I'm haunted by the thought of what Ray Anderson calls 'tomorrow's child,' asking why we didn't do something on our watch to save sharks and bluefin tuna and squids and coral reefs and the living ocean while there still was time. Well, now is that time.

Humans are the only creatures with the ability to dive deep in the sea, fly high in the sky, send instant messages around the globe, reflect on the past, assess the present and imagine the future.

If Darwin could see what we now see, what we now know about the ocean, about the atmosphere, about the nature of life, as we now understand it, about the importance of microbes - I think he would just beam with joy that many of the thoughts and the glimpses of the majesty of life on Earth that he had during his life, now magnified many times over.

The diversity of life on Earth, generally, is astonishing. But despite those large numbers, it's also important to recognize that every species, one way or another, is vulnerable to extinction. And in our time on Earth... our impact on the diversity of life has been profound.

Most of life on Earth has a deep past, much deeper than ours. And we have benefited from the distillation of all preceding history, call it evolutionary history if you will.

As a child, I was aware of the widely-held attitude that the ocean is so big, so resilient that we could use the sea as the ultimate place to dispose of anything we did not want, from garbage and nuclear wastes to sludge from sewage to entire ships that had reached the end of their useful life.

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.