How dangerous has it become in the Alps?
Two years ago, on July 3rd, around 2:00 PM along a popular route at Marmolada in the Dolomites, a glacier collapse occurred, which took the lives of 11 mountain climbers. It was reported that climate change significantly contributed to the accident. ntv.de asks Sudtirol and internationally renowned glaciologist and climate researcher Georg Kaser about how it looks now and in the future with regard to glacier retreats and what has changed in the mountains.
ntv.de: Can one still go glacier hiking in the Alps?
Georg Kaser: Yes, for now, but in a few decades, the glaciers in the Eastern Alps, as well as most in the Western Alps, will have largely disappeared. Climbing on ice will then only be possible in a few, high-altitude and shady gullies. In high, shady hollows, the ice will be covered in debris and the rest of the glacier will have melted.
What should one pay attention to during a hike in glacier areas today, which was not an issue before 30 years?
When mountain climbers are once on the ice, walking on it is not really different today than before 30 years. The most difficult and dangerous part is still the transition from the snow-covered, i.e., aperen, to the glacier tongue and then from the ice to the rocky terrain near the summit. This was also the case before 30 years ago, but the glacier edges are changing rapidly and significantly at the top and bottom due to the ice retreat, making these transitions often very complicated and new routes and approaches no longer feasible. In the mountain slopes, loose rock material is being exposed due to the disappearing ice, increasing the rockfall hazard. Of course, the approaches from the hut, cable car, or valley to the glaciers have also become longer and more laborious.
Are the rocks more crumbly today?
Not necessarily. Many rock faces and gullies were still ice-covered before 10-20 years ago and were therefore relatively easy to climb or cross. Under the melting ice, not only solid rock but also centuries-old, loosened material comes to the surface. This increases the risk of rockfall, as well as rockfalls and landslides in some sections. It will take several decades for the terrain to stabilize in these areas. In the case of unstable rock formations, the ice-free terrain will remain unstable.
One must pay more attention than before to where one steps.
In the area of glacier edges, yes. The difficulty of walking on the ice depends on the weather-dependent ice condition. Warm, wet weather can make the glacier surface very smooth, while snow can cover cracks.
Why can glacier lakes be dangerous?
"Glacier lakes" are often only temporary water accumulations in the glacier field, at the glacier margins or on a glacier itself. Glacier field lakes form when a glacier retreats either behind a moraine or in a melting, depressing basin in the former glacier bed. They can be long-lasting but also suddenly burst, when the damming moraine can no longer withstand the water pressure. This is a relatively common and threatening phenomenon in the Himalayas and the Andes. The consequence are so-called GLOFs (glacier lake outburst floods) with often catastrophic effects downstream. In the Alps, such events occurred frequently during the Little Ice Age. Lakes on glacier margins and on glaciers usually form in the course of spring and break almost always in the course of summer.
Can glacier lakes burst in our latitudes?
Yes, indeed. For example, the annual lake that forms on the Swiss Gornerglacier above Zermatt in the Monte Rosa Massif at the confluence of Gorner- and Grenzglacier, where meltwater accumulates and then usually finds a sudden way through the ice and into the valley.
Was a glacier lake the cause of the tragedy on the Marmolada?
No, there was no lake involved. However, it is very likely that meltwater had accumulated locally at the glacier bed, which contributed to the accelerated ice avalanche. But it was mainly the exceptionally long-lasting and high atmospheric temperatures that had destabilized the ice on this slope. A consequence of human-induced climate change. An Italian colleague described the situation very nicely and aptly compared it to the "ghiacciolo" - the colorful and very popular Italian water ice. When you take it out of the refrigerator, it is hard, firm and brittle. Initially, you can hardly bite into it. But on a hot summer day, you have to eat it quickly, otherwise it suddenly breaks into soft, crumbly pieces. Something similar happened at the Marmolada two years ago.
Can such an accident happen again?
Glacier collapses like the one on the Marmolada are not entirely unusual in the context of the strong glacier retreat in the advancing climate change. Similar glacier collapses will also occur in the future, albeit less and eventually not at all with the disappearance of the glaciers. Most events take place far from popular routes. The glacier collapse on the Marmolada, however, hit a popular mountain climbing route at the exact moment when so many people were on it. I would therefore not say that such a thing will never happen again, but the likelihood that it will hit a popular route again is low.
Interview with Georg Kaser conducted by Andrea Affaticati.
ntv.de: How does global warming affect glaciers in the Alps, particularly the Marmolada?
Georg Kaser: Global warming is causing glaciers in the Alps, including the Marmolada, to retreat at an alarming rate. This not only leads to the loss of valuable ice for recreation and research but also changes the landscape, making hiking and climbing more dangerous due to unstable terrain and ice conditions.
In light of the climate crisis, should schools incorporate more education about glaciers and their importance?
Yes, I believe it is crucial for schools to incorporate lessons on climate change, glaciers, and their role in the environment. This not only helps to raise awareness among young people about the consequences of global warming but also encourages them to take steps towards reducing their carbon footprint and preserving our planet for future generations.
