swisster - climate.

This article was published by Swisster on July 3, 2008.

Valais glacier bluntly illustrates climate change

Tom Armitage - Zurich

The Aletsch Glacier in southern Switzerland cascades down the Alps, seemingly pushing apart the mountains on either side. Its tongue, marked by two dark strips of moraine, stretches out across the broad valley and tumbles down the rock. That is how it looked in 1856. Viewed from the same vantage point 150 years later, you have to look far up into the mountains to see the snow and ice.

The Aletsch glacier in Valais has retreated 2.8 kilometres up the mountainside since records began in 1870, revealing a rocky landscape that once hid beneath hundreds of metres of ice. The shrinkage has been going on since Europe began to warm up in the mid-19th century following a cold snap that lasted almost 250 years. “Glacial retreat is a clear indication of global warming and it is quite clear to me that humans are at least partly responsible,“ said Laudo Albrecht, director of a conservation centre near the Aletsch, run by the environmental group Pro Natura.

What alarms researchers, however, is the speed at which Switzerland’s glaciers are melting and what this means for the Alps as a whole, which are literally glued together by ice. The Aletsch, now measuring about 23 kilometres from top to bottom, used to melt at about 20 to 40 metres a year, but in 2006 a massive 115-metre retreat was recorded. This was the biggest annual contraction on record. The glacier is also thinning out.

“The rate of melting is accelerating significantly and that is what is important,” Albrecht said. Over the last century and a half, Alpine glaciers have lost around a third of their surface area and around half of their mass. Awareness of the problems has increased in recent years, scientists say, but the problems have been a long time in the making and cannot be reversed.

“Changes in the length of the glacier’s tongue are one of the most significant indirect indicators of climate change that we have,” said Frank Paul, a glaciologist at Zurich University. Glaciers such as the Aletsch respond slowly to changes in the climate. The retreat is a result not of the weather conditions this year but of the climate 20, 30 or 40 years ago. “The glaciers are only starting to react to the warmer years of the 1990s,” Paul said. “This is only the beginning.”

In a bid to highlight the dramatic nature of what is happening to the Aletsch and other glaciers like it, Greenpeace commissioned American photographer Spenser Tunick to snap pictures there last summer. Tunick, famous for his series of photos of unclothed humans, assembled a cast of 600 naked people of all ages to pose on the receding ice. The images, beamed around the world by news media organizations, were used by the environmental group for its climate change campaign.

Switzerland has around 2,200 glaciers, the remnants of an ice field that covered the country during the last ice age some 20,000 years ago. Glaciologists have been tracking them for years. Of 85 glaciers in Switzerland that were measured in 2006, all but one receded, according to data gathered by the Swiss Glacier Monitoring Network. Most of them – over 80 percent by Paul’s reckoning – are relatively small, about a square kilometre in size, and are only about 30 metres thick on average.

Not only do these smaller glaciers show signs of retreat in response to the more long-term climate trends, but their upper surfaces are also more responsive to short-term changes in weather. Over the past 25 years, the rate at which the frozen sheets thin out has accelerated. In some cases, a metre or more of thickness a year is being lost. Within a generation, many of Switzerland’s unique glaciers could be gone. A European Union report issued in 2005 after three particularly hot Alpine summers said that by mid-way through this century, around three-quarters of Switzerland’s glaciers will have disappeared if current conditions prevail.

“Ten percent of Alpine glaciers (by volume) disappeared during the summer of 2003 alone,” the European Union said. “Europe has not seen climate changes on this scale for 5,000 years.” The consequences could be devastating for densely populated Alpine regions and communities dependent on tourism. Already, many lower-lying ski resorts in Switzerland face shorter seasons and a lack of decent snow. And where t-shirt clad skiers once ploughed down glaciers in the height of summer, workers are now erecting special reflective tarpaulins in order to save at least some ice.

Scientists say the measures will work, but only in the short term: “It’s a drop in the ocean really,” Paul said. More worryingly, the rapid glacial melt increases the risk of flash floods and landslides that have been known to wipe out mountain communities and destroy the infrastructure they rely on. Losing the glaciers as a store of water could cause shortages in Switzerland and its neighbours, who are supplied via the Rhine, Rhone and Danube rivers. Crippling electricity supply problems could also become widespread in Europe, since many power stations – both hydroelectric and nuclear – rely on glacial lakes to operate.

At present, mineral-poor Switzerland derives about 60 percent of its domestic power from hydroelectric power stations located high in the Alps that are driven by glacial lakes. A recent Swiss government predicted a seven percent decline in hydroelectric output by 2050 as a result of the dwindling glacial reservoirs. The problem is likely to worsen in the coming years. Scientists predict that the average temperature in the Alps will rise by two degrees Celsius in autumn, winter and spring and three degrees in summer by 2050, compared with 1990. Like its European neighbours, Switzerland has begun to take steps to mitigate the impact of transport emissions and industrial pollution on the environment. The country has vowed to cut levels of greenhouse gases by 10 percent by 2010 and some politicians are pushing for more stringent goals.

But with temperatures rising and the glaciers and permafrost only now beginning to show the effects of the late 20th century, it will be hard to predict how Switzerland’s natural landmarks will react in years to come. “The situation is a very different from how it was thousands of years ago,” Paul said. “At this point in time, we can no longer learn anything from history. We are entering a new period of imbalance in nature.”