The poles of this planet are going through quite a lot at the moment. While Earth has warmed by an average of around 1°C (1.8°F), the Arctic has seen a far greater amount of warming, with parts of Alaska experiencing temperature rises of an astonishing 11°C (19.8°F).
Unfortunately, it now turns out that the ice sheet covering Greenland, the largest in the Northern Hemisphere, has been melting at a faster rate than previously thought.
The cap that covers Greenland is vast. It is thought that if it were all to melt, it would cause the world’s oceans to rise by an incredible 6 meters (20 feet), swamping many of the major coastal cities around the globe. Researchers have now found that the ice sheet has been shedding much more ice into the oceans than previously thought, adding up to 19 cubic kilometers (4.6 cubic miles) more ice per year into the oceans. This increases earlier figures by about 8 percent.
The team of scientists, whose work has been published in the journal Science Advances, has been able to use more sophisticated measuring techniques to calculate exactly how much ice is being lost from the island every year. The standard way to measure the loss of ice sheets across Greenland and Antarctica has been to use satellites that track the changes in gravity underneath them.
The ice covering the landmasses at both ends of the poles is so heavy that it causes the ground to be depressed. This means that as the ice melts, the ground in effect comes back up to take the place of the ice that has disappeared.
While earlier studies tried to take this into account, they inevitably counted some of the rising rock beneath the sheets as ice, meaning they were underestimating the amount of loss. This latest study has used other data taken from global positioning satellites in order to account for this, and have come to the worrying conclusion that the recent losses are worse than previously thought.
“If you look at the last 15 years since we've been having these measurements, it's clearly getting worse, the ice loss,” says Michael Bevis, from Ohio State University, in a statement. “It is pretty scary.”
While the rate of loss has been vastly increasing in the last few decades due to man-made climate change, the researchers found that the ice sheet has actually been melting for the last 20,000 years. This may sound like a get-out-of-jail free card for climate deniers, but it also means that the sheet is likely to continue melting for many more years to come.
