Narrator: This is Science Today. Researchers are warning that the Earth is on the brink of mass extinction, similar to the five prehistoric mass extinctions that wiped out three-quarters of all animal species. Paleobiologist Anthony Barnosky of the University of California, Berkeley, discovered that existing animal species are becoming extinct at an accelerated rate and could reach 75 percent species loss in as little as 300 years.
Barnosky: Look out your window and imagine that three-quarters of the kinds of living things that you see out there won't be there anymore. And ask yourself if that's the kind of world that you want to live in?
Narrator: Extinction rates are rapidly increasing because of human activity, including climate change, but Barnosky says it's not too late to turn the problem around.
Barnosky: The most important thing to get across is that we are in an extinction crisis but that we are not so far down the road that we can't do something to reverse it. Once we begin to try to help a population recover, we can see significant results in as little as a decade.
Narrator: For Science Today, I'm Larissa Branin.