Permafrost is frozen soil that, as the name suggests, is permanently frozen soil or soil that is below freezing point temperatures year-round. This happens within the ‘permafrost zone’ which embodies predominantly polar regions. These polar regions are succumbing to the effects of climate change at a much more rapid pace compared to the rest of the globe, particularly the Arctic which has seen record low ice extents this summer. Permafrost is also one of the largest sinks of carbon on our planet, storing twice as much as the atmosphere.
When temperatures increase above the usual climatic range for an extended period, the thawing begins. This thawing (think melting), activates microbial decomposition of organic matter which releases carbon dioxide, methane and nitrous oxide. If this process happens gradually, we can expect much, but not all, of the emissions to be washed away and buried in sediments or sink to the depths of the ocean, however, if it happens abruptly it can release emissions much faster. As you can imagine, human-induced climate change has the potential to cause rapid and abrupt thawing.
Why is this of concern to scientists? Firstly, it seemingly is occurring sooner than previously expected. Secondly, because of those aforementioned stored emissions; one could assume that if all stored gasses were released into the atmosphere, our fight to keep temperatures below 1.5 degrees, or even 2 degrees, frivolous. But lastly, the potential for a positive feedback loop causing rapid runaway warming is possible. If the greenhouse gasses are released abruptly and cause rapid warming, then it will lead to further gasses being released even sooner and ultimately creating a continuous cycle of rapid warming.
If we continue on our worst-case-scenario 8.5 (RCP) emissions reductions; recent modelling suggests we can expect 23-174Pg of carbon released by 2100 (and then the release will rapidly continue post 2100. For context, we emitted about 9.5Pg per year from 2009-2018. If we see progressive policy and more serious action by global governments, we may see RCP 4.5 obtained in which case the permafrost thawing is likely to release just 6-33Pg of carbon by 2100. This modelling which was explained in the science journal Nature is still early in our understanding of the new field of permafrost melting. The concerning aspect of all of this is the reality that many of the current trajectories that we continue to record and see are on par with the worst-case scenario.
Should you be worried? Probably. Should you lose hope? No. We can still reduce the worst of the climate crisis. We have the technology, the potential, the possibility. The only barriers we now face are political, corporate and individual will.
Information sourced from Nature (2020) https://www.nature.com/articles/s41561-020-00668-y
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