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.

If you want to swim across the English Channel from England to France - you have to leave your doubt on the beach in England.

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

Going against the tide has never been difficult for me. It wasn't even a conscious decision but the natural consequence of following my own instinct.

Of all the creatures in the world that really frighten me - the hyena in Africa, the great white shark - leopard seals are near the top of the list. They're killers. If my team spots one, they'll pull me out of the water.

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.

We need to save the Arctic not because of the polar bears, and not because it is the most beautiful place in the world, but because our very survival depends upon it.