Seasonal ice roads across the Arctic, already less feasible as global temperatures rise, will be an increasingly unviable transport option, especially in Canada’s polar regions, researchers say.

Between rising temperatures, reduced snow cover, and thawing permafrost, potential ice roads that would enable community access, deliveries of critical supplies, and resource exploration are becoming increasingly vulnerable infrastructure, finds a new study published in the journal Nature Communications: Earth & Environment. Built by deliberately compacting, watering, and freezing snow, seasonal ice roads are facing a decline of suitable climate conditions, which will present a challenge to Arctic overland travel.

Polar regions warming much faster than the rest of the planet put the already fragile connectors even more at risk, says the new study. The researchers, a team of geographers and geohazard experts, used a purpose-built potential ice road assessment model that crunches satellite remote sensing and meteorological data. They found that increases in surface air temperature and decreases in snow depth reduced the climatic suitability of potential ice roads across all Arctic regions between 1979 and 2017.

Potential ice road days decreased by an average of 7.45 days per decade across the polar region. The Canadian Arctic’s loss was well above average at 10.17 days per decade.

This week, CBC reports unseasonably mild weather across much of the Northwest Territories, 14°C milder than seasonal averages. The unexpected heat wave “has done serious damage to some of the territory’s winter roads, including the Mackenzie Valley winter road, which was expected to see one of its busiest seasons ever this year.” While NWT infrastructure officials in the Sahtu region expect temperatures to fall in time to avert long-term impacts on good resupply, drivers can expect to take twice as long to navigate the roads until then.

Looking ahead, the Nature study cites decreased snow depth as the biggest immediate threat to ice roads, especially in the Arctic reaches of North America. The Canadian Arctic is particularly exposed, given that its current network of ice roads each winter stands at roughly 10,000 kilometres. With heavier snow cover, ice roads in Eurasia stand a better chance, at least for the next decade or so.

Beginning around 2050, permafrost thawing will become an increasingly “strong stressor” across all polar regions due to increasing surface air temperatures.

The team was also able to map changes in climactic suitability of potential ice roads in a region within a single year, zeroing in on suitability during the standard periods of ice road growth (October to November), stabilization (December to February), and decline (March to May).

Particularly in Nunavut, potential ice road onset dates were more severely damaged by climactic factors than potential end dates.

The authors write that the increasingly shortened and uncertain ice road season is bad for all dimensions of human life in the Arctic. “Changes in ice road availability due to the unprecedented climate change in the North can impact the amount of minerals, supplies, and food shipped, which can impact not only economy but also the safety of the people,” they write.

The research also singles out the impact of instability on “precious metal/diamond accessibility.” While “excellent” potential ice roads are fast becoming things of the past, “good” ice roads are possible across much of the Arctic, particularly in January and February, and especially in Canada, out to 2050.

The situation rapidly worsens between 2050 and 2100, however, and especially in the Canadian Arctic.

“Spatially, future utilization of ice roads for precious metal and diamond exploration in Russian Siberia is more environmentally advantageous and resilient than in North America,” the authors write.