Ancient glaciers are disappearing faster than ever
By Michael McCarthy environment editor Melting ice is pouring off Greenland and Antarctica into the sea far faster than was previously realised because of global warming, new scientific research reveals today. The accelerating loss from the world’s two great land-based ice sheets means a rise in sea levels is likely to happen even more quickly than UN scientists suggested only two years ago, the findings by British scientists suggest. Although floating ice, such as that in the Arctic Ocean, does not add to sea-level rise when it melts as it is already displacing its own mass in the water, melting ice from the land raises the global sea level directly. At present it is thought that land-based ice melt accounts for about 1.8mm of the current annual sea level rise of 3.2mm – the rest is coming from the fact that water expands in volume as it warms. But the new findings, published online today in the journal Nature, imply that this rate is likely to increase. High-resolution satellite laser measurements have shown that along both the Greenland and Antarctic coastlines, the glaciers and ice streams which for thousands of years have slowly carried ice into the sea are now rapidly thinning, meaning they are speeding up in their flow. In both cases, the increased flow rate is extending back far into the ice sheets’ interior. This is happening all the way around Greenland, even at the high northern latitudes, and around much of Antarctica, especially in West Antarctica and around the Antarctic Peninsula. … “The fact that the changes are so large is alarming, and you wonder how far they will go,” Dr Pritchard said. “The thinning effect must be relatively recent, as it is so strong that it could not have been sustained previously without the glaciers melting away.” …
