Rock glaciers on a rapid descent

Rock glaciers, like here in the Swiss Valais, are mixtures of debris and ice and typical forms of alpine permafrost that slowly creep downhill. Photo: Kellerer-Pirklbauer/Uni Graz

Whether in Siberia, Alaska or the Alps – rising temperatures are affecting permafrost worldwide. In the high mountains, this can be seen in what are known as rock glaciers. These forms, reminiscent of lava flows, are a mixture of debris and ice that does not thaw on the inside all year round. They slowly creep downhill, whereby the rate of movement is mainly related to the thermal regime of the permafrost body. Based on long-term observation data, an international study has now shown for the first time for the entire Alpine region that the velocity of rock glaciers, which has increased overall since the 1990s, is a reliable climate indicator. The research results were recently published in the scientific journal "Environmental Research Letters".

Actively creeping rock glaciers can be found in the Alps from an altitude of around 2300 metres above sea level. "As long as their ice content is high enough, these forms of permafrost move downhill," explains Andreas Kellerer-Pirklbauer from the Department of Geography and Regional Science at the University of Graz. He is the lead author of the current publication, in which colleagues from Graz University of Technology, the University of Innsbruck and the Austrian Academy of Sciences are also involved.

The study compares rock glacier velocities across the entire Alpine arc. And these have been increasing overall since the 1990s, even if there have been phases of slowdown in between. "Higher temperatures and more ground moisture accelerate the movement of the interesting debris-ice mixtures. When it gets colder, the speed decreases. But even if the ice content falls below a certain limit and the internal friction increases, the creep rate slows down. If the permafrost ice melts completely, the landform comes to a standstill and becomes a relic landform of the former permafrost expansion," explains Kellerer-Pirklbauer.

For the study, 23 scientists used observation data from France, Italy, Austria and Switzerland from 1995 to 2022 and compared the rock glacier velocity values. "Among other things, the analysis revealed that the westernmost and easternmost of the more than 40 rock glaciers were quite similar in their movement behaviour. This means that they accelerate and decelerate to a similar extent at the same time, even though they are 570 kilometres apart," Kellerer-Pirklbauer reports a remarkable result. "This clearly shows that their speed is controlled by the climate. Our work thus provides profound evidence that rock glacier velocity is a product of the Essential Climate Variable (ECV) Permafrost and critically contributes to the characterisation of Earth's climate," says the researcher. The ECVs were defined by the Global Climate Observing System (GCOS) to provide a picture of climate change on a global scale.

The study authors suggest including more rock glaciers in the long-term monitoring. This data could provide additional valuable information on the effects of the expected evolution of climate.

Publication
Acceleration and interannual variability of creep rates in mountain permafrost landforms (rock glacier velocities) in the European Alps in 1995–2022
Andreas Kellerer-Pirklbauer et al.
Environmental Research Letters, Feb. 2024
DOI 10.1088/1748-9326/ad25a4

Gudrun Pichler

Related news

Legal scholar Clarissa Groß on European values at the EU’s external borders

The tense situation in the Spanish exclave of Ceuta has been making headlines for weeks. The exodus of thousands of Moroccans has once again placed migration and border policy at the very top of the EU’s agenda. Clarissa Groß, a research assistant at the Institute for European Law, is examining the reform of the Common European Asylum System (CEAS), the design and practical implementation of the new border procedures, and their compatibility with the right to personal liberty as part of her doctoral thesis. She recently visited the Greek island of Lesbos, which remains a migration hotspot, to assess the situation on the ground.

Graz is a magnet for 750 physicists: international conference on campus

Whether in mobile phones, medical devices or solar power systems: physical phenomena are part of our everyday lives. The vast scope of this discipline will be explored at a major conference taking place at the University of Graz from 20 to 25 September 2026. More than 750 scientists will transform the campus into a European hub for physics.

A fresh start, a calling, holidays: what draws people from other career paths to teaching

They used to develop software; now they teach maths in the classroom. Career changers are expected to help address the shortage of qualified teachers in Austria’s schools. In their doctoral theses at the Institute for Educational Research and Teacher Training at the University of Graz, Melanie Gürentz and Claudia Mair examined how these new teachers perceive their new professional roles.

Talent Talks bridge the gap in career guidance

The Styrian Chamber of Commerce (WKO Steiermark), the Styrian Chamber of Labour (AK Steiermark) and the AMS are joining forces when it comes to training young people and, through the “Talent Talks”, are creating a seamless pathway to career guidance. This takes preparation and follow-up support – just in time for the start of the term and the scheme’s tenth anniversary – to a whole new level. A new survey conducted by the Talent Centre among 2,687 former participants to mark the anniversary shows just how important this development is. Of the young people who received follow-up support from the Talent Report, 74.6 per cent stated that they had a good understanding of their own strengths and talents following the Talent Check. Without follow-up support, the figure was 66.5 per cent – a significant difference of 8.1 percentage points.