THE CARBON

DIOXIDE

REVIEW

Guest Editorial

W I L L I A M C. C L A R K Institute for Energy Analysis, Oak Ridge Associated Universities, P.O. Box 117, Oak Ridge, Tennessee 37830, U.S.A.

The carbon dioxide question was raised at the end of the last century, crystallized twentyfive years ago during the International Geophysical Year, and became politicized over the last decade. It has elicited increasing speculation, discussion, and analysis. There has been talk of cornucopias and catastrophes, of winners and losers, of hothouses and ice ages. Carbon dioxide has become a focus of newspaper editorials, Congressional hearings, and an international research program involving hundreds of scientists. This growing concern over the CO2 question has been accompanied by many official reports, among them the President's Science Advisory Committee's, Restoring the Quality o f Our Environment (1965), the international Study o f Man's Impact on Climate (1971), the National Research Council's Energy and Climate (1977) and Charney Report (1979), and the Council of Environmental Quality's Global Energy Futures and the Carbon Dioxide Problem (1981). The U.S. National Academy of Sciences, U.S. Department of Energy, and several international organizations have scheduled further reports to appear over the next several years. The most recent addition to this list is the Carbon Dioxide Review: 1982, prepared by the Institute for Energy Analysis (IEA) in Oak Ridge, Tennessee and recently published by Oxford University Press. Why a Carbon Dioxide Review? Where science bears on social concerns, official reports are constrained by their official status. Looked upon to provide authoritative assessments, such reports must often seek to develop a comprehensive perspective and a scientific consensus. But comprehensive perspectives are gained at the expense of selective attention to the few key issues that might make a difference. Consensus is bought at the price of blunting open debate over major uncertainties and controversies. And, as C. E. Lindblom has argued, the 'pursuit of authoritativeness' is often a mistake, conflicting with the need for rapid but tentative incorporation of new ideas into our evolving understanding. Finally, science can never provide more than part of the answer to broad 'trans-scientific' questions like those posed by carbon dioxide. The real challenge for the scientific community is to contribute as effectively as possible to the larger social debate upon such questions. The Carbon Dioxide Review is one response to this challenge. Bearing neither official sanction nor responsibility, it is simply the attempt of more than 50 active researchers from around the world to explicate and reflect upon current issues in the CO2 debate. Three principal concerns shaped IEA's decisions in designing the Review. First, we sought to provide a public forum for critical debate on the carbon dioxide question, its Climatic Change5 (1983) 3-5. 0165-0009/83/0051-0003500.45. Copyright 9 1983 by D. Reidel Publishing Co., Dordrecht, Holland, and Boston, U.S.A.

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William C. Clark

implications, and the options for dealing with it. Anonymous peer reviews, though necessary to promote quality control, are not sufficient where investigations cross lines of disciplinary expertise or where the contributions surface in unrefereed preprints, conference submissions, and even news conferences. To complement the anonymous review process, we adopted for the Carbon Dioxide Review a format of open discussion. The core of the Review thus consists of a series of exchanges on selected topics of current interest. Each begins with an extended essay authored by an internationally recognized expert, and is accompanied by several commentaries in which other experts with other viewpoints offer their critiques. The authors' written replies extend the dialog, while an editorial introduction provides context and links related issues debated elsewhere in the Review. The essay-commentary format proved effective in discovering and highlighting weak or controversial aspects of several fundamental arguments in the current CO2 debate. In some cases, the commentaries provided more searching and balanced reviews than we would have expected via anonymous channels. Not surprisingly, when areas of real disagreement surfaced, the process became awkward for both the publicly critiquing and the publicly critiqued. To the credit of our contributors, however, the debate almost always remained both civil and penetrating. A close reading is necessary to appreciate the extent of certain disagreements, but the relevant arguments remain in the written lines rather than between them. In light of this obvious willingness of our contributors to question each other's most basic assumptions and calculations, it was all the more gratifying to find a solid consensus expressed on several key findings and research priorities. These areas of present agreement are summarized in our introduction to the Review. A second principal concern in designing the Review was to focus attention on a few issues where wider knowledge of recent progress, or better articulation of current difficulties, might significantly promote overall understanding of the CO2 question. In selecting issues for discussion in the 1982 Review, we tried not to duplicate the material covered in other recent reports, most notably the SCOPE/Bolin volume on carbon cycle modeling, and the U.S. National Research Council/Smagorinsky review of climate model controversies. Our f'mal selection of topics included a critical review of previous climate-related impact studies; a consumer's guide to climate models; an assessment of the likelihood and consequences of melting the Arctic sea-ice; a discussion of the prospects for detecting climate change; an analysis of the climate effects of 'trace' greenhouse gases; an overview of possible agricultural impacts of increasing CO2; and a summary of alternative CO2 production scenarios. The Review also contains shorter notes on the COa concentration in the atmosphere; the roles of land-use changes, industrial activity, and proposed synthetic fuel programs as sources of CO2; and possible positive feedbacks in the interactions among climate and the carbon cycle. Second-guessing this selection of topics is both tempting and easy. A couple of the issues we chose turned out to be less ripe for discussion than we had hoped. Their treatment in the Review will probably add little to current thinking. Similarly, a few retro-

The Carbon Dioxide Review

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spectively 'obvious' issues should have been covered but were not. Some shortcomings of selection are inevitable, however, if only because of the rapidly evolving nature of the overall carbon dioxide question. For this reason, our thkd principal concern in designing the Review was to make it part of an iterative process in which our first mistake did not need to be our last. No report will provide the last word on issues as uncertain, complex, and rapidly developing as those posed by CO2. Practically speaking, however, any report faces a trade-off between timeliness and authoritativeness. As noted earlier, it takes time to tbrm an authoritative consensus - so much time that the most authoritative reports, when finally published, often serve more to certify conventional wisdom than to influence the course of contemporary investigations. Since the majority of official reports on the CO2 question have emphasized authoritativeness, the R e v i e w has stressed timeliness. In particular, we sought to develop in the Review an iterative format conducive to the rapid identification, articulation, and reconsideration of contemporary issues in the CO2 debate. Mistakes and omissions arising in the 1982 edition will serve as lessons to be used in improving both the content and concept of subsequent editions, if indeed subsequent editions turn out to be warranted. To help ensure that the 'key issues' selected for discussion in the 1982 Review would still be 'key' when the R e v i e w was published, we set (and met!) a one-year deadline: the major essays were commissioned in July of 1981, and the completed 500-page volume was released by Oxford University Press in July of 1982. Meeting this schedule demanded very close, often stressful, and occasionally heroic cooperation among authors, the scientific and editorial staff in Oak Ridge, and the Oxford University Press. Each of these groups felt rushed; each would have liked additional time to improve its contribution to the overall effort. Whether they should have been given that time, or whether even a one-year cycle is fast enough to make the Review an effective contribution to the contemporary C02 debate, is something only our readers can assess. In short, the Carbon Dioxide Review is an experiment, the results of which will be the reactions of its readers. Does the essay-comlnentary-reply format meet the need for open, critical debate, or would something else do better? What of the level at which the contributions are written? Whose needs are served well, and whose badly, by the Review as a whole? What next step would be most useful to the C02 community? As editor of the Review, I would welcome your comments.