Study: 21-25% Of Northern Permafrost Will Thaw @ "Safe" 1.5C Warming; Worst-Case 87% Loss By 2100
In the far north, the land is rippling, trembling, subsiding, and blowing up as greenhouse gasses are released from thawing frozen soil. Meanwhile, old diseases are being released from thawing carcasses and presenting a health hazard to locals. Strange processes that are likely to accelerate soon as global warming approaches 1.5 degrees Celsius and between 21 and 25.5 percent of all the vast region of Northern Permafrost thaws out.
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(More methane blowholes like this one in Yamal are likely as permafrost thaw accelerates in the coming years and pockets of methane explosively remove the land above. How extensive permafrost thaw becomes is directly dependent on how much fossil fuel human societies decide to burn. Image source: The Siberian Times.)
Carbon feedbacks from the thawing permafrost are a serious concern. And they should be. There’s about 1,400 billion tons of carbon locked away in that massive region of frozen ground. More than twice the amount humans have already emitted into the atmosphere. And though frozen permafrost carbon stays locked away, thawed permafrost carbon tends to become biologically active — releasing into soils, the water and the air.
Already, this thawing has generated a worrying effect. During the 20th Century, it was estimated that about 500,000 tons of methane were released from the Siberian land-based permafrost region. By 2003, as this permafrost zone warmed, the annual rate of release was estimated to be 3.8 million tons per year. And by 2013, with still greater warming, the rate of release had grown to 17 million tons per year. This compares to a global emission of methane from all sources — both human and Earth System-based — of about 500 million tons per year.
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But, unfortunately, these kinds of weird, disturbing, and often dangerous changes to northern environments are just a foreshadowing of more to come. For a recent scientific study has found that just 1.5 degrees Celsius worth of warming will force between 21 and 25.5 percent of the northern permafrost to thaw. A process that is already underway, but that will continue to accelerate with each 0.1 degree Celsius of additional warming. The study found that the faster human atmospheric greenhouse gas emissions build up, the more rapidly permafrost would thaw once the 1.5 C threshold was reached. Under a rapid human reduction of greenhouse gasses (RCP 2.6 scenario), permafrost thaw was reduced to 21 percent in the study. But under worst case human fossil fuel emissions (RCP 8.5 scenario), the accelerated rate of warming resulted in 25.5 percent permafrost thaw.
Perhaps more concerning was the fact that the study found that this 1.5 C temperature threshold was reached by as early as 2023 under the worst case fossil fuel burning scenario even as it was held off only to 2027 if rapid fossil fuel burning reductions were achieved. A broader sampling of studies and natural variability hold out some hope that 1.5 C might be pushed back to the early to mid 2030s in the absolute best case. However, considering the amount of human emissions already released and in the pipeline even under the best cases, it appears that crossing the 1.5 C threshold sometime in the near future is unavoidable at this time (barring some unforeseen massive global response and mobilization).
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(Permafrost losses under different human emissions scenarios through 2100 show that continued fossil fuel burning results in between 47 and 87 percent loss of permafrost area by 2100 [RCP 4.5 and 8.5]. Image source: Responses and changes in the permafrost and snow water equivalent in the Northern Hemisphere under a scenario of 1.5 C warming.)
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https://robertscribbler.com/2017/07/25/more-fire-and-anthrax-for-the-arctic-study-finds-21-to-25-percent-of-northern-permafrost-will-thaw-at-just-1-5-c-of-warming/
