Paper cross-examines global warming advocacy science and finds rhetorical tricks used to oversell and to hide uncertainty

A highly-recommended paper from the University of Virginia School of Law, Property and Environment Research Center cross-examines in detail the peer-reviewed literature of 'global warming advocacy science' and finds 

"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." 

The paper notes, 

"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."

Full paper available here

Global Warming Advocacy Science: A Cross Examination

Jason Scott Johnston 

University of Virginia - School of Law ; PERC - Property and Environment Research Center 
May 1, 2010

U of Penn, Inst for Law & Econ Research Paper No. 10-08 

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.


From the conclusion:



III. Conclusion: Questioning the Established Science, and Developing a Suitably
Skeptical Rather than Faith-based Climate Policy


Even if the reader is at this point persuaded to believe that there remain very important open questions about ghg emissions and global warming, and important areas of disagreement among climate scientists, she may well ask: So what? After all, such a reader might argue, CO2 is a ghg, and if we continue to increase CO2, then it seems clear that despite whatever uncertainty there may be about how much temperatures will increase as a consequence of increasing CO2 in the atmosphere,  and about the impacts of such rising temperatures, there is no doubt that temperatures will increase with increasing CO2, and that at some point, such rising temperatures will cause harm, so that one way or another, at one time or another, we simply have to reduce our emissions of CO2.


However beguiling, such an argument not only oversimplifies the policy questions raised by human ghg emissions, it is also misunderstands the significance of the scientific questions revealed by my cross examination for the predictability of anthroprogenically-forced climate change.  Consider first the scientific questions. If climate were a simple linear system – with increases in atmospheric CO2 directly and simply determining future warming – then while a detailed understanding of the earth’s climate system might still of scientific interest, there would be little policy justification for expending large amounts of public money to gain such an understanding.   But if one thing is clear in climate science it is that the earth’s climate system is not linear, but is instead a highly complex, non-linear system made up of sub-systems – such as the ENSO, and the North Atlantic Oscillation, and the various circulating systems of the oceans – that are themselves highly non-linear.  Among other things, such non-linearity means that it may be extremely difficult to separately identify the impact of an external shock to the system – such as what climate scientists call anthropogenic CO2 forcing – from changes that are simply due to natural cycles, or due to other external natural and anthropogenic forces, such as solar variation and human land use changes.   Perhaps even more importantly, any given forcing may have impacts that are much larger – in the case of positive feedbacks – or much smaller – in the case of negative feedbacks – than a simple, linear vision of the climate system would suggest.  Because of the system’s complexity and non-linearity, without a quite detailed understanding of the system, scientists cannot provide useful guidance regarding the impact on climate of increases in atmospheric ghg concentration.


As a large number of climate scientists have stressed, such an understanding will come about only if theoretical and model-driven predictions are tested against actual observational evidence.  This is just to say that to really provide policymakers with the kind of information they need, climate scientists ought to follow the scientific method of developing theories and then testing those theories against the best available evidence.  It is here that the cross examination conducted above yields its most valuable lesson, for it reveals what seem to be systematic patterns and practices that diverge from, and problems that impede, the application of basic scientific methods in establishment climate science.  Among the most surprising and yet standard practices is a tendency in establishment climate science to simply ignore published studies that develop and/or present evidence tending to disconfirm various predictions or assumptions of the establishment view that increases in CO2 explain virtually all recent climate change. Perhaps even more troubling, when establishment climate scientists do respond to studies supporting alternative hypotheses to the CO2 primacy view, they more often than not rely upon completely different observational datasets which they say confirm (or at least don’t disconfirm) climate model predictions. The point is important and worth further elucidation: while there are quite a large number of published papers reporting evidence that seems to disconfirm one or another climate model prediction, there is virtually no instance in which establishment climate scientists have taken such disconfirming evidence as an indication that the climate models may simply be wrong.  Rather, in every important case, the establishment response is to question the reliability of the disconfirming evidence and then to find other evidence that is consistent with model predictions.  Of course, the same point may be made of climate scientists who present the disconfirming studies: they tend to rely upon different datasets than do establishment climate scientists.  From either point of view, there seems to be a real problem for climate science: With many crucial, testable predications – as for example the model prediction of differential tropical tropospheric versus surface warming – there is no indication that climate scientists are converging toward the use of standard observational datasets that they agree to be valid and reliable.


Without such convergence, the predictions of climate models (and climate change theories more generally) cannot be subject to empirical testing, for it will always be possible for one side in any dispute to use one observational dataset and the other side to use some other observational dataset.  Hence perhaps the central policy implication of the cross-examination conducted above is a very concrete and yet perhaps surprising one: public funding for climate science should be concentrated on the development of better, standardized observational datasets that achieve close to universal acceptance as valid and reliable.  We should not be using public money to pay for faster and faster computers so that increasingly fine-grained climate models can be subjected to ever larger numbers of simulations until we have got the data to test whether the predictions of existing models are confirmed (or not disconfirmed) by the evidence.


This might seem like a more or less obvious policy recommendation, but if it were taken, it would represent not only a change in climate science funding practices, but also a reaffirmation of the role of basic scientific methodology in guiding publicly funded climate science.  As things now stand, the advocates representing the establishment climate science story broadcast (usually with color diagrams) the predictions of climate models as if they were the results of experiments – actual evidence.   Alongside these multi-colored multi-century model-simulated time series come stories, anecdotes, and photos – such as the iconic stranded polar bear -- dramatically illustrating climate change today.   On this rhetorical strategy, the models are to be taken on faith, and the stories and photos as evidence of the models’ truth.  Policy carrying potential costs in the trillions of dollars ought not to be based on stories and photos confirming faith in models, but rather on precise and replicable testing of the models’ predictions against solid observational data.