Professor James Lovelock, the man who developed the Gaia theory which says the Earth functions as a kind of giant, self-regulating organism, has said that humanity should not feel guilty for global warming.
Speaking to Today presenter John Humphrys, he said that the human race was like a walker who found a gun in a forest and pulled the trigger, not knowing what it would do.
"We're not really guilty," he says. "We didn't deliberately set out to heat the world."
"But as a result of what we've done, to build our civilization, we've set things in motion."