Saharan dust accelerates the melting of Alpine glaciers

Global warming is the main cause of the disappearance of Alpine glaciers. But another, much more discreet phenomenon is also contributing to accelerating their melt : mineral dust carried by winds from the Sahara. After travelling thousands of kilometres, these particles settle on snow and ice, darkening their surface. Snow albedo decreases : it reflects less solar radiation, absorbs more energy, and melts more quickly.

A study conducted on the Argentière Glacier, in the Mont Blanc massif, shows that these deposits were responsible for 9 to 15% of summer melt between 2019 and 2022. In some areas of the glacier, their contribution reached nearly 25%. The year 2022, marked by a snow-poor winter, several episodes of Saharan dust and exceptional heatwaves, particularly illustrates this phenomenon : the impact of the dust was then almost twice as high as in previous years, locally resulting in the equivalent of around one additional metre of ice melting.

For scientists, these findings show that it is essential to incorporate desert dust and other particles that darken snow into models simulating glacier evolution. This issue extends far beyond the Alps : in regions such as the Andes and the Himalayas, where millions of people depend on water from glacier melt, better anticipating these mechanisms is becoming a major challenge.

References

Léo Roussel, Marie Dumont, Matthias Réveillet, Delphine Six, Maxime Kneib, Paola Nabat, Kevin Fourteau, Diogo Monteiro, Simon Gascoin, Emmanuel Thibert, Antoine Rabatel, Jean-Emmanuel Sicart, Mathieu Bonnefoy, Luc Piard, Olivier Laarman, Benjamin Jourdain, Mathieu Fructus, Matthieu Vernay & Matthieu Lafaysse, Saharan dust impacts on the surface mass balance of Argentière Glacier (French Alps), The Cryosphere, 29 October 2025.
DOI : 10.5194/tc-19-5201-2025.

Local scientific contacts

• Marion Réveillet, IRD Research Scientist at the Institute of Environmental Geosciences (IGE-OSUG)
• Léon Roussel, PhD student at the Snow Research Centre (CEN-CNRM)

This article was written by Olivier Blot for IRD le Mag’.