Permafrost thaw impacts are wide, but not climate tipping point: study
An international research team has found that while permafrost is melting in sync with global warming, it is not contributing to a climate tipping point.
“The idea of permafrost being a global tipping element is a controversial one in the research community,” Jan Nitzbon, from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), and the paper’s lead author, said in a statement.
“Our goal was to close this gap in our knowledge.”
To do the study, published on Monday in the journal Nature Climate Change, the researchers did their own data analysis as well as examine existing academic literature on what influences and accelerates permafrost thaw.
They then used that information to determine the conditions under which thawing could lead to self-sustaining melting and a ‘tipping point’ on three levels: locally, regionally and globally.
After analyzing the data, they found that while some geological, water-related, and physical processes were self-amplifying and sometimes irreversible, these effects were only observed locally or regionally, not globally.
“There is no evidence of self-amplifying internal processes that, from a certain degree of global warming, affect all permafrost and accelerate its thawing globally,” Nitzbon said.
“Moreover, the projected release of greenhouse gases wouldn’t lead to a global upsurge in warming by the end of the century. As such, portraying the permafrost as a global tipping element is misleading.”
Lakes, forests and local amplification
One example of local amplification is thermokarst lakes, the result created when depressions on permafrost form once ice melts in the soil. The water collected here creates a large dark surface that collects solar energy and thus creates increased thawing around the lake.
Another local or regional example, is boreal wildfires which removes the insulating effect of tree cover from solar energy, meaning the ground absorbs more heat.
The researchers stressed however, that while their findings suggest melting permafrost won’t lead to an abrupt surge, it still carries significant far-reaching impacts.
They anticipate that as global warming progresses, melting will become more intense with complete thawing once global temperatures rise by five to six degrees from pre-industrial levels.
“That’s why we need to keep a close eye on the permafrost regions through even better monitoring, gain a better grasp of the processes involved, and represent them in climate models to further reduce the sources of uncertainty,” Nitzbon said.
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Related stories from around the North:
Canada: Makivvik launches climate adaptation strategy for Nunavik, Eye on the Arctic
Greenland: Alarming, above-average ice loss in Greenland due to rising temperatures, Eye on the Arctic
Finland: Experts urge policy overhaul to address climate tipping point risks, Eye on the Arctic
Norway: Polar heat record. July average above 10°C, The Independent Barents Observer
Sweden: Another year of shrinking glaciers predicted in Sweden’s Far North, CBC News
United States: Bursting ice dam in Alaska highlights risks of glacial flooding around the globe, The Associated Press
