article: With a 'megadrought' forecast to hit the US in the coming decades, parched states are turning to increasingly radical solutions to fill their reservoirs. Arizona is leading the way with plans to create artificial rain clouds by flying planes over the Rockies and seeding the sky with silver iodide. They hope the technology will allow them to mitigate some of the worst impacts of climate change – but not everyone is convinced. With a 'megadrought' forecast to hit the US in the coming decades, parched states are turning to increasingly radical solutions to fill their reservoirs. Arizona is leading the way with plans to create artificial rain clouds by flying planes over the Rockies, and seeding the sky with silver iodide . The process of cloud seeding was first proposed in the 1940s at the General Electric labs in Schenectady, New York. Two decades later, the Central Arizona Project and the Salt River Project invested in research to make it a reality. 'It hasn't been taken off the table as a potential tool as we work our way through drought now and in the future,' Nancy Selover, Arizona's state climatologist told Becky Brisley at Cronkite News. Since 2007, CAP has put about $1 million toward research happening in other states to increase the supply of water in the Colorado River system. Water in the air, even in dry areas, can be transformed into ice crystals by using planes to seed the atmosphere with chemicals such as silver iodide or dry ice . If it seems like it never stops raining, blame the Russians. Or even the North Koreans. CIA chiefs fear hostile nations are trying to manipulate the world's weather, a conference heard in February. A leading academic told how he got a mysterious phone call asking whether foreign countries could be triggering droughts or flooding. Professor Alan Robock, from Rutgers University in New Jersey, said: 'Consultants working for the CIA rang and said we'd like to know if someone is controlling the world's climate would we know about it? 'Of course they were also asking - if we control someone else's climate would they then know about it.' The professor is one of many scientists from around the world are actively looking at manipulating the weather as a way of combating climate change. Professor Robock told the callers that any attempts to meddle with the weather on a large scale would be detectable. The system works on the premise that rainfall takes place when supercooled droplets of water form ice crystals. As a result they become too heavy to remain suspended in the air, and fall, often melting on their way down to form rain. Water in the air, even in dry areas, can be transformed into ice crystals by seeding the atmosphere with chemicals such as silver iodide or dry ice. They create rain by inducing nucleation – a process in which water is in the air condenses around the particles and crystallises to form ice. But some scientists are concerned about silver building up in river basins, as well as legal uncertainties over who should get the additional water. Compared to other alternatives, such as desalinating seawater, cloud seeding is the cheapest option, though it isn't going to be a drought-buster on its own. In a recent Wyoming Weather Modification pilot project, the technology resulted in an increase of seasonal snow water accumulations of 5 to 15 per cent. But Selover, the state climatologist, told Cronkite News that the trickiest part of cloud seeding is measuring whether an area got more rainfall. 'So the effectiveness of it is in doubt,' she said. 'It's not that it's completely ineffective – they're pretty sure it has some impact – but it's pretty hard to measure.' Some scientists are concerned about silver building up in river basins, as well as legal uncertainties over who should get the additional water. Pictured is Lake Powell, near Page, Arizona .
highlights: Central Arizona Project invested $1 million to research cloud seeding .
  Process involves seeding clouds over the Rockies with silver iodide .
  Some scientists are concerned about silver building up in river basins .
  There are also legal uncertainties over who should get additional water .
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