The Arctic is an ocean. The southern pole is a continent surrounded by ocean. The North Pole is an ocean, or northern waters. It's an ocean surrounded by land, basically.

The sudden release of five million barrels of oil, enormous quantities of methane and two million gallons of toxic dispersants into an already greatly stressed Gulf of Mexico will permanently alter the nature of the area.

By the end of the 20th century, up to 90 percent of the sharks, tuna, swordfish, marlins, groupers, turtles, whales, and many other large creatures that prospered in the Gulf for millions of years had been depleted by overfishing.

I find the lure of the unknown irresistible.

The image of Earth from space transformed our view of ourselves. It is maybe the most important image that exists - because we can see ourselves in context in a way that otherwise would be really hard to explain. It should inspire us to wonder about it, to want to know everything we can about it and do everything we can to take care of it.

We've got to somehow stabilize our connection to nature so that in 50 years from now, 500 years, 5,000 years from now there will still be a wild system and respect for what it takes to sustain us.

There are a lot of smart creatures out there. Dolphins, elephants, and whales are smart. And there are some really smart birds. I know some really intelligent fish. But they cannot know what humans know and are incapable of inflicting as much damage.