In terms of personal choices, let's all think more carefully about where we get our protein from.

It's taken us a short time to change the nature of nature. In my lifetime, more change than during all preceding human history put together.

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

It's baffling why the issues relating to climate change - [which] have far more obvious and tangible and much more clear-cut evidence about the cause - have been slower for people to accept as a given.

Fish from all over the world, from deep in the sea, wind up in countries from Germany to Japan. That is just crazy.

Since I began exploring the ocean in the 1950s, 90 percent of the big fish have been stripped away. Tuna, sharks, swordfish, cod, halibut, you name it, the numbers have just collapsed. Also, about half of the coral reefs are gone, globally, from where they were just a few decades ago.

Fortunately, we know more about the problems that we have than in all preceding history. We know now the consequences of the things that we put into the air, into the water - of the way we treat life on Earth.