Heat waves thawing Arctic permafrost

The northern part of the planet is melting at an accelerated rate. For more than a decade, an international team of researchers have observed topographical pock marks. When frozen layers of soil melt, the hillslopes are vulnerable to slides. The risk of the release of carbon that has been stored in the permafrost for tens of thousands of years was signaled by the slide.

There is a risk for the release of carbon.

Their findings have been published in the European Geosciences Union journal The Cryosphere. The study shows a big increase in retrogressive thaw slump activity and a big increase in carbon mobilization. The increase coincides with an extreme heat wave that occurred in northern Siberia in 2020 in which temperatures are said to have reached 38 degrees Celsius.

According to the paper's lead author, the increase in thaw slump activity is due to the rise in temperatures.

There are changes to the permafrost in the northern part of the planet.

The research team has been able to develop a new method to quantify carbon in the soil. There is no other large-scale method that can measure the changes in the permafrost regions. Researchers can give a more accurate estimate of the state of the carbon cycle.

Building on an earlier field and airborne flight study conducted in Canada, the researchers collected pre-study data that they used to compare and analyze satellite acquired data over the same region. The TanDEM-X mission was launched in 2010 to collect 3-dimensional elevation data over the ground. In addition to the radar data, researchers analyzed data obtained from the optical Sentinel-2 satellites deployed as part of the European Space Agency's Earth Observation mission.

Part of the carbon cycle in the north was neglected.

Siberia's Taymyr peninsula is a remote and nearly impossible place to conduct field studies. The summer heatwaves and warming arctic regions pose a significant environmental risk that are worth monitoring.

Approximately 1.5 trillion metric tons of organic carbon is encased in the permafrost of the north. The potential risks associated with this type of carbon mobilization is a major part of the carbon cycle. According to the research team, satellite remote sensing will be an indispensable tool for continuous monitoring of carbon movement due to melting permafrost.

More information: Philipp Bernhard et al, Accelerated mobilization of organic carbon from retrogressive thaw slumps on the northern Taymyr Peninsula, The Cryosphere (2022). DOI: 10.5194/tc-16-2819-2022

Philipp Bernhard and his team used single-pass tanDEM-X observations to map retrogressive thaw slumps. The article is titled "JSTARS.2020.3000648".

Journal information: The Cryosphere