Predictably, they found that the more exposed Americans are to conservative media, the less certain they become that climate change is happening. The problem, they discovered, isn’t just that programs like Fox News are sowing the seeds of doubt about climate change, it’s that they’re decreasing people’s trust in the scientists who say it’s happening. That’s 97 percent of them, for the record.

The researchers took a nationally representative sample of Americans who were quizzed, by phone, on their media diets and their belief in climate change on a scale from 0 (extremely sure global warming is not happening) to 8. They controlled for variables like race, income and education level. Almost 2,500 people were surveyed in 2008; 1,036 were reinterviewed in 2011. They also analyzed the climate change coverage across Fox News, ABC, CBS, NBC, MSNBC, CNN, NPR, the New York Times and the Wall Street Journal during that period.

The study’s lead author, Jay Hmielowski, explained in an email that his team found a 13 percent decrease in the amount of trust between people who do not watch or listen to Fox News or Rush Limbaugh and the programs’ most loyal devotees. Those who watched or listened to left-leaning and mainstream news sources — CNN, MSNBC, NPR and network news — experienced the opposite effect: They were more likely to trust scientists and thus be more certain that global warming is happening. The researchers were able to show that this influence occurs over time, as the years of tuning in accumulate.