Several papers on permafrost thawing have been published in Nature Reviews Earth & Environment.
Comment below mainly refers to the paper on impacts of permafrost degradation on infrastructure:
Dr Poul Christoffersen, Glaciologist, Scott Polar Research Institute, said:
“Climate change is warming the permafrost and there is high confidence amongst scientists that this trend will continue. There is also high confidence that permafrost releases greenhouse gasses such as carbon dioxide or methane to the atmosphere when it thaws. Around 20% of land masses in the northern hemisphere contains permafrost, so there is a real risk of permafrost exacerbating climate change when it thaws.
“However, the authors1 focus their study on the structural consequences of permafrost thaw and it is clear that the impact on infrastructure is high and growing. Continental permafrost covers 65% of Russia and 50% of Canada but permafrost thaw is equally a risk in high altitude regions such as the Tibetan Plateau and the word’s many mountain ranges. The authors estimate the current damage to infrastructure and estimate that 30-50% of all infrastructure in areas of permafrost will become structurally at risk if not compromised by mid-century. While there are engineering solutions that can alleviate the effects, they are expensive and not implementable given the scale of the problem.
“The authors recommend practical solutions such as better land-use planning and permafrost hazard mapping in order to reduce risk, but that doesn’t change the fact that much of the existing infrastructure in, or between, cities, town and communities has become structurally at risk because of climate change. The problem is that permafrost makes the ground solid when it is intact, but often much weaker when it thaws. Much of the infrastructure in cold regions across the globe were not designed to endure permafrost thaw.
“The growing risk of structural damage by permafrost thaw is in my view akin to the increased risk of flooding in coastal areas exposed to rising sea levels. There is only so much engineering solutions can do, which means many millions of people simply live with the growing risk until – of course – the cost of doing so becomes unacceptably high. In the Arctic there are many examples of villages that were abandoned due to flooding or coastal erosion. The logical next question is when similar steps are taken in response to the growing risk of permafrost thaw farther inland.
“Thawing permafrost is weakening the integrity of slopes, posing a real risk for communities in mountain regions. In 2017, a large portion of a mountain side fell almost 1 km into the sea in the Avannaata municipality in northern Greenland, killing four people and forcing the Greenland government to close the Nuugaatsiaq village and move all its inhabitants to another town. Displacements like this is devastating, especially for people who have a deep sense of belonging. “With permafrost covering one fifth of all land masses in the northern hemisphere, my expectation is that the economic and social costs of permafrost thaw is going to be very high.
“So, let’s return to the question of what we can do? Most scientists would probably agree that the sensible solution is to reduce our dependency of greenhouse gases and thereby lower the degrees to which our planet will warm. The cost of taking these steps may ultimately be cheap compared to the likely enormous cost of living in the utopia of “as is”, with the expectation that we can fix the climate problem without doing much at all.
“Note: we use the term ‘thaw’ rather of ‘melt’ for permafrost. This is because permafrozen ground contains rock or soil and other things that don’t necessarily melt.
“In terms of the speed of changes in the Arctic, they are rapid! The Arctic is warming roughly twice as fast as the global average due e.g. to loss of reflectance when ice disappears. I have spent many consecutive summers in Greenland and it is evident that rapid changes are taking place across the Arctic.”
1 ‘Impacts of permafrost degradation on infrastructure’ by Jan Hjort et al. was published in Nature Reviews Earth & Environment at 4pm UK TIME on Tuesday 11 January 2021.