By Glynn Wilson –

A majority of Americans, 57 percent, believe increases in the Earth’s temperature during the past century are due to pollution from human activities, while 40 percent still say it is due to naturally occurring changes in the environment, in spite of overwhelming scientific evidence and incredibly rare scientific consensus showing that the burning of fossil fuels is the culprit.

According to the latest Gallup poll on the subject, the breakdown of views on this issue is essentially unchanged from 2013, although the latest data reflects broader agreement with the idea that humankind is responsible for global warming than was the case from 2010 through 2012, when barely half said they agreed with that position. Agreement that human activities are behind global warming reached its historical peak in 2007, when 61 percent took that position.

Even though a majority of Americans agree with the scientific evidence, and a record high of 33 percent of people say they understand the issue “very well,” not that many express great concern over the potential consequences, according to Gallup. The percentage of Americans worried about global warming as well as “climate change” still ranks low relative to economic issues, and barely a third of people expect global warming to pose a serious threat in their own lifetimes.

“Leading climate science researchers in the U.S. and globally — including those at the International Panel on Climate Change, a U.N. body that is at the forefront of climate research — are convinced that elevated levels of carbon dioxide and other byproducts of fossil fuel use are the reason the Earth’s temperature has warmed,” Gallup says. “Nevertheless, Americans who say they are highly knowledgeable about global warming are no more likely than those who profess little knowledge of the issue to believe humans are to blame.”

Partisan Differences

Between 2008 and 2010, Republicans became much more likely to claim a solid understanding of global warming, according to Gallup, while high understanding among Democrats remained relatively low at that time.

The pattern changed “sharply” between 2007 and 2010, according to Gallup’s numbers, when the group that claimed to be the most informed became the most skeptical according to public opinion research. That period spanned the release of some hacked emails that were leaked in 2009 that became an over-sensationalized story in the news media called “Climategate,” which handed partisan global-warming skeptics ammunition to claim researchers were suppressing scientific information and simply profiting from research. Since then it was proved that the discussions had little impact on the research itself, and claims to the contrary were overblown.

“Since then, Democrats’ knowledge has surged, while Republicans’ has been fairly steady,” Gallup says. “Self-reported knowledge about the global warming issue is … up among all three political groups compared with a decade ago.”

Gallup’s research shows little relation between Americans’ levels of formal education and their agreement with the idea that human activities cause global warming. College graduates are just slightly more likely than adults without a college degree to believe human activities are to blame, but the number is not significant.

Far more than education or self reported knowledge levels, political affiliation dictates the degree to which Americans believe humans are responsible for global warming, with Democrats much more likely to hold this position than Republicans. The partisan gap has widened in recent years, no wonder since Americans more than ever turn to news sources they agree with more than objective news sources for information. Republicans still get much of their news from talk radio and Fox News, while Democrats turn to a wider array of news outlets for news and information, including newspapers, news Websites, public radio and the like.

Gallup’s Bottom Line

“Despite (a self-reported) increased knowledge, slightly fewer Americans today than in 2001 agree with global warming proponents that the Earth’s warming is ‘anthropogenic,’” according to Gallup, “in other words, the result of humans’ influence on nature.”

The 57 percent who believe humans are the cause is up from the low point recorded in 2010 (50 percent), but still not back to earlier levels.

“Importantly, public skepticism about the human role in global warming is not based on lack of education. College-educated Americans are barely more likely than those without a college degree to ascribe global warming to humans,” Gallup says. “Nor do Americans who consider themselves knowledgeable on the subject show more support for the pollution theory. Rather, as is the case with so many other measures of public attitudes on global warming, politics are the guiding force, with most Democrats accepting the prevailing scientific view that pollution is the cause and most Republicans believing it is a natural climatic cycle, not man-made.”

Survey Methods

Results for this Gallup poll are based on telephone interviews conducted March 6-9, 2014, with a random sample of 1,048 adults, aged 18 and older, living in all 50 U.S. states and the District of Columbia. For results based on the total sample of national adults, the margin of sampling error is plus or minus 4 percentage points at the 95 percent confidence level.