Coastal Permafrost Erosion

B. M. Jones¹, A. M. Irrgang², L. M. Farquharson³, H. Lantuit², D. Whalen⁴, S. Ogorodov⁵, M. Grigoriev⁶, C. Tweedie⁷, A. E. Gibbs⁸, M. C. Strzelecki⁹, A. Baranskaya⁵, N. Belova⁵, A. Sinitsyn¹⁰, A. Kroon¹¹, A. Maslakov⁵, G. Vieira¹², G. Grosse^2,13, P. Overduin², I. Nitze², C. Maio¹⁴, J. Overbeck¹⁵, M. Bendixen¹⁶, P. Zagórski¹⁷, and V. E. Romanovsky³

¹Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK, USA
²Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
³Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK, USA
⁴Natural Resources Canada, Geological Survey of Canada-Atlantic, Dartmouth, Nova Scotia, Canada
⁵Faculty of Geography, Lomonosov Moscow State University, Moscow, Russia
⁶Mel’nikov Permafrost Institute, Siberian Branch, Russian Academy of Sciences, Yakutsk, Russia
⁷Department of Biology, University of Texas El Paso, El Paso, TX, USA
⁸U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA, USA
⁹Institute of Geography and Regional Development, University of Wroclaw, Wroclaw, Poland
¹⁰SINTEF AS, SINTEF Community, Trondheim, Norway
¹¹Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
¹²Centre of Geographical Studies, Institute of Geography and Spatial Planning, University of Lisbon, Portugal
¹³Institute of Geosciences, University of Potsdam, Potsdam, Germany
¹⁴Geography, University of Alaska Fairbanks, Fairbanks, AK, USA
¹⁵Alaska Division of Geological & Geophysical Surveys, Anchorage, AK, USA
¹⁶Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, USA
¹⁷Institute of Earth and Environmental Sciences, Marie Curie Skłodowska University, Lublin, Poland

Highlights

• Since the early 2000s, erosion of permafrost coasts in the Arctic has increased at 13 of 14 sites with observational data that extend back to ca. 1960 and ca. 1980, coinciding with warming temperatures, sea ice reduction, and permafrost thaw.
• Permafrost coasts along the US and Canadian Beaufort Sea experienced the largest increase in erosion rates in the Arctic, ranging from +80 to +160%, when comparing average rates from the last two decades of the 20th century with the first two decades of the 21st century.
• The initiation of several national and international research networks in recent years has enabled closer coordination and collaboration of measurements and a better understanding of pan-Arctic permafrost coastal dynamics.

Introduction

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).

Changes in permafrost coasts are primarily due to erosion (Lantuit et al. 2012). However, coastal change rates have high temporal and spatial variability, which is driven largely by diversity in internal and external factors. For example, sediment composition, permafrost properties, and coastline exposure contribute to the spatial variability in coastline change, while changing hydrometeorological and ocean forcing conditions determine the temporal evolution of coastline change (Shabanova et al. 2018). The highest erosion rates occur in unconsolidated sediment deposits that represent 65% of permafrost coasts in the Arctic (Lantuit et al. 2012). The remaining 35% of permafrost coasts are classified as rocky or consolidated material that exhibit more stability. In unconsolidated permafrost coasts, the presence of ice-rich permafrost is a weak but statistically significant contributor to higher coastal erosion rates (Lantuit et al. 2012). The primary drivers of erosion of ice-rich permafrost coasts are summer warmth and solar radiation (thermo-denudation) and wave action (thermo-abrasion) (Aré 1988).

Historic and contemporary decadal-scale changes

Baseline measurements of both historic and contemporary permafrost coastal change were established through the collaborative international efforts of the Arctic Coastal Dynamics program in the late 1990s and early to mid-2000s (Brown and Solomon 2000; Rachold et al. 2005). Historical benchmarks of permafrost coastal change typically integrate observations collected between the 1950s and the 1980s, with those acquired in the early to mid-2000s (Fig. 2; Lantuit et al. 2012). Data were synthesized from field observations and remote sensing-based coastline datasets. Information was compiled on measures of erosion and accumulation occurring in a specific area, and the aggregate mean was reported.

Over the period ~1950 to ~2000, the mean Arctic-wide coastal permafrost change rate was -0.5 m yr^-1 (where negative values indicate erosion), with substantial variability within and among different regions (Lantuit et al. 2012). According to the primary subdivisions of the Arctic Ocean, change rates have historically been highest along permafrost coasts along the US and Canadian Beaufort Sea (-1.1 m yr^-1), East Siberian Sea (-0.9 m yr^-1), Laptev Sea (-0.7 m yr^-1), and Kara Sea (-0.7 m yr^-1). Sites that were historically at or below the mean Arctic-wide coastal permafrost change rate were the Russian (-0.3 m yr^-1) and US (-0.5 m yr^-1) Chukchi Seas, Barents Sea (-0.4 m yr^-1), Canadian Archipelago (0.0 m yr^-1), and Svalbard (-0.02 m yr^-1) (Lantuit et al. 2012).

Since the early 2000s, observations from 14 coastal permafrost sites have been updated, providing a synopsis of how changes in the Arctic system are intensifying the dynamics of permafrost coasts in the 21st century (Table 1; Fig. 2). Observations from all but 1 of the 14 coastal permafrost sites around the Arctic indicate that decadal-scale erosion rates are increasing. The US and Canadian Beaufort Sea coasts have experienced the largest increases in erosion rates since the early 2000s. The mean annual erosion rate in these regions has increased by 80 to 160% at the five sites with available data, with sites in the Canadian Beaufort Sea experiencing the largest relative increase. The sole available site in the Greenland Sea, on southern Svalbard, indicates an increase in mean annual erosion rates by 66% since 2000, due primarily to a reduction in nearshore sediment supply from glacial recession. At the six sites along the Barents, Kara, and Laptev Seas in Siberia, mean annual erosion rates increased between 33 and 97% since the early to mid-2000s. The only site to experience a decrease in mean annual erosion (-40%) was located in the Chukchi Sea in Alaska. Interestingly, the other site in the Chukchi Sea experienced one of the highest increases in mean annual erosion (+160%) over the same period. In general, a considerable increase in the variability of erosion and deposition intensity was also observed along most of the sites.

There is overwhelming evidence that erosion at ice-rich and ice-poor unconsolidated permafrost coasts is increasing in the Arctic since the early to mid-2000s when compared to decadal-scale measurements taken between ca. 1960 and ca. 1980. Higher and more fluctuating erosion rates reflect increasing coastal dynamics associated with intensified environmental changes. These larger-scale environmental changes include increases in summer air temperature, permafrost thaw and land subsidence, rising sea levels, reductions in sea ice cover and the resulting increase in open water period, and increasingly impactful storms. Combined, these changes have led to an increase in the effect of thermo-denudation and thermo-abrasion on permafrost coasts and document the cumulative effects of climate change on the Arctic System.

The future of permafrost-affected coastal research

Ongoing coastal issues in the Arctic transcend borders. A high proportion of Arctic residents live in the coastal zone, and many derive their livelihood from terrestrial and nearshore marine resources (Forbes 2011). Industrial, commercial, tourist, and military presence in the Arctic is expanding. Each will need to grapple with coastal permafrost erosion and the related impacts on the dynamics of the nearshore zone. The socio-economic consequences of an increasingly dynamic system will become a recurring theme and have a profound impact across the Arctic, influencing human decision making and adaptation planning. For example, take the remote Yupik Village of Newtok, Alaska, located in a zone of discontinuous permafrost along the Bering Sea. Annual erosion rates as high as 22 m yr^-1 along the low-lying bluffs of Newtok have reinforced its recent relocation efforts. In the Canadian Beaufort Sea, the natural deep-water harbor in the Hamlet of Tuktoyaktuk is protected by Tuktoyaktuk Island. This island is at risk of being breached in the next 20-25 years, exposing the harbor to larger waves and intensified erosion. With the increasingly rapid pace of environmental and social change, there is ever greater need for international collaboration between researchers and impacted local societies to focus on permafrost coasts in transition.

Fortunately, more accurate, frequent, and extensive mapping of permafrost coasts has been made possible by an increase in spatial and temporal earth observations from spaceborne and airborne platforms. Access to commercial high-resolution satellite imagery, available through national and international federally-funded research projects in the US, Europe, and Russia, has increased the number of observations by several orders of magnitude at specific key sites, relative to the previous 50 years. More readily available ancillary datasets on climate, sea ice, storms, and permafrost dynamics have increased our capacity to better model and predict future coastline positions and their impacts on infrastructure. The initiation of several national and international research networks, in recent years and in past decades, has enabled closer coordination and collaboration of measurements and a better understanding of permafrost coastal dynamics. Future efforts will focus on expanding the permafrost-affected coastal change knowledge base beyond the continuous permafrost region, to include vulnerable coasts located in the discontinuous permafrost zone as well as rocky permafrost coasts. Connections between researchers and Indigenous communities have increased beyond hub communities, which allows for a more informed dialogue and representation of key issues and the factors driving rapid changes along permafrost coasts. The formation of interdisciplinary research teams and increasing collaboration across knowledge systems, such as Western science and Indigenous knowledge, has increased the scope and breadth of studies being conducted along permafrost coasts as well as their societal relevance. Combined, these developments show great promise for understanding future changes in coastal permafrost dynamics and the potential impact on both the natural and built environments.

Acknowledgments

Benjamin Jones, Louise Farquharson, Craig Tweedie, Chris Maio, and Vladimir Romanovsky were supported by grants (OISE 1927553 and 1927137) from the US National Science Foundation Office of International Science and Engineering (OISE) and Office of Polar Programs (OPP). Anna Irrgang, Hugues Lantuit, Paul Overduin, and Gonçalo Vieira were funded by the EU project Nunataryuk (grant number 773421). Stanislav Ogorodov and Alexey Maslakov were funded by the Russian Science Foundation Project 16-17-00034 and the State Budget Theme AAAA-A16-116032810055-0. Alisa Baranskaya was funded by the Russian Foundation for Basic Research (RFBR) grant 20-35-70002. Ann Gibbs, U.S. Geological Survey, Coastal/Marine Hazards and Resources Program. Piotr Zagórski was supported from the project of the National Science Centre (Poland) No. 2013/09/B/ST10/04141, Matt Strzelecki was supported by NAWA Bekker Programme (PPN/BEK/2018/1/00306). Ingmar Nitze and Guido Grosse were funded by the ESA GlobPermafrost and ESA CCI+ Permafrost projects. Mette Bendixen is funded by The Danish Independent Research Council with grant number 8028-00008B.

References

Aré, F., 1988: Thermal abrasion of sea coasts. Polar Geography and Geology, 12, 1-157.

Belova, N. G., A. V. Novikova, F. Günther, and N. N. Shabanova, 2020: Spatiotemporal variability of coastal retreat rates at western Yamal Peninsula, Russia, based on remotely sensed data. J. Coastal Res., 95, 367-371, https://doi.org/10.2112/SI95-071.1.

Biskaborn, B. K., and Coauthors, 2019: Permafrost is warming at a global scale. Nature Comm., 10, 264, https://doi.org/10.1038/s41467-018-08240-4.

Brown, J., M. T. Jorgenson, O. P. Smith, and W. Lee, 2003: Long-term rates of coastal erosion and carbon input, Elson Lagoon, Barrow, Alaska. In Eighth International Conference on Permafrost, Vol 21, 101-107.

Brown, J., and S. Solomon, 2000: Arctic Coastal Dynamics-Report of an International Workshop, Woods Hole, MA, November 2-4, 1999. Geological Survey of Canada Open File 3929.

Casas-Prat, M., and X. L. Wang, 2020: Projections of extreme ocean waves in the Arctic and potential implications for coastal inundation and erosion. J. Geophys. Res.-Oceans, 125, e2019JC015745, https://doi.org/10.1029/2019JC015745.

Cunliffe, A. M., G. Tanski, B. Radosavljevic, W. F. Palmer, T. Sachs, H. Lantuit, J. T. Kerby, and I. H. Myers-Smith, 2019: Rapid retreat of permafrost coastline observed with aerial drone photogrammetry. Cryosphere, 13, 1513-1528, https://doi.org/10.5194/tc-13-1513-2019.

Farquharson, L. M., D. H. Mann, D. K. Swanson, B. M. Jones, R. M. Buzard, and J. W. Jordan, 2018: Temporal and spatial variability in coastline response to declining sea-ice in northwest Alaska. Mar. Geol., 404, 71-83, https://doi.org/10.1016/j.margeo.2018.07.007.

Forbes, D. L., 2011: State of the Arctic coast 2010: scientific review and outlook. Land-Ocean Interactions in the Coastal Zone, Institute of Coastal Research, 178 pp.

Fritz, M., J. E. Vonk, and H. Lantuit, 2017: Collapsing Arctic coastlines. Nat. Climate Change, 7, 6-7, https://doi.org/10.1038/nclimate3188.

Gibbs, A. E., B. M. Jones, and B. M. Richmond, 2020: A GIS compilation of vector shorelines and coastal bluff edge positions, and associated rate of change data for Barter Island, Alaska: U.S. Geological Survey data release, https://doi.org/10.5066/P9CRBC5I.

Grigoriev, M. N., 2019: Coastal retreat rates at the Laptev Sea key monitoring sites. PANGAEA, https://doi.org/10.1594/PANGAEA.905519.

Irrgang, A. M., H. Lantuit, G. K. Manson, F. Günther, G. Grosse, and P. P. Overduin, 2018: Variability in rates of coastal change along the Yukon coast, 1951 to 2015. J. Geophys. Res.-Earth, 123, 779-800, https://doi.org/10.1002/2017JF004326.

Jones, B. M., and Coauthors, 2018: A decade of remotely sensed observations highlight complex processes linked to coastal permafrost bluff erosion in the Arctic. Environ. Res. Lett., 13, 115001, https://doi.org/10.1088/1748-9326/aae471.

Lantuit, H., and Coauthors, 2012: The Arctic coastal dynamics database: a new classification scheme and statistics on Arctic permafrost coastlines. Estuar. Coasts, 35, 383-400, https://doi.org/10.1007/s12237-010-9362-6.

Lim, M., D. Whalen, J. Martin, P. Mann, S. Hayes, P. Fraser, H. Berry, and D. Ouellette, 2020: Massive ice control on permafrost coast erosion and sensitivity. Geophys. Res. Lett., 47, e2020GL087917, https://doi.org/10.1029/2020GL087917.

Nielsen, D. M., M. Dobrynin, J. Baehr, S. Razumov, and M. Grigoriev, 2020: Coastal erosion variability at the southern Laptev Sea linked to winter sea ice and the Arctic Oscillation. Geophys. Res. Lett., 47, e2019GL086876, https://doi.org/10.1029/2019GL086876.

Novikova, A., N. Belova, A. Baranskaya, D. Aleksyutina, A. Maslakov, E. Zelenin, N. Shabanova, and S. Ogorodov, 2018: Dynamics of permafrost coasts of Baydaratskaya Bay (Kara Sea) based on multi-temporal remote sensing data. Remote Sens., 10, 1481, https://doi.org/10.3390/rs10091481.

Rachold, V., F. E. Aré, D. E. Atkinson, G. Cherkashov, and S. M. Solomon, 2005: Arctic coastal dynamics (ACD): An introduction. Geo-Mar. Lett., 25, 63-68.

Radosavljevic, B., H. Lantuit, W. Pollard, P. Overduin, N. Couture, T. Sachs, V. Helm, and M. Fritz, 2016: Erosion and flooding—Threats to coastal infrastructure in the Arctic: a case study from Herschel Island, Yukon Territory, Canada. Estuar. Coasts, 39, 900-915, https://doi.org/10.1007/s12237-015-0046-0.

Shabanova, N., S. Ogorodov, P. Shabanov, and A. Baranskaya, 2018: Hydrometeorological forcing of western Russian Arctic coastal dynamics: XX-century history and current state. Geogr. Environ. Sustain., 11, 113-129.

Sinitsyn, A. O., E. Guegan, N. Shabanova, O. Kokin, and S. Ogorodov, 2020: Fifty four years of coastal erosion and hydrometeorological parameters in the Varandey region, Barents Sea. Coastal Eng.,157, 103610, https://doi.org/10.1016/j.coastaleng.2019.103610.

Tanski, G., D. Wagner, C. Knoblauch, M. Fritz, T. Sachs, and H. Lantuit, 2019: Rapid CO₂ release from eroding permafrost in seawater. Geophys. Res. Lett., 46, 11244-11252, https://doi.org/10.1029/2019GL084303.

Zagórski, P., K. Jarosz, and J. Superson, 2020: Integrated assessment of shoreline change along the Calypsostranda (Svalbard) from remote sensing, field survey and GIS. Mar. Geod., 43, 433-471, https://doi.org/10.1080/01490419.2020.1715516.

November 9, 2020