For example, to examine the influence of advocacy, the researchers counted the number of stories on climate change in environmental and conservative magazines, as well as the number of New York Times mentions of Al Gore’s “An Inconvenient Truth,” between 2002 and 2010.

The researchers also looked at several additional control variables that could possibly influence public concern about the environment, such as the unemployment rate and the gross domestic product (if the public is highly concerned with these economic issues, they would be less likely to worry about climate change).

After plugging all this information into computer models, they found that access to scientific information has a minimal effect on the public’s opinion about climate change, while weather extremes have no noticeable effect whatsoever (which slightly contrasts with a 2011 study). Media coverage seems to exert an important influence, but the researchers conclude that this coverage is inextricably tied to other factors, such as political opinions and the state of the economy.