[font face=Serif][font size=5]Climate benefit for cutting soot, methane smaller than previous estimates[/font]

August 12, 2013

Mary Beckman, PNNL, (509) 375-3688
Frances White, PNNL, (509) 375-6904

[font size=4]PNNL study: Focus on all greenhouse gases needed to limit climate change[/font]

[font size=3]RICHLAND, Wash. – Cutting the amount of short-lived, climate-warming emissions such as soot and methane in our skies won't limit global warming as much as previous studies have suggested, a new analysis shows. The study also found a comprehensive climate policy (including methane) would produce more climate benefits by 2050 than if soot and methane were reduced alone.

"Cutting back only on soot and methane emissions will help the climate, but not as much as previously thought," said the study's lead author, climate researcher Steve Smith of the Department of Energy's Pacific Northwest National Laboratory. "If we want to stabilize the climate system, we need to focus on greenhouse gases such as carbon dioxide, nitrous oxide and methane. Concentrating on soot and methane alone is not likely to offer much of a shortcut."

The new study is being published this week in Proceedings of the National Academy of Sciences Early Edition online. Smith works at the Joint Global Change Research Institute in College Park, Md., a joint venture between PNNL and the University of Maryland.

At least two studies have been published since 2010 that suggest reducing soot and methane would cut human-caused global temperature increases by half of a degree Celsius, or about 1 degree Fahrenheit, by 2050. International leaders took note and formed the Climate and Clean Air Coalition to Reduce Short-Lived Climate Pollutants in 2012.

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