despite a snowy winter, the melting of Swiss glaciers has been “massive” this year, warn glaciologists

Summer heat, the absence of fresh snow in summer and dust from the Sahara have led to significant melting of Swiss glaciers, even if the volume lost is less than in 2022 and 2023.

No respite for Swiss glaciers. Despite a very snowy winter, the summits lost 2.4% of their volume in the summer of 2024, announced Tuesday, October 1, the Swiss glaciological survey network Glamos in a study of the past hydrological year, which is between the 1st October 2023 and September 30, 2024. Melting, aggravated by climate change caused by greenhouse gas emissions resulting from human activities, is “a little more moderate” that in 2022 and 2023, two record years during which around 10% of the Swiss glacial volume had disappeared. It remains “massive again”, lamented Matthias Huss, director of the Glamos network, quoted by AFP.

In detail, the annual reduction in volume has fluctuated between -1% and -3% per year over the past two decades, with the exception of 2022 and 2023. But the 2.4% loss recorded this year exceeds the average for the decade 2010-2020, which amounted to 1.9%.

The glaciers “are on the verge of disappearing”insisted Mathias Huss. While the water resources of downstream areas depend on these glaciers, he recalled “the urgent need to act now, not in one, two or three decades” in the face of global warming. “They will only be here in 100 years if we manage to stabilize the climate”he insisted.

The volume loss calculated over the last 12 months remains “considerable given the snow cover which is significantly above average” which was prevalent in late winter, Glamos noted. Until June, Swiss glaciers benefited from exceptionally favorable conditions: winter snow 30% more abundant than average and a rainy start to summer. But that was without counting the summer heat. According to Météo Suisse, the average temperatures in July and August exceeded those of 2003 and 2022, themselves considered particularly hot. Furthermore, the absence of snowfall in July and August did not allow the snow cover to be renewed.

Finally, the coloring of the surface of the snow cover by dust coming from the Sahara in winter and spring accelerated the melting, making August the month with the greatest loss of ice since the beginning of measurements, Glamos further pointed out. This dark deposit on the ice leads to a reduction in the albedo effect, whereby the lighter a surface is, the more light and therefore heat it reflects.

Thus, if Glamos is not yet able to precisely quantify the effect of Sahara dust, the study estimates “plausible” an increase in melt rates of 10 to 20% compared to normal conditions due to this phenomenon.

Since the 19th century, the average temperature of the Earth warmed by 1.1°C . Scientists have established with certainty that this increase is due to human activities, which consume fossil fuels (coal, oil and gas). This warming, unprecedented in its speed, threatens the future of our societies and biodiversity. But solutions – renewable energies, sobriety, reduced meat consumption – exist. Discover our answers to your questions on the climate crisis.