Although the world is warming, it is not warming at the same rate everywhere. A study of local variations in people's responses to climate change reveals that residents of places where change has been slow are more likely to doubt the global data than those directly experiencing rapid shifts. The news may not be surprising, but it is certainly important.
"One of the greatest challenges to communicating scientific findings about climate change is the cognitive disconnect between local and global events," said co-author Michael Mann of George Washington University. "It is easy to assume that what you experience at home must be happening elsewhere."
A team led by Professor Robert Kaufmann of Boston University decided to test for the extent of these effects by comparing parts of the United States that have warmed rapidly with those that in the last 10 years have kept more in line with the previous 20 years.
Kaufmann's team chose to focus on record maximums and minimums rather than averages. For their study, published in the Proceedings of the National Academy of Sciences, they compared the ratio of record highs to record lows over the last 30 years at 18,713 weather stations across the United States. Almost half the stations across America have significantly more highs in the last 10 years than would be anticipated under a static climate, while 10 percent have experienced significantly more record lows. After extrapolating these ratios to temperatures in a county, the results were compared with polling data of local views on climate change.
A possible problem for Kaufmann was to clear out the other factors that could be affecting people's views of climate change. Denial of climate change correlates with right-wing politics, so demographic variations would also be expected to affect local differences. The South is overrepresented among stations that had a cool period since 2005, providing an important confounding factor.
After attempting to control for these demographic factors, Kaufmann's statistical modeling indicates that exposure to more record high temperatures than the national average translates into 4 percent more people believing climate change data than would otherwise. A similar sized reduction is seen where the last 10 years have been cool. High agreement with warming is seen in liberal strongholds such as the West Coast and North-East, but also in south Florida, New Mexico, and Colorado, which have also experienced notably warm conditions. On the other hand, the lack of local warming in the Mississippi and Ohio River valleys is reflected in particularly strong denial there.
Personal experience appears to have less influence on people's views than political affiliation, but the difference is not trivial. Kauffmann's work suggests it is much easier to convince people the world is warming when their home is doing the same thing.
Image credit: Michelle Gilmore