The Swiss Commission for the Observation of the Cryosphere, of the Swiss Academy of Sciences, has no qualms about using the term "catastrophic" for the years 2022 and 2023 to refer to the impact that the high temperatures recorded in this period have had on the ice masses of the peaks of the Swiss country.
The figures are more than eloquent: in 2022 there was a 6% reduction in the volume of ice in Switzerland's glaciers and so far in 2023 there has been a 4% decrease. In round figures, 10% less ice in just two years.
"Swiss glaciers are melting at an increasing rate. The acceleration is spectacular: in just two years, as much ice was lost as between 1960 and 1990," summarizes this specialized commission in the information note published this week.
The two consecutive extreme years have caused glacier tongues to collapse and many smaller glaciers to disappear. As a result, for example, measurements of the St. Annafirn glacier in the canton of Uri had to be suspended.
This massive ice loss is the result of a winter with very low snow volumes and high temperatures during the summer. The melting of glaciers affected the whole of Switzerland: glaciers in southern and eastern Switzerland melted almost with the same intensity as in the record year of 2022. In southern Valais and the Engadine Valley, melting of several meters at a level higher than 3,200 meters, an altitude at which the glaciers had maintained their balance until recently.
The average ice thickness loss here is up to 3 meters (e.g. the Gries glacier in Valais, the Basòdino glacier in the canton of Ticino and the Vadret Pers glacier system in Grisons) and is considerably higher than the values recorded in the hot summer of 2003. The situation between the Bernese Oberland and Valais is less dramatic (for example, the Aletsch glacier in Valais and the Plaine Morte glacier in the canton of Bern), since more snow accumulates during the winter. However, a loss of more than 2 meters of average ice thickness is extremely high.
In the winter of 2022/2023 there was hardly any precipitation on both sides of the Alps and temperatures were very high. As a result, much less snow than usual was observed in all seasons. Conditions at levels above 1,000 m are highlighted in February and early March. The snow layers measured in the first half of February were generally somewhat higher than in the winters of 1964, 1990 or 2007, which were characterized by low snowfall. However, snow levels fell to a new record in the second half of February, reaching only around 30% of the long-term average. More than half of the automated stations above 2,000 meters with a minimum of 25 years of measurement series also indicated new record low levels.
The situation briefly returned to normal in spring, but a dry and extremely warm June caused the snow to melt 2 to 4 weeks earlier than usual. The third warmest summer since measurements began and a record zero degree line, which lasted until September, were responsible for some summer snowfalls generally melting very quickly, which did not help the situation of the glaciers, it indicates the Swiss Commission for the Observation of the Cryosphere of the Swiss Academy of Sciences.
