The purpose of the IPCC was to assess the state of knowledge on the various aspects of climate change including science, environmental and socio-economic impacts and response strategies.
I.e. it was meant to report on and asses the scientific knowledge. This includes the question of how much evidence and (as a result) how much agreement amongst experts (consensus) there is for human induced climate change.
Some science historians point to other important aspects of IPCC’s history. The National Academy of Sciences wrote in 1979:
A plethora of studies from diverse sources indicates a consensus that climate changes will result from man’s combustion of fossil fuels and changes in land use.
Oreskes shows that the IPCC was set up in response to the emerging consensus in the 70’s/80’s that global warming due to GHG emissions would likely become a problem.
Spencer Weart writes:
The concern [about impending climate change] gave rise to the IPCC.
And also points to the Reagan administration being in favor of the clumsy IPCC approach, hoping that it would downplay the scientists’ fears.
When pointing to scientists who disagree with the IPCC consensus, it is important to note that people can agree in basically two directions. The survey by Brown, Pielke Sr and Annan for example shows this to be an approximate bell curve: Most (45-50%) of the respondents (scientists) more or less agree with the main thrust, and sizeable minorities (15-20%) think that IPCC overstated or understated its case. I discussed this survey and the broader question of why the consensus matters before. And I probably will pick this up again soon.
Scientifically, the more uncertain areas are the most interesting. However, if I look at the political decision making in terms of emission reductions and knowledge of the big picture (and the length of time that we’ve known about this big picture, albeit in gradually more certain terms), I can’t but conclude that the politics is hopelessly lagging behind the scientific knowledge in taking this problem seriously. (see e.g. my Dutch post “tijd voor de politiek om wetenschap serieuzer te nemen”.) Of course I’m aware that there’s more that informs politics than just the science, but still, there seems to be an uncomfortably big disconnect there. Stark warnings from science are ignored at our peril.
At this point in time, the uncertainties are pretty much irrelevant for policymaking, because any realistic change in the uncertain details is not going to affect the main trust of what we know, and thus the policy response that people may favour. For the long term, of course we need to finetune our knowledge, so research is still needed. (Hey, I’m a scientist, so I kind of have to say that, right?)
As Herman Daly said:
“Focusing on them [the big picture of what we know] creates a world of relative certainty, at least as to the thrust and direction of policy.” On the other hand, focusing on the more uncertain rates and valuations creates “a world of such enormous uncertainty and complexity as to paralyze policy”.
Perhaps that’s indeed what’s happening now, also cf. Judith’s uncertainty monster and complexity monster.
“To make the point more simply, if you jump out of an airplane you need a crude parachute more than an accurate altimeter.”
Funny how Daly and Curry both address the huge issues of uncertainty and complexity and arrive at diametrically opposed strategies of dealing with them. In terms of public communication, I’m with Daly.
From the principles governing IPCC work:
The role of the IPCC is to assess on a comprehensive, objective, open and transparent basis the scientific, technical and socio-economic information relevant to understanding the scientific basis of risk of human-induced climate change, its potential impacts and options for adaptation and mitigation.
IPCC reports should be neutral with respect to policy, although they may need to deal objectively with scientific, technical and socio-economic factors relevant to the application of particular policies.
Funnily enough, a commenter at Judith’s, Paul in Sweden, took this as proof of a “blatantly biased agenda”. Which is a little strange in light of the history of climate science and of the IPCC as mentioned above. Its mandate is a consequence of the scientific evidence for human induced climate change having become increasingly strong and societally relevant. It doesn’t state what the conclusion ought to be –it has to follow the science-, but of course it states what it’s supposed to assess.
Judith Curry also seems to suggest that the IPCC reports are working towards a predetermined conclusion, when she claims that they are akin to a legal brief (meant to persuade). If true, that should be reflected by large differences between the scientific evidence and the IPCC reports, and between scientists’ opinions and the IPCC reports. I have not seen evidence of either.
Tom Curtis made some very thoughtful comments on the consensus thread at Judith’s, e.g.
In other words, the IPCC was tasked with reporting the consensus view of the science, were such a consensus existed; and to explain and report the differing opinions where no such consensus existed. Whether they have done that is not best judged by whether they have explained and included the opinions of every crackpot fringe group with an axe to grind on global warming; nor even those of every climatologist, no matter how small a number might support their views. Rather, they are to be judged by the agreement between the IPCC reports and the known consensus and divergences of scientific opinion.
Fortunately, we have available several anonymous surveys of the scientists opinions, which show conclusively that the IPCC reports fairly represent the consensus of relevant scientists on those topics on which it reports. (…)
The purpose of IPCC is to provided as succinctly as possible the best possible scientific advice for policy deciders to operate on. If they were required to consider all and every idea on climate change that circulates on the blogosphere; then the resulting document would be to large, and to ill organised to be usefull as a guide to policy.
Nevermind that the politicans still wouldn’t have a clue as to what is more likely true. The science has to be assessed and weighted; that is what makes the IPCC process useful. There already is another outlet for every crackpot idea out there (NIPCC report); it doesn’t need to be done by the IPCC as well.
To quote the Dutch newspaper “Volkskrant” again:
its work has political implications, but that that doesn’t mean that it’s engaged in doing politics.
And since I discussed history as well, see also my first blog post where I described the IPCC process. I don’t think anyone has read it yet, so I’d be much obliged. And while doing self-promotion, I kind a like this oldie featuring Fred Singer.