WASHINGTON — Drip, drip, drip come the studies one after another, reinforcing the threat to the Northeast from rising sea levels along the U.S. and Canadian east coast.

If Greenland's ice melts at moderate to high rates, ocean circulation by 2100 could shift and cause sea levels off the Northeast coast of North America to rise by about 12 to 20 inches more than other coastal areas, researchers report Wednesday in Geophysical Research Letters.

"Major northeastern cities are directly in the path of the greatest rise," researcher Aixue Hu of the National Center for Atmospheric Research said.

The report comes on the heels of two other studies with similar warnings.

• Just over a week ago scientists at Britain's University of Bristol reported that while collapse of the West Antarctic Ice Sheet would not raise global sea levels as much as had previously been feared, the maximum increase is expected along the East and West Coasts of the USA.

• And in March, researchers at the University of Maryland warned that, however much the oceans rise by the end of the century, add an extra eight inches or so for New York, Boston and other spots along the coast from the mid-Atlantic to New England because of predicted changes in ocean currents.

The Intergovernmental Panel on Climate Change in 2007 projected that sea levels worldwide could rise by an average of seven to 23 inches this century.

"The oceans will not rise uniformly as the world warms," NCAR scientist Gerald Meehl, a co-author of the new paper, said in a statement. "Ocean dynamics will push water in certain directions, so some locations will experience sea level rise that is larger than the global average."

In recent years, the melting of the Greenland ice cap has been increasing at a rate of about 7% per year. The researchers calculated the sea level impact if that were to continue and also if the increase declined to 3% or 1% annually.

At the middle or 3% rate, the Northeast would see an extra foot of sea level rise because of ocean circulation changes, in addition to the global sea level increase, they reported.

A drop to 1% would mean eight additional inches of water in the Northeast, and a continued 7% increase would result in an extra 20 inches, the new study said.

The research was supported by the U.S. Department of Energy, National Science Foundation and NASA.

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