by Judith Curry
Nature and Culture has a special issue on postnormal climate science.
[T]he concept of post-normal science helps to open up scientific discourse, to identify complex cultural and political situations, and to improve and extend the range of practices of an applied science. – Kraus, Schafer, and von Storch.
Die Klimazwiebel also has a post on this special issue, and Werner Krauss and Hans von Storch played major roles in putting this special issue together. I’ve posted previously on Beck’s paper (Between tribalism and trust), and have referenced several of these papers in my article No consensus on consensus.
Postnormal science is a particular view of the interface between science and policy for complex problems with deep uncertainties that are associated with value commitments and involvement of an extended peer community. If you are participating in this blog, you are part of the extended peer community surrounding climate change and most likely have value commitments that are impinged upon by climate change and/or its solutions, e.g. environmental quality, social justice, intergenerational equity, economic development, etc.
When Ravetz first introduced the concept of postnormal science at WUWT, he got hammered. His essay in the special issue describes his engagement at WUWT, which led to a critical clarification of the concept to distinguish between postnormal ‘situations’ and postnormal ‘practice.’
Contents of special issue in Nature and Culture:
Introduction: Post-Normal Climate Science
Authors: Krauss, Werner; Schäfer, Mike S.; von Storch, Hans
The Significance of the Hamburg Workshop: Post-Normal Science and the Maturing of Science
Author: Ravetz, Jerome
Post-Normal Practices Between Regional Climate Services and Local Knowledge
Authors: Krauss, Werner; von Storch, Hans
Unfortunately, all of these papers are behind paywall (click on the titles to read the abstracts). Jeroen van der Sluijs was kind enough to send me copies of the papers. I’ll highlight several passages that illuminate the concept of PNS.
Jeroen van der Sluijs
From the Introduction of van der Sluijs paper:
Climate change has many characteristics that make it hard to tackle with normal scientific procedures. It requires new ways of interfacing science and policy. Funtowicz and Ravetz (1993) have called this class of problems post-normal, where “normal” refers to Kuhn’s 1962 concept of normal science. Kuhn describes normal science both as “a strenuous and devoted attempt to force nature into the conceptual boxes supplied by professional education” and as the practice of uncritical puzzle solving within an unquestioned framework or “paradigm.” Funtowicz and Ravetz signalized that such a normal science approach runs into serious limitations when addressing societal issues (in that time nuclear reactor safety) where scientific evidence is highly contested and plagued by uncertainties.
At the same time decisions need to be made well before conclusive supporting evidence can be available and decision stakes are high: the potential impacts of wrong decisions can be huge. In such situations actors tend to strongly disagree on the values that should guide the decision making, for example solidarity or economic growth. The available knowledge bases are typically characterized by imperfect understanding (and imperfect reduction into models) of the complex systems involved. Models, scenarios, and assumptions dominate assessment of these problems, and many (hidden) value loadings reside in problem frames, indicators chosen, and assumptions made.
The science involved in such issue-driven integrated assessments of complex environmental issues differs substantially from the practice of normal science in curiosity-driven laboratory research. Risk assessment of anthropogenic climate change involves uncertainties of many sorts, not all of which can be tamed. We cannot perform a statistically satisfying series of reproducible experiments to test the effect of higher atmospheric greenhouse gas concentrations, because there is only one Earth available, and even the one available is poorly monitored.
In addition, other factors that influence climate are—in contrast to the situation in a laboratory—largely beyond our control. Scientific assessments of climate change are unavoidably based on a mixture of knowledge, assumptions, models, scenarios, extrapolations, and known and unknown unknowns. Because of the limited knowledge base, scientific assessments will unavoidably use expert judgments and subjective probability judgments. It comprises bits and pieces of knowledge that differ in status, covering the entire spectrum from well-established knowledge to judgments, educated guesses, tentative assumptions, and even crude speculations. Research on climate change comprises a large variety of scientific disciplines leading to the well-known problem that when quantitative information is produced in one disciplinary context and used in another, important caveats tend to be ignored, uncertainties compressed, and numbers used at face value. This poses additional requirements with regard to the systematic analysis, documentation, and communication of uncertainty. Knowledgeutilization for environmental risk governance requires a full and public awareness of the various sorts of uncertainty and underlying assumptions. Knowledge needs to be robust both technically and socially.
Post-normal science is a reflective approach to interface science and policy in complex situations as sketched above. It is based on three defining features:
- The management of uncertainty. Post-normal science acknowledges that uncertainty is more than a technical number-range or methodological issue. Ambiguous knowledge assumptions and ignorance give rise to epistemological uncertainties;
- The acknowledgement of a plurality of legitimate perspectives—both cognitive and social. Complex problem solving requires scientific teamwork within an interdisciplinary group and joint efforts by specialists from the scientific community and from business, politics, and society. Scientists from different backgrounds often have irreconcilable and conflicting yet tenable and legitimate scientific interpretations of the same body of scientific evidence;
- The management of quality. An extended peer community includes representatives from social, political, and economic domains who openly discuss on various dimensions of uncertainties, strengths, weaknesses, and ambiguities in the available body of scientific evidence and its implications for all stakeholders with respect to the issue at hand.
Where in normal science the key task in interfacing science and policy is to get the facts right, in post-normal science this is complemented with a new key task of exploring the relevance of deep uncertainty and ignorance that limit our ability to establish objective, reliable, and valid facts. In post-normal problem solving, scientific fact-finding is still regarded as necessary but no longer sufficient. Scientific facts have become “soft” in the context of the “hard” value commitments that will determine the success of policies.
Excerpts from Ravetz’s paper:
For PNS it implies that the combination of uncertainties and value-commitments requires the participation of an “extended peer community.” The extension of democracy from political processes involving science, to the work of science itself, is still not universally accepted among scientists. This is the challenge of PNS. When Silvio Funtowicz and I first sketched the idea of PNS, we knew that its realization would take time. We could not anticipate how that would happen, or what would bring it about. Now we know: it is the blogosphere.
In respect of uncertainty, climate change science had the same sort of weakness that was fatal in the case of finance science. There it was assumed that all the arcane, frequently incomprehensible speculative financial products had the same “Gaussian” distribution of uncertainty as the heights of Army recruits. For climate science, the distributions were less ridiculous, but the depth and variety of uncertainties, even in the most mathematical areas, could never be effectively controlled. In the event, finance science collapsed with a big bang, while climate science seems to be going down with a whimper.
The conceptual weakness here is worse than the application of “normal science” methodologies to post-normal conditions. We have a case where the assumptions of simplicity, of both causation and evidence, were appropriate for a controlled, reproducible laboratory situation rather than the long-term behavior of the total global climate system. This is partly a result of the prejudice, among scientists and philosophers alike, to consider the mathematical-experimental sciences as the “real” ones, while the sciences of complex systems, defined by extent, duration, variety, or multiple scales, are denigrated and neglected. Sometimes this bias is effective, as with the triumphs of molecular biology. But even there it can be over-extended, as in the case of “genetic medicine,” which absorbed nearly a hundred billion dollars over several decades (Latham 2011), and achieved little beyond what was known at the beginning. In the case of climate-change science, the failure to appreciate the complexities of knowledge and uncertainty could well have ensured its futility. In Scientific Knowledge and Its Social Problems ( 1996), I devoted a chapter to a discussion of “Immature and Ineffective Sciences.” I recall that it was very imperfect, but it did raise an issue that has been insufficiently discussed.
The issue of quality is even more vexed. This includes far more than the evidential strength of particular items of information in relation to their policy implications. Of greater importance are the judgments of quality related to the scientific work. These extend over the scientific procedures themselves (as debated in connection with the circulation models and tree-ring analyses), through the probity of the scientists in their management of information and of criticism, and even extending to accusations of corruption of the whole enterprise.
JC comment: the concept of postnormal situations for science provides some valuable insights for climate science, the associated policy interface, and the resulting politicization of climate science. Of particular interest is the concept of the ‘extended peer community’, and the role of the climate blogosphere.