I hope that someday we will find evidence that there is intelligent life among humans on this planet.

My first breath was just...it just seemed impossible that you could actually breathe underwater. I knew in my mind it was possible, but actually experiencing it was such a gulp of joy and I feel it every time I go under the ocean. I love doing it, to be able to feel weightless, to spin on one finger, to do somersaults, to be like a graceful ballerina - even with a huge tank on your back you can do the most extraordinary things.

Meat reared on land matures relatively quickly, and it takes only a few pounds of plants to produce a pound of meat.

Scientists never stop asking. They're little kids who never grew up.

We have been far too aggressive about extracting ocean wildlife, not appreciating that there are limits and even points of no return.

Since the middle of the 20th century, more has been learnt about the ocean than during all preceding human history; at the same time, more has been lost.

Throughout all of human history we've enjoyed certain benign circumstances: an envelope of atmosphere, an envelope of temperature. A kind of resilience that if you cut down trees, then they'll grow back. You take fish, they recover. You put stuff into the atmosphere that you know is not good for us, but we can still breathe. We haven't awakened, generally, to the sense of urgency that does exist.