Greenland’s Melting Ice Sheet Mapped in Unprecedented 3D Detail

​Recently, NASA and the NOAA confirmed that 2014 was the hottest year on the books, and projected that even warmer years are ahead of us. The finding underscores the need to not only confront climate change on a political level, but also to anticipate some of the most dramatic effects it will have on Earth.

One of the most unpredictable and threatening consequences of a warming planet will be rising sea levels caused by massive melting of ice at the poles. Given that coastal regions are among the most populated areas in the world, this issue has the potential to displace millions of people. Indeed, some communities have already had to concede their homes to the advancing oceans.

That's why NASA has made climate research a top agency priority, greenlighting dozens of projects designed to get a handle on the scope of this global environmental crisis. The agency's latest win was producing the most comprehensive 3D map of Greenland's ice sheets ever created, as part of the multi-year Operation IceBridge initiative.

NASA Goddard video on Operation IceBridge. Credit: NASA Goddard/YouTube

"This new, huge data volume records how the ice sheet evolved and how it's flowing today," said glaciologist Joe MacGregor in a NASA statement. (MacGregor is also the lead author of a new study in The Journal of Geophysical Research Earth Surface, based on Operation IceBridge data.)

Greenland's ice sheet is the second largest in the world, packed with enough water to raise sea levels a full 20 feet. The bad news is that it is melting with ominous rapidity. The good news is that Operation IceBridge is collecting valuable information about climates of the past from its intricately layered glaciers. Figuring out how Greenland responded to previous warming periods will enable scientists to project its reaction to human-driven climate change, and how to best prepare for it.

The scientists involved in Operation IceBridge have taken an exhaustive, multi-pronged approach to monitoring Greenland's evolution. The most "hands-on" part of the initiative is the extraction of enormous cylindrical ice cores from the depths of the sheet.

Much like the sedimentary layers of solid ground or the rings of a tree, these samples are data-rich time capsules containing multitudes of information about bygone epochs. For example, volcanic ash from ancient eruptions is exquisitely preserved in these cores, and the rates of ice melts can be discerned from the thickness of each layer.

Never content with ground operations alone, however, NASA has also been studying Greenland's ice sheet from the skies, and even from space. Operation IceBridge initially consisted of an orbiter called ICESat, which was specifically designed to keep tabs on the planet's most vulnerable ice sheets, but it was retired after a malfunction in 2010. A replacement will be launched in 2016, but to fill the gap, NASA has deployed several fleets of airplanes to the region over the last six years.

Though planes can't cover as wide an area as satellites, they can be decked out with a lot more equipment, including laser altimeters, precision radars, and mapping instruments. These devices have allowed scientists to delve deeper into Greenland's glacial history than ever before. It's also paved the way for novel discoveries, such as the 2013 discovery of the longest canyon on Earth, nestled under layers of ice.

"Prior to this study, a good ice-sheet model was one that got its present thickness and surface speed right," MacGregor said. "Now, they'll also be able to work on getting its history right, which is important because ice sheets have very long memories."

It remains to be seen whether policy changes will slow the rate of climate change over the 21st Century. But regardless of the outcome, we will need to know what to expect from Greenland's disappearing ice sheet. The best way to do that is to model its past with the kind of unprecedented detail afforded by Operation IceBridge.