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Climate models in modal adverbials : representational practice and deep uncertainty in the IPCC summary documents Roeder, Geoffrey Gilbert


In a warming climate, policymakers require the best available information to develop the most effective responses. These responses could work to mitigate the worst consequences of climatic change or support adaption to the unavoidable ones. However, the challenges of communicating deeply uncertain information from statistical climatology to a non-technical audience are manifold. The complex uncertainties inherent in the development and study of General Circulation Models (GCMs), statistical climatology’s primary inferential tool, exacerbate these challenges. The Intergovernmental Panel on Climate Change (IPCC) is a U.N. body formed to solve this problem. Employing standardized sets of modal adverbials to indicate the certainty of a finding, the IPCC works to regularly communicate all policy-relevant uncertainties. The present thesis, analyzing the IPCC’s “Climate Change 2007: Synthesis Report” (SYR) and its attendant “Summary for Policymakers” (SPM), argues that the IPCC’s recently much-criticized treatment of uncertainty is a direct response to the combative politics of climate change. A comparison of the IPCC’s treatment of a few key findings to a number of independent analyses of the same highlights the problem. Through a linguistic and rhetorical analysis of the SYR and SPM, I argue that a number of problematic uncertainties are represented as if politically manageable. Independent literature on the reliability of long-term inference from GCMs cautions against such an interpretation. Partly motivating the IPCC’s practice (evidenced in IPCC-internal literature) is desire to control politically hostile and possibly inaccurate interpretations of the uncertainties. Nevertheless, forming adaptive policies on such highly uncertain findings could lead to ineffectual and economically wasteful infrastructure projects. Such policies could also distract from effective responses that might mitigate the worst climatic changes. Following recent sociological and historical work in the discipline of Science and Technology Studies, I argue that the IPCC’s problematic schema for the communication of uncertainty is best understood as a response to the contemporary democratic climate of distrust and distance. The IPCC’s modal adverbials, interpreted as a complex form of social and literary technology, are an attempt to erect a new and ambitious boundary around what constitutes a politically-stable scientific fact and what constitutes a scientific topic under deep investigation.

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