Alpine melt
October 14, 2009
The second Wednesday in October is the International Day for Disaster Reduction. Click on the picture gallery below for a look at other natural disasters that result from climate change.
Every year, Switzerland spends around 2.5 billion Swiss francs ($2.45 billion) on preventing damage resulting from natural disasters. Most of this damage is caused by flooding. Nearly 40 percent of the allocated funds go into catastrophe prevention - into projects like drainage tunnels for the Grindelwald glacier.
Located in an idyllic mountainous district in the canton of Bern, the Grindelwald glacier is one of the most rapidly melting glaciers in the Alps. By winter, a two-kilometer-long (1.2-mile) artificial drainage tunnel at the foot of the glacier should be finished. Starting in spring 2010, it will help to drain the unpredictable glacial lake that has formed there due to global warming.
Preparing for trouble
Four years ago, the glacial valley filled with melt water for the first time. Since then, the water level has risen every year. Some spontaneous drainage occurs in summer, causing small floods in the Luetschine River below.
The floodwater has not yet caused any damage in the valley, but the local authorities are alarmed. They have allocated 15 million Swiss francs to the construction of the drainage tunnel, sharing the costs with the canton of Bern and the federal government.
For Nils Haehlen, a hydraulic engineer supervising the construction, the decision to build the tunnel is based on a rational assessment of costs and benefits.
"If the water unexpectedly floods over, it will mean tens of millions of francs in damages," said Haehlen. "What's more, such flooding can occur several times in one year, so the 15 million francs we're spending on tunnel construction are not out of proportion."
Glacial lakes a new risk
The tunnel is the first of its kind in the Alps, but it sets a useful example. Glacier researchers at the University of Zurich have calculated that, at the current rate of global warming, at least 80 percent of Alpine glaciers will disappear by the end of the century.
"Glacial lakes are a new phenomenon in the Alps, the Himalayas, South America and everywhere," said geologist Hans-Rudolf Keusen, who assesses the risk that the Grindelwalder Lake poses. "Through the melting of glaciers, these lakes appear in many places, and it's a source of danger we didn't have before."
Keusen regularly checks the sensors located in the lake. They measure changes in water depth every minute. If a sudden rise occurs, Keusen is automatically informed and has the chance to warn the local authorities.
Something like this occurred in May of this year, when a large moraine (a glacially-formed accumulation of rock and soil debris) was about to slide into the lake. Fire departments in the valley were notified and put up flood barriers, but, fortunately, no flooding occurred.
According to Keusen, the lake had drained itself subterraneously, revealing yet another unpredictable feature.
"It works in a very complicated way," he said. "There are blockages, drainages and underwater pressure. It's very difficult to predict. The lake behaves in a capricious way."
Landscape changing rapidly
The valley's residents are relaxed about the recent developments. Having grown up in the mountains, most are familiar with the various dangers present there. However, they are concerned about the speed at which their natural surroundings have changed in the last 10 years.
"It all happened so quickly," said Hans Lohner, a 75-year-old former mountain guide. "Every year it's almost one or two degrees warmer. It's a bit frightening. Sixty years ago I could still ski over the glacier into the valley, but these times are over now."
The communities around the Grindelwald glacier are prepared to adapt to the effects of climate change. The region lives off tourism, and the local tourism authorities have played down the glacier melting phenomenon for fear of spoiling the area's image. At the same time, however, they have confronted the issue by creating so called "climate paths," where tourists can witness the effects of climate change with their own eyes while walking through the still idyllic landscape.
This conveys an urgent message: Visit the glaciers while they still exist.
Author: Claudia Witte (ew)
Editor: Kate Bowen