A new survey has appeared which claims to show that the notion of a "consensus" existing among climate scientists re the causes/effects of Global Warming is incorrect. This claim seems to be misleading.
The survey, conducted by Fergus Brown, James Annan (FRCGC), and Roger Pielke Sr. (University of Colorado), is entitled "Is there agreement amongst climate scientists on the IPCC AR4 WG1?". In their abstract, they put their findings this way:
An online poll of scientists' opinions shows that, while there is strong agreement on the important role of anthropogenically-caused radiative forcing of CO2 in climate change and with the largest group supporting the IPCC report, there is not a universal agreement among climate scientists about climate science as represented in the IPCC's WG1. Claims that the human input of CO2 is not an important climate forcing, or that 'the science is more or less settled', are found to be false in our survey.
The problem I have has to do with how the phrase "the science is settled" gets employed within the survey as opposed to how it has been typically been employed in the broader debate over climate change. Our three authors state their result in general terms as follows:
No scientists were willing to admit to the statement that global warming is a fabrication and that human activity is not having any significant effect on climate [0%]. In total, 18% responded that the IPCC AR4 WG1 Report probably overstates the role of CO2, or exaggerates the risks implied by focusing on CO2-dominated Anthropogenic Global Warming (AGW), to a greater or lesser degree. A further 17% expressed the opinion that the Report probably underestimates or seriously underestimates the consequences of anthropogenic CO2-induced AGW and that the associated risks are more severe than is implied in the report. The remaining 65% expressed some degree of concurrence with the report's science basis, of which the largest group [47% of all respondents] selected option 5. The exact response rates are given in Figure 1.
Well, okay, but I would argue that "the science is settled", as it gets deployed in the broader discussion, means something like it is settled that 1) the planet is warming, 2) it is warming because of rising C02 levels which 3) are primarily caused by human activity. In other words, within the broader context, if
Claims that the human input of CO2 is not an important climate forcing...are found to be false in our survey.
...then the science is more or less settled, and the rest is quibbling over detail.
And using my three part explication of "It is agreed that the science is settled." (making reference to the authors' Histogram of Responses), 77% of the survey respondents agree with all three of its parts (choose response number 5 or higher as being representative of their views). I don't know what exactly it takes to make a "consensus", but if over three out of every four climate scientists concur, I would argue that you have a consensus.
And of course the issue is that as the results of this survey play out in the larger political arena, the authors' claim that the "science is not settled" will be interpreted to be a refutation of the claim that climate scientists do not agree with the three elements of my definition (or something more like my definition than theirs).
Which is why, I would argue, that it is already getting quoted with approval in places like this.
(PS. James Annan has noted, in a personal communication that,
Of course the "science is settled" phase has a bit of a life of its own (settled for what purposes? I don't see climate scientists resigning in droves to do other things). For that very reason, I wouldn't have chosen this wording myself, but I didn't think it sufficiently wrong to veto it.
Well, the wording chosen has given hope and comfort to some in the denialist movement...)