Man-made climate change causes 'even more certain'
26 September 2013 Last updated at 19:14 BST
A report published on Friday aims to answer questions regarding the extent of global warming, and how much of the problem is man-made.
The study, drawing on the work of thousands of researchers, is likely to state with even greater certainty than before that present-day, rapid warming of the planet is man-made.
David Shukman reports.