In an interview with the Guardian, James Hansen, the world's pre-eminent climate scientist, said any agreement likely to emerge from the negotiations would be so deeply flawed that it would be better to start again from scratch. "I would rather it not happen if people accept that as being the right track because it's a disaster track," said Hansen, who heads the Nasa Goddard Institute for Space Studies in New York. Hansen, in repeated appearances before Congress beginning in 1989, has done more than any other scientist to educate politicians about the causes of global warming and to prod them into action to avoid its most catastrophic consequences. But he is vehemently opposed to the carbon market schemes -- in which permits to pollute are bought and sold -- which are seen by the EU and other governments as the most efficient way to cut emissions and move to a new clean energy economy . In Hansen's view, dealing with climate change allows no room for the compromises that rule the world of elected politics. "This is analagous to the issue of slavery faced by Abraham Lincoln or the issue of Nazism faced by Winston Churchill," he said. "On those kind of issues you cannot compromise. You can't say let's reduce slavery, let's find a compromise and reduce it 50% or reduce it 40%." He added: "We don't have a leader who is able to grasp it and say what is really needed. Instead we are trying to continue business