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Cuts in some greenhouse gases could slow sea level rise

Methane, ozone and other short-lived pollutants have a big impact on ocean heights

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6:19pm, April 12, 2013
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A quick way to stave off impending sea level rise is to cut emissions of short-lived climate warmers such as methane and soot, researchers suggest.  

Carbon dioxide, the main cause of anthropogenic climate change, can linger in the atmosphere for more than a century. So slashing CO2 output will not immediately halt global warming and its consequences. A faster way may be to limit methane, ozone, hydrofluorocarbons and soot, also known as black carbon. These greenhouse gases and particles warm the atmosphere but they stay aloft only weeks to years. Recent work showed that this approach may reduce the expected rise in global temperatures by 0.6 degrees Celsius by 2050.

A team led by Veerabhadran Ramanathan of the Scripps Institution of Oceanography in La Jolla, Calif., wondered whether cutting these four climate pollutants would also slow global sea level rise. Scientists expect sea levels to jump because of melting ice sheets and thermal expansion of the oceans. The researchers ran climate simulations in which emissions of these pollutants — or gases that ultimately produce the pollutants — shrank by 30 to 50 percent over the next few decades. Sea level rise dropped 10 percent by 2050 and 22 percent by 2100 compared with simulations without these cuts, the team reports April 14 in Nature Climate Change.

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