Understanding Climate Risk

Science, policy and decision-making

IPCC uncertainty management – new paper

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I’ve just had a paper, The latest iteration of IPCC uncertainty guidance—an author perspective, published online at Climatic Change. It claims that the new uncertainty management for the IPCC’s Fifth Assessment Report (pdf) is most suited to managing uncertainty in the physical sciences, and climate change as a complex, or ‘wicked system’ risk requires a more applied approach. The paper is open source so can be downloaded and read by anyone. Happy to get comments here. It’s part of a special issue in honour of the late Stephen Schneider, the chief uncertainty cop with the IPCC and climate science community, and founding editor of Climatic Change.

I can take credit for planting the seed of this issue in the minds of the new editors, Michael Oppenheimer and Gary Yohe. Abstract and special issue announcement over the fold. Links to open source papers so far posted and to the guidance documents, past and present, can also be found.


The latest iteration of Intergovernmental Panel on Climate Change (IPCC) uncertainty guidance is simpler and easier to use than the previous version. However, its primary focus remains assessing “what is at risk” under climate change, thus is most suitable for dealing with the scientific uncertainties in Working Group I and part of Working Group II findings. I distinguish between tame and complex risks, arguing that the guidance is most suited to assessing tame risks. Climate change is a complex risk, and as such as can be divided into idealized, calculated and perceived risks. While science has claims to objectivity, risk has a specific value component: when measuring gain and loss, calculated risks compete with risky options to manage those risks. The IPCC is charged with calculating risk (IPCC 2007, p22) but the communication of key findings takes place in an environment of competing perceived risks. Recommendations for managing this complex environment include separating scientific and risk-based findings, treating uncertainties for each separately; strengthening the philosophical basis of uncertainty management; application of a methodical scientific research program; clearly communicating competing findings, especially in the social sciences; and application of multiple frames to policy-relevant findings as reflected in the literature.

Announcing the publication of a Special Issue on Guidance for Characterizing and Communicating Uncertainty and Confidence in the Intergovernmental Panel on Climate Change in Climatic Change  

August 2011

Since its inception in 1988, the Intergovernmental Panel on Climate Change (IPCC) has worked with the growing recognition that uncertainty is pervasive in our understanding of the climate system: what drives climate change, what will determine its future course, and what influence it will have on important social and ecological aspects of our world.  It is not news that the IPCC has struggled, with varying degrees of success, in its efforts to describe these uncertainties and to judge the confidence with which it can offer its major conclusions.

Stephen Schneider and Richard Moss took the lead in IPCC’s first attempt to provide some guidance for authors during the preparation of the Third Assessment Report.  A second guidance document was created by an author team headed by Martin Manning and Rob Swart to support the Fourth Assessment ReportYet another version was produced last year as chapter authors assembled to begin their work on the Fifth Assessment Report (AR5)  This most recent attempt, informed by the history of previous assessments, is the point of departure for the papers in this special issue of Climatic Change.

This Special Issue on Guidance for Characterizing and Communicating Uncertainty and Confidence in the Intergovernmental Panel on Climate Change was designed to provoke a wide-ranging discussion of IPCC’s past and possible future approaches to the evaluation, characterization, and communication of uncertainty.  Authors who were invited to contribute to this collection of papers approached their assignments from a variety of perspectives.  Some, like Richard Moss, Michael Mastrandrea, and Katharine Mach, were intimately involved in producing the guidance documents; their contributions describe the objectives of these documents and offer some introspective considerations of past experience.  Others, like Kristie Ebi, Gian-Kasper Plattner, Ottmar Edenhofer, Thomas F. Stocker, Christopher B. Field, and Patrick R. Matschoss, are playing key roles as working group co-chairs or members of associated technical support units in the AR5 process; their contributions describe their aspirations and concerns as the AR5 authors set to work.  Still others, like Granger Morgan and Baruch Fischoff, articulate weaknesses and strengths in IPCC guidance efforts from an extraordinarily experienced and informed vantage point: that of research into uncertainty judgment and communication.   Meanwhile, Marcus King and Sherri Goodman use their experience with the defense and national security communities to describe an approach to communicating and coping with profound and unique types of risk and uncertainty.  Roger Pielke, Jr. and Rachel Jonassen offer an empirical evaluation of uncertainty language in the Fourth Assessment while James Risbey and Judith Curry suggest “ignorance” as another category of confidence – not one that brings the process to a complete standstill, but one that best describes the state of affairs in some circumstances.  Humility, they would all argue, would be a virtue.  Brenda Ekwurzel, Peter Frumhoff and James McCarthy (former IPCC Working Group co-chair) have worked from IPCC documents to try to communicate with broader audiences in language that is more accessible than the dense prose that IPCC prefers; their paper describes some of the challenges and opportunities that they have faced or enjoyed, respectively.  John Sterman and Robert Socolow represent users of that information from within the broader research community; they express some frustration in interpreting summary statements from previous assessments and offer suggestions for reducing that burden.  Finally, Richard Tol,  has thought seriously about the structure and efficiency in the entire enterprise to produce an analogy between a standard natural monopoly in economic theory and the IPCC in practice vis a vis providing climate information to the international community.  It allows him to offer some stark but constructive hypotheses and some novel but intriguing remedies.

The hardcopy collection will appear in October of 2011.


Written by Roger Jones

September 25, 2011 at 7:46 am

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