Assigning credibility or expertise is a fraught issue, particularly in a wicked phenomenon like climate change—as Anderegg et al. (1) discussed in a recent issue of PNAS. However, their analysis of expert credibility into two distinct “convinced” and “unconvinced” camps and the lack of nuance in defining the terms “climate deniers,” “skeptics,” and “contrarians” both oversimplify and increase polarization within the climate debate.

Unlike contrarian or skeptic, the term climate denier is listed in their key terms. Using the language of denialism brings a moralistic tone into the climate change debate that we would do well to avoid. Further, labeling views as denialist has the potential to inappropriately link such views with Holocaust denial. The article then uses the terminology “skeptic/contrarian” throughout. However, skepticism forms an integral part of the scientific method, and, thus, the term is frequently misapplied in such phrases as “climate change skeptic.” Contrarianism, on the other hand, implies a rather different perspective on anthropogenic climate change.

McCright (2) defines climate contrarians to be those who vocally challenge what they see as a false consensus of mainstream climate science through critical attacks on climate science and eminent climate scientists, often with substantial financial support from fossil fuels industry organizations and conservative think tanks. We expand on the connections between claims-making and funding to also include ideological motives behind criticizing and dismissing aspects of climate change science. Importantly, this definition of contrarian specifically identifies those who critically and vocally attack climate science—those who Anderegg et al. (1) indiscriminately identify as skeptics, contrarians, and deniers. It does not include individuals who are thus far unconvinced by the science (due, in part, to the voracious media coverage garnered by climate contrarians as identified above) or individuals who are unconvinced by proposed solutions.

The use of the terms skeptic, denier, or contrarian is necessarily subject-, issue-, context-, and intervention-dependent. Blanket labeling of heterogeneous views under one of these headings has been shown to do little to further considerations of climate science and policy (3). Continued indiscriminate use of the terms will further polarize views on climate change, reduce media coverage to tit-for-tat finger-pointing, and do little to advance the unsteady relationship among climate science, society, and policy.