MORTERATSCH, SWITZERLAND – The hourlong walk from the local railway station to the Morteratsch glacier is a winding trek through a valley littered with rocks that the retreating ice left behind.
The walk was not always this long. In the mid-19th century, the Morteratsch glacier stretched all the way to the station in Morteratsch, a hamlet in southeastern Switzerland.
By 1900, people had to walk about 1 km to touch its shimmering blue surface.
In the past century, the ice has shrunk around 2.4 km, and signposts marking the glacier’s “tongue” over the past century point to a decline that in recent years has accelerated dramatically.
“Each year we come here, we have to walk further to get to the glacier,” said Joerg Wyss, a 43-year-old tourist from Lucerne, who said he has been visiting Morteratsch for 25 years.
Ursula Reis, a 73-year-old from Zurich, said she has been coming for even longer, visiting almost every year since 1953.
“I have seen the shrinkage. It’s amazing and frightening at the same time,” she said.
As closely studied by scientists as it is loved by the Swiss, the Morteratsch glacier provides one of the clearest examples of climate change in action, experts say.
Like almost all documented Alpine glaciers, it has been steadily shrinking for decades, and only its highest points are expected to see the turn of the next century.
“The glaciers are kind of a direct signal of climate change,” said Samuel Nussbaumer, a scientist with the World Glacier Monitoring Service at the University of Zurich.
Since 1950, the glacier has receded by about 1.6 km. Its tip today is hidden in a forest of high trees, and even the 2010 signpost is separated by a good 200 meters of rocks from the glacier mouth, which emits gushing meltwater into an icy river.
“This is one part of the Morteratsch glacier where you can really see how fast the ice is melting away,” said glacier guide Gian Luck, standing in a rock-strewn area that only three years ago was still covered with a system of ice caves, before they suddenly collapsed and disappeared.
A 2011 report from the European Topic Center on Air Pollution and Climate Change Mitigation, a consortium of institutes known by its acronym of ETC/ACM, found that more than half of the ice-covered areas and probably two-thirds of the ice volume in the Alps has disappeared since 1850.
From 2000 to 2010, the Alpine glaciers on average lost more than a meter of thickness each year, according to the study.
The rate of shrinkage is increasing.
“They are shrinking, and the rate of shrinkage is increasing,” Nussbaumer said, adding that while factors like precipitation and wind play a part, rising temperatures are the main explanation.
Glaciers cover some 2,900 sq. km in the Alps, including 1,342 sq. km in Switzerland alone.
Scientists have warned that a summer temperature increase of around 4 degrees from today’s levels will leave Europe’s biggest mountain range almost iceless by 2100.
The Alps, like the Arctic and the Antarctica Peninsula, are considered a hot spot where warming can be two or three times greater than the global average.
“These ice giants could disappear literally in the space of a human lifetime, or even less,” said Sergio Savoia, who heads conservation group WWF’s Alpine office in Switzerland, stressing the need to “prepare for the serious consequences.”
Globally, glaciers are one of the main contributors to sea level rise, and their contribution to shrinking shorelines is believed to have doubled in recent decades.
The new U.N. report on global warming, released in Stockholm on Friday, for the first time includes detailed estimates for melting ice from glaciers and ice sheets in its calculation of sea level rise.
The issue of rising sea levels is not as relevant to the Alps, though. If all of the region’s glaciers melt, this will add only about 1 mm to ocean levels.
Locally, though, the effects will be dramatic.
The thick ice cover functions as a water tower that stores water, releasing it when it is most needed — in the hot and dry summer months.
The Alpine glaciers feed into some of Europe’s biggest river systems, including the Rhone, Po and Danube, and if this source disappears, the effects will be felt across Europe, said Savoia.
“It’s very hard to predict what will happen when the temperatures rise even more and we no longer have the compensating function of the glaciers,” he said.
Melting glaciers can also cause natural hazards, ripping open crevasses, creating glacier lakes that can burst suddenly and increasing the risk of flash floods, landslides and mudslides.
While the effects of the vanishing Alpine glaciers will mainly be felt locally, only global action to reduce emissions of carbon dioxide can truly slow down the trend, Savoia said.