Alpine glaciers shrunk by half since 1850
Researchers from the University of Zurich have warned the European Geosciences Union (EGU) annual meeting in Vienna that Alpine glaciers are in severe danger, having lost more than 50 per cent of their area since 1850. And the rate of loss is accelerating. According to the report, if the all the world's ice melted, the corresponding rise in sea-levels would be around 80 metres. Alpine glaciers would 'contribute less than a millimetre' to that figure. However, while European glaciers contribute only a tiny proportion of the world's total ice cover, their contribution to local wildlife, tourism, irrigation and drinking water is incalculable. Since the 1850s, the total ice cover in the Alpine regions has decreased from 4,474 square kilometres to 2,272 square kilometres in 2000. 'From 1850 to the 1970s, there is an average loss of 2.9 per cent per decade,' said Michael Zemp from the World Glacier Monitoring Service (WGMS) and University of Zurich. 'From the 1970s until 2000 it is 8.2 per cent per decade, and we see most of that increase since 1985,' he said. However, as is seen in Greenland today, there can be a paradoxical effect - as there is more melting of the ice at the edges, so the altitude at which the glaciers form rises, there is also increased precipitation, and so more snow in the winter, which can bulk the glaciers in the middle. The WGMS developed a computer model to see how increases in temperature will influence the area glaciers cover. By 2100, 'the summer temperature increase is 3C, which is very bad for glaciers,' Dr Zemp told the BBC news website, 'and the annual precipitation increases, which creates a bit better conditions for glaciers. You get a rise of 340m in the level that enables glaciation,' he said. If the models are shown to be accurate, then this rise in the height needed for glaciation would correspond to a loss of 75 per cent of the area of Alpine glaciers, although snowfall in winter would also increase. Worse, according to Dr Zemp, 'Even if you halted climate on today's level, glaciers would continue to retreat because of very bad years in the last two decades.' Such a year occurred in 2003, which the WGMS report describes as 'extraordinarily warm'. This year alone contributed to a loss of some five to 10 per cent of glacial loss. By 2100, which is within the lifetimes of those born today, 'Even a rise of just one degree centigrade would see a loss of 40 per cent' of glacial cover said Dr Zemp, corresponding to a 100m rise in altitude before glaciers form.
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