USA Today | Mar. 7, 2011
Long before the study of weather became scientific people tried to control the weather -- think of rain dances.
When the study of the atmosphere became scientific, people began looking for scientific understanding that would help them exercise at least some control over the weather.
From the late 1940s into the 1960s, the term "weather control" was sometimes used. But, scientists know that no one can "control" the weather. The best that can be done is to change the weather in small ways, such as squeezing a little more precipitation out of clouds than would have otherwise fallen. For a time the term "weather modification" was popular, but few use this term today.
The success of cloud seeding using silver iodide or other materials to increase the amount of precipitation from clouds led to the big interest in scientific weather control in the 1950s. It is the one technique of planned weather modification that has been shown to work, at least to some extent.
Chapter 5 of the USA TODAY Weather Book has quite a bit of information on the history of cloud seeding and how it works. (Related: Books about weather)
The Web sites below also have information:
The scientific basis of cloud seeding, on the Atmospherics, Inc. Web site.
Weather Modification by Cloud Seeding - A Status Report 1989-1997, by William Cotton of Colorado State University
The American Geophysical Union Web site has an extensive report on ''Progress in planned weather modification research: 1991-1994,'' which is a good introduction to the issues and the science involved.
Trying to control hurricanes
From 1961 into 1980 U.S. scientists conducted extensive research into the possibility of weakening hurricanes with cloud-seeding techniques. The project was known as Project Stormfury. While a clear-cut answer to whether hurricanes could be weakened wasn't found, the project made major contributions to hurricane research that are still helping to improve forecasts.