Studies suggest more rapid rise in sea level

WASHINGTON – Two new scientific studies measuring Greenland’s rapidly melting ice sheet and the pace of Antarctic snowfall suggest that the sea level may be rising faster than researchers previously assumed.

The papers, both published Thursday in the journal Science, provide the latest evidence of how climate change is transforming the global landscape. University of Texas researchers, using twin satellites, determined that the Greenland ice sheet, the Earth’s second largest reservoir of fresh water, is melting at a rate three times faster than during the previous five years. A separate study by 16 international scientists concluded that Antarctic snowfall accumulation has remained steady over the past 50 years, with no increases that might have mitigated the melting of the ice shelf, as some researchers had assumed would occur.

Taken together, the two reports indicate that global sea level rise may increase more rapidly in the coming years, though the Greenland study is based on only 2 1/2 years of data. The melting of 57 cubic miles a year from Greenland’s ice sheet could add 0.6 millimeters alone, which is higher than any previously published measurement for Greenland, according to University of Texas Center for Space Research scientist Jianli Chen.

“It’s a very big number,” Chen said, noting that for the past few hundred years the sea level has increased an average of 1.8 millimeters annually.

Byron Tapley, one of Chen’s co-authors, said the ice loss along the sheet’s eastern shoreline is particularly significant because it could help weaken the counterclockwise flow of the North Atlantic Current. The more buoyant fresh water from the ice melt could lower water temperatures and ultimately make Western European winters colder, he said.

But Myron Ebell, director of energy and global warming policy at the libertarian Competitive Enterprise Institute, questioned why scientists are drawing broad conclusions while looking at data covering such a short time span.

“We now have ‘the sky is falling down’ on the basis of a few years of data,” said Ebell, whose group is partly funded by the fossil-fuel industry.

The second paper, written by 16 scientists from seven different countries, challenges computer projections that warmer temperatures in the southernmost continent will spur greater snowfall accumulation and compensate for the world’s melting ice sheets. Using satellite data, the researchers concluded there has been no real increase in precipitation in the region in the last five decades.