Greenland ice may melt faster due to increase in temperature

A new study has shed light on Greenland Ice demonstrating that the more temperatures increase, the faster the ice will melt.

The model experiments conducted by Penn State geoscientists suggested that if all the ice in the Greenland Ice Sheet melts, global sea level would rise by about 24 feet.

Patrick Applegate, research associate, Penn State's Earth and Environmental Systems Institute, said that although lots of people have thought about sea level rise from the ice sheets, they don't really know how fast that will happen.

Greenland might be especially vulnerable to melting because that area of the Earth sees about 50 percent more warming than the global average. Arctic sea ice, when it exists, reflects the sun's energy back through the atmosphere, but when the sea ice melts and there is open water, the water absorbs the sun's energy and reradiates it back into the air as heat. Arctic sea ice coverage has decreased over the last few decades, and that decrease will probably continue in the future, leading to accelerated temperature rise over Greenland. Floating ice does not add to sea level, but the Greenland Ice Sheet rests on bedrock that is above sea level.

The researchers looked at two models of the Greenland ice sheet that include some of the important feedbacks. The first model is a three-dimensional ice sheet model. The second model looks at a transect across the island and was developed by Byron Parizek, associate professor of geosciences and mathematics, Penn State Dubois. To run both models, Robert Nicholas, research associate, EESI, estimated how much warming might take place over Greenland using results from global climate models.

Both the three-dimensional and transect models showed that the time necessary for ice mass loss from the Greenland ice sheet decreases steeply with increases in temperature. Shorter time scales-faster melting-imply faster sea level rise. The interplay between the height-melting feedback and ice flow causes this acceleration.

The researchers said that their analysis suggests that the benefits of reducing greenhouse gas emissions, in terms of avoided sea level rise from the Greenland Ice Sheet, may be greatest if emissions reductions begin before large temperature increases have been realized.

The study is published in the journal of Climate Dynamics.