Geoengineering attempts to reduce global warming could reduce rainfall

Attempts to geoengineer the climate to reduce greenhouse gases in the atmosphere could reduce vital rains in some parts of the world, U.S. scientists say. A technological approach to reducing future global warming could also interfere with rainfall and snowfall, an international study led by scientists at the National Center for Atmospheric Research in Boulder, Colo., found. Global warming caused by a massive increases in greenhouse gases could spur a nearly 7 percent average increase in precipitation compared to preindustrial conditions, the scientists said, but trying to resolve the problem through geoengineering could result in vital monsoonal rains in North America, East Asia and other regions dropping by 5-7 percent compared to preindustrial conditions, and average precipitation could decrease by about 4.5 percent globally, they said. "Geoengineering the planet doesn't cure the problem," NCAR scientist Simone Tilmes, the study's lead author, said. "Even if one of these techniques could keep global temperatures approximately balanced, precipitation would not return to preindustrial conditions." Some proposed geoengineering approaches to reduce future warming would capture carbon dioxide before it enters the atmosphere, while others would attempt to shade the atmosphere by injecting sulfate particles into the stratosphere or launching mirrors into orbit with the goal of reducing global surface temperatures. "It's very much a pick-your-poison type of problem," NCAR scientist and study co-author John Fasullo said. "If you don't like warming, you can reduce the amount of sunlight reaching the surface and cool the climate. But if you do that, large reductions in rainfall are unavoidable. There's no win-win option here."