The world will eventually run out of cheap fossil fuels. But before we run out, we'll probably try to siphon every last drop out of the earth. This means we'll dig so deep that it will become costly and inefficient to extract the fuel. What happens then? The answer may be found in one of the simplest forms of life on Earth- algae.

Originally released by American Institute of Physics, 2016. Streaming video file encoded with permission for digital streaming by Infobase on September 19, 2016.