Greenland, North America
After Antarctica, the Greenland ice sheet has the largest concentration of fresh water on the planet.
80% of Greenland is covered in ice
A group of NASA scientists have spent over a decade measuring the effects of global warming here in Greenland.
But how do they do it?
From the skies, a satellite measures the plane's altitude.
Whilst lasers on board penetrate the ice below, giving precise dimensions of the ice.
Lasers measure the ice to an accuracy of 10cm
5000 laser beams are fired every second
At five-year intervals, they have flown an identical route over the island. Each time monitoring the same stretch of the ice sheet.
By comparing the two measurements they can clearly see whether the ice is growing or shrinking.
What did they find? 100 billion tonnes of ice was melting off the sheet every single year.
Besides this, Greenland's ice sheet has an even bigger problem.
NASA scientists also measured the largest chunk of floating ice in Greenland, the Petermann Glacier.
Bob Tomas, NASA – "Less than 10 years ago, five years ago, it was moving at about 6, 7km a year, and that was more or less in balance with the snowfall. Now in the five years since then the speed has almost doubled."
It's the fastest moving glacier on the planet, it dumps enough fresh water in to the ocean every day to supply New York for three whole months.
Bob Tomas, NASA – "Well I myself am convinced that global warming has affected the dynamics of the Greenland ice sheet, and erm and that is possibly because increased meltwater is creeping in to the bed through crevasses, moulins, and lubricating the bed and making it far easier for the ice to flow."
Greenland is not alone, over the past 50 years, 99% of Alaska's glaciers have retreated, and 87% of Antarctica's have done the same.
The planet's ice acts as a huge climate buffer, as well as controlling sea levels, and providing habitats.
If this gigantic ice sheet continues to melt at this rate, the consequences could be catastrophic.