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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.