The University of Colorado Boulder has announced that the university’s research into global warming has shown that volcanoes have helped suppress global temperatures since 2000.
Volcanoes’ sulfur dioxide emissions rise up to 20 miles into the stratospheric aerosol layer of the atmosphere. At such altitudes, chemical reactions form sulfuric acid and water particles that block sunlight from reaching the Earth’s surface.
Scientists used two sophisticated computer models—the Whole Atmosphere Community Climate Model, Version 3, and the Community Aerosol and Radiation Model for Atmosphere—that showed that the optical depth in the stratospheric aerosol layer has increased between 4 to 7 percent since 2000, meaning that the atmospheric transparency has decreased while its reflective properties have increased.
Image: Mount St. Helens, Washington (Credit: S.R. Brantley/USGS)