Wednesday, February 8, 2012

Cloud seeding -- uncertain solution for Mexico's drought

Emilio Godoy in IPS via Tierramérica: As half of Mexico endures one of the most severe droughts in its history, cloud seeding appears to be a promising way to bring desperately needed rain, although it remains a source of controversy. While some promote the benefits of cloud seeding, others insist that there is no solid evidence of its effectiveness, in addition to the fact that the potential effects on the air, water and soil of the chemicals used have not been sufficiently studied.

"The methodology is not proven; the investment made has not yielded any results that demonstrate that cloud seeding leads to more precipitation," Graciela Binimelis of the Atmospheric Sciences Centre at the public National Autonomous University of Mexico told Tierramérica. Binimelis, who holds a PhD in atmospheric sciences from the University of Washington, has studied the physics of clouds for more than two decades.

Cloud seeding involves the spraying of selected clouds with chemicals, usually silver iodide, either from aircraft or from the ground through the use of generators or rockets. This leads to the formation of ice crystals, which grow in size until they reach the necessary weight to fall in the form of rain at lesser altitudes. Silver iodide can cause possible residual injury to humans and mammals with intense or continued but not chronic exposure.

Cloud seeding is practiced along the border between the southern United States and northern Mexico, as well as in Argentina, Chile, Spain and China, the country that uses it most....

The Sonora Desert in Mexico, shot by Tomascastelazo - Tomas Castelazo, Wikimedia Commons, under the Creative Commons Attribution 3.0 Unported license

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