IPCC history and mandate

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.

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Herman Daly on climate policy

Found via Michael Tobis’ blog: From “know how” to “do now”, an excellent speech by Herman Daly (full text available here), on the interplay between climate science, economics and policy. Take home message: We know enough to start doing something about the problem. My addition: Any realistic change in our knowledge is not going to affect that conclusion.

“Can we systematically continue to emit increasing amounts of CO2 and other greenhouse gasses into the atmosphere without eventually provoking unacceptable climate changes? Scientists will overwhelmingly agree that the answer is no. The basic science, first principles, and directions of causality are very clear. Arrhenius discovered the basics a century ago. Focusing on them creates a world of relative certainty, at least as to the thrust and direction of policy.”

Parachute or altimeter?

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. “To make the point more simply, if you jump out of an airplane you need a crude parachute more than an accurate altimeter.” Discussing the probabilities of a certain temperature change and sea level rise by 2100 may be very interesting scientifically, but it is not necessarily the most relevant for policy. If the main thrust of the change is clear (more greenhouse gases causing more warming, eventually leading to unacceptable climate changes), then society should leave the quantitative mangling over details to the scientists, and focus on what to do about it. Because any realistic change in the details is not going to affect this main thrust. 

The main thrust
Just in case you think that this main thrust is not at all certain; it is. The rates, the exact magnitude and exact consequences, the details, are uncertain, and as such are being investigated by scientists. But there’s no way that more greenhouse gases would not lead to a warming. Even a serious “skeptical” position would not change this main thrust; it would merely change the timing of “eventually”. If we burn all currently recoverable fossil fuels (dominated by coal), CO2 levels will not be double pre-industrial, but more like quadruple. (pre-industrial CO2 concentration is 280 ppm; current levels are 385 ppm.) Even with a wholly unrealistic, low climate sensitivity of 1 degree warming per doubling of CO2, put forward by die-hard “skeptics” like Lindzen, this is a recipe for disaster: The Greenland and West Antarctic ice sheets are not likely stable in the long run at 4 degrees higher temperatures than pre-industrial. Mind you, I write “in the long run”. The main uncertainty is in the rate, not in the eventual fate at such high temperatures.

If it’s bad, it’s really bad. If it’s good, it’s still pretty bad. 

The current best estimate for the equilibrium warming if CO2 levels are quadrupled (i.e. if all recoverable fossil fuels are burned) is ~6 degrees over pre-industrial temperatures [corrected Dec 2014]. Can you imagine what the world would be like? If we consider a picture, however improbable, of what would happen at the low end of the response curve (a “skeptical” viewpoint of e.g. 1 degree per doubling of CO2), we should also consider what would happen on the high end (an “alarmist” viewpoint of e.g. 6 degrees per doubling of CO2): That’s beyond my imagination. Btw, the empirically determined bounds for climate sensitivity are between 2 and 4.5 degrees per doubling of CO2. But even within the extreme bounds (e.g. 1 and 6), there’s no situation imaginable where the consequences of burning all fossil fuel reserves are benign: If it’s bad, it’s really bad. If it’s good, it’s still pretty bad. Therefore, (ab)using scientific uncertainty as an alibi to not do anything is clearly irrational.

Energy policy & economics

To come back to Herman Daly, he suggests that our energy policy should focus on “a sustainable aggregate level of energy consumption” rather than on “efficient patterns of consumption”. Increases in efficiency are over time often (more than) counterbalanced by increases in consumption (the rebound or Jevons effect). Daly goes on to say that “GDP growth at the current margin in the US is in fact uneconomic growth—that is, growth that increases social and environmental costs faster than it increases production benefits”. I have no relevant expertise to comment on that claim, but the notion that it’s better “to stop uneconomic growth and free up resources and ecological space for truly economic growth by the poor” makes certain sense, though it’s politically a hard sell, and it runs counter to how we’ve got used to think about economics. Moreover, “beyond a threshold of absolute income already passed in the West, welfare or self-evaluated happiness becomes a function of relative income rather than absolute income.” This is confirmed e.g. here: 

Hapiness and money

The solution? “Tax bads (depletion and pollution), not goods (income).” I.e. shift taxes from human capital to natural resources.

“To continue business as usual while debating the predictions of complex models in a world made even more uncertain by the questions we ask, is to fail to pull the parachutes’ ripcord. The empirical consequences of this last failure, unfortunately, are all too certain.”