Weather Modification 



Both deliberate and inadvertent weather modifications are possible today. Po- 

 tential benefits and potential risks are great and raise grave social, legal, eco- 

 nomic, and jusisdictional issues. In this section NACOA discusses the effort it be- 

 lieves desirable in: legislation to define rights, responsibilities, and a sense of 

 purpose; research to hasten and extend our abilities to reduce risks; and in- 

 ternational agreement to promote peaceful uses of weather modification and to 

 eschew its hostile uses. 



ON THE THRESHOLD OF ENVIRONMENTAL CONTROL 



NACOA is persuaded that we stand on the threshold of a new era 

 of environmental control. The scientific literature indicates today, that 

 under certain limited conditions, man can increase or decrease rainfall, 

 increase or decrease snowpack in the mountains, and clear fogs over run- 

 ways and highways. Claims of suppressing hail in the Soviet Union are 

 impressive. A large-scale effort is now being mounted to develop better 

 methods of hail suppression in the United States. The capabiHty to di- 

 minish the force of a hurricane (though not the ability to steer it) seems 

 to be near at hand. Further research and development make it likely that 

 some of today's limitations will soon be removed and man may before long 

 deliberately exert an even greater influence on the weather. These develop- 

 ments require our serious attention now. 



Our ability to treat these problems has been increased by advances in 

 mathematical modeling of atmospheric processes, increases in the speed 

 and capacity of computers on which these models are run, and new forms 

 of instrumentation. Delivery systems for cloud seeding (rockets, land-based 

 and airborne nuclei generators) and predictive methods for local meteo- 

 rological conditions are being rapidly developed. These advances make 

 possible methods of measurement and diminish the reliance on a long 

 expensive series of statistical observations which seek to filter a faint signal 

 from a large background "noise." The result is an acceleration of the en- 

 tire field. 



19 



