Too warm for comfort
Climate researcher Tobias Sauter studies the melting of glaciers
Nowhere are the effects of climate change more visible than in the world’s glaciers. The loss of ice masses is immense. Climate researcher Tobias Sauter investigates how and why the melting of glaciers is accelerating, and what will happen if the ice giants vanish.
Nothing lasts forever—not even perpetual ice. Around ten percent of the Earth’s surface is covered by snow and ice. The glaciers in high mountain regions date back millennia, stretch across several square kilometres, and reach depths of several hundred metres. It seems hard to believe that these vast ice masses could vanish. Yet, glaciers across the globe are retreating at a dramatic pace. One researcher who has devoted himself to studying changes in the so-called cryosphere is Tobias Sauter. The climatologist teaches and conducts research at the Department of Geography at Humboldt-Universität zu Berlin.
With his working group, Sauter examines how glaciers have changed in recent years, how they are likely to change in the coming decades, and when they might disappear altogether. Until the 1990s, the glaciers were receding at a slow pace. This was observable all of the world, albeit with regional differences. Since then, however, the loss of glacier mass has accelerated sharply everywhere.
Sauter illustrates this rapid acceleration using the Alps as an example. According to scientific studies, about 40 percent of all Alpine glaciers have melted between 2000 and 2023–24. In the years 2022–23 alone, ten percent of their total volume was lost. “This means that the process is advancing rapidly. In the past four years, melt rates have been exceptionally high,” says Sauter. “If this goes on like this, by 2050, we’ll have only 20 to 30 percent of the glaciers left—and 95 to 99 percent of Alpine glaciers will likely have disappeared by the end of the century.”
Sauter notes that mountain regions are warming at twice the rate of the lowlands. “The reason lies in the interaction between the atmosphere and the glacier.” It is precisely this interplay that particularly fascinates the climate researcher. As glaciers continue to melt, the atmosphere is no longer cooled from below. At the same time, more dark land surface is exposed, which heats up more and affects evaporation. This, in turn, affects cloud formation and precipitation. “We talk about feedback effects that ultimately explain why mountain regions are warming more rapidly compared to the global average,” explains Sauter.
The consequences are multi-layered. One of the most immediate impacts of glacier retreat is on water availability, as glaciers store vast amounts of water in the form of snow and ice. As they vanish, water resources and reserves are steadily diminishing. “We can already observe this,” explains Sauter, again using the Alps to illustrate. “Mountain rivers such as the Rhine and the Rhône, or even Alpine lakes like Lake Constance, are carrying less water.”
Sauter can often be found conducting fieldwork in the Alps—especially in summer, when he also leads excursions for his students. In earlier years, his research took him to more distant high mountain regions, including Patagonia, Tibet and the Himalayas, as well as Svalbard in the Arctic, and Antarctica.
The climate researcher describes other consequences of enormous scope. In addition to water scarcity, there is an increasing risk of natural hazards such as floods, landslides, rockfalls and droughts. Economic and political crises are also likely to grow, particularly in regions such as India, Kyrgyzstan, Uzbekistan and Central Asia, where people are heavily dependent on freshwater reserves.
What can be done? Tobias Sauter views approaches to adapt to climate change with some scepticism. So far, he says, there are no effective solutions for storing water, for example, through reservoirs or reprocessing plants. In the end, he believes, there is only one real solution: Greenhouse gas emissions must be reduced globally to prevent these scenarios from unfolding. Yet given the current lack of political will worldwide, the glaciologist is not optimistic that the climate targets can still be met. It remains a race against time.
Heike Gläser for Adlershof Journal
Science in the museum
Tobias Sauter’s research work can currently be experienced at Humboldt Lab. The exhibition On Water looks at warms in all its aggregate states, including insights into current glaciology.
www.humboldt-labor.de