Polar bear capital at the edge

A polar bear in the tundra outside Churchil, where a warming climate is double-edged: thawing permafrost has created sinkholes under the rail line’s tracks. — Renaud Philippe/The New York Times

CHURCHILL, on Hudson Bay’s western shore, boasts northern Canada’s only railway to the populated south, an Arctic deepwater port and a runway capable of handling the world’s largest military and commercial aircraft – legacies of the Cold War.

Now, as global powers eye the warming Arctic, the tiny town seems poised to play an outsized role in Canada’s plans to assert sovereignty in one of the world’s newest frontiers.