The top climate scientist at NASA says the Bush administration has tried to stop him from speaking out since he gave a lecture last month calling for prompt reductions in emissions of greenhouse gases linked to global warming. The scientist, James E. Hansen, longtime director of the agency’s Goddard Institute for Space Studies, said in an interview that officials at NASA headquarters had ordered the public affairs staff to review his coming lectures, papers, postings on the Goddard Web site and requests for interviews from journalists. Dr. Hansen said he would ignore the restrictions. “They feel their job is to be this censor of information going out to the public,” he said. Dean Acosta, deputy assistant administrator for public affairs at the space agency, said there was no effort to silence Dr. Hansen. “That’s not the way we operate here at NASA,” Mr. Acosta said. “We promote openness and we speak with the facts.” He said the restrictions on Dr. Hansen applied to all National Aeronautics and Space Administration personnel. He added that government scientists were free to discuss scientific findings, but that policy statements should be left to policy makers and appointed spokesmen. Mr. […]