Projections of Extreme Ocean Waves in the Arctic and Potential Implications for Coastal Inundation and Erosion

Abstract

The Arctic Ocean wave climate is undergoing a dramatic change due to the sea ice retreat. This study presents simulations of the Arctic regional wave climate corresponding to the surface winds and sea ice concentrations as simulated by five CMIP5 (Coupled Model Intercomparison Project Phase 5) climate models for the historical (1975–2005) and RCP8.5 scenario future (2081–2100) periods. The annual maximum significant wave height is projected to increase up to 6 m offshore and up to two to three times greater than the corresponding 1979–2005 value along some coastlines, as waves become more exposed to the fall storms there. The connection between the Atlantic Ocean and the Arctic wave climates is projected to strengthen due to increase of swell influence. Changes in the wave direction also seem to indicate a weakening of the Beaufort High illustrated by a counterclockwise rotation of the mean wave direction for extreme conditions in the Western Arctic. The projected changes in wave conditions lead to a general increase of the wave-driven erosion and inundation potential along the Arctic coastlines. Potentially, hazardous extreme wave events are projected to become significantly more frequent and more intense. For example, in the Beaufort coastlines a once-in-20-year event under the historical (1979–2005) climate is projected to occur, on average, once every 2–5 years during 2081–2100. This is a pressing issue, as it affects many Arctic coastal communities, as well as existing and emerging Arctic infrastructure and activities, with some of them having already suffered severe wave-induced damage in the past years.