On the eve of major international climate change negotiations in Copenhagen, belief in global warming in the United States has slipped to the lowest point in 12 years of measuring, according to a poll from New York-based Harris Interactive Inc.

As U.S. negotiators fly to the Danish capital to forge a political agreement based on President Obama's proposal to cut U.S. greenhouse gas emissions by about 17 percent, most of the American public doesn't know what the talks are about, according to the Harris survey.

Just 51 percent of adults questioned said they believed carbon dioxide and other greenhouse gases would cause the Earth's average temperature to increase. Two years ago, fully 71 percent of respondents linked greenhouse gases directly to global warming.

The Harris results follow polls in recent months from the Pew Research Center for the People & the Press, the The Washington Post and ABC News, and The Wall Street Journal and NBC showing a similar decline in the percentage of people who believe climate change is real and is caused by emissions from fossil fuels.

"This is a big problem for the president," said Julian Zelizer, a professor of history and public affairs at Princeton University. "One of the main tactics of opponents of environmental regulation since the 1940s has been to challenge the science."

The dramatic 30-percentage-point drop over two years in the Harris poll is the starkest indicator yet that belief in climate change has plummeted in a short amount of time. The shift in numbers since 2007 came from a 15-point percentage increase from those saying they "are not sure" about the cause of climate change.

The results of a poll commissioned by the European Commission, released yesterday, showed that 90 percent of Europeans view climate change as a "serious problem," one that ranks second behind concerns about world poverty and starvation. Sixty-three percent of Europeans polled in September, for example, believed that addressing climate change will be beneficial to their economies. The polling in Europe was done in August and September.

Growing 'partisan gap' dominates climate and other issues

For analysts, the roots of the U.S. public's growing climate skepticism lie in an increasing partisanship dominating the political arena on a range of issues, from health care to the federal deficit. Furthermore, climate change already stood as an issue more divisive politically than most, according to many polls.

"We're seeing an increasing partisan gap in perceptions of Obama," said Karlyn Bowman, a senior fellow at the American Enterprise Institute. She noted that most of the disbelief in climate science inherent in the recent assessments is driven by shifts in Republican and independent voters.

The Harris poll, for example, noted that 73 percent of Democrats believe that greenhouse gas emissions cause global warming, compared to 28 percent of Republicans and 49 percent of independents.

Similarly, the Pew poll found that the dive in the overall number of people believing in the existence and cause of climate change came mainly from shifts in responses among Republicans and independents. In April 2008, for example, 75 percent of independents in that poll said there was solid evidence of global warming, compared to 53 percent in October 2009.

When you break down independents even further, into the "lean Republican" or "lean Democrat" category, you find the same partisan patterns on climate change, said Mark Mellman, a Democratic pollster who has met with Democratic leaders and Obama officials. More Republicans and Republican-sympathetic people do not believe that man-made emissions cause the Earth to warm, he said.

Lagging economy and cool summer may also be factors

Yet Carroll Doherty, an associate director at the Pew Center, said that political party affiliation is not the only factor at play, even though it is the dominant one.

The lagging economy may be playing a role in how people feel about climate change, he said. He also noted there was some "trace evidence" that weather factors into people's thinking.

"In places where the areas of summer temperatures were much below normal, people were less likely to say they believe in global warming," Doherty said about some of the Pew Center's recent polling.

As Obama prepares to give a speech in Copenhagen, 52 percent of Americans don't know that the talks there are related to climate change, according to Harris. Nine percent guessed the global economic crisis was the main item on the agenda.

Pew found a parallel lack of awareness in October about "cap and trade" as a concept, with 55 percent of respondents reporting that they had heard nothing about the idea. Cap and trade is the main plan under consideration in Congress to curtail U.S. greenhouse gas emissions via bills passed by the House and a Senate committee this year.

A 'serious problem,' but what is it?

Mellman countered, though, that a lack of a familiarity with the details of climate policies or international negotiations does not mean the public won't get behind a plan to control global warming. He noted that many of the same polls reporting a growing disbelief in climate science also state that the public wants Congress to do something about the issue.

Indeed, amid the low numbers about belief in the cause of climate change, the Harris poll reported that 75 percent of people said global warming should be treated as a "serious problem," though the percentage of respondents who said it was a "very serious" problem decreased from 2007. The Pew poll also revealed that half of the public favors setting limits on carbon dioxide emissions, even if they may lead to higher energy prices.

For an example of how so many contradictory findings could appear in public opinion tracking, Mellman provided an overseas metaphor.

"Very few people know where Kabul is," said Mellman about the capital of Afghanistan. "But they do care about the war."

The Harris poll was conducted online with 2,303 adults, Nov. 2-11. The estimated equivalent margin of error lies somewhere between 1 and 2 percentage points, said Alyssa Hall, a spokeswoman at Harris Interactive.

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