The oceans cover 70% of the surface of the globe and regulate the climate. They're also the greatest reservoir of life on Earth. And yet, between overfishing, plastic pollution and coral bleaching, the oceans are being given a rough ride. Mexico, France, Australia: meet the citizens fighting back.

They directly affect our climate and are gradually disappearing: how to save the glaciers and the people threatened by their melting? Hugo Clément meets Mike Horn and Borge Ousland at the North Pole, together with two volunteer workers, Hilde and Sunniva, who've settled in the Arctic to record climate changes.