Imagine that aliens landed and gifted us a clean, limitless energy source. Instead of killing each other over this technology, we decided to transform the world into a carbon-free society. This wondrous source would power our homes, industries, cars and planes, and humanity's annual rate of carbon pollution would almost instantly fall to zero. What would that mean for global warming?

Originally released by Knowledgemotion, 2018. Streaming video file encoded with permission for digital streaming by Infobase on February 21, 2020.