Erosion of the Arctic coast linked to large-scale climate variability

Source: Geophysical research letters

The Arctic is warming faster than any other region on the planet. The increase in temperatures leads to a decrease in sea ice cover in terms of both concentration and duration. This has a profound effect on Arctic coastal margins as they are subjected to warmer air temperatures and exposed to more ocean waves that act to thaw previously frozen permafrost soils. Coastal permafrost erosion releases large amounts of previously stored carbon which can then exacerbate climate change, creating a vicious cycle.

Major observational monitoring sites in the Arctic Laptev Sea have been maintained for nearly 30 years and provide rare insight into how rates of coastal erosion vary in response to regional factors. Nielsen et al. [2020] find that most of the variability in coastal erosion can be attributed to changes in the length and concentration of sea ice cover in winter as well as to changes in atmospheric wind and temperature patterns in the large-scale air associated with the climatic mode of arctic oscillation.

Paradoxically enough, this is promising news for relatively coarse-resolution Earth System (ESM) models that have largely overlooked the role of Arctic coastal erosion in the carbon cycle. With typical grid scales of hundreds of kilometers, ESMs are inherently better equipped to improve their representation of large-scale factors of arctic climate variability rather than small-scale features of coastal erosion itself.

Quote: Nielsen, DM, Dobrynin, M., Baehr, J., Razumov, S., & Grigoriev, M. [2020]. Variability of coastal erosion south of the Laptev Sea linked to winter sea ice and arctic oscillation. Geophysical research letters, 47, e2019GL086876.

—Janet Sprintall, Editor, Geophysical research letters

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