Climate scientists hit back at the sceptics with new research they say has uncovered the "fingerprint" of man-made global warming.

Researchers working like detectives investigating a crime compared real observational evidence with data from computer simulations to see how they matched up.

They concluded there was an "increasingly remote possibility" of human influence not being the chief driver of climate change. The clues were unravelled using a forensic technique called "optimal detection" that gives different factors - natural and human - an equal chance to explain the changes seen.