How to make it rain: Cloud seeding to combat drought
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With cloud seeding, small particles of silver iodide, a salt with a crystalline structure similar to that of ice, are added to clouds. This process can be performed either from a plane or drone, or particles can be shot up from the ground.
The method allows the water vapor inside clouds to be "tricked" into forming droplets around the silver iodide particles, Jose Miguel Vinas, a meteorologist with Meteored, a Spanish company that runs weather websites in several countries, told DW.
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The way the process works explains why Beijing is currently struggling to cloud seed: There is a need for at least some clouds to already be in the parts of the sky where you want to induce rain, and some of the regions in China that need water most desperately don't have enough cloud cover for the method to work. Humans still cannot create rain clouds out of thin air.
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"If you make it rain one place then you reduce rain downstream," said professor of applied physics at Harvard University David Keith, whose research focuses on the intersection of climate science, technology and policy. He likened the process to "robbing Peter to pay Paul."
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