Under Thin Ice follows Canadian extreme divers and cinematographers Jill Heinerth and Mario Cyr on a journey to investigate how Arctic wildlife is adjusting to global warming. The Arctic is a majestic world, home to wildlife rarely seen further south: bowhead whales, polar bears, narwhals and walruses. Life thrives on and under a legendary blanket of snow and ice, covering millions of square kilometres of land and ocean. At the end of spring, when the sun shines 24 hours a day, life flourishes at the floe edge. Here, where ice meets open waters, living species gather for a feeding frenzy. In the Arctic, the entire polar web of life depends on the ebb and flow of ice. But climate change is threatening this ecosystem. Temperatures are rising and ice is melting at an alarming rate. Since 1980, the film notes, the amount of summer ice cover has dropped by about 80 per cent. Diving with whales, walruses and polar bears, Heinerth and Cyr bring viewers into a majestic underwater world threatened by disappearing ice and rapid climate change.