I have lots of heroes: anyone and everyone who does whatever they can to leave the natural world better than they found it.

For humans, the Arctic is a harshly inhospitable place, but the conditions there are precisely what polar bears require to survive - and thrive. 'Harsh' to us is 'home' for them. Take away the ice and snow, increase the temperature by even a little, and the realm that makes their lives possible literally melts away.

We woke up some years ago about the consequences of ozone depletion, the hole in the atmosphere. You can't see it. You can't taste it. You can't smell it. But now we do regard that as a key issue. It's a scientific finding.

When some people look at a shrimp they think, "Hmm. Delicious." When I look at a shrimp I think, "You're a miracle, absolutely incredible. Your ancestors have gone back hundreds of millions of years." And to develop a thing as simple as a shrimp cocktail, you have to calculate the hundreds of millions of years that have preceded that moment where you're sitting there with your sauce and fork poised.

There are now more than 4,000 places in the sea around the world that have some kind of protection. The bad news: You have to look hard to find them. What you find instead is destructive fishing, mining, gas and oil exploration.

You should ask where your food is coming from.

The ocean is dying, and we have no place to escape to if this experiment doesn't go in our favor.