Retreating glaciers create new ecosystems – rts.ch

Globally, glaciers could lose half of their surface area by the end of this century. He asserts that this will lead to the emergence of new ecosystems, the status of which is still uncertain study With Swiss participation published in the journal Nature.

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According to the evolution of global warming, the retreat of glaciers will free up an area estimated between three and a half to eight times the surface of Switzerland, according to the calculations of the scientists, a multidisciplinary Franco-Swiss team.

Matthias Haas digs a hole to harvest a melting point; This data helps to better document and understand the mass loss of glaciers. [Clara Streule – ESL]This will lead to one of the fastest changes in terrestrial ecosystems, Matthias Haas, a glaciologist at the Swiss Federal Institute of Technology Zurich (ETHZ) and a co-author on this paper, told Keystone-ATS. The researcher added that understanding these post-glacial ecosystems is important.

opportunistic colonization

Christophe Randin, researcher at the University of Lausanne and director of the Flores-Alpes botanical garden, surveys the Valais Alps. This week, head especially to the Petit Combiègne glacier, which, like the others, is receding and leaves behind large swathes of vegetation.

This is not growing at the usual rhythm with pioneers first, then other plants. As if the plants are scurrying about, he explains over La Matinale’s microphone: “It’s rather the open bar! It’s the plants” that colonize opportunistically without really having that structure with pioneer plants, then shrubs, soil formation and then trees. We see we have all these types of plants arriving at the same time.”

But will all of these plants be able to stabilize the soil and its sediments from the melting glacier? “The challenge is figuring out what happens with more extreme events. Right now it’s very hot, but maybe in a few weeks we’ll get a lot of rain, and with a drought, that will mobilize the sediment that’s behind these glaciers. And that sediment isn’t being held by the vegetation, it’s going to the bottom of the valleys. Thus they can pose a danger to everything downstream.

A view of the Greis glacier on Friday, September 2, 2022. The Greglicher is currently one of the fastest melting glacier in Switzerland. [Jean-Christophe Bott – Keystone]

New areas of protection

In particular, new post-glacial ecosystems can serve as a refuge for species driven from elsewhere by global warming. According to Matthias Haas, “These new ice-free surfaces must be put under protection.” Currently, only half of the areas covered by glaciers globally are covered by them.

Scientists’ models show that until 2040, glaciers will continue to retreat at the same rate regardless of the climate scenario. As for the rest, until 2100, estimates range from a loss that fluctuates between 22% with strong measures and 50% without measures.

For Matthias Haas, a large part of the glaciers can still be saved through appropriate climate measures. In addition to the ETHZ, the University of Fribourg and the Research Institute for Forestry, Snow and Landscapes (WSL) also contributed to the study. This research is part of the project Gloria – l Global Initiative for Monitoring Research in Alpine Environments They are conducted at permanent sites in alpine regions around the world to monitor species and their evolution at regular intervals

Radio Subject: Alexandra Richard

Web article: Stephanie Jacquet and the ATS