The Earth's land has warmed by 1.5C over the past 250 years and "humans are almost entirely the cause", according to a scientific study set up to address climate change sceptics' concerns about whether human-induced global warming is occurring.
Prof Richard Muller, a physicist and climate change sceptic
who founded the Berkeley Earth Surface Temperature (Best)
project, said he was surprised by the findings. "We were not expecting this, but as scientists, it is our duty to let the evidence change our minds."
He added that he now considers himself a "converted sceptic" and his views had undergone a "total turnaround" in a short space of time.
Muller said his team's analysis suggested there would be 1.5 degrees of warming over land in the next 50 years, but if China continues its rapid economic growth and its vast use of coal then that same warming could take place in less than 20 years.
"Science is that narrow realm of knowledge that, in principle, is universally accepted," wrote Muller. "I embarked on this analysis to answer questions that, to my mind, had not been answered. I hope that the Berkeley Earth analysis will help settle the scientific debate regarding global warming and its human causes. Then comes the difficult part: agreeing across the political and diplomatic spectrum about what can and should be done."
A video follows (you may get an add to skip sorry)