Coastal Erosion Variability at the Southern Laptev Sea Linked to Winter Sea Ice and the Arctic Oscillation. Issue 5 (2nd March 2020)

• Record Type: Journal Article
• Authors: Nielsen, David Marcolino; Dobrynin, Mikhail; Baehr, Johanna; Razumov, Sergey; Grigoriev, Mikhail
• Is Part Of: Geophysical research letters. Volume 47:Issue 5(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-03-02
• Subjects: Arctic coastal erosion -- interannual variability -- Laptev Sea -- principal components; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2019GL086876
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Arctic coastal erosion experiences pronounced effects from ongoing climate change. The Laptev Sea figures among the Arctic regions with the most severe erosion rates. Here, we use unprecedentedly long records of almost 30 years of annual in‐situ coastal erosion rate measurements from Bykovsky Peninsula and Muostakh Island to separate the main modes of variability, which we attribute to large‐scale drivers. The first (lower‐frequency) and second (higher‐frequency) modes are associated with winter sea‐ice cover in the Laptev Sea and with the Arctic Oscillation, respectively, which together account for 85 . 1 ± 24 . 1 % of the total observed variance. Arctic coastal erosion has so far been neglected in Earth system models (ESMs). The proposed mechanisms set favorable conditions for coastal erosion at large scales (synoptic to planetary scales), compatible with those represented in modern ESMs. Plain Language Summary: The Arctic coasts are vulnerable to the effects of ongoing climate change. Increasing temperatures and decreasing sea‐ice cover cause permanently frozen soil to thaw and coastal erosion to take place, releasing substantial amounts of carbon to the ocean and atmosphere. Here, we use almost 30 years of coastal erosion observations from Bykovsky Peninsula and Muostakh Island at the southern Laptev Sea, which figure among the most severely eroding regions in the Arctic. We link the year‐to‐year changes in erosion rates with large‐scale mechanisms and show that coastal erosion can be mainly explained by changes in sea ice and in the Arctic Oscillation, which set favorable conditions for coastal erosion in large scales (hundreds of thousands of kilometers or larger). Modern climate models are not yet able to represent processes that take place in scales smaller than hundreds of kilometers, while are able to represent the large‐scale climate circulation, including wind and pressure changes, to which our proposed drivers directly respond. Finally, Arctic coastal erosion is a relevant component of the Arctic carbon cycle and has been neglected in climate models so far. Our results allow us to bridge Arctic coastal erosion and large‐scale climate variability. Key Points: Long‐term records of coastal erosion rates from Bykovsky Peninsula and Muostakh Island are compared with a global climate reanalysis The first two main modes of coastal erosion variability account for ∼ 85% of the total variance and are attributed to large‐scale mechanisms The first and low‐frequency mode is driven by changes in sea ice; the second and high‐frequency mode is linked to the Arctic Oscillation