In a finding that could have implications for the 2016 presidential campaign, the poll also found that two-thirds of Americans said they were more likely to vote for political candidates who campaign on fighting climate change. They were less likely to vote for candidates who questioned or denied the science that determined that humans caused global warming.
Among Republicans, 48 percent say they are more likely to vote for a candidate who supports fighting climate change, a result that Jon A. Krosnick, a professor of political science at Stanford University and an author of the survey, called “the most powerful finding” in the poll. Many Republican candidates question the science of climate change or do not publicly address the issue.
Although the poll found that climate change was not a top issue in determining a person’s vote, a candidate’s position on climate change influences how a person will vote. For example, 67 percent of respondents, including 48 percent of Republicans and 72 percent of independents, said they were less likely to vote for a candidate who said that human-caused climate change is a hoax.
The results came as climate change was emerging as a source of debate in the coming presidential campaign.
In 2012, all the Republican presidential candidates but one — Jon M. Huntsman Jr. — questioned or denied the science that determined that humans caused global warming, and opposed policies to curb greenhouse gas emissions. But over the past year, President Obama has proposed a series of Environmental Protection Agency regulations intended to reduce carbon pollution from coal-fired power plants, which Republicans in Congress have attacked as a “war on coal.”
But those positions appear to be out of step with the majority of the electorate.
The poll found that 83 percent of Americans, including 61 percent of Republicans and 86 percent of independents, say that if nothing is done to reduce emissions, global warming will be a very or somewhat serious problem in the future.
The nationwide telephone poll was conducted Jan. 7 to 22 with 1,006 adults and has a margin of sampling error of plus or minus 4 percentage points.
Over all, the number of Americans who believe that climate change is caused by human activity is growing. In a 2011 Stanford University poll, 72 percent of people thought climate change was caused at least in part by human activities. That grew to 81 percent in the latest poll. By party, 88 percent of Democrats, 83 percent of independents and 71 percent of Republicans said that climate change was caused at least in part by human activities.
Jason Becker, a self-identified independent and stay-at-home father in Ocoee, Fla., said that although climate change was not his top concern, a candidate who questioned global warming would seem out of touch.
As a result, many Republicans have begun responding to questions about climate change by saying “I’m not a scientist” or some variant, as a way to avoid taking a definite position.
The poll found that that vague position might well help Republican candidates in primary contests, particularly among conservative voters. The poll found that 27 percent of Americans were more likely to vote for a candidate who took that position, and 44 percent less likely. But among those who support the Tea Party, 49 percent said they would be more likely to vote for a candidate who said “I’m not a scientist” or a variant.
“It recruits more Tea Partyers than it repels,” Mr. Krosnick said.
A pledge to fight climate change appears to have less attraction for older voters. The poll found that older Americans were slightly less inclined to support a candidate who calls for action to reduce global warming and similarly less negative toward a candidate who rejects the premise of global warming.
“Global warming hasn’t much importance to me,” said William Werner, 73, a retired sales manager in San Antonio. “It is not man-made in my opinion because there have been cycles forever, and we can’t do much about that.”