Two manmade pollutants known best as threats to human health have just been charged with two more offenses: shifting rainfall patterns and mucking with food production. Black carbon and tropospheric ozone, both of which derive from the incomplete burning of fossil fuels, may be working in cahoots with greenhouse gases to expand Earth's tropical belt (image).
Two manmade pollutants known best as threats to human health have just been charged with two more offenses: shifting rainfall patterns and mucking with food production.
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Black carbon and tropospheric ozone, both of which derive from the incomplete burning of fossil fuels, may be working in cahoots with greenhouse gases to expand Earth's tropical belt (highlighted above in red).
Unabated, future expansion could drive major shifts in global precipitation patterns, which could in turn disrupt regional agriculture, warns climatologist Robert J. Allen of the University of California, Riverside.
When the tropics widen, wind patterns shift toward the poles, dragging important mid-latitude storm tracks along with them. If storm systems move farther north, for example, southern portions of the U.S. and Asia could become drier, Allen explained in an article published in UCR Today.
Based on comprehensive new climate simulations, Allen and his colleagues reported in Nature that black carbon and tropospheric ozone are the most likely primary drivers of the tropical expansion observed in the Northern Hemisphere. (In the Southern Hemisphere, the main culprit is depletion of stratospheric ozone.)
Article continues at Discovery News
Image credit: Robert J. Allen / UC Riverside
