Why trust thousands of careful scientific observations when you can just ask yourself if it’s hot where you live?
About 97% of climate scientists agree that human carbon emissions are changing our planet’s climate. According to the Union of Concerned Scientists, scientific consensus on climate change is comparable to the scientific consensus that smoking causes cancer. In fact, the scientific consensus on climate change is only slightly lower than the scientific consensus on whether the earth is round (it is). But despite a sea of evidence that climate change is real, many laypeople continue to believe that climate change is a myth.
There are many reasons for climate change skepticism — from wishful thinking to a lack of science education. But psychologists are learning that the automatic “rules of thumb” that people use to make snap judgments — judgmental heuristics — also influence people’s views of climate change. More specifically, for people who live in places with cool climates, the bias known as the availability heuristic fuels skepticism about global warming. The availability heuristic refers to the tendency to base our judgments on how easily something is called to mind. We all know that receiving birthday cards is more common than receiving death threats. This is because most of us have received many more birthday cards than death threats — even if we count the occasional birthday card that includes a death threat. But sometimes the availability heuristic can lead our judgments astray.
In analyses of both the 50 U.S. states and 117 nations across the globe, I found that in places where the climate is generally cool (North Dakota and Norway both come to mind), fewer people believe in global warming. Thus, the more often people are routinely exposed to cold weather themselves, the more likely they are to be skeptical about global warming. This pattern was true in the United States even after controlling for household income, education levels, and the percentage of Democratic versus Republican voters per state.
Studies of how people respond to short-term variation in the local weather, as well as experiments in which people are reminded of unseasonably hot or cold weather, have yielded similar effects. Many concede that our planet is getting warmer only when their own neighborhood has been warm lately — or is chronically warm. One reason the residents of Maine are less likely to believe in global warming than the residents of Maui is that the small portion of the globe known as Maine has a much lower average temperature than Maui. This same pattern of public opinion about global warming applies to Austria versus Australia: people in Austria are more skeptical of climate change than people in Australia.
We once thought that a bit of unseasonably cold weather made people skeptical of global warming for only a week or so. As I already noted, cold waves do temporarily lower people’s beliefs in the reality of global warming. But my recent findings suggest that, on top of these short-term effects, both seasonal temperature variation and long-term regional temperatures also influence public opinion about global warming.
The two images that follow summarize monthly variation in public skepticism about global warming in both the United States and Canada. Using data on people’s Google searches regarding global warming, I found that people searched most often for information that expressed skepticism in global warming at the beginning of winter. They searched for such information least often toward the end of summer. So, rather than trusting measurements taken at thousands of places across the globe, many people judge the reality of climate change by considering the weather in their own backyards.
These finding on public opinion about global warming held true whether I defined public skepticism about global warming based on Google search activity or based on public opinion polls. Finally, analyses in both the U.S. and the international data revealed that cold weather creates skepticism about global warming more than hot weather promotes acceptance of the scientific consensus about it.
I hope it’s clear that those who wish to combat public skepticism of climate change — especially among people living in cold climates — must get people to think globally rather than locally. Because of the availability bias, people’s climate change beliefs are affected by their idiosyncratic personal experiences where they live. The best way to reduce this bias may be to remind people frequently of the weather in other parts of the world.
For Further Reading
Egan, P.J., & Mullin, M. (2012). Turning personal experience into political attitudes: The effect of local weather on Americans’ perceptions about global warming. The Journal of Politics, 74, 796–809.
Pelham, B.W. (2018). Not in my back yard: Egocentrism and skepticism about climate change. Environmental Science and Policy, 89, 421–429.