Two of my most popular posts here at DeSmogBlog were a pair of items documenting 1) just how many surveys have found Fox News viewers to be more misinformed about factual reality and 2) taking PolitiFact to task for giving Jon Stewart a “false” rating when he pointed this out.

Stewart wasn’t wrong, PolitiFact was.

In these pieces, I identified 6 separate studies showing Fox News viewers to be the most misinformed, and in a right wing direction–studies on global warming, health care, health care a second time, the Ground Zero mosque, the Iraq war, and the 2010 election.

I also asked if anyone was aware of any counterevidence, and none was forthcoming. There might very well be a survey out there showing that Fox viewers aren’t the most misinformed cable news consumers on some topic (presumably it would be a topic where Democrats have some sort of ideological blind spot), but I haven’t seen it. And I have looked.

There really does seem to be a “Fox News effect,” then, and one that is playing a central role in driving our political divide over reality in the U.S. And now comes a true tour-de-force seventh study showing that Fox News viewers are the most misinformed, this time once again about global warming.

The new paper, already flagged here by Farron Cousins, is just out in the International Journal of Press/Politics, by communication scholar Lauren Feldman of American University and her colleagues. The paper is quite sophisticated, and performs several powerful analyses. But for our purposes, here’s what matters.

Feldman and her colleagues reported on their analysis of a 2008 national survey, which found that “Fox News viewing manifests a significant, negative association with global warming acceptance.” Viewers of the station were less likely to agree that “most scientists think global warming is happening” and less likely to think global warming is mostly caused by human activities, among other measures. Viewers of CNN and MSNBC were the opposite.

And no wonder: Through a content analysis of Fox coverage in 2007 and 2008, Feldman and her colleagues also demonstrated that Fox coverage is more dismissive about climate science, and features more climate skeptics. That’s no shocker, but the paper does a very good job of linking up the coverage itself with the reality denial that results in Fox viewers.

There is also a fascinating finding that those Republicans who do watch CNN/MSNBC are more persuaded than Democratic viewers are to accept global warming. In other words, Republicans in the study seem much more easily swayed by media framing than Democrats. Put them in the Fox information stream, just add water, and watch denialism sprout. Put them in another information stream, though, and something very different might happen.

I noted in my prior posts that the studies documenting the “Fox News effect” do not necessarily show causation. In other words, watching Fox may make you more misinformed, but people who believe lots of political misinformation may also gravitate towards Fox.

I actually think both things are going on simultaneously–but the new Feldman study does make a strong causal case that Fox is actively driving a lot of the problem.

In other words, why are Americans so divided today over reality and what is factually true? There are surely many causes—but one is that a news network with a powerful sway is constantly sowing right wing misinformation, and an army of followers are watching and believing it.