Sunday, March 16, 2008

'Melting glaciers start countdown to climate chaos'

From The Observer.

For centuries, writers, painters and photographers have been drawn to the wild and seemingly indestructible beauty of glaciers. More practically, they are a vital part of the planet's system for collecting, storing and delivering the fresh water that billions of people depend on for washing, drinking, agriculture and power. Now these once indomitable monuments are disappearing. And as they retreat, glacial lakes will burst, debris and ice will fall in avalanches, rivers will flood and then dry up, and sea levels will rise even further, say the climate experts. Communities will be deprived of essential water, crops will be ruined and power stations which rely on river flows paralysed. . . .

From 1850 to 1970, the team estimates net losses averaged about 30cm a year; between 1970 to 2000 they rose to 60-90cm a year; and since 2000 the average has been more than one metre a year. Last year the total net loss was the biggest ever, 1.3m, and only one glacier became larger. Worldwide, the vast majority of the planet's 160,000 glaciers are receding, 'at least' as much as this, says Haeberli, probably more - a claim supported by evidence from around the world. . . .

UNEP has also reported declines in the last 50-150 years of 1.3 per cent in the Arctic islands to 50 per cent in the North Caucasus in Russia, 25-50 per cent in central Asia, a 2km retreat of the massive Gangotri glacier which feeds the Ganges, 49 to 61 per cent in New Zealand, and 80 per cent in the high mountains of southern Africa. There is also 'considerable' shrinking of medium and small glaciers in central Chile and Argentina accompanied by 'drastic retreat' of glaciers in Patagonia to the south.

The only region where glaciers are advancing is Scandinavia, where climate change has increased precipitation to more than compensate for higher melting, and even there the growth has stagnated . . . .

The problem is perhaps most acute in Asia, where glaciers are an important source for nine major rivers which run through land occupied by 2.4 billion people. In Pakistan, for example, 80 per cent of agricultural land is irrigated by the Indus, which the WWF last year highlighted as one of the world's 10 big at-risk rivers because retreating glaciers provide 70-80 per cent of its flow. . . .