Multi‐Century Impacts of Ice Sheet Retreat on Sea Level and Ocean Tides in Hudson Bay

Abstract

AbstractPast and modern large‐scale ice sheet loss results in geographically variable sea level changes. At present, in Hudson Bay, Canada, sea level is decreasing due to glacial isostatic adjustment, which represents a departure from the globally averaged sea level rise. However, there are large uncertainties in future sea level trends with further polar ice sheet retreat in the coming centuries. Sea level changes affect ocean tides considerably because tides are highly sensitive to changes in bathymetry. Here, we present multi‐century sea level projections associated with a suite of past and future ice loss scenarios and consider the impact of these changes on ocean tides using an established tidal model. Modern tides in Hudson Bay are poorly resolved due to large uncertainties in bathymetry. To establish an initial condition for our simulations, we constrain bathymetry in the bay using tide observations. Due to gravitational, Earth rotational and deformational effects, Greenland ice loss will produce a small sea level fall in the bay, while Antarctic ice loss will produce a larger than average sea level rise. Our results show that the response of the Antarctic ice sheet to climate change strongly impacts the magnitude and sign of future sea level and tidal amplitude changes in the region, with the largest changes predicted in Hudson Strait and Foxe Basin. We emphasize that further constraints on bathymetry and accurate projections of sea level and tides in Hudson Bay are imperative for assessing the associated impacts on coastal communities and ecosystems.