by Judith Curry
There is much angst in the climate community over effective public communication of climate science. Strategies such as framing, messaging and narrative are receiving increasing attention by the climate establishment. The current ideas seem to be focused on “climate distruption” and framing the problem in terms of human health impacts. I can only hope that an uncertainty frame is ascendant.
In my opinion, the communication challenge is a symptom of the main problem, which is the framing and narrative of the overall scientific argument (the IPCC assessment reports) and how the evidence and arguments are presented. The problems in making the overall the argument aren’t associated with any particular incompetence on the part of climate scientists, but rather arise from the complexity of the climate system. It is this extraordinary complexity that makes reasoning about the climate problem extremely difficult.
The second monster in my narrative is the complexity monster. Whereas the uncertainty monster causes the greatest confusion and discomfort at the science-policy interface, the complexity monster bedevils the scientists themselves. Attuned to reductionist approaches in science and statistical reasoning, scientists with a heritage in physics, chemistry and biology often resist the idea that such approaches can be inadequate for understanding a complex system. Complexity and a systems approach is becoming a necessary way of understanding natural systems. A complex system exhibits behavior not obvious from the properties of its individual components, whereby larger scales of organization influence smaller ones and structure at all scales is influenced by feedback loops among the structures. Complex systems are studied using information theory and computer simulation models. The epistemology of computer simulations of complex systems is a new and active area research among scientists, philosophers, and the artificial intelligence community. How to reason about the complex climate system and its computer simulations is not simple or obvious.
A future (guest) post will explore in more detail how the concept of complexity interfaces with the climate problem. This post addresses the overall challenge of making the scientific case for anthropogenic climate change in the face of extreme complexity of the system.
Consider the following overarching argument for anthropogenic climate change and stabilization of greenhouse gases, which fits the three working group reports by the IPCC:
- Global climate change is occurring, and it is very likely that most of the climate change in the latter half of the 20th century can be attributed to human causes
- Climate change is already having adverse impacts, and further change would have dangerous impacts
- Actions are needed to stabilize greenhouse gas concentrations, which is feasible
In this argument, the 3rd point is contingent on the 2nd point, and the 2nd point is contingent on the 1st point, making the physical basis of climate change the foundation of the overall argument.
Both “sides” present their case
Using Johnston’s legal analogy first introduced in the consensus thread, lets consider the arguments presented by the side representing the IPCC and the side representing the NIPCC (each presented as a legal brief), with the IPCC side making the primary case and the NIPCC side rebutting the IPCC’s case. Note, there is no “smoking gun” here; the case is a circumstantial one that depends on evidence, expert witnesses, and the strength of the arguments.
The IPCC side presents a case consisting of 3000 pages of evidence (arguably more, if you count the previous IPCC reports) that are supported by refereed journal publications plus additional documentation. The “expert witnesses” are the 2500 or so people that participated in the IPCC process (more if you include the previous IPCC assessments) plus the numerous statements from professional societies and petitions and other statements/petitions that have been signed by scientists. The basic argument underlying the 1st point on the physical basis for climate change includes evidence about infrared emission and absorption by greenhouse gases, increasing greenhouse gases from human activities, observations of increasing surface temperature, attribution of the surface temperature increase to human activities, and climate model projections of future climate change. The gist of the argument for the 2nd point is that there is a broad range of adverse impacts that can be attributed to anthropogenic climate change. And finally the gist of the argument for the 3rd point is that stabilization of atmospheric CO2 is feasible.
The NIPCC’s case focuses on point #2, arguing that the effects of warming (even if caused by humans) won’t be dangerous and might actually be good. Their case consists of circumstantial evidence (a much smaller pile than that presented by the IPCC) and “expert witnesses” (a longer list than the IPCC has).
The IPCC side claims a consensus of scientists that “matter,” and attempts to discredit the expertise of the group supporting the NIPCC through discussion of the qualifications and motives of the experts supporting the NIPCC. The NIPCC side counters by criticizing the motives of the IPCC experts. While the NIPCC side definitely scores some points on point #2, the IPCC attempts to discredit the NIPCC’s case by focusing on their arguments re point #1; whereas the NIPCC’s arguments on point #1 may have less support than the IPCC’s arguments, the level of uncertainty is sufficiently large that a decisive victory isn’t justified by the evidence.
Judge Judy’s verdict: The IPCC side fails to make a convincing case on points #2 and #3. The IPCC side has a lot of evidence to support point #1, but needs to do a much better job of actually making the argument. The “expert witness” strategy is a red herring (lose it); arguments from consensus don’t carry much weight in a scientific argument particularly when both sides claim a large number of experts as part of their consensus. Both sides are ordered into counseling where they work together to sort out the scientific issues, clarify the uncertainties, come up with better scientific and logical arguments to explain and interpret the evidence, and present justification for the different sides of each argument.
Pondering a better frame and narrative for the scientific argument
A large compilation of scientific evidence (updated every 6 years or so) combined with expert judgement in a consensus approach doesn’t comprise a robust scientific argument, in my opinion. The crux of the argument made by the IPCC regarding the physical basis for climate change seems to be attribution of 20th century climate change that is based upon model simulations and comparison to observations. For such an argument to be convincing at a high level of confidence requires a much better understanding of what we can learn from a complex system model and how to actually design and interpret the model experiments.
But my broader concern is about the logic of the arguments being made. Causal calculus, counterfactual reasoning, belief revision and other logical frameworks can be applied in a formal way to the problem. I’m trying to envision some sort of chain of evidence and arguments that is nested in a tree-like structure using the hyperlink capability of the web (a logical narrative of a complex problem). Such a framework would uncover weak arguments and circular reasoning (a topic that I will expand on in a future post on the IPCC’s attribution argument.) I’m hoping the discussion on this thread can generate some ideas on how this might be done.
In the absence of formal logical arguments, individual people put different logical frames on the interpretation of evidence. A classic example of this is the reaction of the climate establishment vs the climate skeptics to the NRC report on the evaluation of the hockey stick (North Report). While the report contained some harsh criticisms, the reaction of climate establishment (and even North’s public statements) were that the criticisms didn’t “matter” to the overall case. The skeptics were incensed by this; they thought these criticisms should have been a death knell to the hockey stick argument and a major blow to the overall AGW argument. So is climate science some sort of “teflon” science whereby criticisms and refutations just bounce off?
The “doesn’t matter” versus “death knell” interpretations can be explained by the use of two different logics represented by the jigsaw puzzle analogy and the house of cards analogy. Consider a partially completed jigsaw puzzle, with many pieces in place, some pieces tentatively in place, and some missing pieces. Default reasoning allows you to infer the whole picture from an incomplete puzzle if there is not another picture that is consistent with the puzzle in its current state. Under a monotonic logic, adding new pieces and locking existing pieces into place increases what is known about the picture. For a climate scientist having a complex mental model of interconnected evidence and processes represented by the jigsaw puzzle, the evidence in the North report merely jiggled loose a few puzzle pieces but didn’t change the overall picture. The skeptics, lacking the puzzle frame but focused on the specific evidence of the North report, viewed the evidence as collapsing the house of cards and justifying major belief revision on the subject. Which frame is “correct”? Well, both frames are too simplistic and the use of both frames are heuristics used in the absence of formal logical arguments. The puzzle frame is better suited to the complexity of the problem, but as a mental model it can be subject to many cognitive biases.
While I don’t have any solutions, I do think this problem with the logic of the scientific argument is at the heart of framing and narrative challenge that the climate establishment has in communicating climate change to the public. Not to mention the need for a better logical framing and argument of the scientific case itself. This is a huge challenge given the complexity of the system under consideration. Strategies for taming the complexity monster have to start with acknowledging its existence and that simple approaches to understanding and reasoning about climate science are inadequate.
Postscript: I just finished reading the Royal Society assessment. Overall, I give it a much higher grade than the IPCC Summary for Policy Makers (SPM). I know about half of the scientists on the Working Group; they are absolutely “top drawer.” I don’t disagree with anything they say for the first 7 pages. Then they characterize some statements as “Aspects of climate change where there is a wide consensus but continuing debate and discussion.” The “wide consensus” is not a good way of putting this, too bad they didn’t have an Italian flag. A better way of saying it might have been “our best judgement based upon current evidence and background knowledge” and actually using the word “uncertainty.” The list of “Aspects that are not well understood” is far too skimpy. As a narrative, this makes much more sense than the IPCC SPM, and assesses a lower level of confidence, which is appropriate. Overall, I give it a “B” grade (compared to a C- for the IPCC SPM).