The percentage of conservative Republicans who consider global warming a threat shot up 19 points in two years, to 47 percent, according to public opinion researchers at Yale University and George Mason University. Overall, 56 percent of Republicans agree that it’s happening. Including Democrats and independents, the national average for the U.S. is 73 percent.

The new survey results, “ Politics & Global Warming 2016 ,” suggest a growing gap between what most registered Republican voters understand to be true and what the party leadership says it believes, particularly on the presidential campaign trail this year.

Liberal-to-moderate Republicans say climate change is real in much higher numbers than the party’s right wing does. More than 70 percent of GOP moderates say they know the world is warming, up 10 percentage points from two years ago. But only half of these Republicans, and just 26 percent of conservative Republicans, identify the problem as caused mostly by human activities (PDF).

Acknowledging the warming is "a critical first step," said Anthony Leiserowitz, director of the Yale Program on Climate Change Communication. "The first step is admitting that you have a problem."

The two leading Republican presidential candidates have repeatedly dismissed climate change science. Donald Trump told the Washington Post editorial board in March that he is "not a great believer in man-made climate change," adding that "perhaps there's a minor effect."

Senator Ted Cruz of Texas earlier this month tweeted this statement about carbon dioxide in the atmosphere:

The Yale-George Mason poll was conducted March 18-31 and is based on a survey of 1,004 registered voters who reflect the national electorate. The respondents were drawn from Knowledge Panel, a unit of the German marketing company GfK SE that assembles statistically sound sample groups for universities, new organizations, companies, and nonprofits.



The survey confirms that while only liberal Democrats put climate change near the top of their agenda, it remains a litmus test for credibility among many registered voters. Respondents were more likely to pick a candidate who strongly supports fighting climate change, 43 percent to 14 percent. They also reported feeling less likely to vote for an opponent to climate policy.

The issue is generational as well as partisan, according to Sheril Kirshenbaum, director of the University of Texas-Austin Energy Poll. Younger Americans are much likelier to understand climate change—but that doesn't mean they'll vote.

The biggest surprise is just how tenacious far left Democrats have become about the issue. The survey asks liberals and conservatives within each party to rank 23 issues by importance. Global warming, environmental protection, and clean energy all appear among the top eight issues for liberal Democrats—higher than their traditional bread-and-butter topics such as gun control, reproductive rights, and Wall Street reform.

Climate change is also the most divisive of the 23 issues—a fact the researchers will look at in more detail next week, when it reports on what each presidential candidates' supporters think about the issue.