Coastlines' contribution to climate change might have been underestimated
8-NOV-2019
Erosion of permafrost coasts in the Arctic could vent major amounts of CO2
GFZ GEOFORSCHUNGSZENTRUM POTSDAM, HELMHOLTZ CENTRE
MAGE: SHORELINE RETREAT AND EROSION ALONG ARCTIC COASTS (QIKIQTARUK- HERSCHEL ISLAND, YUKON TERRITORY, CANADA) RAPIDLY MOBILIZE ORGANIC CARBON FROM PERMAFROST DEPOSITS, WHICH CAN BE TRANSFORMED QUICKLY INTO CARBON DIOXIDE OR METHANE. view more
CREDIT: G. TANSKI, VRIJE UNIVERSITEIT AMSTERDAM
Permafrost coasts make up about one third of the Earth's total coastline. As a result of accelerated climate change, whole sections of coastline rapidly thaw, and erode into the Arctic Ocean. A new study published in the journal Geophysical Research Letters now shows that large amounts of carbon dioxide are potentially being produced along these eroding permafrost coastlines in the Arctic.
"Carbon budgets and climate simulations have so far missed coastal erosion in their equations even though it might be a substantial source of carbon dioxide," says George Tanski of Vrije Universiteit Amsterdam, lead author of the study. "Our research found that the erosion of permafrost coastlines can lead to the rapid release of significant quantities of CO2, which can be expected to increase as coastal erosion accelerates, temperatures increase, sea ice diminishes, and stronger storms batter Arctic coasts."
The study was carried out during Tanski's time at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), and the GFZ German Research Centre for Geosciences. Co-Authors come from AWI, GFZ, and the Universities of Hamburg and Potsdam. The study is part of the Nunataryuk research project, coordinated by AWI. The project aims to analyse permafrost thaw, understand its impacts on indigenous communities and other populations, and develop mitigation and adaptation strategies.
Simulating erosion effects in the lab
For the new study, the researchers simulated the effects of erosion in a lab experiment. To find out how much carbon is released into the atmosphere along eroding Arctic permafrost coasts, they collected permafrost samples from Qikiqtaruk (also known as Herschel Island) off the northern coast of the Yukon in northwest Canada, and seawater from offshore. They mixed permafrost and seawater samples and then measured the greenhouse gases emitted over the course of four months, the average length of open-water season in the Arctic.
More:
https://www.eurekalert.org/pub_releases/2019-11/ggph-cct110819.php
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