LONDON » Last month hundreds of environmental activists crammed into an auditorium here to ponder an anguished question: If the scientific consensus on climate change has not changed, why have so many people turned away from the idea that human activity is warming the planet?

Nowhere has this shift in public opinion been more striking than in Britain, where climate change was until this year such a popular priority that in 2008 Parliament enshrined targets for emissions cuts as national law. But since then, the country has evolved into a home base for a thriving group of climate skeptics who have dominated recent news reports, apparently convincing many that the warming threat is vastly exaggerated.

A survey in February by the BBC found that only 26 percent of Britons believed that “;climate change is happening and is now established as largely manmade,”; down from 41 percent in November. A poll conducted for the German magazine Der Spiegel found that 42 percent of Germans feared global warming, down from 62 percent four years earlier.

And London's Science Museum recently announced that a permanent exhibit scheduled to open later this year would be called the Climate Science Gallery—not the Climate Change Gallery as had previously been planned.

“;Before I thought, 'Oh my God, this climate change problem is just dreadful,”;' said Jillian Leddra, 50, a musician who was shopping in London on a recent lunch hour. “;But now I have my doubts, and I'm wondering if it's been overhyped.”;

Perhaps sensing that climate is now a political nonstarter, David Cameron, Britain's new Conservative prime minister, was “;strangely muted”; on the issue in the recent election campaign, as The Daily Telegraph put it, although it had previously been one of his passions.

And a poll in January of the personal priorities of 141 Conservative Party candidates deemed capable of victory in the recent election found that “;reducing Britain's carbon footprint”; was the least important of the 19 issues presented to them.

Politicians and activists say such attitudes will make it harder to pass legislation like a fuel tax increase and to persuade people to make sacrifices to reduce greenhouse gas emissions.

“;Legitimacy has shifted to the side of the climate skeptics, and that is a big, big problem,”; Ben Stewart, a spokesman for Greenpeace, said at the meeting of environmentalists here. “;This is happening in the context of overwhelming scientific agreement that climate change is real and a threat. But the poll figures are going through the floor.”;

The lack of fervor about climate change is also true of the United States, where action on climate and emissions reduction is still very much a work in progress, and concern about global warming was never as strong as in Europe. A March Gallup Poll found that 48 percent of Americans believed that the seriousness of global warming was “;generally exaggerated,”; up from 41 percent a year ago.

Here in Britain, the change has been driven by the news media's intensive coverage of a series of climate science controversies unearthed and highlighted by skeptics since November. These include the unauthorized release of e-mail messages from prominent British climate scientists at the University of East Anglia that skeptics cited as evidence that researchers were overstating the evidence for global warming and the discovery of errors in a U.N. climate report.

Two independent reviews later found no evidence that the East Anglia researchers had actively distorted climate data, but heavy media coverage had already left an impression that the scientists had schemed to repress data. Then there was the unusually cold winter in Northern Europe and the United States, which may have reinforced a perception that the Earth is not warming. (Data from the National Oceanic and Atmospheric Administration, a U.S. agency, show that globally this winter was the fifth warmest in history.)

Asked about his views on global warming on a recent evening, Brian George, a 30-year-old builder from southeast London, mused, “;It was extremely cold in January, wasn't it?”;

In a telephone interview, Nicholas Stern, a former chief economist at the World Bank and a climate change expert, said that the shift in opinion “;hadn't helped”; efforts to come up with strong policy in a number of countries. But he predicted that it would be overcome, not least because the science was so clear on the warming trend.

“;I don't think it will be problematic in the long run,”; he said, adding that in Britain, at least, politicians “;are ahead of the public anyway.”; Indeed, once Cameron became prime minister, he vowed to run “;the greenest government in our history”; and proposed projects like a more efficient national electricity grid. Scientists have meanwhile awakened to the public's misgivings and are increasingly fighting back. An editorial in the prestigious journal Nature said climate deniers were using “;every means at their disposable to undermine science and scientists”; and urged scientists to counterattack. Scientists in France, the Netherlands and the United States have signed open letters affirming their trust in climate change evidence, including one published May 7 in the journal Science.

Last month Dr. Simon L. Lewis, an expert on rain forests at the University of Leeds in Britain, filed a 30-page complaint with the nation's Press Complaints Commission against The Times of London, accusing it of publishing “;inaccurate, misleading or distorted information”; about climate change, his own research and remarks he had made to a reporter.

“;I was most annoyed that there seemed to be a pattern of pushing the idea that there were a number of serious mistakes in the IPCC report, when most were fairly innocuous, or not mistakes at all,”; said Lewis, referring to the report by the U.N. Intergovernmental Panel on Climate Change.

Meanwhile, groups like the wildlife organization WWF have posted articles such as “;How to Talk to a Climate Skeptic,”; providing stock answers to doubting friends and relatives, on their websites.

It is unclear whether such actions are enough to win back a segment of the public that has eagerly consumed a series of revelations that were published prominently in right-leaning newspapers like The Times of London and The Telegraph and then repeated around the world.

In January, for example, The Times chastised the U.N. climate panel for an errant and unsupported projection that glaciers in the Himalayas could disappear by 2035. The United Nations ultimately apologized for including the estimate, which was mentioned in passing within a 3,000-page report in 2007.

Then came articles contending that the 2007 report was inaccurate on a host of other issues, including African drought, the portion of the Netherlands below sea level, and the economic impact of severe storms. Officials from the climate panel said the articles' claims either were false or reflected minor errors like faulty citations that in no way diluted the evidence that climate change is real and caused by human activity.

Stefan Rahmstorf, a professor at the Potsdam Institute for Climate Impact Research, successfully demanded in February that some German newspapers remove misleading articles from their websites. But such reports have become so common that he “;wouldn't bother”; to pursue most cases now, he added.

The public is left to struggle with the salvos between the two sides.

“;I'm still concerned about climate change, but it's become very confusing,”; said Sandra Lawson, 32, as she ran errands near Hyde Park.