A while back, a memo surfaced that reportedly came from a Fox News executive, in which he directed his staff to always present opposing views on something we can essentially regard as a fact: our planet has been getting warmer. There has been plenty of anecdotal indications that this strategy has been carried out, including a truly bizarre incident in which Bill Nye, on the channel in order to discuss volcanic activity on the Moon, was asked if these volcanoes raised doubts about climate change.

But it hasn't been clear whether these incidents add up to a clear pattern and, perhaps more importantly, whether they actually caused the Fox viewership to become more confused about the state of climate science. Now, some academics have done an exhaustive evaluation of Fox broadcasts (along with those of CNN and NBC) and demonstrated that there is a systematic bias against presenting the scientific community's conclusions on Fox. And, at least among those with a conservative bent, it works. These viewers are far less likely to understand the state of the science, or even accept the reality that our planet has gotten warmer.

First, given the general issues with the science of climate change outlined in the study, it seems worth taking the time to discuss where things stand. The existence of greenhouse gasses is based on over 100 years of well-validated scientific research, and various measurements indicate that human activity is increasing the atmospheric concentration of a number of these gasses. In line with what one would expect based on this, the temperature of the planet has been rising, a trend that has been measured in so many different ways, we can essentially treat it as a fact.

This information has convinced the vast majority of the scientific community. Surveys of researchers with relevant expertise indicate that well over 90 percent of them find the evidence of an anthropogenic influence on climate persuasive. Every scientific society that has made a statement on climate change has also acknowledged this evidence. That's not to say that there isn't vigorous debate over the details, or that there are some prominent dissenters. But the same is true about other scientific information, including things that we treat as facts, like evolution and the role of HIV in causing AIDS.

But survey after survey indicates that a large portion of the US public doesn't accept even the basic outlines of climate change. This isn't a matter of basic scientific literacy, either; the public also has little idea of the scientific community's broad acceptance of the evidence.

Blame the media?

Most of the public isn't getting its information on climate change by reading the statements released by scientific societies or reading the IPCC reports. Instead, they're getting it from the media, which brings us back to the possibility of biased presentation mentioned at the top of this article. To determine the degree to which cable news channels are feeding the public an inaccurate picture, a group of researchers looked at transcripts of every news broadcast in 2007 and 2008, searching for keywords like climate on Fox News, CNN, and MSNBC.

With 270 transcripts in hand, they started looking at presentation, coding each show by the degree to which it reflected reality in three ways: the reality of changing climate, its attribution to human influences, and the degree of scientific consensus on the topic. Any guests on news programs were coded in the same way.

There was a very clear pattern. "Although Fox discussed climate change most often, the tone of its coverage was disproportionately dismissive," the authors concluded. The dismissiveness was present in almost every category. A third of Fox's broadcasts rejected the reality of climate change, while only 21 percent accepted it (no other network came close to those figures). Almost four times as many broadcasts on Fox claimed there was no consensus as accepted that one existed; the exact opposite was true on the other networks. A similar pattern was apparent when it comes to the issue of attribution.

Fox was also selective about its guests, nearly half of which doubted the existence of climate change (about 40 percent accepted it). On CNN and MSNBC, the figures were 9 and 15 percent, which is much closer to the level of acceptance by the scientific community.

So, it appears that Fox has adopted a policy of not just ignoring the best scientific information available, but actively attempting to counter it. Neither of the other major cable networks are doing anything of the sort when it comes to the climate.

Or blame the audience?

Does this disproportionately biased coverage actually have an effect? Here, the authors turned to survey data, obtaining information from over 2,000 US adults about their political persuasions, viewing habits, and thoughts on climate change. As with other polls, a bit over half accepted that humans were triggering a warming of the climate. But they were even less certain of the state of the scientific community, with less than half realizing that most scientists agreed on the matter.

On a superficial level, these numbers matched up well with news viewing habits. People who watched Fox News were much less likely to accept that climate change was happening. In contrast, those who watched CNN or MSNBC were far more likely to accept it.

But those who analyze these issues have suggested that there are two possible explanations for this effect. One is causal; getting regularly exposed to a perspective via the media will ultimately lead you to adopting that perspective. The alternative explanation involves selectivity in information sources. Those who are already convinced that climate change is nonsense may choose to watch Fox because it supports their conclusions.

As it turns out, the survey contained information that can help address this issue. Over 40 percent of the self-identified Democrats sometimes watch Fox, while 17 percent of Republicans tune in to CNN and MSNBC. When the numbers for those viewers were broken out, two different trends were apparent. Among Democrats, it didn't matter how often they watched Fox; their acceptance of climate change remained roughly steady. Republicans who watched MSNBC and CNN, however, had a much higher acceptance than their peers who maintained a strict diet of Fox.

"Democrats are relatively unchanged in their beliefs as a function of cable news use," the authors conclude, "whereas the beliefs of Republicans depend on whether they watch Fox News." The authors looked at some measures of how ideologically committed the Republicans were, and found that this could account for some, but not all of the effect.

The authors note that the behavior of Fox viewers is consistent with what they term "biased processing" (which seems to be another term for motivated reasoning), as "Fox News' dismissive view of global warming appears to resonate most with those who share the network's partisan perspective." But that seems to oversimplify matters, as at least a subset of Fox's target audience were open to other ideas, and showed the most dramatic difference in opinion when they were exposed to them (the Republican MSNBC/CNN viewers).

At the same time, the experience of Democratic Fox viewers indicates that at least some portion of the population won't simply accept anything the media feeds them. About the only thing that can be concluded from the study is that, when Fox News misinforms its viewers, a substantial percentage of them happily go along with it—as the authors put this, "To the extent that Fox News presents a different view of reality than does CNN or MSNBC, the knowledge and opinions of the networks' respective audiences will likewise tend to polarize." But this isn't the first study to show that (others are cited in the study).

The disturbing thing here is that it's not simply a different view of reality; Fox is disputing reality itself. The change in our climate and the scientific community's widespread attribution of it to human influences are both factual, yet Fox has managed to help foster doubts about these facts.

This is made even more disturbing by the fact that they didn't actually have to do this. Facts don't necessarily dictate a specific policy response, and there is plenty of ground to argue policy from a partisan perspective. But, rather than focus on the policy, the network has chosen to dispute the facts themselves.

The International Journal of Press/Politics, 2011. DOI: 10.1177/1940161211425410 (About DOIs).