An article published by the European Geosciences Union takes stock of the retreat of the snow line from Arctic glaciers over the last forty years, while NASA has just released disturbing images of the glaciers of Svalbard.
One hundred and fifty-two meters. This is the average rise of the snow line on Arctic glaciers over the last 40 years.
These are the conclusions of research published on August 15 on the European Geosciences Union (EGU) website. All located above the 60th parallel, the 269 glaciers included in the study were carefully analyzed by researchers, who examined images taken by Landsat satellites between 1984 and 2022.
And what the research team, led by Laura J. Larocca, assistant professor at Northern Arizona University, has discovered is disturbing, to say the least: the snow line of Arctic glaciers has been steadily rising over the past few decades. Let’s remind that glaciers are formed by snowfalls that accumulate and settle. The air contained in the snow is then expelled and transformed into ice.
Constantly in motion, the mass of ice that makes up a glacier must be renewed. This is why part of the glacier is formed by the accumulation zone, where snowfall is transformed into ice. This zone, delimited by the snow line, corresponds to the part of the glacier where the snow does not melt, even in summer, thus protecting the ice already accumulated.
However, if this snow line rises in altitude, the ice is exposed and will melt more.
But that’s not all. The researchers also noted an overall decrease in snowfall, an increase in precipitation and a reduction in the total number of days with a daily mean temperature of 0°C or less.
These combined effects are likely to have a major impact on the future of Arctic glaciers. According to the authors of the study, 50% of the glaciers studied could see their snowline disappear completely in summer by 2100 if the observed trend continues.
An observation already corroborated by NASA observations over Svalbard.
Taken on August 9 and published on the space agency’s website under the evocative title ” Svalbard melts “, Landsat 8 satellite images show Nordaustlandet, the island to the north-east of the archipelago, in a sorry state.
The cause is global warming, which has hit Svalbard hard, combined with a torrid summer that saw temperatures soar. On August 11, Svalbard’s capital, Longyearbyen, set its latest heat record at 20.3°C, four degrees above the usual average.
As a result, seasonal snow and older snow melted, exposing glacier ice zones and breaking a sad record in the process. On July 23, Svalbard dumped 55 millimetres of water equivalent, five times higher than normal.
This gigantic melt probably released large quantities of sediment into the waters surrounding Nordaustlandet, which can be seen in the form of coloured eddies escaping from the coast. At present, it’s difficult to know what impact this high concentration of sediment might have on marine organisms that need light for their development and survival.
Mirjana Binggeli, Polar Journal AG
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