On Qikiqtaruk, off Canada, researchers at the frontier of climate change are seeing its rich ecology slide into the sea as the melting permafrost leaves little behind

Last summer, the western Arctic was uncomfortably hot. Smoke from Canada’s wildfires hung thick in the air, and swarms of mosquitoes searched for exposed skin. It was a maddening combination that left researchers on Qikiqtaruk, an island off the north coast of the Yukon, desperate for relief.

And so on a late July afternoon, a team of Canadian scientists dived into the Beaufort Sea, bobbing and splashing in a sheltered bay for nearly two hours. Later, as they lay sprawled on a beach, huge chunks of the island they were studying slid into the ocean.