(AP Photo/Subhankar Banerjee)

Why do Democrats and Republicans differ so much on the fundamental science of global warming? A key reason is the politicization of climate science. Politicization means emphasizing the inherent uncertainty of science in order to cast doubt on the existence of a scientific consensus. The result is that citizens become uncertain about whether to trust politicized scientific information — even though, in the case of climate change, there is a clear scientific consensus about the reality of human-induced global warming.

Unfortunately, our new research shows how far this politicization extends: not simply to citizens, but to congressional staffers and even scientists themselves. Our study is one of the first to simultaneously assess the beliefs of the U.S. public and key elites in the policy-making process – that is, scientists who conduct research on new technologies that may offer solutions, and advisers to members of Congress who help enact legislation.

We conducted simultaneous surveys of the U.S. public, scientists who are actively publishing research on energy technologies in the U.S., and congressional staffers in August 2010. (More information about these surveys is in our article.) We asked each of these groups about whether global warming is happening and, if so, whether it is the result of human activity.

We found that ideology and party identification affected beliefs about global warming in each group. Both scientists and congressional staffers were more likely than the public say that human-caused global warming is happening. But ideology and party identification influenced beliefs across each of the three samples — although to a lesser extent among energy scientists compared to the public and staffers.

More alarmingly, we asked a series of factual knowledge questions on each survey related to science comprehension, energy knowledge, and political knowledge. We find that as conservatives and Republicans become more knowledgeable about energy, politics, and science they become less likely to say that human-caused global warming is happening.

Some recent work by Dan Kahan and others argues that this type of reasoning is individually rational, because it helps to uphold social identities, cultural commitments, and personal worldviews, but it is collectively detrimental to society because it undermines the ability of science to arbitrate debates where science can inform the public. Once a debate has become politicized, educating the public about the facts associated with global warming rarely leads individuals to change their incorrect beliefs.

A true scientific consensus is rare. When a consensus is reached, we should do everything possible to make certain the public is aware. The challenge is finding ways to counteract the politicization, and thereby negate the ability of political actors to render that consensus useless.

Toby Bolsen is an assistant professor of political science at Georgia State University. James N. Druckman is the Payson S. Wild Professor of Political Science, and a faculty fellow at the Institute for Policy Research at Northwestern University. Fay Lomax Cook is a Professor of Education and Social Policy at Northwestern University.

This post is part of a series on politics and science.  Other posts in the series include:

“A scientific perspective on politics and science”

“You can change the mind of climate change skeptics. Here’s how.”

“Why science teachers sow doubt about evolution (even when they don’t mean to)”

“Neuroscience is coming to law. Can we keep politics out of it?”

“Biased interpretations of science? Liberals do it too.”