Posted November 7, 2013; 10:00 a.m. by Morgan Kelly, Office of Communications, News at Princeton
In research meant to highlight how the destruction of the Amazon rainforest could affect climate elsewhere, Princeton University-led researchers report that the total deforestation of the Amazon may significantly reduce rain and snowfall in the western United States, resulting in water and food shortages, and a greater risk of forest fires.
The researchers report in the Journal of Climate that an Amazon stripped bare could mean 20 percent less rain for the coastal Northwest and a 50 percent reduction in the Sierra Nevada snowpack, a crucial source of water for cities and farms in California. Previous research has shown that deforestation will likely produce dry air over the Amazon. Using high-resolution climate simulations, the researchers are the first to find that the atmosphere’s normal weather-moving mechanics would create a ripple effect that would move that dry air directly over the western United States from December to February.
Princeton University-led researchers report that the total deforestation of the Amazon may significantly reduce rain and snowfall in the western United States, including a 50 percent reduction in the Sierra Nevada snowpack that is a crucial source of water for cities and farms in California. The simulation showed that the water equivalent of the snowpack by April 1 decreased in range and depth from pre-deforestation levels (left) when the Amazon was cleared (right). The depth is measured in centimeters with the redder areas indicating more snow.(All images by David Medvigy, Department of Geosciences)
Specifically, a denuded Amazon would develop a weather cycle consisting of abnormally dry air in the sun-scorched northern Amazon around the equator weighted by wetter air in the cooler south. Research has speculated that this pattern would be similar to the warm-water climate pattern El Niño, which during the winter months brings heavy precipitation to southern California and the Sierra Nevada region while drying out the Pacific Northwest.
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