Find out how and why the Earth's climate is changing as Paris hosts a major summit to discuss global warming.
1. What is the problem?
The world is getting warmer
The average temperature of the Earth's surface has increased by about 0.85°C (1.4F) in the last 100 years. Thirteen of the 14 warmest years were recorded in the 21st Century, with 2015 on course to set another record.