The Swiss Alps are often called 'Europe's water tower'. Nearly 60 billion cubic metres of water are stored in its glaciers. Matthias Huss, glaciologist and senior lecturer at the Department of Geosciences at the University of Fribourg explains that glaciers fulfil a balancing function: "They release water exactly when we need it, while storing it in periods when we need it less."
In other words, glaciers store water during the cold and wet winter months. From May to September, snow and ice melt on the glacier surface and provide the water that is dearly needed during the hot and dry season. That same mechanism also balances year-to-year variations: in colder, wetter years glaciers accumulate water that is released in relatively hot and dry summers like in 2003.
The threat posed to alpine glaciers' essential contribution has long been recognised. However, a new study presented by Matthias Huss in the scientific journal 'Water Resources Research' found that the proportion of glacier water running down major European streams is larger than previously assumed.
"I have compared water runoff data from glaciers with actual runoff at gauges along the entire length of four major streams originating in the Swiss Alps," explains the glaciologist. His study is based on measurements along the Rhine, Rhone, Po and Danube rivers. The comparison allowed Huss to determine the relative share of glacier water running down those streams. "Consequently, I was able to quantify how much the runoff of those streams could decrease in case the glaciers' contributions are entirely lost," he says.
Matthias Huss of the University of Fribourg also stresses that the current picture is deceptive. "Due to climate change, we currently get more water from the glaciers than normally, as they're melting. At first glance it looks like there's no problem," he says. But Huss warns that soon the picture will change and the remaining glaciers won't be able to provide enough water during the summer months. Huss' glacier models are linked to specific climate scenarios. Diverging global warming estimates therefore affect prognoses regarding glacier shrinkage significantly...
The tongue of the Rhone Glacier in Switzerland, shot by Jamcib, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported
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