Most likely, you don’t write down the number of days each year when the temperature in your town reaches a record high or record low. But, in fact, you do keep track — subconsciously — and this practice could influence your attitude about climate change.

Subliminal awareness of local climate change can push people into either accepting or doubting climate change, depending on local climate patterns, according to new research published recently in the Proceedings of the National Academy of Sciences (PNAS).

“Even when you know the facts, understand the science, and have seen the maps of global trends, it is very tempting to rely on what you are experiencing,’’ said Michael Mann, co-author of the PNAS study and an associate professor of geography at George Washington University (and not the climate scientist of the same name).

Americans who live in regions with more record highs relative to record lows, such as the West and East coasts, are more inclined to believe in global warming, the researchers found. On the other hand, people who dwell in places where there are more record lows relative to record highs, such as southern portions of Ohio and the Mississippi River basins, tend to be more skeptical.

“In the end, we would do much better talking to our grandparents about their experiences, than relying on our own.’’

The study’s authors took other demographic factors — such as political leaning, which is highly correlated with climate views — into account. The impact of temperature extremes on population viewpoints was still significant.

The research is believed to be the first to study the effects of local climate change on people’s attitudes. “This study points out that we need to be aware of our bias towards experiential learning and over-emphasizing recent events,” Mann said.

“Despite our whole-hearted desire to confirm or deny climate change with a single weather event, we need to remember that a climate is described by averages over a 25- to 30-year period,’’ he said. “In the end, we would do much better talking to our grandparents about their experiences, than relying on our own.’’

A survey recently released by the Brookings Institution found that weather is one of the strongest reasons why those who accept the scientific evidence of climate change are significantly more confident of their stance today than they were eight years ago.

“Events like drought, strong storms, mild winters and experiences with warmer temperatures are all claimed by Americans to have a strong impact on their conclusions that global warming is happening,” said Christopher Borick, one of the Brookings authors and a professor of political science at Muhlenberg College, who was not involved in the PNAS study. “These comments regularly reflect weather-related factors such as lack of snow, different planting dates for gardens, more air-conditioning use and more flooding.”

“Just saying ‘Scientists say that climate change is real’ isn’t going to convince them,’’

The PNAS study confirms that Americans interpret climate change based largely on their own experiences rather than on the word of climate experts. To be sure, there are numerous factors that affect whether Americans accept that climate change is real, including political leanings — conservatives tend to be more skeptical. But personal experiences with weather — especially extreme weather such as heat waves, hurricanes, floods, and drought — are also an important factor.

“Who do Americans trust about climate change — scientists or themselves?” said Robert Kaufmann, the study’s lead author and a professor of earth and environment at Boston University. “For many Americans, the answer seems to be themselves. If you’re not going to believe the scientists and [instead] go on your gut, your gut — for a lot of people — accurately reflects what’s happening in their own local climate. And that’s how they are deciding whether to believe in climate change or not.’’

That leaves the question of how do scientists and communicators use what people are experiencing in their everyday lives to reinforce the facts of climate change.

The scientists suggest that Americans could better grasp climate change if agencies and news outlets focused more on record high temperatures and low temperatures throughout the year because people are already tracking that information, even if subconsciously.

“We think it’s a more effective way to communicate what’s happening with climate,” Kaufman said. “How many record high temperature days did we set compared to how many record low days?’’

“If you’re living in a place where there’s been more record cold weather than record heat lately, you may doubt reports of climate change.”

Moreover, the study points out that early terminology used to describe climate change focused on the earth simply warming, rather than explaining that it was undergoing innumerable and calculable changes. This may have led those experiencing an unusually cold winter to doubt that climate change was occurring.

“Just saying ‘Scientists say that climate change is real’ isn’t going to convince them,’’ Kaufmann said.

Furthermore, Kaufmann notes that cold days may not really be as measurably cold as in times past, but feel that way compared “to the average temperature, which has warmed,’’ he said.

The information compiled by the researchers is based on a statistical model of more than 12,000 survey respondents across the United States from 2008 to 2013 gathered by the Yale Project on Climate Change Communication and the George Mason Center for Climate Change Communication.

“The local weather conditions people experience likely play a role in what they think about the broader climate,’’ said Peter Howe, another co-author of the study and an assistant professor of environment and society at Utah State University. “Climate change is causing record-breaking heat around the world, but the variability of climate means that some places are still reaching record-breaking cold. If you’re living in a place where there’s been more record cold weather than record heat lately, you may doubt reports of climate change.”

One of the biggest challenges to communicating climate change science is getting people to understand what they see happening locally within the context of global climate change.

To do this, the study authors propose crafting a theoretical gamble.

“These records could be framed as a wager against the hypothesis that global temperatures are warming, in which a dollar is won for each record low and a dollar is lost for each record high,” Mann said. “This is essentially a bet against the house. Loss aversion would enhance the effect with each dollar lost seeming more valuable than a dollar earned.”

Put more simply: “For every record high, the climate change believers win,” Kaufmann said. “For every record low, the deniers win. At the end of two years, let’s see who’s won more money.”


Marlene Cimons writes for Nexus Media, a syndicated newswire covering climate, energy, policy, art and culture.