Global Warming: Advocacy or Science?

A University of Pennsylvania Law School Study  authored by Jason Scott Johnston, concludes it is more of the former, less of the latter. By comparing the claims of the IPCC and other advocates with the content of peer reviewed literature on the subject, he finds  a tendency to, shall we say, creative interpretation, and rhetorical stratagems protective of cherished and prior held beliefs.

More leaks from sinking hot air balloon.

Abstract:



Legal scholarship has come to accept as true the various pronouncements of the Intergovernmental Panel on Climate Change (IPCC) and other scientists who have been active in the movement for greenhouse gas (ghg) emission reductions to combat global warming. The only criticism that legal scholars have had of the story told by this group of activist scientists - what may be called the climate establishment - is that it is too conservative in not paying enough attention to possible catastrophic harm from potentially very high temperature increases.


This paper departs from such faith in the climate establishment by comparing the picture of climate science presented by the Intergovernmental Panel on Climate Change (IPCC) and other global warming scientist advocates with the peer-edited scientific literature on climate change. A review of the peer-edited literature reveals a systematic tendency of the climate establishment to engage in a variety of stylized rhetorical techniques that seem to oversell what is actually known about climate change while concealing fundamental uncertainties and open questions regarding many of the key processes involved in climate change. Fundamental open questions include not only the size but the direction of feedback effects that are responsible for the bulk of the temperature increase predicted to result from atmospheric greenhouse gas increases: while climate models all presume that such feedback effects are on balance strongly positive, more and more peer-edited scientific papers seem to suggest that feedback effects may be small or even negative. The cross-examination conducted in this paper reveals many additional areas where the peer-edited literature seems to conflict with the picture painted by establishment climate science, ranging from the magnitude of 20th century surface temperature increases and their relation to past temperatures; the possibility that inherent variability in the earth’s non-linear climate system, and not increases in CO2, may explain observed late 20th century warming; the ability of climate models to actually explain past temperatures; and, finally, substantial doubt about the methodological validity of models used to make highly publicized predictions of global warming impacts such as species loss.


Insofar as establishment climate science has glossed over and minimized such fundamental questions and uncertainties in climate science, it has created widespread misimpressions that have serious consequences for optimal policy design. Such misimpressions uniformly tend to support the case for rapid and costly decarbonization of the American economy, yet they characterize the work of even the most rigorous legal scholars. A more balanced and nuanced view of the existing state of climate science supports much more gradual and easily reversible policies regarding greenhouse gas emission reduction, and also urges a redirection in public funding of climate science away from the continued subsidization of refinements of computer models and toward increased spending on the development of standardized observational datasets against which existing climate models can be tested.

Johnston, Jason Scott, Global Warming Advocacy Science: A Cross Examination (May 1, 2010). U of Penn, Inst for Law & Econ Research Paper No. 10-08. Available at SSRN: http://ssrn.com/abstract=1612851

And a bit from the body of the study:

 Rather than laying out contrasting positions that one finds in the literature, the IPCC and other leading establishment climate scientists either simply ignore or tersely dismiss scientific work that disputes or casts doubt upon the assumptions underlying or projections made by climate models and establishment climate science more generally. My cross examination clearly reveals a rhetoric of persuasion, of advocacy that prevails throughout establishment climate science.


Perhaps the most straightforward justification for this rhetorical stance is that theIPCC’s job is to assess the science – to adjudicate whatever disputes or disagreements may exist in the literature -- and to then make a decision as to which side is most likely correct. Having made such a decision about which is the “best” science currently available, and in particular decided that there is “unequivocal” evidence that anthropogenic ghg emissions have caused recent global warming, the IPCC’s job is then to present that science in as persuasive a way as possible. Especially when potentially planet-saving policy responses are on the line, to present the science in a way that instead highlights questions and uncertainties would be to encourage doubt and potentially harmful delay in adopting policies to reduce ghg emissions.


The problem with this justification is that the optimal policy to adopt with respect to reductions in anthropogenic ghg emissions itself depends upon a fine, rather than coarse-grained understanding of the state of scientific understanding. The more certain and immediate is the threatened harm from continuing increases in anthropogenic ghg emissions, the more will the cost-benefit policy calculus tip in favor of very expensive, immediate and irreversible policy commitments to ghg emission reduction (and also, although often overlooked, to adaptation investments). The more questionable is the magnitude, timing and even existence of harm from continuing increases in human ghg emissions, the greater the case for policies toward ghg emission reduction that are less costly in the short run and more easily reversible in the long run. If policymakers are to craft the correct policy, then they must understand the nature of the threat posed. The rhetorical strategy that has come to dominate establishment climate science is not designed to promote such fine-grained understanding; it is designed instead to convince the public of what some, but by no means all, climate scientists have come to believe by conveying a very scary and also very simple picture of the state of the science. Such coarse understanding leads to a very coarse policy prescription: “Do something, anything,now!” Such a policy prescription justifies virtually any policy, however costly or inefficient, that can plausibly be argued to lead to ghg emission reductions at some point in the future. The cross examination undertaken in this Article clearly reveals important questions, uncertainties and disputes in climate science. It is hard to imagine that any policymaker who becomes aware of these and of the overall complexity of climate science could rationally advocate the “Do something, anything, now!” policy prescription so easily drawn from the alternative picture painted by the climate change establishment.


A very astute diagnosis of motivations. Need I say: Read the whole thing!