The subject of the hearing was accusations of administration interference with the work of government climate scientists. Almost to a person, Republicans on the panel proclaimed their agreement that the earth’s climate was warming and that the principal culprit was greenhouse gases.

Witnesses spoke about how the administration had delayed, altered or watered down the findings of government scientists, the kind of thing they had not experienced in Clinton’s administration.

Drew Shindell, a NASA scientist who said he was speaking as an individual, described research he and his colleagues did on ozone depletion and greenhouse gases over Antarctica. Dr Shindell said the findings helped explain recent cooling on the continent. And, he said, the findings suggested Antarctica might warm rapidly in the future. By the time the administration had signed off on the work, he said, its importance had been played down and references to “rapid warming” had been deleted.

Another witness, Rick Piltz, said he resigned in protest in 2005 from his job with the federal Climate Change Science Programme when he became convinced that the administration’s goal was to “impede” the understanding of climate science. Part of his job, Piltz said, was to compile periodic assessments of government climate research for the Congress. “This report has essentially been made to vanish by the Bush administration,” he said.

Dr Francesca Grifo drew largely from a report that says it is common for scientists to be pressured to eliminate references to climate change, for their work to be misrepresented, and for climate-related materials to disappear from Web sites. (Information about the report is available at www.ucsusa.org.)

Cow menace on the rise, two dead