Sunday, September 25, 2011

Melting ice is Earth's warning signal – and we cannot ignore it

Damian Carrington in the Guardian (UK): Ice is the white flag being waved by our planet, under fire from the atmospheric attack being mounted by humanity. From the frosted plains of the Arctic ice pack to the cool blue caverns of the mountain glaciers, the dripping away of frozen water is the most crystal clear of all the Earth's warning signals.

It relies on neither the painstaking compiling of temperature records back through history nor the devilish complexity of predicting the future with supercomputers. Ice on Earth is simply and unambiguously disappearing. Last week saw the annual summer minimum of the Arctic ice cap, which has now shrunk to the lowest level satellites have ever recorded. The ice at the roof of the human world is faring little better: mountain glaciers are diminishing at accelerating and historic rates.

The lower glaciers are doomed. Kilimanjaro may be bare within a decade, with the Pyrenees set to be ice-free by mid-century and three-quarters of the glaciers in the Alps gone by the same date. As you climb higher, and temperatures drop, global warming will take longer to erode the ice into extinction. But at the "third pole", in the Himalayas, the ice is melting as evidenced by dozens of swelling milky blue lakes that threaten to burst down on to villages when their ice dams melt.

The threat posed is far greater than even this terrifying prospect: a quarter of the world's people rely on Himalayan meltwater, which helps feed the great rivers that plunge down into Asia. The Yellow, Yangtze, Mekong, Brahmaputra, Ganges and Indus nourish billions and will eventually lose their spring surges...

Glacier flowing down the side of Nordvestfjord (Scoresby Sund), Greenland, shot by Hannes Grobe, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 2.5 Generic license

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