As the western U.S. continues to grapple with drought worsened by climate change, technology aimed at making it rain is attracting more attention. What’s known as “cloud seeding” is a decades-old practice of spraying special particles, like silver iodide, into the air to boost precipitation (with vastly varying outcomes). It’s one of the world’s most popular forms of weather modification, and it’s practiced across much of the western U.S,. as well as in China, Russia, parts of the Middle East and other countries. But now scientists are trying a new approach: electrically charged water particles, write POLITICO's E&E News reporters Chelsea Harvey and Corbin Hiar. Here’s how it works: As water droplets condense in the sky, they form clouds. The bottom of those clouds are naturally filled with negatively charged water. Hit the cloud with a stream of positively charged water particles and droplets will collide, coalesce and fall from the sky — at least that’s the theory. A big caveat: The jury is out about how well the technology works. That’s because it’s hard to test. Still, studies suggest that the practice may boost rainfall by as much as 20 percent. One 2017 study by a University of Colorado researcher in Idaho’s Payette River Basin estimated that clouds seeded over three days produced 286 Olympic-sized swimming pools’ worth of snow. Who’s investing: While cloud seeding is not a silver bullet, dry regions are increasingly turning to the technology for help. The Agriculture Department is conducting an ongoing experiment that seeded clouds over Texas last summer. Last March, a top Saudi Arabian oil company obtained a U.S. patent for generating rain to support precipitation in remote desert oil fields, where water is hard to come by. Drillers need water to test wells and increase oil production. The United Arab Emirates is another cloud seeding powerhouse, which makes sense given that the Middle East is heating up faster than the global average and precipitation is declining. In 2020, China announced plans to rapidly expand its weather modification program to encompass an area covering more than 2 million square miles. Cloud seeding can marginally increase water supplies in the American West, but it has its limits. For one thing, it requires clouds, making it less useful during droughts. “If I were a water manager, I would consider it,” Katja Friedrich, an atmospheric scientist, told Chelsea and Corbin. “But this is not the Holy Grail or what really solves all the problems.”
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