"The World Set Free" is the twelfth episode of the American documentary television series Cosmos: A Spacetime Odyssey. It premiered on June 1, 2014, on Fox, and aired on June 2, 2014, on National Geographic Channel. The episode was written by Ann Druyan and Steven Soter, and directed by Brannon Braga. The episode explores global warming, humanity's effect on the Earth's atmosphere, and what we can do to mitigate it, including a look at alternative energy technologies.