Permafrost soils store large quantities of organic carbon and are often portrayed as a critical tipping element in the Earth system, which, once global warming has reached a certain level, suddenly and globally collapses.
Permafrost soils store large quantities of organic carbon and are often portrayed as a critical tipping element in the Earth system, which, once global warming has reached a certain level, suddenly and globally collapses. Yet this image of a ticking timebomb, one that remains relatively quiet until, at a certain level of warming, it goes off, is a controversial one among the research community. Based on the scientific data currently available, the image is deceptive, as an international team led by the Alfred Wegener Institute has shown in a recently released study. According to their findings, there is no single global tipping point; rather, there are numerous local and regional ones, which “tip” at different times, producing cumulative effects and causing the permafrost to thaw in step with climate change. As such, taking decisive action today is all the more important if our goal is to preserve as much permafrost as possible. The study was just released in the journal Nature Climate Change.
Permafrost ground covers roughly a quarter of the landmass in the Northern Hemisphere and stores tremendous quantities of organic carbon in the form of dead plant matter. As long as it remains frozen, this matter remains intact – but when permafrost thaws, microorganisms begin breaking it down, releasing large amounts of carbon into the atmosphere as CO2 and methane. Accordingly, rising temperatures worldwide could activate this massive reservoir and substantially worsen climate change through additional emissions. Consequently, in the public debate you’ll frequently encounter the idea of a “ticking carbon timebomb”. This is based on the assumption that the permafrost, like the Greenland Ice Sheet, is one of several tipping elements in the Earth system. In this view, permafrost will initially experience only gradual thawing in response to global warming; then, once a critical threshold value is surpassed, the thawing processes will suddenly begin amplifying one another, leading to the rapid and irreversible collapse of permafrost across the Arctic. Though many have speculated that this type of thawing scenario is possible, to date it has remained unclear whether there really is any such threshold value, and if so, what the corresponding temperature limit is.
Read more at: Alfred-Wegener-Institute
The eroding cliffs at Herschel Island. The Alfred Wegener Institute Helmholtz Center for Polar and Marine Research (AWI) commenced research in the western Canadian Arctic with the funding of the young researcher project titled Coastal Permafrost Erosion. (Photo Credit: Alfred Wegener Institute / Boris Radosavljevic)
