Although preliminary estimates from published literature and expert surveys suggest striking agreement among climate scientists on the tenets of anthropogenic climate change (ACC), the American public expresses substantial doubt about both the anthropogenic cause and the level of scientific agreement underpinning ACC. A broad analysis of the climate scientist community itself, the distribution of credibility of dissenting researchers relative to agreeing researchers, and the level of agreement among top climate experts has not been conducted and would inform future ACC discussions. Here, we use an extensive dataset of 1,372 climate researchers, and their publication and citation data to show that (i) 97-98% of the climate researchers most actively publishing in the field support the tenets of ACC outlined by the Intergovernmental Panel on Climate Change, and (ii) the relative climate expertise and scientific prominence of the researchers unconvinced of ACC are substantially below that of the convinced researchers.Of course, consensus is no guarantor of scientific truth. Copernicus and Galileo were both right about heliocentrism despite strong contemporary religio-scientific consensus to the contrary. Appropriately, the authors of the study in yesterday's PNAS caution that "[u]ltimately ... scientific confidence is earned by the winnowing process of peer review and replication of studies over time." As that process continues, it is clear that, at present, the weight of the scientific evidence and expertise strongly supports theories of anthropogenic climate change.
Why, then, doesn't the public believe it? Is it just a messaging problem? Certainly, the media's misguided sense that being "fair and balanced" means presenting both sides of every issue, no matter how one-sided are the merits, does not help. In the context of climate science, "fair and balanced" would mean that the media would present dissenting views three times out of every 100 or so stories on climate change. Imagine if CNN felt the need to include dissent from an Aristotelian geocentrist every time it presented a scientific story on the earth's rotation around the sun. (Fox News may already do that.)
The larger impediment to public acceptation of anthropogenic climate change as a scientific fact, in my view, is the lack of any catalytic event that can definitively associated with it. Members of the public are not scientists and cannot be expected to respond to scientific studies until they begin to perceive real problems for themselves or things they care about. My guess is that it will take something like the extinction of polar beers in their natural range to galvanize public opinion and generate public support for serious climate mitigation measures.