James Hansen told to be quiet on global warming issues.

Nasa's senior climate scientist accused the Bush administration yesterday of trying to stop him speaking out about global warming. James Hansen said Nasa officials ordered his lectures, papers and website postings to be reviewed before publication after he called last month for an immediate reduction in greenhouse gas emissions. Requests for interviews were also being screened. He said he had been told there would be "dire consequences" if he repeated his warnings about climate change. "They feel their job is to be this censor of information going out to the public," he told the New York Times. His accusation goes to the heart of the claim of opponents of President George W Bush that his administration is one of the more secretive in recent history. Veteran Washington reporters claim that it is harder to speak to officials in this administration than any other in living memory. The White House is also accused of politicising science. Mr Hansen's calls for significant mandatory cuts in greenhouse emissions run directly counter to the policy of the administration which disputes the science linking emissions to climate change. Dean Acosta, Nasa's deputy head of public affairs, denied there was an attempt to muzzle Mr Hansen. "That's not the way we operate here," he said. But Mr Hansen, the director of Nasa's Goddard Institute for Space Studies, said the public had been sheltered from findings about the potential risks of climate change. He said: "Communicating with the public seems to be essential because public concern is probably the only thing capable of overcoming the special interests that have obfuscated the topic". Mr Hansen has been sparring over global warming since 1998, when he began warning of the potential threat from fossil fuels.