2 November 2014 Last updated at 18:47 GMT
The unrestricted use of fossil fuels should be phased out by 2100, if the world is to avoid dangerous climate change, a UN-backed expert panel says.
The Intergovernmental Panel on Climate Change’s Synthesis Report summarises the causes, impacts of, and solutions to rising temperatures.
It says most of the world’s electricity can – and must – be produced from low-carbon sources by 2050.
David Shukman reports.