US belief in climate science lowest since polling began 13 years ago

Nearly half of Americans believe the climate change threat is exaggerated. Photograph: Getty

Public belief in climate science has seen a precipitous slide in the US, according to new polling that suggests fewer Americans are concerned about the threat posed by global warming.

Nearly half of Americans – 48% – now believe the threat of global warming has been exaggerated, the highest level since polling began 13 years ago, the poll published today by Gallup said.

It directly linked the decline in concern to the controversies about media coverage of stolen emails from the University of East Anglia climate research unit and a mistake about the Himalayan glaciers melting by 2035 in the UN's authoritative report on global warming.

"These news reports may well have caused some Americans to re-evaluate the scientific consensus on global warming," Gallup said.

Half of Americans now believe there is a scientific consensus on climate change. Some 46% believe scientists are unsure about global warming, or that it is not occurring. A UK poll last month showed adults who believe climate change is "definitely" a reality had dropped from 44% to 31% over the past year.

"The last two years have marked a general reversal in the trend of Americans' attitudes about global warming," Gallup said. "It may be that the continuing doubts about global warming put forth by conservatives and others are having an effect."

The poll feeds into fears among some environmentalists that the furore over the hacked emails has given new fuel to opponents of action on climate change, and stopped short the momentum in Congress for passage of a clean energy law.

A troika of Senators trying to draft a compromise climate bill that could get broad support said this week they may not be able to produce a draft until after the Easter recess, further reducing the chances of enacting legislation in 2010.

Meanwhile, the Obama administration faces lawsuits from Virginia, Texas, Alabama and a dozen business lobbies challenging its authority to act on greenhouse gas emissions through the Environmental Protection Agency.

Tim Wirth, a former Colorado senator who led the campaign against acid rain, told a conference call the science squabbles resembled a re-run of efforts to discredit that earlier effort for an environmental clean-up.

He said the scientists who worked on the IPCC report were woefully outmanoeuvred in PR by business groups which have the funds to employ legions of lobbyists and communications experts. "It's not a fair fight," he said. "The IPCC is just a tiny secretariat next to this giant denier machine."

A majority of Americans continues to believe that climate change is real, but they are less convinced of its urgency. Only 32% believe they will be directly affected by the consequences of a warming atmosphere, despite a major report by the Obama administration last year that climate change could bring flooding, heat waves, drought and loss of wildlife to the US.