Manmade Pollutants May Be Driving Earth’s Tropical Belt Expansion
UC Riverside-led team identifies black carbon and tropospheric ozone as most likely drivers of large-scale atmospheric circulation change in the Northern Hemisphere tropics.
RIVERSIDE, Calif. — Black carbon aerosols and tropospheric ozone, both manmade pollutants emitted predominantly in the Northern Hemisphere’s low- to mid-latitudes, are most likely pushing the boundary of the tropics further poleward in that hemisphere, new research by a team of scientists shows.
While stratospheric ozone depletion has already been shown to be the primary driver of the expansion of the tropics in the Southern Hemisphere, the researchers are the first to report that black carbon and tropospheric ozone are the most likely primary drivers of the tropical expansion observed in the Northern Hemisphere.
Led by climatologist Robert J. Allen, an assistant professor of Earth sciences at the University of California, Riverside, the research team notes that an unabated tropical belt expansion would impact large-scale atmospheric circulation, especially in the subtropics and mid-latitudes.