Many people avoid driving on icy roads. But in Northern Canada’s Arctic tundra, some roads are made of ice.

A network of seasonal roads on frozen rivers and lakes allows trucks to reach remote areas. Many of these places are otherwise accessible only by boat or plane. But as the climate warms, the ice road season is getting shorter.

Xiao Yang of the University of North Carolina Chapel Hill analyzed more than three decades of satellite images of rivers around the globe. He looked at which rivers were frozen and when.

“We detect widespread decline in river ice in the past 34 years,” he says. “In general, we have later freeze-up of the river surface and we have earlier breakup of the river surface. … And that has consequences for … when you can actually be on these ice roads.”

Yang also studied what is likely to happen to river ice if global carbon pollution and temperatures continue to rise. He found that by 2100, some rivers could be ice-free for weeks longer than they are now.

So global warming could continue to shorten the ice road season and make it harder and more expensive to reach some remote and isolated places in the Arctic.

Reporting credit: Sarah Kennedy/ChavoBart Digital Media.