Vote to overturn an aspect of climate science marks a worrying trend in US Congress.

As Nature went to press, a committee of the US Congress was poised to pass legislation that would overturn a scientific finding on the dangers of global warming. The Republican-sponsored bill is intended to prevent the US Environmental Protection Agency (EPA) from regulating greenhouse-gas emissions, which the agency declared a threat to public welfare in 2009. That assessment serves as the EPA's legal basis for regulation, so repealing the 'endangerment finding' would eliminate its authority over greenhouse gases.

That this finding is scientifically sound had no bearing on the decision to push the legislation, and Republicans on the House of Representatives' energy and commerce committee have made clear their disdain for climate science. At a subcommittee hearing on 14 March, anger and distrust were directed at scientists and respected scientific societies. Misinformation was presented as fact, truth was twisted and nobody showed any inclination to listen to scientists, let alone learn from them. It has been an embarrassing display, not just for the Republican Party but also for Congress and the US citizens it represents.

It is tempting to write all of this off as petty partisanship, a populist knee-jerk reaction to lost jobs and rising energy prices by a well-organized minority of Republican voters. After all, US polling data has consistently shown that, in general, the public accepts climate science. At a hearing last week, even Ed Whitfield (Republican, Kentucky), who chairs the subcommittee, seemed to distance himself from the rhetoric by focusing not on the science but on the economic effects of greenhouse-gas regulation. “One need not be a sceptic of global warming to be a sceptic of the EPA's regulatory agenda,” said Whitfield.

“The US Congress has entered the intellectual wilderness.”

Perhaps, but the legislation is fundamentally anti-science, just as the rhetoric that supports it is grounded in wilful ignorance. One lawmaker last week described scientists as “elitist” and “arrogant” creatures who hide behind “discredited” institutions. Another propagated the myth that in the 1970s the scientific community warned of an imminent ice age. Melting ice caps on Mars served to counter evidence of anthropogenic warming on Earth, and Antarctica was falsely said to be gaining ice. Several scientists were on hand — at the behest of Democrats on the subcommittee — to answer questions and clear things up, but many lawmakers weren't interested in answers, only in prejudice.

It is hard to escape the conclusion that the US Congress has entered the intellectual wilderness, a sad state of affairs in a country that has led the world in many scientific arenas for so long. Global warming is a thorny problem, and disagreement about how to deal with it is understandable. It is not always clear how to interpret data or address legitimate questions. Nor is the scientific process, or any given scientist, perfect. But to deny that there is reason to be concerned, given the decades of work by countless scientists, is irresponsible.

That this legislation is unlikely to become law doesn't make it any less dangerous. It is the attitude and ideas behind the bill that are troublesome, and they seem to be spreading. Fred Upton, the Michigan Republican who chairs the full energy and commerce committee, once endorsed climate science, but last month said — after being pinned down by a determined journalist — that he is not convinced that greenhouse-gas emissions contribute to global warming. It was yet another blow to the shrinking minority of moderate centrists in both parties.

One can only assume that Congress will find its way at some point, pressured by voters who expect more from their public servants. In the meantime, as long as it can fend off this and other attacks on the EPA, President Barack Obama's administration should push forward with its entirely reasonable regulatory programme for reducing greenhouse-gas emissions where it can, while looking for ways to work with Congress in other areas. Rising oil prices should increase interest in energy security, a co-benefit of the greenhouse-gas and fuel-efficiency standards for vehicles that were announced by the administration last year. The same advice applies to the rest of the world. Work with the United States where possible, but don't wait for a sudden change of tenor in Washington DC.

One of the scientists testifying before Whitfield's subcommittee was Christopher Field, director of the Carnegie Institution's global ecology department in Stanford, California. Field generously hoped that his testimony at last week's hearing took place “in the spirit of a genuine dialogue that is in the best interests of the country”. Maybe one day that hope will be justified.

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