Cloud seeding, a controversial technology that artificially stimulates rainfall, is being applied at 62 municipalities in Mexico to mitigate the effects of the extreme drought affecting the country. 

The technology, discovered over 70 years ago, uses planes or drones to inject silver iodide particles into clouds which attract water droplets from around them, increasing the chance of rainfall. 

CNN reports that some scientists are skeptical about the method’s effectiveness, indicating that it is not a solution for drought. 

“It has a controversial history because it’s very difficult to prove what you are doing from a scientific perspective,” Roelef Bruintjes, a weather modification scientist at the National Center for Atmospheric Research in the US, told CNN.

The technology is “not a drought-busting tool,” Bruintjes adds because during a drought, there is often an absence of clouds. “And that’s the one thing we cannot do. We cannot make a cloud.”

Method and application in Mexico

The substance sprayed on the clouds is composed of silver iodide molecules cooled in acetone, which generates condensation nuclei that generate rainfall precipitation and is a 100% Mexican and environmentally friendly technology, explain the technicians of the National Commission of Arid Zones (Conaza) with the support of the Secretariat of National Defense who are leading the project. 

The program will be applied in 10 producing regions of the country: Sonora, Sinaloa, Durango, Zacatecas, Chihuahua, Aguascalientes, Baja California, Baja California Sur, Coahuila, and Tamaulipas, as well as La Laguna.

Since December 2020 when the Mexican cloud seeding project started running, the government says it’s shown positive results, with 40% more rain created in 2021 where 71 out of the 72 flights conducted registered rain. 

These figures are calculated by measuring the difference between meteorological forecasts and actual rainfall measured by rain gauges.

Additionally, the Mexican government informs that the technology not only benefits rainfed agriculture, trees and water bodies, but it also helps to combat wildfires which are becoming more and more common during summer seasons.