April 8, 2009

NASA: Aerosols may cause arctic warming

U.S. space agency scientists say they've determined aerosols can influence climate by either reflecting or absorbing the sun's radiation in the atmosphere.

National Aeronautics and Space Administration researchers said such aerosols -- tiny airborne particles -- enter the Earth's atmosphere from both natural and human sources such as industrial pollution, volcanoes and residential cook stoves. The scientists said much of the atmospheric warming observed in the Arctic since 1976 might be due to such aerosols.

The researchers, led by climate scientist Drew Shindell at NASA's Goddard Institute for Space Studies in New York, said they used a coupled ocean-atmosphere model to investigate how sensitive different regional climates are to changes in levels of carbon dioxide, ozone and aerosols.

They found the mid and high latitudes are especially responsive to changes in the level of aerosols, which likely account for 45 percent or more of the warming that has occurred in the Arctic during the last three decades.

The study is reported in the journal Nature Geoscience.