>Achim Steiner, executive director of the United Nations Environment Program, said today that the world’s glaciers are melting “at an alarming rate”, based on data collected by the World Glacier Monitoring Service in Zurich.

Juliette Jowit from the Observer writes:

Glaciers act like gigantic water towers: snow falls on the top in wet seasons, where it freezes and compacts over years, while melting water at the bottom is released gradually, keeping rivers flowing even in the hottest weather. ‘Glaciers are like a bank,’ says Professor Wilfried Haeberli, director of the World Glacier Monitoring Service. ‘You have income – mainly snow – and you have expenditure – mainly melting: the difference between snowfall and melting is the yearly balance.’

Since at least 1980 the service has kept a constant record of this net gain or loss in mass balance of 30 ‘reference’ glaciers in nine mountain ranges around the world. It has also used travellers’ diaries, photographs, and the clues left on landscapes scarred by the moving mass of ice and debris to map historic growth and the gradual decline of glaciers since the mid-19th century.

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.

In North America, Dr Bruce Molina of the US Geological Survey says that in Alaska ’99-plus per cent of glaciers are retreating or stagnating’.

In the European Alps, a report last year by UNEP said glaciers declined, from a peak in the 1850s, by 35 per cent by 1970 and by 50 per cent by 2000, and lost 5-10 per cent in the mega-hot year of 2003 alone.

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.

Steiner also mentioned that the Climate Conference to be held in 2009 in Copenhagen “will provide the true litmus test of governments’ commitment to reducing greenhouse gas emissions, the carbon pollution from fossil fuels damaging Earth’s climate system.

Otherwise, and like the glaciers, our room for manoeuvre and the opportunity to act may simply melt away.”