Out of all the planets in our solar system, only Earth has life as we know it.

In fact, life has been on Earth for billions of years, and it permeates every nook and cranny of our planet. Some even think Earth regulates itself to make the environment more hospitable for life. This theory, called the Gaia Hypothesis by the biologist James Lovelock, is not supported by history, says the paleontologist Peter Ward. Instead, the fossil record shows that time and time again, life has suffered major population crashes and extinctions, often due to conditions caused by life at the time.

Now human beings are poised to repeat the process. By pumping so much carbon dioxide and other greenhouse gases into the atmosphere, we are changing the climate and starting a cascade of effects that could lead to our own extinction. Will our self-destructive behavior eventually bring us to our knees?

Science, pop culture & comedy collide on StarTalk w/ astrophysicist & Hayden Planetarium director Neil deGrasse Tyson, comic co-hosts, celebrities & scientists.