Greenland ice could fuel severe U.S. sea level rise

By Deborah Zabarenko, Environment Correspondent

WASHINGTON (Reuters) - New York, Boston and other cities on North America's northeast coast could face a rise in sea level this century that would exceed forecasts for the rest of the planet if Greenland's ice sheet keeps melting as fast as it is now, researchers said on Wednesday.

Sea levels off the northeast coast of North America could rise by 12 to 20 inches more than other coastal areas if the Greenland glacier-melt continues to accelerate at its present pace, the researchers reported.

This is because the current rate of ice-melting in Greenland could send so much fresh water into the salty north Atlantic Ocean that it could change the vast ocean circulation pattern sometimes called the conveyor belt. Scientists call this pattern the meridional overturning circulation.

"If the Greenland melt continues to accelerate, we could see significant impacts this century on the northeast U.S. coast from the resulting sea level rise," said Aixie Hu, lead author of an article on the subject in the journal Geophysical Research Letters.

"Major northeastern cities are directly in the path of the greatest rise," said Hu, a scientist at the National Center for Atmospheric Research in Boulder, Colorado.

This is an even bleaker assessment than an earlier study indicated. A March article in the journal Nature Geoscience said warmer water temperatures could shift ocean currents so as to raise sea levels off the U.S. northeast coast by about 8 inches more than the average global sea level rise.

NOT LIKELY BUT POSSIBLE

However, this earlier research did not include the impact of melting Greenland ice, which would speed changes in ocean circulation and send 4 to 12 more inches of water toward northeastern North America, on top of the average global sea level rise.