Evolving Arctic maritime hazards: Declining sea ice and rising waves in the Northwest Passage

Abstract

The ongoing and projected retreat of Arctic sea ice has garnered international interest toward the utilization of Arctic maritime corridors for shipping, tourism, and development. Yet, with potential for increasing traffic in Arctic regions, it's important to consider additional environmental variables affected by climate change which may threaten maritime operations. Here, we use four climate model projections to produce ocean wave simulations and investigate the future magnitude and seasonality of sea ice risk coupled with wave hazards. Analyzing the potential 5 mo shipping season spanning July to November along the Northwest Passage maritime route between 2020 and 2070, our results show a substantial decline in sea ice risk over the analysis time period, resulting in near open-water conditions along the route for a 5 mo period by 2070. However, as seasonal ice coverage retreats, there is a significant upward trend in wave heights along the route during July and November, with the timing of the greatest wave height shifting away from September toward later in the season. This result is pertinent as the possibility of seasonally unprecedented extreme waves coupled with subfreezing late fall temperatures makes for an especially hazardous environment, thus emphasizing the importance of considering the interaction between evolving sea ice and interdependent hazards when predicting the risks and challenges faced by Arctic maritime operations.

Keywords: Arctic; climate change; maritime development; ocean waves; sea ice.

Fig. 1.

The subregions of analysis making up the Northwestern Passage route analyzed within this study. Subregions were delineated to aid in the discussion of spatial differences in wave hazards and ice risk and to provide sampling areas for narrowing results according to regions of interest in the following figures.

Fig. 2.

Regional monthly (A to I) time series of SIA for the ensemble average (black) and individual climate models (colors). Symbols in the top right corner denote the detection of a significant decreasing trend for individual models. The averaged trend value is only provided for regions and months where at least three ensemble members detect a significant decreasing trend and is derived as the mean of those ensemble member’s Sen’s slopes. Due to the varying resolution in climate model grids, the maximum SIA (SIA assuming all grid cells within the region have 100% SIC) varies between climate models analyzed. However, averaging over the ensemble, the maximum SIA for BS, BB, and CAA is 0.42, 0.43, and 0.53 × 10⁶ km², respectively, and are plotted as a dashed horizontal line within each subplot.

Fig. 3.

Ensemble averaged decadal RIO and H_s,90 fields for 2020 to 2040 and 2050 to 2070 for the months of July, September, and November_.

Fig. 4.

The ensemble averaged linear decadal trend in monthly H_s,90 derived for each model node and plotted as contours. To assess robustness, no hatching indicates a significant trend detected by the modified MK method at the 95% confidence level in half or more of the ensemble members and ≥75% of those agree on the sign of change. Cross-hatching indicates that a significant trend was detected in at least half of the ensemble members, but of those ensemble members, ≥75% sign consensus was not reached—denoting conflicting trends for the area. Single hatching indicates that no significant trend was found in any or for more than one member.