Around the world, sea level is rising due to a combination of factors (in order of magnitude of contribution): thermal expansion of the upper layer of the ocean, melting mountain glaciers and ice caps, the Greenland and Antarctic ice sheets, and land water storage [1]. Certain areas will experience greater changes to the local sea level than others, due to factors such as ocean currents, variations in Earth’s gravitational field, and vertical land motion [2].

In Tuktoyaktuk, the median projected global mean sea level rise relative to 1986 is between 0.44 meters (RCP2.6) and 0.74 meters (RCP8.5) by the year 2100 [1]. Based on water levels recorded at the tide gauge in the harbour, sea level rise in Tuktoyaktuk has been reported between 2.4 and 3.5 millimeters per year since the 1960s [1,2,3,4].

Vertical ground motion has a significant impact on local sea level changes; land uplift will reduce the experienced sea level rise, and land subsidence will increase the experienced sea level rise [2]. The Earth’s mantle is fluid; glaciations push the ground surface down, and the surface rebounds after glaciers melt. Certain regions of Canada, including Hudson Bay and much of the Canadian Arctic Archipelago, are rebounding from the pressure of now-receded glaciers and so the ground is rising, while other regions including the Beaufort coast of Yukon and Northwest Territories are subsiding [2]. In Tuktoyaktuk, nearly half of the observed sea level change is due to ground subsidence; continuous GPS measurements suggest a subsidence rate of 1.68 millimeters per year, corresponding to a relative rate of sea level rise of 1.28 millimeters per year [2].