How do these disasters affect people’s perceptions of climate change?
To those already convinced by climate change science, extreme weather events are evidence that it’s already changing our world. Climate skeptics, however, do not always see the link, as when President Trump insisted the California wildfires resulted from poor forest management, not climate change.
Why is the American public divided on climate change?
Many scientists have been working to determine when strange weather can be attributed to climate change. I have focused my research on examining Americans’ understanding of how strange weather and climate change are related. Here’s what I’ve found:
Political orientation determines attitudes toward climate change and extreme weather
Climate change has become an extremely politicized issue in U.S. discourse, largely thanks to the conservative movement. The fossil fuels industry and conservative think tanks have worked together to discredit the science of climate change. In a nation that is highly polarized politically, climate change has become a litmus test for political identity. Survey after survey has consistently shown that Democrats and liberals are more likely than Republicans and conservatives to believe that humans have an impact on climate change and that climate change will have immediate and serious effects. Republicans and conservatives generally refuse the idea that the climate is changing because of human intervention, in part because they are concerned about the political implications: enforcement of regulatory actions on a massive scale.
As a result, partisan affiliation also powerfully shapes individual perceptions of extreme weather events. Where Democrats perceive rising air temperatures and an increasing number of hurricanes, droughts and floods, Republicans are less likely to agree that climate conditions are changing or that extreme weather is increasing.
In other words, preexisting beliefs about climate change determine how people think about reports of strange weather. People who believe climate change is serious, already underway and must be a political priority are more likely to interpret reports of strange national weather patterns as evidence of climate change. Further, they are likely to register the fact that hurricanes are growing stronger and more frequent. That’s not true for Republicans and conservatives who don’t believe in human-caused climate change.
Attitudes toward climate science — an outgrowth of partisan loyalties — appear to serve as a filter through which people process information about local weather. Confronting the same weather, Democrats and Republicans see a very different reality — even when changing weather is objectively measured and reported.
Curiously, seeing is not believing when it comes to climate change and extreme weather; rather, believing is seeing. Social scientists have a name for this phenomenon — confirmation bias, the tendency to consciously or unconsciously seek or interpret evidence from the outside world to fit one’s preexisting perceptions, views and beliefs. Whether we like it or not, we all see the world through tainted lenses.
So can Americans still change their minds about the climate?
Here is what is going on: The baseline probabilities of Democrats’ and Republicans’ perceptions of climate change and extreme weather are different. To illustrate, imagine that the probability that someone in Party A believes in human-made climate change is 80 percent, while that probability for someone in Party B is only 30 percent. What my research finds is that extreme weather events can change that baseline probability upward, regardless of partisanship or ideology. That change may be more dramatic for those in Party A than Party B. Nevertheless, the change does occur; extreme weather can move the needle.
For instance, Americans who have experienced increasing summer heat over the past 10 years are most likely to perceive climate change as having immediate, severe effects. Specifically, as individuals live through summers that keep getting hotter, the probability that Republicans believe that ‘‘global warming is a very serious problem’’ increases to 23 percent from 16 percent when they experience summers that keep getting warmer. This effect may not be as big as among Democrats, whose probability of holding the same belief increases from 46 percent to 58 percent under the same scenario.
The same is true for people living in communities where summers have been getting warmer while spring temperatures have been getting cooler. In that case, the probability that an individual perceives human-made global warming is 67 percent in places with the largest gap of temperature trends between summer and spring, compared with 36 percent in places with the smallest discrepancy between seasons.
Similarly, those who have experienced more storms tend to perceive stranger weather patterns. As the number of extreme weather events that have occurred in one’s county in the past three years increases from zero to the hundreds, on average, someone’s probability of believing that the local weather is stranger than usual increases by 22 percent.
In other words, extreme weather patterns can change individuals’ opinions about global warming, though the effect is felt more strongly among Democrats than Republicans.
People are especially likely to change their minds after living through rare but major events like hurricanes. When hurricanes have powerful wind speeds at landfall, coastal residents are more likely to perceive hurricanes having become stronger. Even for Republicans, the probabilities of believing that hurricanes are getting stronger will increase from 15 percent in areas where the wind speed of the last hurricane’s landfall was 40 mph to 57 percent in areas where the wind speed reached 150 mph.
In other words, reality can indeed affect partisan preconceptions.
Wanyun Shao is an assistant professor of geography at the University of Alabama and an early-career research fellow at the National Academies of Sciences, Engineering and Medicine’s Gulf Research Program.