Greenland Melting Accelerates; Future Sea Levels Need To Be Revised

Greenland Melting Accelerates; Future Sea Levels Need To Be Revised

Mar 16



By Andrew Freedman
March 16, 2014

Original Link

Three glaciers holding back a vast ice stream in northeast Greenland, a region thought to be the last bastion of stability in that rapidly warming region, are now thinning and moving more rapidly into the sea, a new study found.

The study overturns longstanding assumptions that the northeastern corner of Greenland, which is one of the coldest and driest parts of the world’s largest island, is stable, and instead suggests that sea level rise projections based on this assumption will need to be reevaluated.

The study, by an international group of researchers from Denmark, the Netherlands, the U.S. and China, found that regional warming has likely caused three outlet glaciers bordering Fram Strait and the Nordic Sea in far northeast Greenland, to lose mass in recent years, matching similar observed trends in the southwest, west and northwest of Greenland. One of the outlet glaciers, in fact, has receded 12.4 miles in just the past 10 years.

Study coauthor Shfaqat A. Khan of the Technical University of Denmark told Mashable he was surprised to find such significant ice loss in northeast Greenland, considering how cold and dry that region is. Previous studies of sea level rise had not included the prospect of melting there, he said.
“Nature is changing faster than expected and seems to respond much stronger than expected to small fluctuations,” he said. “This also means that predictions of future sea level rise need to be revised.”

More worrisome, Khan and his coauthors said, is that these glaciers help hold back a nearly 370-mile long ice stream that extends deep into Greenland’s interior. This ice stream accounts for about 16% of the total ice sheet, and if it destabilizes, it could have severe consequences for low-lying coastal cities worldwide.

Greenland is the world’s largest island, extending more than 1,200 miles from its southern to northernmost points, and if all of its ice were to melt — which would likely take many centuries, if not thousands of years — the oceans would rise by more than 20 feet. Already, the melting of the Greenland ice sheet is one of the largest contributors to global sea level rise, accounting for about .02 inches of the 3.3 inches per year global average sea level rise (local rates of sea level rise vary significantly).

Scientists trying to predict how much sea level rise the world will see in the next several decades have had to grapple with uncertainties about the stability of Greenland as well as portions of Antarctica, and this new study adds to the evidence showing that sea level rise may be more likely to be on the higher end of the scale rather than the lower end.

The most recent report from the U.N. Intergovernmental Panel on Climate Change (IPCC) found that global average sea level is likely to increase by 10.2 to 32 inches by the year 2100, with a highest emissions scenario showing a sea level rise of between 21 and 38 inches by the end of the century if greenhouse gas emissions continue to rise unabated…

As Greenland has warmed by an average of about 3.6 degrees Fahrenheit since the 1980s, the average ice-sheet-wide mass loss increased from about 172.4 gigatons per year from April 2003 through 2006, to 359.8 gigatons per year from April 2009 through 2012, the study found. This increase in melting has raised concerns regarding the potential acceleration in global sea level rise…

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