Part of the world's second largest ice sheet lies on Greenland. A huge mass of ice: the ice sheet is on average 2000 metres thick, 82% of Greenland's surface is covered by ice totalling 1.71 million square kilometres. An enormous ice giant, true, but also a very fragile one. This was revealed in research published in Nature Geoscience: Greenland is losing more ice than expected, almost 250 billion tonnes per year. The temperature of the atmosphere above Greenland is increasing due to global warming, causing the continental ice to melt. The meltwater flows into the ocean causing continuous local mixing that brings warm water to the surface; this melts the sea ice that forms along the coastline. So Greenland loses both freshwater and sea ice, which is why the loss of its ice cover is faster than elsewhere.