Marc Boudreaux

An interdepartmental study including researchers from Yale’s Department of Political Science and School of Forestry & Environmental Studies found that people are more likely to accept the existence of climate change when shown that scientists agree on the issue. The study, published in the journal Nature Climate Change, suggests that the populations least concerned with climate change may respond most to educational, pro-climate change messages.

“This opens up an enormous new field of research,” said Anthony Leiserowitz, director of the Yale Program on Climate Change Communication and senior author of the paper. “We can now determine, not just the spatial variation in public opinion across the country but also the spatial variation in likely public responses to messages.”

Last year, Leiserowitz and his team reported that 97 percent of climate scientists agree that climate change is real and attributable to human activities, but only 11 percent of the U.S. population can accurately estimate scientists’ consensus as “more than 90 percent.”

Other research shows that perceived scientific dissent on climate change diminishes support for environmental policy and public concern of harms associated with climate change. In the current study, the authors set out to determine how perception of scientific consensus about climate change changes with geographic location.

The investigation used a nationwide sample of over 6,000 participants, a fraction of whom were shown the phrase, “97 percent of climate scientists have concluded that global warming is happening.” The researchers were interested in how participants’ perceptions of the scientific consensus surrounding climate change were altered after seeing the phrase. Researchers then constructed a statistical model that scaled the analysis to all 50 states and 435 congressional districts.

“We found that there are great spatial variations across the U.S. regarding responsiveness to our climate change message,” said Baobao Zhang GRD ’19, first author on the paper. “Our message produced the greatest effects in more conservative parts of the country.”

At the state level, exposure to the scientific consensus led 12.2 to 24.1 percent of people to change their perceptions. These differences, according to the authors, are associated with prior understanding of climate change. Participants from pro-climate states, such as California, had high pre-testing perception of the climate change consensus and therefore showed smaller post-test effects. Notably, states with the largest perception changes — including West Virginia, North Dakota and Wyoming — are all fossil fuel–producing states, according to Leiserowitz.

The district-level analysis mirrored trends shown by states. Congressional districts, particularly those in rural areas, showed the greatest changes in perception in response to the consensus message; these areas include the Midwest, Appalachia and the American South.

“We know from our prior work on public opinion that these estimates are highly accurate,” Zhang said. “But in this case, with actual messages, we need to do further research in different parts of the country to make sure that this new technique also generates accurate estimates of how people will respond.”

The authors also note that their data indicate potential for people to change their perceptions on climate change in response to scientific consensus; it does not predict if individuals will actually change their views. Despite this limitation, the study provides a useful blueprint to help educators create targeted climate change campaigns.

The Yale team also hopes to conduct further experiments with pro-climate action messages in regions that their data show will be most effective, according to Zhang.

According to NASA, the 17 warmest years on record have all occurred since 2001, and 2016 was the warmest ever recorded.

Marisa Peryer |