Rising waterMelting Greenland ice threatens northeast U.S., Canada
The melting of Greenland’s ice sheets is driving more and more water toward the already threatened coastlines of New York, Boston, Halifax, and other cities in the northeastern United States
Melting of the Greenland ice sheet this century may drive more water than previously thought toward the already threatened coastlines of New York, Boston, Halifax, and other cities in the northeastern United States and in Canada, according to new research led by the National Center for Atmospheric Research (NCAR).
A study published Friday in Geophysical Research Letters finds that if Greenland’s ice melts at moderate to high rates, ocean circulation by 2100 may shift and cause sea levels off the northeast coast of North America to rise by about 12 to 20 inches (about 30 to 50 centimeters) more than in other coastal areas. The research builds on recent reports that have found that sea level rise associated with global warming could adversely affect North America, and its findings suggest that the situation is more threatening than previously believed.
“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,” says NCAR scientist Aixue Hu, the lead author. “Major northeastern cities are directly in the path of the greatest rise.”
A study in Nature Geoscience in March warned that warmer water temperatures could shift ocean currents in a way that would raise sea levels off the Northeast by about 8 inches (20 cm) more than the average global sea level rise. That study did not include the additional impact of Greenland’s ice, which at moderate to high melt rates would further accelerate changes in ocean circulation and drive an additional 4 to 12 inches (about 10 to 30 cm) of water toward heavily populated areas in northeastern North America on top of average global sea level rise. More remote areas in extreme northeastern Canada and Greenland could see even higher sea level rise.
Scientists have been cautious about estimating average sea level rise this century in part because of complex processes within ice sheets. The 2007 assessment of the Intergovernmental Panel on Climate Change projected that sea levels worldwide could rise by an average of 7 to 23 inches (18 to 59 cm) this century, but many researchers believe the rise will be greater because of dynamic factors in ice sheets that appear to have accelerated the melting rate in recent years.
The new research was funded by the U.S. Department of Energy and by NCAR’s sponsor, the National Science Foundation. It was conducted by scientists at NCAR, the University of Colorado
