Abstract

Arctic coasts that are composed of frozen deposits are extremely sensitive to climate change and human impact. They retreat with average rates of 1–2 m per year, depending on climatic and permafrost conditions. In recent decades, retreat rates have shown a tendency to increase. In this paper, we studied the coastal dynamics of two key sites (Ural and Yamal coasts) of Baydaratskaya Bay, Kara Sea, where a gas pipeline had been constructed. Based on multi-temporal aerial and satellite imagery, we identified coastal erosion rates at several time lapses, in natural conditions and under human impact, and discussed their temporal variability. In addition to planimetric (m/yr), we calculated volumetric (m3/m/yr) retreat rates of erosional coasts using ArcticDEM. We also estimated the influence of geomorphology, lithology, and permafrost structure of the coasts on spatial variations of their dynamics. Erosional coasts of the Ural key site retreat with higher mean rates (1.2 m/yr and 8.7 m3/m/yr) as compared to the Yamal key site (0.3 m/yr and 3.7 m3/m/yr) due to their exposure to higher open sea waves, more complex lithology, higher ice content and lower coastal bluffs. Since the 1960s, coastal retreat rates have been growing on both coasts of Baydaratskaya Bay; we relate this effect with Arctic climate warming. From the 1960s to 2005, such growth was moderate, while in 2005–2016 it became rapid, which may be explained by the enhanced wave and thermal action or by the onset of industrial development. The adjacent coastal segments, originally accumulative, remained relatively stable from the 1960s to 2005. After 2005, a considerable part of them began to retreat as a result of changing weather conditions and/or increasing human impact.

Highlights

  • Permafrost coasts make up to 34% of the world’s coastlines and retreat with an average rate of 0.5 m/yr [1]

  • We studied the coastal dynamics of two key sites (Ural and Yamal coasts) of Baydaratskaya Bay, Kara Sea, where a gas pipeline had been constructed

  • As the principal aim of the study was the analysis of coastal dynamics in permafrost conditions, we mainly focused on erosional segments composed of frozen deposits

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Summary

Introduction

Permafrost coasts make up to 34% of the world’s coastlines and retreat with an average rate of 0.5 m/yr [1]. Coastal erosion accelerated in most of the polar regions due to rapid climate change, with its impact on the Arctic two times larger than on the rest of the world [7,8]. The decline of sea ice extent [9,10], storm frequency increase [11,12], thermal and wave action growth [13], and sea-level rise [14] have a dramatic impact on the arctic coastal dynamics [15,16,17,18,19,20]. S.R.; Wolfe, S.; Solomon, S.M. Influence of ground ice and permafrost on coastal evolution, Richards Island, Beaufort Sea Coast, NWT.

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