The report concludes that permafrost ecosystems could be releasing as much as 1.1 to 2.2 billion tons of carbon dioxide per year — almost as much as the 2018 annual emissions of Japan and Russia, respectively
The Arctic is undergoing a profound, rapid and unmitigated shift into a new climate state, one that is greener, features far less ice, and is a net source of greenhouse gas emissions from melting permafrost, according to a major new federal assessment of the region released Tuesday.
The consequences of these climate shifts will be felt far outside the Arctic in the form of altered weather patterns, increased greenhouse gas emissions, and rising sea levels from the melting Greenland ice sheet and mountain glaciers.
The findings are contained in the 2019 Arctic Report Card, a major federal assessment of climate change trends and impacts throughout the region. The study paints an ominous picture of a region lurching to an entirely new and unfamiliar climate state.
Especially noteworthy is the report’s conclusion that the Arctic may have already turned into a net emitter of planet-warming carbon emissions due to thawing permafrost, which would only accelerate global warming. Permafrost is the carbon-rich frozen soil that covers 24% of Northern Hemisphere land area, encompassing vast stretches of territory across Alaska, Canada, Siberia and Greenland.
There has been concern throughout the scientific community that the approximately 1,460-1,600 billion metric tons of organic carbon stored in frozen Arctic soils, which amounts to nearly twice as much greenhouse gases than what is contained in the atmosphere, could be released as the permafrost melts.
Warming temperatures allow microbes within the soil to convert permafrost carbon into the greenhouse gases — carbon dioxide and methane — which can be released into the atmosphere and accelerate warming. Ted Schuur, a researcher at Northern Arizona University and author of the permafrost chapter, said the report “takes on a new stand on the issue” based on other published work, including a study in Nature Climate Change in November.