In the past few decades, Earth's natural systems have endured more pressure than in all preceding human history.

I am driven by what I know; that the world I love is in trouble.

Ten percent of the big fish still remain. There are still some blue whales. There are still some krill in Antarctica. There are a few oysters in Chesapeake Bay. Half the coral reefs are still in pretty good shape, a jeweled belt around the middle of the planet. There's still time, but not a lot, to turn things around.

The oxygen cycle, the nitrogen cycle, the carbon cycle, the water cycle - all of these are linked to the existence of life in the sea.

The Arctic is a place that historically, during all preceding human history, has largely been an icy realm with an impact on ocean currents. That, in turn, influences the temperature of the planet. The Arctic is now vulnerable because of the excess carbon dioxide in the atmosphere, with a rate of melting that is stunning.

There's a vested interest in trying to keep people smoking cigarettes.

The value of sharks' lives is now widely understood to be more important than their value as products. And when you have sharks in an area, it's a sign of good health. They're top predators, which means they feed on old, sick, and slower fish, keeping an entire population healthy.