For over 20 years, Mackie Greene has been pulling entangled whales back from the brink. As co-founder and director of whale rescue for the Canadian Whale Institute, he and his team cover nearly the entire east coast of Canada — one of just a handful of trained response teams in the country, alongside a longstanding team in Newfoundland and Labrador. It's a job that means racing to the water within the hour, tracking whales hundreds of miles offshore, and cutting rope by hand from animals that can weigh anywhere from 5 to 150 tons (roughly 4.5 to 136 metric tonnes).

In this episode, Mackie walks us through what a rescue actually looks like, how the work has evolved since he and co-founder Joe Howlett started with little more than knives taped to poles in 2002, and how a warming ocean is reshaping where — and how often — these rescues happen. ...