Thawing Arctic permafrost hampers CO2 absorption in the Arctic Ocean



Embargoed until:

Publicly released:

2024-08-13 01:00

Increasing coastal erosion may be reducing the Arctic Ocean’s ability to absorb carbon dioxide, according to an international modelling study. The projections found that the annual increase in atmospheric carbon dioxide due to permafrost erosion by 2100 may be equivalent to about 10% of European car emissions in 2021. The authors say that the Arctic is warming four times faster than the rest of the globe, and the thawing of Arctic permafrost (ground that is frozen all year round) is allowing for faster coastal erosion in the region, which is projected to increase by a factor of 2–3 by the year 2100, increasing the supply of organic matter from the land into the ocean. According to the modelling study, previous climate modelling may have misrepresented the Arctic Ocean’s uptake of carbon dioxide from the atmosphere, by not including the areas worst affected by coastal erosion, which release more carbon than they absorb.

Journal/conference: Nature Climate Change

Link to research (DOI): 10.1038/s41558-024-02074-3

Organisation/s: Max Planck Institute for Meteorology, Germany



Funder: D.M.N., J.M., M.M., J.B., V.B. and T.I. are funded by the Deutsche
Forschungsgemeinschaft (DFG, German Research Foundation)
under Germany’s Excellence Strategy – EXC 2037 ‘CLICCS – Climate,
Climatic Change, and Society’ – project no. 390683824, contribution
to the Center for Earth System Research and Sustainability (CEN) of
Universität Hamburg, and to the Max Planck Institute of Meteorology.
J.B. and S.B. were supported by Copernicus Climate Change
Service, funded by the EU, under contract C3S2-370. D.M.N., F.C.,
M.D., T.I. and V.B. are funded by EU Horizon 2020 research and
innovation programme under grant agreement no. 773421 – project
‘Nunataryuk’. F.C., J.M. and T.I. are funded by the EU Horizon 2020
research and innovation programme under grant agreement no.
101003536 (ESM2025-Earth System Models for the Future).

Media release

From: Springer Nature

Climate change: Arctic ocean may absorb less CO2 than projected due to coastal erosion Increasing coastal erosion may be reducing the Arctic Ocean’s ability to absorb carbon dioxide, according to a modelling study published in Nature Climate Change. The authors project that the annual increase in atmospheric carbon dioxide due to permafrost erosion by 2100 may be equivalent to about 10% of European car emissions in 2021.The Arctic is known to be particularly sensitive to climate change as a result of human activity and is warming about four times faster than the rest of the planet. Rising temperatures increase the thawing of Arctic permafrost (ground that is frozen all year round) allowing for faster coastal erosion in the region, which is projected to increase by a factor of 2–3 by the year 2100. This erosion increases the supply of organic matter from the land into the Arctic Ocean, but the consequences of this on the biological and chemical processes in the water column are unclear.David Nielsen and colleagues utilized an Earth system model to test how increased carbon and nutrient levels could affect the Arctic Ocean’s future seasonal carbon dioxide cycle. They found that previous climate modelling may have misrepresented the Arctic Ocean’s uptake of carbon dioxide from the atmosphere, by not including the areas worst affected by coastal erosion, which release more carbon than they absorb. This occurs because eroded organic matter is quickly metabolized by bacteria that release carbon dioxide, which increases surface water acidity so that less atmospheric carbon dioxide can be absorbed.This erosion is projected to reduce carbon dioxide uptake from the atmosphere by up to 13.2 billion kilograms of carbon per year by 2100, which is about 7–14% of the inner Arctic Ocean uptake. Nielsen and colleagues also projected that coastal permafrost erosion may exert a positive feedback loop on the climate, increasing atmospheric carbon dioxide by 1–2 billion kilograms of carbon per year for every degree Celsius that global surface air temperature increases.

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