World leaders will soon meet in Paris, tasked with stopping the world from heating up by more than two degrees. Nature Video investigates the basis of this limit, and how much carbon we can burn before we reach it.

Read more of the research behind this video: The geographical distribution of fossil fuels unused when limiting global warming to 2 °C; AR5 Climate Change 2014: Impacts, Adaptation, and Vulnerability; AR5 Synthesis Report: Climate Change 2014