If you think the ocean isn't important, imagine Earth without it. Mars comes to mind. No ocean, no life support system.

It doesn't matter where on Earth you live, everyone is utterly dependent on the existence of that lovely, living saltwater soup. There's plenty of water in the universe without life, but nowhere is there life without water.

What we put into the atmosphere in terms of burning fuel is unprecedented.

Throughout all of human history we have consumed the natural world. All creatures do. Birds do. Fish do. Earthworms do. We consume the natural world as a source of our survival. But no creature has ever consumed at the scale that humans have, and now there are seven billion of us. I think the good news is that a large percentage of those seven billion minds can work to make better decisions.

If we have a hope of really understanding our place in nature and of carving out a place for ourselves that is sustainable, it's primarily because of the new level of communication. It used to be, 'What you don't have in your mind, you have on your shelf.' But now we have the Web.

The observations that have developed over the years have given us perspective about where we fit in. We are newcomers, really recent arrivals on a planet that is four and a half billion years old.

There is not a well-funded campaign among scientists to say, "Look, here's the evidence. You can read it yourself. Here are the facts. We're not making this up."