W5: What happens when the permafrost thaws?

Almost half of Canada sits on permanently frozen land called permafrost, but climate change is causing it to thaw and erode rapidly. W5's Avery Haines investigates a looming ecological disaster that poses a threat to the entire world.
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W5 is Canada’s most-watched investigative, current affairs and documentary program. Tackling major stories and investigations W5 is in its 51st season.