Rapid CO 2 Release From Eroding Permafrost in Seawater

• Published in: Geophysical Research Letters
• Main Authors: Tanski, G., Wagner, D., Knoblauch, C., Fritz, M., Sachs, T., Lantuit, H.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2019
• Subjects: Arctic; carbon cycling; climate warming; coastal erosion; greenhouse gases; permafrost; /dk/atira/pure/sustainabledevelopmentgoals/climate_action; name=SDG 13 - Climate Action; /dk/atira/pure/sustainabledevelopmentgoals/life_below_water; name=SDG 14 - Life Below Water
• Online Access: https://research.vu.nl/en/publications/5b85740e-5900-4ff8-b3f5-c6660bd1b1ce; https://doi.org/10.1029/2019GL084303; https://hdl.handle.net/1871.1/5b85740e-5900-4ff8-b3f5-c6660bd1b1ce; http://www.scopus.com/inward/record.url?scp=85074801663&partnerID=8YFLogxK; http://www.scopus.com/inward/citedby.url?scp=85074801663&partnerID=8YFLogxK

Permafrost is thawing extensively due to climate warming. When permafrost thaws, previously frozen organic carbon (OC) is converted into carbon dioxide (CO 2 ) or methane, leading to further warming. This process is included in models as gradual deepening of the seasonal non-frozen layer. Yet, models neglect abrupt OC mobilization along rapidly eroding Arctic coastlines. We mimicked erosion in an experiment by incubating permafrost with seawater for an average Arctic open-water season. We found that CO 2 production from permafrost OC is as efficient in seawater as without. For each gram (dry weight) of eroding permafrost, up to 4.3 ± 1.0 mg CO 2 will be released and 6.2 ± 1.2% of initial OC mineralized at 4 °C. Our results indicate that potentially large amounts of CO 2 are produced along eroding permafrost coastlines, onshore and within nearshore waters. We conclude that coastal erosion could play an important role in carbon cycling and the climate system.