More Americans believe increases in the Earth’s temperature over the last century are due to pollution from human activities (57%) than to naturally occurring changes in the environment (40%).Gallup reports that “The balance of views on this issue is essentially unchanged from 2013, but reflects broader agreement with the idea that mankind is responsible for global warming than was the case from 2010 through 2012, when barely half believed it. Agreement that human activities are responsible has yet to return, however, to the 61% level seen as recently as 2007. This trend comes from Gallup’s annual Environment poll, a nationally representative telephone survey conducted each March since 2001. The 2014 update was conducted March 6-9.
“Americans’ prevailing view that human activity is responsible for global warming doesn’t necessarily translate into concern over the issue. The percentage of Americans worried about global warming (as well as “climate change”) still ranks low relative to other issues, and barely a third expect global warming to pose a serious threat in their own lifetime.In the same survey, Gallup asks Americans to describe their general understanding of global warming, with 33% this year — a record high — saying they understand global warming “very well,” up from 27% in 2013 and triple the level seen in the initial 1992 measure.The proportion understanding the issue “fairly well” has also increased over the long term, from 42% in 1992 to 51% today, while the percentage who don’t understand has dropped by more than half, from 44% to 16%.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. 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.In fact, in recent years, those with the highest level of knowledge — those saying they understand the global warming issue very well — are the least likely to believe global warming is the result of pollution from human activities. This is somewhat of a change from 2001 to 2007, when the most informed Americans were generally among the most likely of all knowledge groups to consider pollution the cause.The pattern changed sharply between 2007 and 2010, when the most informed group became the most skeptical. That period spanned the release of some hacked emails in 2009 that global-warming skeptics say proved climate researchers were suppressing scientific information — a controversy that ultimately became known as “Climategate.”