When I'm preparing for a swim, I imagine absolutely everything about it: the color of the water, how cold it is, the taste of salt in my mouth. I visualize each and every stroke.

The swim at Deception Island was by far the hardest swim I've ever done. Antarctica is a very unforgiving environment. If you don't train properly, you'll die.

There is nothing more powerful than the made-up mind.

Climate change is the Everest of all problems, the thorniest challenge facing humankind.

I think that I was slightly naive. I thought that if I showed people the beauty of the Arctic and the beauty of the polar bears that they would care so much that they would stand up and try to make a change.

When I'm preparing for a swim, I imagine absolutely everything about it: the color of the water, how cold it is, the taste of salt in my mouth. I visualize each and every stroke.

When I was born, the world's population was 3.5 billion. There are now 6.8 billion people on the planet. By 2050, that's expected to rise to 9.4 billion. What's more, the Earth's resources aren't growing; they're decreasing - and rapidly.