• The biggest danger we face is overfishing. We literally could fish out our oceans, some scientists believe, in the next 40, 50, 60 years. We are fishing out the top of the food chain, and it's pretty crucial because about 200 million people depend on fish and fishing for their livelihood, and about a billion people, mostly in poorer countries, depend on fish for their protein. So this is a big problem. Good news is, it's fixable.