeding of a supercooled cloud, as he scattered three pounds of dry ice along a 3-mile line over a cloud to the east of Schenectady, X.Y. At 14.000 feet the cloud temperature was —20° C. and in about § minutes after seeding the entire cloud turned into snow, which fell 2,000 feet before evaporating.56
Dr. Bernard Vonnegut had also worked on aircraft icing research and in 1946 at General Electric was pursuing a variety of nueleation problems ; but. after Schaefer's laboratory experiments, he again turned his attention to ice nueleation research. He discovered that silver iodide and lead iodide had crystal structures close to that of ice and were also insoluble in water, and after repeated initial failures, owing to impurities in the material, Vonnegut was able to produce ice crystals, using very pure silver iodide powder, at temperatures only a few degrees below freezing. Soon means were developed for generating silver iodide smokes, and man's first successful attempt at artificial nueleation of supercooled clouds was accomplished.57
Langmuir explained that dry ice could make ice crystals form by lowering the temperature to that required for natural nueleation on whatever might be present as nuclei, or even in the absence of all nuclei; however, the silver iodide provided a nucleus that was much more efficient than those occurring naturally.58
" Ibid., pp. 9-10.
" Halacy, "The Weather Changers/' ions. pp. S2-S3.
« langmuir. Irvinp. "The Growth of Particles in Smoke, and Clouds and the Production of Snow from Supercooled Clouds. Proceedings of the American Philosophical Society, vol. 92, no. 3, July 1048, p. 182. ' , , _ ,
Schaefer, Vincent J.. "The Production of Ice Crystals in a Cloud of Supercooled Water Droplets.'- Science, vol. U>4. No. 2707. Nov. 15. 1946, p. 459.
" Byers, "History of Weather Modification," 1074. p. 12.
57 H>id . p. 13.
M Langmuir, Irvine. "Cloud Seeding by Menus of Dry Ice. Silver Iodide, and Sodium Chloride." Transactions of the New York Academy of Sciences, ser. II, vol. 14. November 1951, p. 40.
39
Following Schaefer's successful flight of November 13, 1946, and in the months and immediate years thereafter, Langmuir was quoted in the popular press as being very optimistic in his predicted benefits from weather modification. In a 1948 paper he said that k>* * * it becomes apparent that important changes in the whole weather map can be brought about by events which are not at present being con- sidered by meteorologists." 59 His publications and informal statements of this character touched off years of arguments with professional meteorologists, by whom refutation was difficult in view of Langmuir s standing in the scientific community. His enthusiasm for discussing the potential extreme effects from weather control was unrestrained until his death in 1957. 60
RESEARCH PROJECTS SINCE 19 4 7
Project Cirrus
Although the business of the General Electric Co. had not been in meteorology, it supported the early research of Langmuir and his associates because of the obvious importance of their discoveries. Realizing that weather modification research was more properly a con- cern of the Federal Government, the company welcomed the interest of, and contract support from, the U.S. Army Signal Corps in February 1947. Subsequently, contract support was augmented by the Office of Naval Research, the U.S. Air Force provided flight support, and the U.S. Weather Bureau participated in a consultative role. The entire program which followed, through 1951, under this arrangement, including the field activities by Government agencies and the labora- tory work and general guidance by General Electric, was designated ''Project Cirrus." 61 According to Byers :
The most pronounced effect produced by Project Cirrus and subsequently sub- stantiated by a number of tests by others, was the clearing of paths through supercooled stratus cloud layers by means of seeding from an airplane with dry ice or with silver iodide. When such clouds were not too thick, the snow that was artificially nucleated swept all the visible particles out of the cloud. * * * In one of the first flights, * * * the supercooled particles in stratus clouds were removed using only 12 pounds of dry ice distributed along a 14-mile line. In later flights even more spectacular results were achieved, documented by good photography. BL'
Initial Project Cirrus studies were made during the summer of 1947 on cumulus clouds near Schenectady, but the important seeding experiments were conducted the following year in New Mexico. Also during 1947, there was an attempt on October 13 to modify a hurricane east of Jacksonville, Fla., through seeding with dry ice.63 Visual ob- servations, reported by flight personnel, seemed to indicate a pro- nounced change in the cloud deck after seeding, and, shortly there- after, the hurricane changed its course and headed directly westward, striking the coasts of Georgia and South Carolina. Even though there was precedent for such erratic behavior of hurricanes, there was speculation about the effect of seeding on the storm path, and the pos- sibility of legal responsibility for damages which might be caused by
59Lanfrmuir. Irvinp. "The Production of Rain by a Chain Reaction in Cumulus Clouds at Temperatures Above Freezing." Journal of Meteorology, vol. 5. No. 5. October 1948. p. 192. 6°T?vprs. "Historv of Weather Modification." 1974. pp. 13-14.
61 ThH.. p. 14.
62 Thirl.
M See discussion of Project Stormfury in ch. 5. p. 290 ff.
40
such experiments in the future provided reason to avoid seeding thereafter any storms with the potential of reaching land. The legal counsel of the General Electric Co. admonished Langmuir not to relate the course of the hurricane to the seeding; however, throughout the remainder of his career he spoke of the great benefit to mankind of weather control and of the potential ability to abolish evil effects of hurricanes. As a result, it was expected that the U.S. Weather Bu- reau would undertake massive efforts in weather control. Meteorolo- gists within and without of the Bureau were in a defensive position, with many other scientists, impressed by Langmuirs arguments, op- posing their position. Thus great controversies which developed between Langmuir and the Weather Bureau and much of the meteoro- logical community followed these and other claims, and often resulted from the fact that Langmuir did not seem to fully comprehend the magnitude and the mechanisms of atmospheric phenomena.04
Langmuir wanted to ^work where he thought storms originated rather than in upstate New York. He chose Xew Mexico as operations area for Project Cirrus, also taking advantage of the opportunity to collaborate there with Dr. E. J. Workman at the New Mexico Institute of Mining and Technology, whose thunderstorm research included radar observations and laboratory experiments on the effects of ire on storm electrification. After cloud-seeding flights there in October 1948, Langmuir reported that, as a result of the seeding, rainfall had been produced over an area greater than 40,000 square miles (about one-fourth the area of the State of New Mexico) . 63
The Project Cirrus group returned to Xew Mexico in July 1040, and 10 additional seeding nights were conducted. When Langmuir learned that Vonnegut was dispensing silver iodide from a ground generator in the same area and had, in fact, also been doing so during the flights of the previous October, he concluded that both the July 1919 results and the widespread effects of October 1948 were caused by the silver iodide rather than the dry ice seeding as he had theorized previously. Spectacular results continued to be reported by him. spurred on by meteorologists' challenges to his statistical methods and conclusions. Noting that Vonnegut had operated the ground generator only on certain days, Langmuir observed that rainfall responses corresponded to generator "on" times, leading him to his controversial "periodic seeding experiment.'' to which the remainder of his life was devoted.66
In the periodic seeding experiment, the silver iodide generators were operated in an attempt to effect a 7-day periodicity in the behavior of various weather properties. Langmuir was convinced that unusual weekly weather periodicities in early 1950 resulted from periodic seed- ings begun in Xew Mexico in December 1949. concluding that the effects were more widespread than he felt earlier and that temperatures and pressures thousands of miles away were also affected. Meteorologists observed that, while these correlations were the most striking seen, yet such periodicities were not uncommon.67 The Weather Bureau under- took a study of records from 1919 to 1951 to see if such weather perio-
" Ibid., pp. 14-16. ■ Ibid., p. 1«. w Ibid., p in. r~ Ibid., pp. in 20.
41
dickies had occurred in the past. Glenn W. Brier, author of the report on this study, indicated that a T-day component in the harmonic anal- ysis of the data appeared frequently, though seldom as marked as dur- ing the periodic seeding experiment.68 Byers' opinion is that the evi- dence appeared just as reliable for occurrence of a natural periodicity as for one controlled artificially. He contends that the most important discoveries in cloud physics and weather modification were made in the General Electric Research Laboratory before Project Cirrus was orga- nized, that the effect of clearing stratus decks was shown soon after the project was underway, and that the seeding experiments thereafter became more of a "program of advocacy than of objective proof." The project * * failed to demonstrate that seeding of cumulus clouds increased rainfall, that seeding initiates self -propagating storms, that the atmosphere responds periodically to periodic seeding, or that a hurricane could be deflected in its path by seeding." 69
Seeding under Project Cirrus ended in 1951 and the final report appeared in 1953. After the close of the project, Langmuir continued his analyses and wrote two more papers before his death in 1957. The final paper was titled "Freedom — the Opportunity To Profit From the Unexpected." a report that Byers feels provided a fitting philosophical close to his career.70 The Defense Department sponsored another series of experiments, called the Artificial Cloud Xucleation Project, from 1051 to 1953.
Tlie Weather Bureau Cloud Physics project
Amid increasing publicity and spectacular claims of results from cloud seeding in Project Cirrus, the U.S. Weather Bureau initiated in 1048 a project to test cloud seeding, with the cooperation of the Na- tional Advisory Committee for Aeronautics, the Navy, and the Air Force. The Cloud Phvsics Project, the first systematic series of seeding experiments in stratiform and cumuliform clouds, continued for 2 years, with flight operations in Ohio, California, and the Gulf States. Findings of Project Cirrus were substantiated in that striking visual cloud modifications occurred: however, there was no evidence to show spectacular precipitation effects, and the experiments led to a conserva- tive assessment of the economic importance of seeding.71 Cloud dissi- pation rather than new cloud development seemed to be the general result from seeding, the only precipitation extractable from clouds was that contained in the clouds themselves, and cloud seeding methods did not seem to be promising for the relief of drought.72
Bosults of the cloud physics experiment had almost no effect on the prevalent enthusiasm at the time for rainmaking through cloud soedino-, oxcent in the "hard core" of the meteorology community.73 As r result of thes<* experiments and the interpretation of the results, the TToather Bureau and its successor organizations in the Commerce Department, the Environmental Science Services Administration and the "National Oceanic and Atmospheric Administration, have been
os Brier. Glenn W.. "Seven-Dar Periodicities in May 19.~2." Bulletin of the American Me^eorolosricPl Societr. vol. 35. No. 3. March 1954. pp. 118-121. p? B^ers. "History of Weather Modification." 1974. pp. 20-21. 70 Ibid., p. 20..
" Flpfisrle. Robert G.. "Background and Present Status of Weather Modification." 196S. pp 0-10.
■2 B-ers. "^'storv of Weather Modification." 1074. pp. 10-17. »» Ibid,, p. 17.
42
regarded by some critics as unimaginative and overconservative on weather modification.74
The U.S. experiments of 1953-54
In 1951 the Weather Bureau, the Army, the Navy, and the Air Force appointed an advisory group, chaired by Dr. Sverre Petterssen of the University of Chicago, under whose advice and guidance the following six weather modification projects were initiated : 75
1. Seeding of extratropical cyclones, sponsored by the Office of Naval Research and conducted by Xew York University.
2. Seeding of migratory cloud systems associated with fronts and cyclones, conducted by the Weather Bureau.
3. Treatment of connective clouds, supported by the Air Force and conducted by the University of Chicago.
4. Research on the~dissipation of cold stratus and fog, conducted by the Army Signal Corps.
5. Studies of the physics of ice fogs, sponsored by the Air Force and conducted by the Stanford Research Institute.
6. Investigation of a special warm stratus and fog treatment svs- tem, sponsored by the Army and conducted by Arthur D. Little, Inc.
Field experiments on these projects were carried out in 1953 and 1954, and reports were published under the auspices of the American Meteorological Society in 195T.76
The purpose of the extratropical cyclone seeding project, called Project Scud, was to "* * * ascertain whether or not it would be possible to modify the development and behavior of extratropical cyclones by artificial nucleation. * * *" 77 Analysis obtained in Scud from Florida to Long Island showed that "* * * the seeding in this experiment failed to produce any effects which were large enough to be detected against the background of natural meteorological variance." 7S
The Weather Bureau project on migratory cloud systems was con- ducted in western Washington on cloud systems that enter the area from the Pacific during the rainy winter months. This project was criticized by commercial seeders since it was conducted in the West, which was considered "their territory," and by those who accused the Weather Bureau of seeking a negative result to support their conserva- tive view toward weather modification. Byers feels that there was an attempt to avoid this negative impression by giving a more positive interpretation to the results than the data possibly justified.79 In sum- marizing results. Hall stated:
Considering the results as a whole there is no strong evidence to support a con- clusion that the seeding produced measurable changes in rainfall. * * * the eval- uations do not necessarily furnish information on what the effect might have been with more or less intense seeding activity, rate of release of dry ice, etc. Also it
71 Pleagle. "Background and Present Status of Weather Modification.'' 1998, p 10»
« Byers, "History of Weather Modification," 1074. p. 25.
7.) Prtterssen, Sverre. Jerome Sp;ir. Ferguson Hall. Roscoe R. Braham. Jr., Louis J. Rat- tan. Horace R. Byers, H. J. aufm Kamoe. J. J. Kelly, and H. K. Welcfcraann. "Cloud and Weather Modification; a Croup of Field Experiments." Meteorological Monographs, vol. 2. No 11 American Meteorological Society, Boston. 10."»7. Ill pp.
"Petterssen, Sverre. "Reports on Experiments with Artificial Cloud Nucleation: Intro- ductory Note." In Petterssen et al . "Cloud and Weather Modification : ii Croup of Field
Experiments," Meteorological Monographs, vol. 2. No. n. American Meteoroio.^icnl Society. Boston. 1957, p, S.
T" Spar. Jerome "Prolecl Send." in Petterssen et al.. "Cloud mid Weather Modification ; :i Group of Field Experiments." Meteorological Monojrra plis. vol. 2. No. 11. American Mete- orological Society, P.oston. ior>7, n 22.
"Byers. "History of Weather Modification," 1074. p. 26.
43
might be speculated that the seeding increased rainfall on some occasions and decreased it on others.80
The aim of the University of Chicago Cloud Physics project was as follows : 81
The formulation of a consistent and immediately applicable picture of the processes of formation of cumulus clouds, charged centers, and precipitation with a view toward testing the possibility that one can modify these processes and influence the natural behavior of clouds.
So that as many cumulus clouds as possible could be tested, work was conducted in the Middle West in the summer and in the Caribbean in the winter, realizing that the warm trade-wind cumulus clouds in the latter region might be amenable to seeding with large hygroscopic nuclei or water spray, and that the ice-crystal process would operate to initiate precipitation in the colder clouds of the Middle West.82, Of the numerous conclusions from this project 83 a few will serve to indicate the value of the project to the understanding of cloud phenomena and weather modification. In the Caribbean tests, water spray from an air- craft was seen to increase rainfall as determined by radar echoes ; anal- ysis showed that the treatment doubled the probability of occurrence of a radar echo in a cloud. From tests on dry ice seeding in the Middle West it was found that in the majority of cases treated clouds showed an echo, while untreated ones did not, although the sample was consid- ered too small to be significant. In all cases clouds were considered in pairs, one treated by seeding and the other untreated, and only those clouds showing no echo initially were chosen for study.84
The seeding experiments with supercooled stratus clouds by the Army Signal Corps essentially substantiated the results of Project Cirrus; however, from these carefully conducted tests a number of new relationships w^ere observed with regard to seeding rates, spread of glaciating effect, cloud thickness, overseeding, and cloud formation after seeding.S5 The report on this project carefully summarized these relationships and conclusions for both dry ice and silver iodide seeding.86
The Air Force project on the physics of ice fogs, conducted by Stanford Research Institute, was intended to learn the relationship to such fogs of synoptic situations, local sources of water, and pollu- tion. Investigations in Alaska at air bases showed that most fogs developed from local sources of water and pollution. In the Arthur L). Little investigation for the Army attempts were made to construct generators which were capable of producing space charges, associated with aerosols, that could bring about precipitation of the water drop- lets in warm fogs and stratus.87
» Hail, Ferguson. "The Weather Bureau ACN Project." In Petterssen et al., "Cloud and Weather Modification ; a Group of Field Experiments," Meteorological Monographs, vol. 2. No. 11. American Meteorological Society. Boston. 1957. pp. 45-46.
slBraham. Roscoe R., Jr.. Louis J. Battan. and Horace R. Byers. "Artificial Nucleation of Cumulus Clouds." In Petterssen et al.. "Cloud and Weather Modification : a Group of Field Experiments," 1957, p. 47.
& Byers, "History of Weather Modification," 1974, pp. 26-27.
83 Conclusions are precisely spelled out in somewhat technical terms in : Braham, Battan. and Byers. "Artificial Nucleation of Cumulus Clouds," 1957, pp. S2-S3. fi Byers, "History of Weather Modification," 1974, p. 27.
86 IMd. . » ,
86aufm Kampe, H. J., J. J. Kelly, and H. K. Weickmann, "Seeding Experiments m Sub- cooled Stratus Clouds." In Petterssen et al.. "Cloud and Weather Modification : a Group of Field Experiments." Meteorological Monographs, vol. 2, No. 11. American Meteorological Society. Boston, 1957, p. 93. , T . , .
57 Petterssen, "Reports on Experiments With Artificial Cloud Nucleation: Introductory Note," 1957, p. 4.
44
Brers, in retrospect, wonders why the results of this series of six experiments, which were carefully controlled statistically, did not receive more attention than was accorded them. He attributes some of this lack of visibility to the publication in the somewhat obscure monograph of the American Meteorological Society 88 and to the delay in publishing the results, since the Petterssen committee held the manu- scripts until all were completed, so that they could be submitted for publication together.89
Arizona mountain cumulus experiments
After 1954, the University of Chicago group joined with the Insti- tute of Atmospheric Physics at the University of Arizona in seeding tests in the Santa Catalina Mountains in southern Arizona. These experiments were conducted in two phases, from 1957 through 1960 and from 1901 through 1964, seeding mostly summer cumulus clouds, but some winter storms, with silver iodide from aircraft. In the first phase, analysis of precipitation data from the first 2 years revealed more rainfall during seeded than on nonseeded days ; however, during the latter 2 years, considerably more rainfall was achieved on non- seeded days. Combining all data for the 4 years of the first phase yielded overall results with more rain on unseeded days than on seeded days; hence, the experiments were modified and the second phase undertaken. Of the 3 years in the second phase, only one showed more rain on seeded days than on nonseeded ones. None of the analyses attempted could support the hypothesis that airborne silver iodide seeding increased precipitation or influenced its area! extent. Byers suggests that the failure to increase rainfall may have been due to the fact that precipitation initiation resulted from the coalescence process rather than the ice-crystal process.90
Project Whitetop
According to Byers, perhaps the most extensive and most sophisti- cated weather modification experiment (at least up to the time of Byers' historical review in 1973) was a 5-year program of summer convective cloud seeding in south-central Missouri, called Project Whitetop. Conducted from 19G0 through 1964 by a group from the University of Chicago, led by Dr. Roscoe 11. Braham, the purpose of Whitetop was to settle with finality the question of whether or not summer convective clouds of the Midwest could be seeded with silver iodide to enhance or initiate precipitation. Experimental days were divided into seeding and no seeding days, chosen randomly from operational days suitable for seeding, based on certain moisture cri- teria. Another feature of the project was the attempt to determine the extent of spreading of silver iodide smoke plumes from the seeding line. Precipitation effects were evaluated by radar and by a rain-gage network.01
Final analysis of all of the Project Whitetop data showed that the overall effect was that, in the presence of silver iodide nuclei, the rain- fall was less than in the unseeded areas. Byers attributes these negative
88 Petterssen et al.. "Cloud and Weather Modification; a Group of Field Experiments," 1957.
*> livers. "History of Weather Modification," 11)74, p. 2S.
»° Il)ld., p. 29.
« Ibid., pp. 20-30.
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results to the physical data obtained from cloud-physics aircraft. "Most of the Missouri clouds produced raindrops by the coalescence process below the freezing line, and these drops were carried in the updrafts and frozen as ice pellets at surprisingly high subf reezing temperatures ( — 5° C to —10° C)." He further points out that the measured con- centrations of ice particles, for the range of sizes present, were already in the natural unseeded conditions equivalent to those hoped for with seeding; consequently, the silver iodide only had the effect of over- seeding.92
Climax experiments
Following the initial General Electric experiments, it was concluded by Bergeron 93 that the best possibility for causing considerable rain- fall increase by artifical means might be found in seeding orographic 94 cloud systems. Consequently, there were almost immediate efforts to increase orographic precipitation, the greatest concentration of such work being in the Western United States. Commercial groups such as power companies and irrigation concerns took the early initiative in attempts to augment snowfall from orographic cloud systems in order to increase streamflow from the subsequent snowmelt.
Colorado State University (CSU) began a randomized seeding experiment in the high Rocky Mountains of Colorado in 1960, under the direction of Lewis O. Grant, to investigate snow augmentation from orographic clouds. The project was designed specifically to (1) evaluate the potential, (2) define seedability criteria, and (3) de- velop a technology for seeding orographic clouds in central Colorado.95 It followed the 1957 report of the President's Advisory Committee for Weather Control, in which it had been concluded that seeding of oro- graphic clouds could increase precipitation by 10 to 15 percent, basing this judgment, however, on data from a large number of seeding pro- grams that had not been conducted on a random basis.96
The first group of the CSU seeding experiments took place from 1960 to 1965 in the vicinity of Climax, Colo., and has been designated Climax I. A second set of tests in the same area from 1965 to 1970 has been referred to as Climax II. The Climax experiments are impor- tant in the history of weather modification because they were the first intensive projects of their kind and also because positive results were reported.97 The precipitation for all seeded cases was greater than for all of the unseeded cases by 9, 13, and 39 percent, respectively, for Climax I, Climax II, and Climax IIB. The latter set of data are a subsample of those from Climax II, from which possibly contaminated cases due to upwind seeding by other groups were eliminated.98
Ibid., p. 30.
93 Bergeron, Tor, "The Problem of an Artificial Control of Rainfall on the Globe ; General Effects of Ice Nuclei in Clouds." Tellus, vol. 1, No. 1, February 1949, p. 42.
94 A definition of orographic clouds, a discussion of their formation, and a summary of attempts to modify them are found in ch. 3, p. 71 ff.
95 Grant, Lewis O., and Archie M. Kahan, "Weather Modification for Augmenting Oro- graphic Precipitation." In Wilmot N. Hess (editor), "Weather and Climate Modification," New York, Wiley, 1974, p. 295.
98 Advisory Committee on Weather Control. Final Report of the Advisory Committee on Weather Control, Washington, D.C., U.S. Government Printing Office, Dec. 31, 1957, vol. I, p. vi. (The establishment of the Advisory Committee and its activities leading to publica- tion of its final report are discussed in ch. 5, under activities of the Congress and of the executive branch of the Federal Government, see pp. 195. 214, and 236.)
97 Byers, "History of Weather Modification," 1974, pp. 30-31. „
98 Grant and Kahan, "Weather Modification for Augmenting Orographic Precipitation, 1974, p. 298.
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Lightning suppression experiments
From 1947 until the close of Project Cirrus, interspersed with his other activities, Vincent Schaefer visited U.S. Forest Service instal- lations in the northern Rockies in order to assist in attempts to sup- press lightning by cloud seeding. As early as 1949 an attempt was made to seed thunderstorm clouds with dry ice, dumping it from the open door of a twin-engine aircraft flying at 25,000 feet." This stimulated curiosity among those involved, but also showed that light- ning-prevention research wTould require a long and carefully planned effort. These early activities led to the formal establishment of Proj- ect Skyfire in 1953, aimed at lightning suppression, as part of the overall research program of the Forest Service. Throughout the his- tory of the project, research benefited from the cooperation and sup- port of many agencies "and scientific groups, including the National Science Foundation, the Weather Bureau, Munitalp Foundation, the Advisory Committee on Weather Control, the National Park Service, General Electric Research Laboratories,