As the Arctic melts, carbon creeps out

New research on how permafrost melting in the Arctic releases carbon dioxide and methane show cause for concern, and some limited optimism.

We know that Arctic ice is melting. The latest Snow Water, Ice, and Permafrost Assessment  (SWIPA) estimate showed that the change is happening so fast that if things go along as before, there will probably no ice coverage of the Arctic at all during the summer by the end of the 2030s.

This has led to both excitement and consternation. Excitement among nations on what that might mean for transport and mineral extraction, consternation because the water from the melting ice will flood nations and displace millions of people that live along the coastline – many of them in poor nations like Bangladesh, India and Pakistan.

We are now learning more about an additional consequence which is likely to supercharge global warming – the release of carbon deposits from the peatlands buried under the Arctic permafrost.

Unaccounted carbon in the Arctic

recent study has some detail on how this may add to our challenges. To give an idea of what is at stake, the research paper mentions that permafrost soils in the Arctic store “~1035 Pg ( around 1,035 billion tons) of organic carbon in the upper 3 metres”.

This amount of carbon would overwhelm our ability to keep global temperature rise below 2 degrees Celsius as pledged by all nations (except the US) in the Paris Climate Agreement, leave alone the aspiration to limit warming to 1.5 degrees Celsius above the pre-industrial level.

Permafrost carbon release has been poorly understood, partially because it is difficult to study in laboratory conditions as well as in the field.

The new paper by researchers from Canada, Scandinavian countries and Germany states, “the magnitude of this permafrost–C feedback is poorly constrained (McGuire et al., 2018) and not included in current Intergovernmental Panel on Climate Change projections, likely underestimating the climate feedback of the Arctic. Recent climate simulations predict an additional warming of ~0.2°C caused by permafrost C loss by the end of this century.”

In this study, the scientists dug out 16 sections of peat permafrost from Finnish Lapland, half of them bare, half of them covered in vegetation, and moved them to laboratories where they were frozen, and the conditions of the Arctic simulated.  

After storage for five months at -5 degrees Celsius, the samples were allowed to unfreeze in controlled stages over 32 weeks, and the release, as well as the method of release, of both carbon dioxide and methane (which has a warming potential 30 times higher than carbon dioxide) from the permafrost.

Their studies showed an initial peak of carbon dioxide release, as well as a continuing slow release of carbon dioxide as the permafrost melts. The good news, though, was that methane was not released in large abundance, and in dry conditions, the peat could act as a methane sink. This is an important discovery, and one that may help countries deal with the issue as the Arctic ice melts.

There are two additional challenges that the study does not focus on, but is worth thinking about. First, the Arctic is melting very fast, and thus the scope for quick response is difficult. Second, the Arctic is not the only place where the permafrost is melting. As the International Centre for Integrated Mountain Development’s recently-released HIMAP report made clear, higher temperatures in the Hindu Kush Himalayan region are also creating a more active permafrost layer.

It is unclear how much carbon will be released from the Himalayan region, the world’s largest reservoir of frozen was after the two poles but still one of the most understudied transboundary regions in the world. Given the latest round of conflict between India and Pakistan, in which China was also involved at a secondary level, cooperation on research looks increasingly difficult.

This story was published with permission from The Third Pole.

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