Rapid coastal erosion of ice-bonded deposits on Pelly Island, southeastern Beaufort Sea, Inuvialuit Settlement Region, western Canadian Arctic

Abstract

This paper quantifies rates of shoreline change and investigates the influence of surficial geology on shoreline dynamics between 1950 and 2018 on Pelly Island, located 10 km off the Mackenzie Delta. Long-term changes in shoreline position were calculated using imagery analysis and Analysing Moving Boundaries Using R (AMBUR). The influence of shoreline exposure to predominant storm direction and influence of surficial geology were examined for Northwest and Southeast zones. The average annual linear regression rate (LRR) rate during the 1950-2018 observation period was -3.8 m∙a-1. The end point rate (EPR) was calculated for six observation periods: 1950-1972, 1972-1985, 1985-2000, 2000-2018, 2013-2018. A mean EPR of -5.5 ± 0.7 m∙a-1 was calculated for the 2000-2018 period, and a maximum retreat rate of 46.7 ± 2.1 m∙a-1 was recorded during the 2013-2018 observation period. By comparing the rate of change for sections of historical shorelines with differing surficial geology and exposure to storms, it was possible to draw conclusions on why Pelly Island continues to have the highest retreat rates in the Mackenzie-Beaufort region. Greater retreat rates were observed in lacustrine deposits (5.3 m∙a-1) compared to moraine deposits (2.7 m∙a-1). In addition, shoreline exposure to the predominant storm direction from the Northwest was found to be a major influence on rates of shoreline change in all observation periods.

Landscape and Seascape Responses to Canada’s Changing Climate

“…This coast has some of the highest erosion rates in the world, with the rates depending on the nature of coastal materials, among other factors. Malenfant et al (2022) and document erosion rates for Pelly Island (one of the islands bordering the Mackenzie Delta) and Tuktoyaktuk Island, respectively. Under current erosion rates, breaching of Tuktoyaktuk Island is expected in less than 25 years, which will render Tuktoyaktuk Harbour vulnerable to increased wave action.…”

Exposure of Arctic coastal settlements to coastal erosion and permafrost warming

“…At the interface between land and sea, the permafrost coastline and local communities are subject to various pressures. Arctic permafrost coasts are among the fastest eroding coasts of the globe and are registering extreme erosion rates locally exceeding 40 m/yr (Malenfant et al, 2022). The average pan-arctic coastal retreat rate was estimated at 0.5 m/yr from Lantuit et al (2012) and is expected to double before the end of the century (Nielsen et al, 2022).…”

An agent-based modeling approach to household adaptation for flooding and coastal erosion at Channel-Port aux Basque

“…Storms render coastal regions particularly vulnerable and place heavy costs on coastal regions (Hawick, 2014). Tropical cyclones affect roughly 120 million people annually, and between 1980 and 2000, tropical cyclones killed about 250,000 people (Malenfant et al, 2022). Nicholls et al (2007) asserted that through the twentieth century, global sea level rise contributed to increasing coastal flooding, erosion, and ecosystem losses, although with significant local and regional heterogeneity owing to other reasons such as coastal dynamic action.…”

“…Strong winds are particularly dangerous in coastal areas since they cause devastating waves and storm surges that lead to coastal erosion. Malenfant et al (2022) asserted that coastal flooding has been extensive, contributing to the high degree of sea-ice impacts and resulting in record-setting high-water levels in sections of Prince Edward Island, southeastern New Brunswick, Nova Scotia, and Newfoundland.…”

“…This has put the towns and cities that depend on coastal infrastructure and activities in danger (Hawick, 2014). Malenfant et al (2022) added that in addition to reducing social and economic prospects, coastal erosion can destroy infrastructure and property and the extinction of ecosystems. Climate change is making the issue worse on the coast of Newfoundland; therefore, finding a solution in the area is essential.…”