When fossil fuels are burned they produce carbon dioxide.
The extra carbon dioxide makes the Earth's temperature rise.
This graph from Stanford University shows the effect.
New research has been published into how fossil fuels warm the Earth.
Exactly how much warmer will it become as human activities produce more carbon dioxide?
Warming and carbon emissions are linked by processes in the oceans, which take up heat and carbon.
This link means that whatever warming we experience, it will stay around for many centuries after carbon emissions are stopped.