Climate change models may be inaccurate

PHOENIX, Aug. 11 (UPI) -- U.S. scientists say they've discovered some measures used in atmospheric science overlook important factors affecting climatic warming and cooling.

The Arizona State University researchers led by Associate Professor Peter Crozier said their discovery could lead to more accurate forecasting of global-warming activity.

Crozier, along with Ira Fulton and Duncan Alexander, studied nanoscale atmospheric aerosols called brown carbons, which they said are largely being ignored in climate computer models in favor of carbon dioxide and other greenhouse gases.

But the researchers say there are other atmospheric components that can also contribute to climate change -- including carbonaceous and sulfate particles from combustion of fossil fuels and biomass, salts from oceans and dust from deserts.

They said brown carbons from combustion processes are the least understood of all aerosol components, but their effect is complex because it both cools the Earth's surface and warms the atmosphere.

"Because of the large uncertainty we have in the radiative forcing of aerosols, there is a corresponding large uncertainty in the degree of radiative forcing overall," Crozier said. "This introduces a large uncertainty in the degree of warming predicted by climate change models."

The research appears in the Aug. 8 issue of Science magazine.