Cutting short-lived pollutants slows sea level rise

WASHINGTON, April 14 (Xinhua) -- U.S. scientists said on Sunday that it's possible to greatly slow down sea level rise this century, by cutting emissions of so-called short-lived pollutants that cycle comparatively quickly through the atmosphere.

The study, published in the journal Nature Climate Change, found that a sharp reduction in four pollutants beginning in 2015, namely, methane, tropospheric ozone, hydrofluorocarbons, and black carbon, could offset warming temperatures by up to 50 percent by 2050, and reduce sea level rise by 22 to 42 percent by the end of the century.

However, the new study also found that delaying emissions cuts until 2040 would reduce the beneficial impact on the year 2100 sea level rise by about a third.

The researchers used mostly percentage changes for sea level rise, rather than actual estimates in centimeters, because of uncertainties over future temperature increases and their impacts on rising sea levels.

"It is still not too late, by stabilizing carbon dioxide concentrations in the atmosphere and reducing emissions of shorter-lived pollutants, to lower the rate of warming and reduce sea level rise," said Veerabhadran Ramanathan of the Scripps Institution for Oceanography, who led the study.

"The large role of the shorter-lived pollutants is encouraging since technologies are available to drastically cut their emissions."

The potential impact of rising oceans on populated areas is one of the most concerning effects of climate change. Many of the world's major cities, such as New York, Miami, Amsterdam, Mumbai, and Tokyo, are located in low-lying areas by the water.

As glaciers and ice sheets melt and warming oceans expand, sea levels have been rising by an average of about 3 millimeters annually in recent years. If temperatures continue to warm, sea levels are projected to rise between 18 and 59 centimeters this century, according to a 2007 assessment by the Intergovernmental Panel on Climate Change.