New Digital Map Reveals Record Ice Sheet Decline in Antarctica and Greenland

It turns out that the ice sheets are in record decline, according to some new maps of the ice in Greenland and Antarctica. Scientists have examined newly created digital maps of ice sheet height and have found that elevation has changed significantly due to melting.

"The new elevation maps are snapshots of the current state of ice sheets," said Veit Heim, lead author of the new study, in a news release. "This is 500,000 square kilometers more than any previous elevation model from altimetry."

For the new study, the researchers evaluated all data by the CryoSat-2 altimeter SIRAL. The satellite altimeter measured the height of ice sheets by sending radar or laser pulses in the direction of Earth. These signals were then reflected by the surface of the glaciers or the surrounding waters and were then retrieved by the satellite.

So what did they find? IT turns out that Greenland alone is reducing in volume by about 375 cubic kilometers per year. The largest changes occurred at Jakobshavn Glacier in West Greenland and Pine Island Glacier in West Antarctica. Since February 2014, scientists have known that the Jakobshavn Glaciers is moving ice into the ocean at a record speed of up to 46 meters per day.

"When we compare the current data with those from the ICESat satellite from the year 2009, the volume loss in Greenland has doubled since then," said Angelika Humber, one of the study authors. "The loss of the West Antarctic Ice Sheet has in the same time span increased by a factor of three. Combined the two ice sheets are thinning at a rate of 500 cubic kilometers per year. That is the highest rate observed since altimetry satellite records began about 20 years ago."

The findings reveal exactly how much these ice sheets are declining. This is important to note not only to predict rising sea levels, but also to create more accurate climate models of conditions in the future.

"We need to understand where and to which extent the ice thickness across the glaciers has changed," said Veit Helm. "Only then can we analyze the drivers of these changes and find out how much ice sheets contribute to global sea level rise.