"The Polar Sea" begins in Reykjavik, Iceland with Richard Tegner, an ordinary Swedish man embarking on an extraordinary expedition to cross the Northwest Passage with his friends.

It is late July and the Northwest Passage is still choked with ice. In the small village of Ilulissat, Greenland, a motley collection of Arctic voyagers assembles to prepare for their expeditions while they wait for the sea to melt.

The explorers cross Baffin Bay to the tiny Inuit village of Pond Inlet. The new accessibility of this region has brought an unprecedented wave of tourists to Pond. For residents this is one of the many mixed blessings of climate change.

We depart coastal civilization for Lancaster Sound, a wilderness teeming with whales, birds and bears which is now being swarmed by scientists racing to understand the biological effects of climate change.

Crossing the Northwest Passage remains an immense challenge despite the melting ice. Halfway through their journey, some explorers break down and fall back, leaving others exiled.