Thursday, November 22, 2007

Is The Science Settled Or What? Notes On A New Survey

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...)


Anonymous said...

No, it's not. It's inadequately understood, but the belief in AGW is being shoved down our throats by elite corporate moneygrubbers.

Anonymous said...

settled like crap in the bottom of the shitter.

The current level of apoplectic sky-is-fallingism is driven by knowledge that the actual climate data has, for the past nine years, shown the beginning of a cooling trend/period.

There is not much chance the Believers can continue to stampede the herd when the herd looks out ans sees a pride of cute kittens pretending to be a fear driven pride of lions.

The game is almost over. No worries.

On a personal note, I actually hope all this CO2 taxation crap goes ahead. I stand to make a lot of money off the stupidity.

Not as much as Al Gore, but enough to laugh all the way to early retirement

Ti-Guy said...

How many sock-puppets are you "show me the money"...aka "ding dong kyoto's dead" aka "steffi something or other?"

Anyway, you're a complete lunatic:

I actually hope all this CO2 taxation crap goes ahead. I stand to make a lot of money off the stupidity.

Well then, what the hell are you moaning on here for? Go out and spend it on meth and hookers. Mazel Tov!

Anonymous said...

Hi Bcl. I'm copying my (somewhat slow) response to your comment on my blog, here. Sorry it's a bit long.

Most importantly, though, I'd like to correct your initial assumption that the purpose of the poll or the paper is to show that there is no consensus; this is a misunderstanding (perhaps induced by Roger's involvement). The poll was conducted because a question existed about how much agreement there is among climate scientists about the science as presented by the IPCC AR4 WG1, and, being a simple soul, I concluded that the best way to resolve the question was to ask the scientists themselves. The paper is a summary of what we did and what the results were. We knew that the results were going to be 'interpreted' in different ways, but, in the spirit of proper scientific enquiry, having received the replies to our (admittedly imperfect) poll, we agreed that it should be presented for publication.

Here's the rest of my response:

Hi bcl; I’d like to know who’s got hold of our paper, as it’s not been published, (yeah, I know that James and Roger have it flagged up on their pubs. lists.) and I’m still waiting to hear from EOS, though we have agreed that if Fred doesn’t reply soon, we’re going to send it elsewhere.

I’ll say that there are one or two things in it which probably do merit changing. Both William and Eli have also made very useful suggestions about how I could have done it better in the first place. We were expecting some comments from EOS, but they haven’t been very forthcoming so far.

There is an ambiguity in both the statements, which are often heard in discussions. The ambiguity of the first is the measure of significance of the role of CO2 - which was something we were trying to get a grip on in the poll. The actual number of people who responded that CO2 was not important (compared to natural or other factors) was very low; on this basis, it can be argued that there is a consensus that CO2 is an important forcing.

The ambiguity of the second statement is that it can be read to imply that the science of climate change is ‘more or less settled’, or that the science supporting the role of CO2 is ‘mols’. If the second were the case, you would have a natural contradiction to the first; in the other case, though, the results of the poll suggest that there are still sufficient uncertainties about a number of things to be able to say the the ’science is not settled’; certainly, the idea that it is is apparently falsified by our results (again, a suggestion, not a hard conclusion).

If you go to Richard Black’s environment blog on the BBC, you’ll find the survey/paper being used to demonstrate that there is a consensus; as per, then, it is being interpreted by different people in line with their existing prejudices, whatever those happen to be. As far as I am concerned, it seems to suggest that there is a degree of ‘discomfort’ which some scientists feel personally about the AR4 WG1, which is not reflected in some of the statements made about the scientific basis of AGW, and which deserves further investigation. This neither means that there is no ‘real consensus’ about the fundamentals, nor that the IPCC is necessarily a ‘flawed’ report. Indeed, a mean response of exactly ‘5′ would imply that the IPCC presentation of the science is exactly at the middle-point of a predictable range of views, which we should probably find reassuring.

Sorry about the delays in responding; life can be complex, sometimes…


Anonymous said...

At least Liberal brains are clean from all that washing . . .

and in like-new condition from hardly ever having been used.

Anonymous said...


Anonymous said...

On a liberal would think a 'survey' can substitute for legitimate scientific research and analysis.