Heat waves are destroying Arctic permafrost


Heat waves are destroying Arctic permafrost

Heatwaves across the globe are rocking the climate this 2022 summer season. And they are all paying the price. Global warming, desertification and melting of the ice are now news that arrive every day. Arctic permafrost is melting faster and faster.

An international team of researchers from ETH Zurich, the University of Alaska Fairbanks and the German Aerospace Center has observed signs of topographical pitting, retrogressive thaw collapses, observed for over ten years.

The research was published in The Cryosphere journal: it demonstrates changes in the topography of the Siberian peninsula of Taymyr in northern Russia.
The results of the study reveal a sharp 43-fold increase in the regressive activity of thaw collapse and a 28-fold increase in carbon mobilization.

Heat waves are destroying Arctic permafrost

Philipp Bernhard, Institute of Environmental Engineering, ETH Zurich, explained: "The sharp increase in thaw activity due to the Siberian heat wave shows that carbon mobilization from permafrost soils can respond abruptly and non-linearly to the increase.

temperatures. " Collapses occur when permanently frozen layers of soil melt leaving Arctic slopes vulnerable to landslides. Landslides signal a risk for the potential release of carbon that has been stored in permafrost for tens of thousands of years.

Using satellite data, the research team was able to develop a new method for quantifying soil carbon mobilization of permafrost. The increase also coincides with an extreme heat wave that occurred in northern Siberia in 2020 in which temperatures would have reached 38 degrees Celsius, record temperatures for the Arctic region.

The permafrost has a particularly solid structure for fixing structures or building foundations. However, it must be considered that defrosting, even if temporary, can compromise this stability in the defrosted part, while it is obviously maintained in the part that remains frozen.

It is in fact necessary to consider that the term does not refer to a material but to the physical state of the same; very often this material with a solid structure in appearance, in normal conditions can be brittle, muddy or incoherent, so that even the support of roads and railways becomes more unstable.

In buildings that rest on permafrost, it is necessary to be placed on uniformly frozen ground or on equally stable ground in both states. The maintenance of the frozen soil, in case it is necessary, can be compromised by the very application of the structures, which transfer heat in depth, if of large dimensions.