Preprints
https://doi.org/10.5194/egusphere-2023-321
https://doi.org/10.5194/egusphere-2023-321
23 Mar 2023
 | 23 Mar 2023

Coastal retreat rates of high-Arctic rock cliffs on Brøgger peninsula, Svalbard, accelerate during the past decade

Juditha Aga, Livia Piermattei, Luc Girod, Kristoffer Aalstad, Trond Eiken, Andreas Kääb, and Sebastian Westermann

Abstract. In many Arctic regions marine coastlines change rapidly in the currently warming climate. In contrast, coastal rock cliffs on Svalbard are considered to be comparably stable, based on previous studies that considered only a few years and limited coastal reaches. Long-term trends of coastal retreat rates in rock cliffs on Svalbard are unknown so far, but their quantification could improve the understanding of coastal dynamics on the Arctic archipelago. This study presents coastal retreat rates in rock cliffs along several kilometers of the Brøgger peninsula, Svalbard. The work is based on high-resolution orthoimages from 1970, 1990, 2010, and 2021, corroborated by high-precision dGNSS measurements along selected segments of the coastline and by rock surface temperature measurements during the period 2020–2021. Our analysis shows that coastal retreat rates accelerate statistically significant along the Brøgger peninsula in the time period of 2010 to 2021. This is true for both the northeast facing coastline, with retreat rates increasing from 0.04 ± 0.06 m/a (1970–1990) and 0.04 ± 0.04 m/a (1990–2010) to 0.07 ± 0.08 m/a (2010–2021) and the southwest facing coastline, where retreat rates of 0.26 ± 0.06 m/a (1970–1990), 0.24 ± 0.04 m/a (1990–2010) and 0.30 ± 0.08 m/a (2010–2021) are measured. Furthermore, the parts of the coastline affected by erosion increase along the northeast facing coastline from 47 % (1970–1990) to 65 % (2010–2021), while they stay consistently above 90 % along the southwest facing coastline. Measurements of rock surface temperature show mean annual values close to the thaw threshold with −0.49 °C at the southwest facing coastline, while records at the northeast facing coastline are lower with −1.64 °C. The recently accelerated retreat rates coincide with increasing storminess and retreating sea ice, together with increasing ground temperatures, all factors that can enhance coastal erosion.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
Juditha Aga, Livia Piermattei, Luc Girod, Kristoffer Aalstad, Trond Eiken, Andreas Kääb, and Sebastian Westermann

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-321', Anonymous Referee #1, 19 Apr 2023
    • AC2: 'Reply on RC1', Juditha Aga, 26 Oct 2023
  • RC2: 'Comment on egusphere-2023-321', Anonymous Referee #2, 10 May 2023
    • AC3: 'Reply on RC2', Juditha Aga, 26 Oct 2023
  • RC3: 'Comment on egusphere-2023-321', Gregor Luetzenburg, 28 Jun 2023
    • AC1: 'Reply on RC3', Juditha Aga, 26 Oct 2023
Juditha Aga, Livia Piermattei, Luc Girod, Kristoffer Aalstad, Trond Eiken, Andreas Kääb, and Sebastian Westermann

Data sets

Supplementary data for "Coastal retreat rates of high-Arctic rock cliffs on Brøgger peninsula, Svalbard, accelerate during the past decade" Juditha Aga https://doi.org/10.5281/zenodo.7756973

Juditha Aga, Livia Piermattei, Luc Girod, Kristoffer Aalstad, Trond Eiken, Andreas Kääb, and Sebastian Westermann

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Short summary
Coastal rock cliffs on Svalbard are considered to be fairly stable, however, long-term trends of coastal retreat rates are unknown so far. This study presents changes in the coastline along Brøgger Peninsula, Svalbard, based on aerial images from 1970, 1990, 2010 and 2021. Our analysis shows that coastal retreat rates accelerate in the time period 2010–2021, which coincides with increasing storminess, retreating sea ice and increasing ground temperatures.