Arctic Report Card 2020: Coastal Permafrost Erosion

Permafrost coasts in the Arctic make up more than 30% of Earth's coastlines (Fig. 1; Lantuit et al. 2012) and they are sensitive to Arctic Ocean/permafrost-influenced land linkages (Nielsen et al. 2020). The changes currently taking place along these coasts are both indicators and integrators of changes occurring in the global climate system. Reductions in sea ice extent and increases in the duration of the open water period (see essay Sea Ice), rising air (see essay Surface Air Temperature) and sea surface temperatures (see essay Sea Surface Temperature), absolute and relative sea-level rise (see essay Greenland Ice Sheet), warming permafrost (Biskaborn et al. 2019), subsiding permafrost landscapes (Lim et al. 2020), and increased storminess and wave heights (Casas-Prat and Wang, 2020) all interact to amplify coastal permafrost erosion (Forbes, 2011). Recent changes in these conditions have increased the vulnerability of permafrost coasts to erosion and altered coastal morphologies (Farquharson et al. 2018), ecosystems (Fritz et al. 2017), carbon export to oceans (Tanski et al. 2019), infrastructure (Fritz et al. 2017), and human subsistence lifestyles (Irrgang et al. 2018).