Climate change and global warming A new role for science in decision making
Peter Rogers Haward University Cambridge, MA 02138 The recent discussion of global warming in the popular media and in political fora raises difficult questions wncerning the use of science and the role of scientists in helping frame a political debate about courses of action to be taken by governments. The hypothesis that global warming is a result of human interference is not a new idea-in 18% Arrhenius estimated an 8 "C increase resulting from a doubling of carbon dioxide in the atmosphere. His figure, although higher than any of the current predictions, was arrived at without the use of supercomputers or elaborate general circulation models of the atmosphere. His calculations did not cause wncern or panic in the general population and do not seem to have been the subject of much political d e bate at the time. What distinguishes the current widespread concern of the public at large and their political representatives from the earlier wncem that was restricted to scientific circles? How did global warming get on the political
agenda? One reason for the change may be that measured CQ concentrations in the atmosphere have increased from less than 316 parts per million in 1958 to more than 345 ppm at present (and up from an estimated 280 ppm in 1870). This oftquoted fact alone a p pears to be the deciding piece of information for many people. Unfortunately, the overall increase involves a few unexplained phenomena. For example, only 60% of the CQ caused by fossil fuel use and land clearing over the past 100 years has remained in the atmosphere. What happened to the 40% that disappeared? And using the predictive models starting from the end of the last century, an increase in CQ of the magnitude actually observed 428 Environ. Sci. Technoi., Vol. 24, No, 4, 1990
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should have caused a temperature increase of about 1 “C by now. However, this is almost double the temperature increase of 0.5 “C claimed by the most ardent supporters of climate warming (many observers believe that the historical data do not support even this amount of warming). Does this imply that the forecasts using these models might also be high by a factor of two? Although there is a sound theory to predict temperature increases caused by C02 buildup-the greenhouse effectthe basis for predicting future warming is weakened by considerations of ice core data from the past 150,000 years which show both simultaneous increases in C 0 2 concentrations and temperature (reaching close to. but not as high as present levels) as well as simultaneous decreases in C 0 2 concentrations and temperature. Both took place at periods when anthropogenic contributions must have been very small. None of the models seems able to replicate or explain this behavior of historical data. Hence, the present increase in measured C 0 2 alone, without a convincingly measured rise in temperature in this case, is not an adequate reason for the prominence of anxiety at the political level about human influence on the atmosphere. To explain this prominence we have to look back at the role science and technology have played in our society over the last century. When Arrhenius was making his calculations most of the scientific developments that affect every person living today were largely inconceivable. The public health, transportation, and communications revolutions had not yet occurred. The era of physically exploring the globe was still in full swing; the great empires of Britain, France, Portugal, and Spain spanned the globe; and the idea of man’s subduing the earth and nature was widely embraced. Apart from a few rumblings by the likes of John Muir in the United States, there was little anxiety that humans would be capable of causing large-scale changes in the ecosystems of regions or nations. At the end of the 19th century, even as we were destroying many natural systems, most people had some intimate knowledge of how nature functioned-for example, how food was produced. The population was, furthermore, inured to the vagaries of nature. People expected life to be “nasty, brutish and short.” The application of science during the 20th century changed all of these “natural” expectations in the industrialized countries. The uncertainties of nature were largely replaced by the uncertainties of the nation state. War became the “grim reaper.” Science came to the aid
of the warring parties and helped create weapons of unprecedented destructive power. Even on the domestic front, technology in the form of automobiles and rapid-fire handguns became the major cause of death for young males. Now, with increasing urbanization and affluence, most people have a much less immediate understanding of how nature works. Recent competition for Nobel prizes, research funds, patent rights, and media attention has led many otherwise cautious scientists to announce their research findings at press conferences rather than in the traditional scientific literature. We have seen this most recently with the startling claims about cold fusion and superconductivity, In many instances the individuals involved have also presented analyses of data or model studies in the traditional scientific literature. These papers have been peer-reviewed and represent major contributions to the scientific literature. But the presentation of the same material in press conferences, or as testimony in congressional hearings, lacks the subjunctive mode employed in the original. There seems to be no way to present the high levels of uncertainty in the analyses reported in the scientific papers to journalists and politicians, who make a living by relaying views with complete assurance. The results have been quite catastrophic. Scientists who eschew exact prediction in their scientific writings look earnestly into the television camera and tell us that by the mid-1990s the number of days per year in Omaha, Nebraska, on which the temperature will exceed 95 OF will increase by more than 50% over the present. (These predictions seemed more credible when they were made, during the unusually hot, dry summer of 1988.) The situation becomes worse when scientists are asked to comment on the consequences of their temperature predictions upon other aspects of the ecosystem. These other aspects, often dealing with economic or social matters, are typically not within the purview of the model studies, but are nevertheless presented as though they are part of the scientific analysis. The result is that conclusions become shakier the further we proceed. Very rarely is the public informed that these predictions are based on elaborate research models that have not been fully validated and that the future funding of these model studies is subject to being cut off at any moment. This leads to an unconscious desire to present the model results in the best (i.e., most frightening) light to Congress and the federal government, which are ultimately the sole source of funding for this research. It is well
known that Congress has a short attention span-so short that it often appears capable of dealing only with crises. Because everyone else is crying “crisis,” responsible scientists are forced to join the chorus or risk losing their research programs. Unfortunately, carrying out research under these conditions can lead to bizarre outcomes. In response to the crisis atmosphere many politicians, environmental groups, and citizens’ groups are demanding immediate action-this is not what the scientists had in mind. I have juxtaposed climate change and global warming in the title of this piece because climate change is what the discussion should be about. That the climate is going to change is one of the few things we can be certain about. Historical records show that temperatures have been higher and lower, and places have been wetter and drier than they are now. The argument made by climatologists who stress global warming is that the rate of climate change caused by human actions is rapid and is increasing. Some climatologists claim that human-induced global warming has already taken place; some also claim that unless we act now, even before we have observed the global warming, it will be too late to reverse the impact. Most commentators also state that global warming will be catastrophic for humans and nature and, hence, should be avoided at all costs. In the general public, many discuss the greenhouse problem with the ozone depletion problem as though they were the same phenomenon. It is difficult to deal effectively with all of these arguments at once. Some of these claims are difficult to discuss because they are of a trans-scientific nature. (The “act now, observe later” school tends to be of this kind.) However, many of the other claims could be dealt with effectively through normal scientific channels. For example, careful analysis of the historical data by several independent scientific groups could help put to rest the issue of whether the global temperature has been increasing and by how much. Much is being done but more could be done to improve the predictive power of the general circulation models. More scientific work could be done on the global carbon cycle and on tracing the sources and the fate of other greenhouse gases. Careful analyses of both the positive and the negative impacts of climate change should be presented in ways easily understood by the general public. However, it would be naive to assume that even the expenditure of large amounts of research money over the next 20 years will resolve the issue of Environ. Sci. Technol., Vol. 24, No. 4, 1990 429
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climate change sufficiently to allow us to make predictions with the levels of certainty that we would like to see. It therefore behooves us to change the focus of the debate from argument over scientific fact to how to make good decisions under high levels of uncertainty; we must cut the Gordian knot of our inability to decide on levels of socially acceptable uncertainties and focus on social goals and desires that can be articulated with a high level of acceptability. We already have a strong consensus on the need to maintain and improve environmental quality. Similar consensus needs to be developed on conserving natural resources such as energy, minerals, and forests. This consensus could be the starting point for discussions of response strategies. We see a new role for science as an aid to political decision making. First, we need to emphasize that the role of science is different in classes of problems such as climate change. The old idea of replicable experiments has to be replaced with the concept of nonreplicability of the underlying phenomena. This means that the old approaches to accepting or rejecting hypotheses about the phenomenon need to be completely revised. The idea that we may never fully understand the phenomenon but that we can give merely a statistical estimate of its likelihood has to be ingrained in the choice of policy options. Methods to communicate with the general public on how to make good decisions in the face of such uncertainty need to be developed if we are ever to move beyond the current levels of hysteria on these issues. We have to learn to live with the uncertainty surrounding climate change. This can only be achieved if the climatological community expands its research methodology and membership to include many other disciplines such as statistics, hydrology, and operations research. This expansion could enable us to assign priorities to possible responses as follows: first, responses that are good things to do in their own right; second, those that may be good things to do but that will require more examination and effort to implement; and third, those that are mandated by direct consequence of confirmed or incipient climate change. In the first category would be most of the work on improving our knowledge base of the phenomenon itself and the analysis and plans for response strategies. In the second category would be most of those responses that would lead to conservation of fossil fuel energy resources and, hence, a reduction of the anthropogenic stress on the system. The final category would include actions that would be undertaken only if absolutely needed,
such as building sea walls around urban areas or providing irrigation facilities in the Grain Belt. Approaching the subject in this measured way will help us avoid a premature and exaggerated response based on the present crisis frame of mind in political circles and among the general public. Pushing draconian economic policy changes before the mechanisms of C02 concentration and temperature change are better understood could prove unnecessary-and therefore massively wasteful-if worry about anthropogenic causation is mistaken. But there is another important danger that arises when major scientific questions move to the political and media center stage and that must be equally avoided. Much public attention and the heavy funding that can come with it o p erate on a logic that is not only not scientific, but notoriously fickle. The media, broad publics, and political leaders lose interest and abandon crises as quickly as they take them up. We must remember that large, long-term financial commitments are needed for thorough and extended study of global climate change. It is of the greatest importance that the needed resources not be swept away in a few years' time by other apparently more pressing issues. We must avoid lowering our standards of discourse and methodological rigor and exploiting the limelight for short-term gains, because serious scientific concern about climate and other large-scale global environmental issues must not be allowed to go the way of the pogo stick and the HulaHoop. There appears to be great merit in trying instead to commit nations now to a long-term structured program of research and a readiness for contingent action.
Peter Rogers has taught at 1 wrd Unin to coversity since 1966. In ad6 authoring six book. he has, 'sed, consulted, and done research on environmental management in 28 countries. He recently headed the U.S. team evaluating the causes of the I988 joods in Bangladesh.
