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4
Making Climate Forecast Information More Useful

Skillful climate forecasts are valuable to society to the extent that they provide knowledge that can be used to cope better with climate variations. This chapter examines what forecasts might offer to improve the outcomes of weather-sensitive activities and what is known about how individuals and organizations are likely to interpret and use forecast information. We first consider what kinds of climate forecast knowledge might prove valuable. We then examine the limited available information about how coping systems have actually responded to skillful seasonal-to-interannual climate forecasts, supplementing this with other sources of insight, including basic knowledge about human information processing and knowledge about human use of information in situations that may be relevant by analogy. This examination yields a set of hypotheses about the characteristics that make forecast messages and information systems useful.

Useful Information that Climate Forecasts Might Provide

Chapter 3 shows the variety of ways in which individuals and organizations cope with variable climates. Climate forecasting is intended to help them cope better, but not all forecast information will necessarily be useful toward this goal. Forecast information can have value only if people can change their actions in beneficial ways based on the content of the information. As the following examples show, different kinds of



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Page 63 4 Making Climate Forecast Information More Useful Skillful climate forecasts are valuable to society to the extent that they provide knowledge that can be used to cope better with climate variations. This chapter examines what forecasts might offer to improve the outcomes of weather-sensitive activities and what is known about how individuals and organizations are likely to interpret and use forecast information. We first consider what kinds of climate forecast knowledge might prove valuable. We then examine the limited available information about how coping systems have actually responded to skillful seasonal-to-interannual climate forecasts, supplementing this with other sources of insight, including basic knowledge about human information processing and knowledge about human use of information in situations that may be relevant by analogy. This examination yields a set of hypotheses about the characteristics that make forecast messages and information systems useful. Useful Information that Climate Forecasts Might Provide Chapter 3 shows the variety of ways in which individuals and organizations cope with variable climates. Climate forecasting is intended to help them cope better, but not all forecast information will necessarily be useful toward this goal. Forecast information can have value only if people can change their actions in beneficial ways based on the content of the information. As the following examples show, different kinds of

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Page 64 forecast information are useful, depending on the climate-sensitive sector, the region, and the coping strategies used. In agriculture, a forecast is useful to the extent that it permits more advantageous ex ante actions, such as altered choice of crop species and cultivars and timing of tillage (Mjelde et al., 1988) or altered composition or allocation of herds (Stafford Smith and Foran, 1992; Ellis and Swift, 1988). For example, a skillful forecast may allow a farmer to diversify less and to match cropping decisions more closely to expected climatic events. A farmer who can anticipate that rainfall is likely to be unusually ample can grow seeds that are sensitive to water availability to improve profits; conversely, a farmer who knows that there is a high probability that rainfall will be unusually low can conserve on inputs, use less water-sensitive inputs, or refrain from application of any unfruitful inputs at all. Forecasts of growing season length or degree-days may be useful in similar ways. However, forecasts are helpful only if they arrive before planting or stocking decisions are made and if the producer is capable of responding. Some responses, such as changing livestock species, may require resources available only to the most successful producers. Regional conditions affect the usefulness of forecasts. In South Asia, where models of El Niño/Southern Oscillation (ENSO) allow for fairly skillful predictions of average temperature and precipitation several months in advance, it might seem that climate forecasts would be broadly useful to farmers. But this may not be so. Forecasts can benefit the 10 to 15 percent of farmers in the semiarid areas who would lose money by planting in bad-climate years (Rosenzweig and Binswanger, 1993): they could decide not to farm. But the majority of farmers, who can expect to profit even in a dry year, might not benefit from the forecasts. The reason is that no farming practices can be undertaken prior to the onset of the monsoon, so that even if a long-range forecast of the monsoon onset could be made, it would provide no benefit. A prediction of the magnitude of the monsoon may also provide no benefit to farmers whose practices would be the same regardless of its magnitude. Institutional factors may affect the value of forecasts. In the United States, the usefulness of a climate forecast may depend in complex ways on whether a farmer is covered by crop insurance. Some analysts (e.g., Gardner et al., 1984) argue that federally subsidized crop insurance imposes a ''moral hazard'' by encouraging farmers to take imprudent risks, for example, by being less diversified and more dependent on dryland practices in regions of marginal climate than their uninsured counterparts. Insurance also decreases the incentive for farmers to change their practices on the basis of a climate forecast, since they are covered against disasters. In water management, distinct kinds of forecast information are use-

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Page 65 ful depending on the decision and its context. For example, water managers in the western United States typically base streamflow forecasts on existing hydrologic conditions (e.g., current water content of the snowpack) and historic records of high, normal, and low precipitation during the remainder of the forecast period. This procedure gives managers a rough indication of the upper and lower bounds and most likely inflow conditions for the system. Climate forecasts can improve decisions based on this procedure if they provide more accurate expectations about rainfall at the watershed level. However, the value of such forecasts is likely to hinge on whether adequate representations of forecast accuracy and uncertainty are provided. Forecasts may also help water project managers inform irrigators, whose water entitlements are calculated as a share of the available supply, of impending shortfalls early in the season so they can make adjustments. Although such advice may be helpful, if it is based on a poor-quality forecast or on unskilled interpretation of the forecast, water users may take inappropriate actions, such as fallowing unnecessarily or incurring unneeded expenses for wells or water purchases to protect perennial crops. An example involving such outcomes is discussed in the next section. The usefulness of forecasts also depends on the state of preexisting water management institutions. For example, it may be supposed that the prior appropriation system in the western United States is rigid, leaving water users with little discretion to make adjustments that take forecast information into account. However, by providing a clear link between water availability and use rights, the senior priority rule allows water users and managers to calculate the probability of obtaining water under any particular right given the predicted climatic conditions and to make appropriate investments or water purchases to achieve desired levels of reliability (Hutchins, 1971; Trelease, 1977). Forecasts that give additional lead time might also allow more efficient adjustments by enabling irrigation districts and individual irrigators to plan more effectively for fallowing, crop switching, or other methods of water use reduction and for improved operation of water banks. The insurance industry and its clients might benefit from forecasts that accurately estimate the probabilities of hurricanes, floods, droughts, or wildfires striking policy holders in particular areas. For example, insurers and reinsurers could calculate premiums based on risk rather than history. However, this would be an improvement only if available predictions are sufficiently accurate and if insurance regulators allow the change. The usefulness of forecasts to insurers is also constrained by difficulties transforming the kinds of information forecasts provide into forms used in insurance firms' procedures of risk analysis (Golnaraghi, 1997). Crop insurers might use climate forecasts to decide how much

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Page 66 reinsurance to purchase. This information is needed with enough lead time—which can be several months—to sign with the federal government for reinsurance. Forecasts as little as one month in advance may be sufficient to help insurers provide farmers with risk-management services (Golnaraghi, 1997). Climate forecasts might give public health systems an unprecedented degree of early warning of the likelihood of epidemics, based on climatic or ecological analysis before disease organisms appear. ENSO forecasts, to the extent they can be linked to conditions conducive to disease outbreaks (Epstein et al., 1995), may facilitate early public health interventions. Taking advantage of the forecasts would require a sufficient level of knowledge to link climate parameters to ecological events affecting disease organisms, an adequate surveillance system, and appropriate training and communication systems for health early warning. Given these advances, public health responses might include immunizations, neighborhood clean-ups, and pesticide applications. For example, a combination of climate forecasting and remote sensing imagery can help in preparing for outbreaks of eastern equine encephalitis by determining where and when temporary pools of standing water are likely to appear and how long they may last. With such information, it is possible to take preventive action to control the population of infected Aedes vexans mosquitoes with larvicide applications. Because maturation of larvae to adults occurs in about seven days, accurate information on standing pools of water after a rain is necessary within two days, to allow time for dip sampling and application of larvicide (Epstein et al., 1993a). In the energy industry, improved forecast skill might help gas companies with inventory management and with anticipating price fluctuations. Hydro-dependent utilities might benefit from seasonal forecasts of precipitation and runoff, and utilities with seasonal demand profiles might benefit from seasonal forecasts of heating or cooling degree-days; their specific information needs and lead times are unknown. These examples illustrate that the usefulness of climate forecast information depends on the match between various attributes of the information and the needs and capabilities of individuals and organizations who may be affected and on the ability of these users to get the information processed to fit their needs. Among the attributes of climate information that are frequently important are lead time, the particular climatic parameters being forecast, the spatial and temporal resolution of the forecast, and its accuracy. These are discussed in more detail at the end of the chapter. Whatever new information forecasts provide, some actors may benefit more than others because they are in better positions to take advantage of the information. For example, some individuals may have more

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Page 67 savings or better access to credit that allows them to take better advantage of a forecast of favorable climatic conditions. Some may own a specialized resource, such as a senior water right or a piece of farmland whose value varies with climatic conditions. Some actors may gain advantage in contractual negotiations if they receive and correctly interpret forecast information earlier than others. Such distributional consequences are shaped by actors' situations and by the institutions that shape them (e.g., water law, insurance regulations), by the availability of insurance and credit, and by the design of disaster preparedness and relief programs. It is possible that, in some sectors or regions, the overall benefits of climate forecasts may be distributed so that some groups gain greatly while others do not benefit at all, or even find themselves worse off. If such outcomes arose, they might greatly dampen enthusiasm for climate forecasting. Responses To Past Climate Predictions A useful source of information on how weather-sensitive sectors and actors may respond to climate forecasts in the future is their response to past climate forecasts. Unfortunately, skillful forecasts are very recent, so there has been relatively little opportunity to learn from experience. A few case studies have been done of situations in which affected groups have acted on climate or hydrological forecasts on the time scale of months. Three are described below, with the tentative lessons that seem to flow from them. This body of research is far too limited to treat these lessons as more than hypotheses. However, they are valuable because they show responses to actual climate forecasts. Systematic studies based on responses to forecasts of the 1997-1998 El Niño could add greatly to understanding. Drought Forecasts in the Yakima Valley Glantz (1982) examined the case of an erroneous forecast of drought in the Yakima valley of Washington state in 1977. Irrigation in the Yakima valley supports some high-value crops, including orchards and mint. In February 1977, the Bureau of Reclamation forecast that water available for summer irrigation in the valley would be less than 50 percent of normal. On the basis of this forecast, they told senior water rights holders that they would receive 90 percent of their allocations and more junior water rights holders that they would only receive 6 percent of their normal allocations—insufficient to protect their perennial crops and orchards from drought. Farmers responded by drilling deep wells at costs of $25,000 to $250,000 per farmer; deciding not to plant a crop but to fallow;

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Page 68 leasing or selling water to those with perennial crops at up to four times the normal price; transplanting valuable crops to regions with senior water rights; and weather modification activities costing $400,000. As the season advanced, the bureau revised its forecast, and by May, long after most of these adjustments had been made, it announced that junior rights holders would, in fact, receive 50 percent of their allocations. By the end of the summer, it was clear that water supplies had been almost 83 percent of normal and that junior rights holders had received 70 percent of normal allocations—more than enough to protect crops and orchards against drought damage without dramatic adjustments. Farmers were sufficiently angry about having spent large sums on unnecessary adjustments in response to the bureau's erroneous forecast that they sued the bureau for more than $20 million in compensation—a suit that never went to trial. Glantz discusses several specific problems with the bureau's forecast, including estimation errors in the original prediction (they had failed to include return flow), poor communication of uncertainties, and lack of openness about errors in the forecast. Long-standing institutional water rights arrangements also created a very difficult situation for junior rights holders faced with a drought forecast. Several lessons can be drawn from the Yakima study. The most striking is that responses based on acceptance of erroneous forecasts can have serious economic, distributive, and legal consequences. The case also suggests the need to check forecasts very carefully for errors before releasing them, to clearly communicate uncertainties and the message that forecasts evolve during a season, and to consider how institutional frameworks can redistribute the impacts of a forecast as well as the event. ENSO-based Forecasts in Northeast Brazil, 1991-1992 and 1996 Droughts sometimes associated with El Niño have often caused serious agricultural losses and human suffering in northeast Brazil, a region where there is widespread poverty and vulnerability to climatic variations. In addition, the cold phase of ENSO, La Niña, is associated with abundant rainfall over the region, sometimes leading to floods that also disrupt the region's economy. Researchers in climate modeling have used the onset of El Niño to forecast drought in the region up to 6 months in advance and, more recently, have learned that droughts in northeastern Brazil are even more strongly correlated with Atlantic sea surface temperature. Therefore, accurate prediction of ENSO and Atlantic sea surface temperature has the potential to improve well-being in the region by providing policy makers with information on anticipated climate variations.

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Page 69 In 1983, when no preparations were made for El Niño, yields of cotton, rice, beans, and corn were less than 50 percent of normal. In the state of Ceara, corn yields fell from 0.54 to 0.12 tons per hectare. The government spent $1.8 billion in short-term relief, which included employing 3 million people in public works to construct irrigation systems and reservoirs and trucking in drinking water. By contrast, the state government of Ceara responded vigorously to a forecast of the 1991-1992 El Niño, which was released by the state's Foundation for Meteorological and Hydrological Resources (FUNCEME) (Golnaraghi and Kaul, 1995). The government instituted several policies, including guiding farmers on what and when to plant (distributing seeds more resistant to water stress and maintaining a strict planting calendar); controlling water consumption in Fortaleza (Ceara's capital city); and rushing the construction of a new dam on the Pacajus River. Policy implementation included the organization of a grassroots campaign in which the governor himself traveled through the state's countryside to vouch for the reliability of FUNCEME's forecast and the benefits that could stem from its application. One way to estimate the value of the forecast is by comparing agricultural output in 1987 and 1992. During the 1987 El Niño episode, 30 percent less rainfall resulted in output of approximately 15.5 percent of the region's mean output; in 1992, when rainfall was 27 percent below normal, agricultural output in Ceara was approximately 82 percent of the region's mean. These data suggest that the application of a seasonal forecast greatly benefited agricultural output. However, a recent study of the social implications of seasonal forecasting in northeast Brazil (Lemos et al., 1998) suggests that the picture is much more complex. For example, agricultural subsidies were much more easily available in 1992 than in 1987 and would have boosted agricultural production even in the absence of a seasonal climate forecast. Also, the link between ENSO and regional climate is rather weak, with ENSO accounting for only about 10 percent of the rainfall variation over northeast Brazil (Hastenrath and Heller, 1977). Drought and high rainfall in northeast Brazil may also be associated with other phenomena, such as Atlantic sea surface temperatures and the movement of the intertropical convergence zone. In addition, many small and subsistence farmers have little flexibility in responding to forecasts (Lemos et al., 1998). The credibility of seasonal forecasts in northeast Brazil was reduced in 1996 when FUNCEME's seasonal forecast of higher than normal rainfall proved inaccurate. As a result, policy makers were very cautious about issuing a forecast of the 1997-1998 El Niño, and there was considerable skepticism among the public. Forecasters delayed issuing a forecast in 1997 and farmers were reluctant to change their strategies; the consequences are not yet fully known. Another cause of resistance to seasonal

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Page 70 forecasts in northeast Brazil is that the prediction of a drought raises a set of unpleasant expectations for many in the region. Past governments typically responded to droughts with large-scale relief efforts that included infrastructure projects and emergency food and work projects and that sent relief funds to certain powerful interests and created a sense of dependency in the population. Many policy makers are concerned about drought forecasts because they do not want, nor can they afford, to perpetuate this drought "industry" (Magalhaes and Magee, 1994). The case of northeast Brazil provides several lessons about the value of seasonal forecasting in a region where drought can have devastating impacts. It demonstrates the ease with which forecasters can lose their nerve, and the public its trust, as a result of an inaccurate forecast such as occurred in 1996, and the implications for subsequent forecasting efforts. It also shows that some farmers are unable to use seasonal forecasts because they do not have the resources or flexibility to respond. Another important insight is that it is important to include economic and political factors such as subsidies in assessing the effects of a prediction for agriculture, in order not to overestimate forecast value and to consider local history in making assumptions about how a forecast will be received. The Credibility of Famine Early Warning Systems Seasonal climate forecast information is also used in famine early warning systems. Since the 1970s, the U.S. government has used climate information to anticipate the onset of famine, to target people at risk, to reduce response time, and to estimate food and other relief requirements, especially in Africa (Walker, 1989; Hutchinson, 1998). The U.S. Agency for International Development has had a warning system for Sub-Saharan Africa since 1981, initially based on information about rainfall, vegetation, and crop yields. The key indicator has been a vegetation index, derived from the AVHRR (Advanced Very High Resolution Radiometer) satellite of the National Oceanic and Atmospheric Administration, which provides information about the progress of the rainy season through monitoring the productivity of natural pasture and large-scale agriculture. Forecasts of seasonal agricultural production are made based on past relationships between early season rainfall and yields. The famine early warning systems can be considered a form of seasonal forecasting because they anticipate conditions up to 6 months in advance, through a combination of qualitative assessment and crop predictions. By the mid-1980s it was obvious that biophysical information needed to be linked to socioeconomic information in order to provide useful famine warning because famine is created as much by social, economic and political conditions as by drought. Thus, the system now couples a wide

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Page 71 variety of biophysical and satellite measurements with information on health and nutrition, agricultural inputs and markets, and indicators of socioeconomic stress such as livestock and jewelry sales. These indicators are combined into country reports (e.g., for Ethiopia or Mali), which are published and distributed on a regular basis as the growing season progresses and used to plan any relief efforts. Local governments and nongovernmental organizations receive the reports as well as U.S. government and international agencies. Several lessons can be drawn from the experience with famine early warning systems for the new developments in seasonal forecasting. These include the importance of combining environmental and social information to provide accurate assessments of agricultural production and other social impacts and the value of including local decision makers and nongovernmental organizations in the development and distribution of forecasts. Indirect Sources of Insight into Responses to Climate Forecasts Although climate forecasts have been widely available in the United States for more than three decades from government, academic, and private sources, little is known about how they are used. Because of the limited amount of direct knowledge about responses to climate forecasts, a considerable portion of the knowledge relevant to providing people with improved climate forecast information is indirect. Some of this is in the form of general knowledge of how people think about weather and climate; some consists of knowledge about how human beings as individuals and in organizations acquire and process new information generally; some comes from knowledge about how people use information in possibly analogous situations. Beliefs About Weather and Climate Until recently, nonspecialists' beliefs about weather, climate, and climate changes and variations have been of interest mainly to academic anthropologists. Research on ethnometeorology, perceptions of weather, and hundreds of other topics in nonwestern societies can be examined through the web site of the Human Relations Area Files at Yale University (http://www.yale.edu/hraf/home.htm). Many traditional societies, including those in ENSO-sensitive areas, have long-standing and complex theories about weather and climate, some of which they use for forecasting deviations from seasonal averages (e.g., Antunez de Mayolo, 1981; Ramnath, 1988; Bharara and Seeland, 1994; Pepin, 1996; Eakin, 1998).

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Page 72 Cultures that are highly dependent on variable climate-ecosystem relationships tend to observe these relationships closely, so their skill in forecasting may have increased over time. Many elements of traditional forecasting methods are in fact explainable by modern scientific principles (Pepin, 1996); however, there has been little if any investigation of how much skill these forecasting systems provide. The persistence of folk theories of climate does not establish their predictive value: some of them, particularly those tied closely to religious rituals, may serve mainly to allay anxiety among people utterly dependent on unpredictable and variable climatic events (Wilken, 1987). Whatever their level of skill, the existence of traditional climate forecasts has implications for the coping strategies people use and for their acceptance of information from modern climate forecasts (e.g., Oguntoyinbo and Richards, 1978). On the positive side, traditional forecasting indicates the receptivity of certain social groups to the concept of climate forecasting and presumably also their appreciation of the fact that seasonal forecasts are imperfect. In addition, the traditional forecasts probably identify the climatic parameters that are most relevant to their users' subsistence decisions. On the negative side, adherents of traditional forecasting systems may resist new systems, even if they are more skillful, and once modern forecasting systems are adopted, any value the traditional explanatory systems may have for purposes other than climate forecasting (e.g., forecasting crop diseases) may be discredited or lost. There has been little research in Western societies on beliefs about seasonal-to-interannual climate variability. However, research on beliefs about climate change suggests that people tend to assimilate new information about climate into cognitive structures or mental models that they use for conceptually related matters—other environmental problems affecting the atmosphere. For example, nonspecialists frequently confuse climate change and stratospheric ozone depletion; there is also a widespread belief that "air pollution" (which for many people is associated with phenmena like smog, ozone alerts, and acid rain) is a cause of climate change (Kempton, 1991; Löfstedt, 1992, 1995). Weber (1997) found a strong effect of mental models on perceptions of climate change and variability among cash-crop farmers in the U.S. Midwest. Their beliefs about climate change had more effect than length of personal experience on their ability to detect recent increases in maximum July average temperatures in their locality and in the variability of those temperatures. Farmers with longer experience were slightly less likely to notice the recent warming, but a much more reliable predictor was whether or not the farmers believed in global warming. The majority of believers in global warming correctly detected and classified the temperature increase, which fit their mental models, whereas the majority of

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Page 73 disbelievers incorrectly remembered no change in maximum July temperatures. The disbelievers were more accurate, however, in detecting increased variability in recent temperatures, probably because they interpreted recent increases in average high temperatures as reflecting variability rather than a trend. Human Information Processing and Climate Information Recent advances in cognitive psychology regarding information processing provide insight that can be applied to human beliefs about weather and climate and can put the above findings into a conceptual framework. This research has established that people are not passive recipients of information that they accumulate and store for future reference; rather, they attend to and encode information selectively. Also, people often construct beliefs when needed for a situation, rather than simply recalling them from memory (Payne et al., 1992). Such construction has been shown to be based on mental models of the phenomenon under question, which usually involve causal connections between variables in the mental model but often omit relevant variables and their relationships (Bostrom et al., 1994). Understanding the mental models people might use to assimilate climate forecast information may therefore help with the task of making this information intelligible to the potential users. A historical example concerning interannual climate variations illustrates how human beings assimilate climatic information into preexisting mental models—and the shortcomings of this cognitive strategy (from Kupperman, 1982). It also shows that predictions based on preexisting mental models often survive a long series of disconfirming empirical evidence. English settlers who arrived in North America in the early colonial period operated under the assumption that climate was a function of latitude. Newfoundland, which is south of London, was thus expected to have a moderate climate, and Virginia was expected to have the climate of southern Spain. Despite high death rates due to weather that was consistently much colder than expected, the resulting failure of settlements, and pressure from investors disappointed by the colonies' inability to produce the rich commodities associated with hot climates, colonists clung with persistence to their expectations about the local climate based on latitude. Reluctant to accept the different climatic conditions as a new fact in need of explanation, they instead generated ever more complex rationalizations and alternative explanations for these persistent deviations from their expectations. Samuel de Champlain, for example, took a single mild winter in 1610 as indication that his mild climate expectations

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Page 84   to deliver climate forecast information. A first step toward understanding them is to identify their parts; a second is to examine the readiness and ability of these parts to assimilate, interpret, and transmit the information in climate forecasts and to interact effectively with each other. The research literature on information systems for disaster provides a long list of relevant questions to ask (Mileti and Sorenson, 1990). 3. Use participation to enhance information delivery. In the health field, "people are more likely to change and maintain the change in their behavior if they have participated actively in setting the goals and plans for the change" (Green, 1984:221-222). Striking support for the value of community-based and initiated and peer education programs comes from research on high-risk behavior and AIDS transmission (Aggleton et al., 1994), and a review of the literature on health promotion has concluded that active involvement of people in their own health care—patient education, self-care groups, and so forth—could bring about significant reductions in risk factors for chronic diseases (Green and Kreuter, 1990). Similar conclusions have been drawn regarding proenvironmental behavior. For example, participatory approaches have been said to make education more effective because they give greater access to target audiences and provide increased credibility (Gardner and Stern, 1996). Research on disaster warnings emphasizes the need for local officials and organizations to learn and practice their responsibilities in advance of warnings, although it does not emphasize the value of their participation in designing the information (Mileti and Sorenson, 1990).   Participatory approaches to delivering climate information might include structured dialogues between climate scientists and forecast users to identify the climate parameters of particular importance to users and the organizations that users might rely on for climate forecast information: such dialogues could establish communication channels among scientists, information-transmitting organizations, and users that might direct forecasting research toward users' needs and clear up questions likely to arise, such as about forecast accuracy and uncertainty. If these approaches work as well as they sometimes have in other fields, they would tend to make forecast information more decision relevant, to improve mutual understanding between scientists and forecast users, and to encourage appropriate interpretation and use of forecast information. 4. Combine information with other intervention types for enhanced effect. The field of health behavior emphasizes the powerful influences of individuals' contexts on their behavior. In fact, the concept of health promotion evolved from the earlier one of health education largely because of the difficulty of changing behavior solely by targeting information to individuals. Researchers have concluded that the most effective programs use combinations of individual and structural strategies, such as

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Page 85   health education combined with organizational, economic, and environmental supports for the behavior (Green, 1984; Becker and Rosenstock, 1989).   Similarly, education for proenvironmental behavior has been found to work best when combined with other strategies of intervention (Gardner and Stern, 1996). Education and information address only some of the barriers to proenvironmental behavior—ignorance, misinformation, and the like. Interventions tend to be most effective when they also address contextual factors that serve as barriers to actions in the audience's particular situation.   In the research literature on disaster warning, it is well established that information is of little use without well-functioning information delivery systems (Mileti et al., 1985), and considerable research has been devoted to identifying the characteristics of such systems (Mileti and Sorenson, 1987, 1990). 5. Apply principles of persuasive communication, subject to audience willingness to accept direct influence attempts. These principles, which derive from decades of research (e.g., Hovland et al., 1953; McGuire, 1969, 1985), have been elaborated in great detail in the disaster warning literature (Drabek and Boggs, 1968; Mileti, 1975; Quarantelli, 1980; Perry et al., 1981; Mileti et al., 1992). This literature distinguishes between public alerts and public warnings. Alerts, such as sirens or short "crawlers" across the bottom of television screens, draw people's attention to the need to obtain additional information. Warnings, which provide that additional information, must be available if large-scale public protective action is to follow. Effective shorter-term warnings (hours to days before the expected event) contain short and simple information about the expected risk, tell people how much time they have to complete the recommended actions, identify the experts and officials giving the warning, are repeated frequently over the original communication channel and many others, and, most importantly, give people guidance about what to do to protect themselves.   Longer-term warnings (days to months or years before the expected event) work most effectively when they are planned as long-term communication processes or campaigns rather than as singular acts. An example would be multiple communications via electronic media for several months, followed by distribution of written material such as a brochure mailed to people's homes or a publicized newspaper insert, followed by several additional months of other communications. Information campaigns like these are most effective when supplemented by distributing additional useful written documents and pamphlets in the community at risk for people obtain when they have the interest. An ongoing communication process generates public interest, fosters addi-

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Page 86   tional information seeking, and thus promotes protective responses. Written means of communication, such as newspapers, are the most used by the U.S. general public to obtain longer-term warning information.   These conclusions are consistent with results from the other literatures, although researchers in the other fields are less sanguine about the effectiveness of information campaigns if unaccompanied by other strategies. The discrepancy may be due to some special characteristics of immediate disasters. It is relatively easy to recognize the importance of disaster predictions and to judge their accuracy, relative to predictions about long-term threats to personal health or environmental quality. Those who warn of oncoming floods and hurricanes on the time scale of hours to days have developed a widely recognized track record of predictive skill, and the outcomes for those who heeded or ignored past warnings are easy for nonexperts to interpret. These characteristics may make some kinds of disaster warnings more convincing than many other kinds of warnings.   The implications for climate forecasts are as yet unknown, but in terms of the accuracy of forecasts, their usual lead times, and their importance to their audiences, climate forecasts would appear to be more like longer-term disaster warnings or the information offered by health and proenvironmental behavior programs than like short-term disaster warnings. 6. Information delivery systems are inequitable. The typical strategies for delivering information—distribution of written material, publication in newspapers, presentation in broadcast news stories, and so forth—are oriented primarily to the educated, the affluent, the cultural majority, and people in power. The distribution systems are largely controlled by government or wealthy corporations. In implementation, information sent through these channels is least effective in reaching the elderly, cultural minority groups, people with low incomes, and those without power. These biases can be counteracted to a degree by designing information systems specifically to reach marginalized groups, for example, by involving information sources that these groups use and trust as information providers (Perry and Greene, 1982; Perry, 1987; Stern et al., 1986). Alternative Models for Designing Information Programs The above general principles have coalesced into somewhat different approaches to disseminating information in different fields. In the health promotion field, a community-based approach to health has developed that pursues what a study by the Institute of Medicine has called a "willing compliance" model of change, as distinguished from an "authoritarian" model (Institute of Medicine, 1997:68; see also Evans and Stoddart,

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Page 87 1994; Patrick and Wickizer, 1995). This approach seeks to develop community coalitions that involve the affected groups, to use these coalitions to identify health priorities, and to maintain these coalitions throughout the process of implementing community-based efforts to bring about change. Similarly, in the field of proenvironmental behavior, there has been increasing recognition that community-based programs that employ a variety of behavioral change strategies, including participatory approaches, are among the most promising strategies available (Gardner and Stern, 1996). In the field of disaster warning, however, a more authoritarian model of persuasive communication, relying on scientists to gather information and government agencies and private-sector organizations to disseminate it, has proven useful. The divergence in the lessons drawn from research in apparently analogous fields may be reconciled by examining the various purposes and contexts of information programs. A National Research Council (1989) study that examined risk communication about a broad range of health, safety, and environmental hazards distinguished two distinct and sometimes conflicting purposes for providing information about hazards: to inform audiences and to influence them. The study pointed out that the appropriateness (especially for government) of using messages to influence people to respond in particular ways to hazards is judged quite differently depending on which behaviors are being promoted, the degree of scientific consensus about the information being delivered, the compatibility of government influence with individual autonomy and related values, and the influence techniques employed in designing the message (National Research Council, 1989:80-93). In this light, the differential emphasis on "participatory" and "authoritarian" models of communication in different fields most likely reflects the content and history of the fields. In certain environmental risk areas, such as management of potentially carcinogenic chemicals and radioactive materials, a high degree of uncertainty and controversy has surrounded scientific information; it is not always evident which actions are most appropriate for reducing risk; and there is a long history of accusations, sometimes substantiated, that corporations and government agencies have misinformed the public. Highly participatory approaches are necessary in these areas to allow for discussions of how to proceed under uncertainty and to address the problem of mistrust of official sources of information. In other areas, such as earthquake engineering, commercial aviation, hurricane warning, and infectious disease, the historical legacy of risk communication includes greater consensus on how to reduce risks, a much higher level of trust in expert sources of information, and a greater willingness to accept authoritarian styles of communication.

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Page 88 A more recent National Research Council study reached similar conclusions. It found that developing a useful understanding of risks depends ''on incorporating the perspectives of the interested and affected parties from the earliest phases of the effort to understand the risks'' in order to meet "the challenges of asking the right questions, making the appropriate assumptions, and finding the right ways to summarize information" (National Research Council, 1996b:3). This study proposed a participatory strategy for developing most kinds of environmental information, recognizing, however, that the most effective degree and type of participation is situation specific. What kind of model is most appropriate for delivering climate forecast information? Without much of a base in empirical knowledge, it is necessary to hypothesize on the basis of analogy. In our judgment, the context of climate forecast information at its current stage of development is more similar to that of information about health promotion, energy conservation, and hazardous substances than to that of short-term disaster warnings. There is too much uncertainty and potential controversy about what the available scientific information implies for human response to use an authoritarian approach aimed at influencing people. Even an authoritarian style of informing people seems inappropriate because of the large gaps in knowledge about which information would be decision relevant for which recipients. Consequently, we believe much can be gained by using participatory approaches that rely heavily on the involvement of communities of potential forecast users both for developing climate forecast information and for designing information delivery systems. Such approaches are likely to provide climate scientists with useful and timely information about the attributes of forecasts that will make them useful for the intended recipients, to build understanding among the recipients of what forecasts can and cannot do, and to develop an appropriate level of trust in forecast information. The evidence from analogs suggests that in the future, if and when the accuracy and importance of climate forecasts is convincingly demonstrated to users and forecasts are prepared and presented in ways that meet users' information needs, something more like the disaster warning model of information delivery may prove effective. However, inappropriately high levels of expressed confidence in forecasts, acrimonious controversy about forecasting models, and forecasts that deliver information recipients perceive as irrelevant are all likely to delay the coming of such a future. These judgments, of course, are preliminary and should be tested by empirical research. An example from Mexico illustrates one way a participatory approach to developing forecast information might proceed. Dialogues between climate forecasters and forecast users have led to an effort to seek a com-

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Page 89 promise between climatological research agendas and the needs of users. As a result, Mexican climatologists have begun to work on correlating the frequency of "black" frosts with El Niño years despite the extreme difficulty of predicting frost hazards. They have done this largely because consultations with farmers have shown that frost is one of the greatest risks they face. Some scientists fear that early consultations with forecast users may unduly raise their expectations. It may take several years for scientists to produce predictions with the necessary detail and accuracy to be useful to a particular sector and, in the meantime, users may lose confidence or interest in the process or use unreliable information to make costly decisions. Explaining the limitations and challenges of the predictive research may be critical to maintaining user confidence. For example, it may be impossible to predict a midseason dry spell or the date of a significant frost. Explaining why the science is more uncertain about certain topics than others and conveying uncertainty in terms understandable to specific user groups can help recipients make more appropriate use of available information and participate constructively in forecast development. There is a lack of systematic knowledge at this time concerning how to convey the state of prediction science to particular types of forecast users in a helpful way. Findings The limited research on responses to actual climate forecasts and larger bodies of knowledge on information use generally and in partially analogous situations have yielded some promising findings and hypotheses, as well as developing a set of methods for assessing the ways scientific information is used and the ways information delivery systems function. Although the general findings need further validation as applied to climate forecast information, they suggest ways to go about organizing and distributing such information so it can be used effectively within social coping systems. They also suggest directions for research on how to make climate forecasts more valuable. 1. Climate forecasts are useful only to the extent that they provide information that people can use to improve their outcomes beyond what they would otherwise have been. Different kinds of forecast information are useful for different climate-sensitive activities, regions, and coping systems, and messages about forecasts are most likely to be effective if they address recipients' specific informational needs. As Chapter 3 shows, each weather-sensitive sector employs a variety of strategies for coping with climatic variation, and each actor within a sector may use only a subset of the available strategies. For

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Page 90   climate forecasts to be useful in the near term, they must present information that is relevant and timely in terms of the coping strategies that recipients are likely to use. (In the longer term, it may help to devise new coping strategies.) There is little systematic knowledge at present for matching activities, sectors, and actors with their informational needs. However, the following attributes of climate forecast information are among those it is important to match.   a. Timing, lead time, and updating. When a forecast is made can have great importance for decisions. One factor is whether or not the forecast is available before key decisions must be made. For example, crop yield forecasts are much more useful to farmers if they are made before the crop is planted; storm and flood forecasts are much more valuable if they are made before insurance policy renewal dates. Another important factor is lead time. For example, if it takes a certain number of weeks or months to get a famine relief system functioning, forecasts will be much more valuable if they provide at least that much lead time. Finally, the usefulness of a forecast may depend on how frequently it is updated and how well recipients understand the implications of updating, because forecasts often improve in accuracy as time passes and their implications for action may change. Obviously, the necessary timing, lead time, and frequency of updating depend on the decision that a forecast might affect.   b. Climate parameters. Climate forecasts typically provide estimates of average temperature or precipitation for a future month or season. However, these are not always the most decision-relevant parameters. Indian farmers want to know when the monsoon will begin—an estimate climate forecasters may not be able to provide—at least as much as they want to know the total precipitation during the monsoon season. Public health officials may want estimates of the average or lowest daily minimum temperature for the breeding season of a disease vector that is sensitive to that parameter. Citrus growers are also concerned with the minimum temperature parameter. Number of days reaching above or below a certain temperature may be a concern to public health and safety officials who wish to prevent deaths from heat stress or hypothermia in vulnerable populations. Some decision makers might find it useful to have estimates of other parameters, such average cloud cover, likelihood of storms producing rainfall greater than certain levels, or length of growing season. The most important climate parameters for decision making clearly depend on the decision. Some decision makers may benefit greatly from estimates of climate parameters that are not currently being offered but that could be provided with skill if climate scientists made the effort to do so.

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Page 91   c. Spatial and temporal resolution of the forecast. Climate forecasts are typically offered for large regions, and this is useful if the regional forecast is more or less equally accurate throughout the region. However, this is not always the case. In the United States, for example, a spatial resolution of several hundred kilometers may be quite sufficient in the Great Plains but inadequate in the Pacific Northwest because of the great climatic variations within tens of kilometers in that region. For water management purposes, it matters whether the spatial units of a climate forecast lie within or across the boundaries of watersheds. It may also make a difference whether a forecast provides annual, seasonal, monthly, or daily averages and variances. Natural gas suppliers may want averages for a whole heating season, whereas fruit farmers may want averages for the period of a week or two when pollination occurs.   d. Accuracy of the forecast. For some decision purposes, a forecast that provides any measurable skill beyond historical averages may be quite valuable. This is likely to be the case for decisions based on highly aggregate phenomena, such as those of commodity market traders. For other decisions, a higher threshold of accuracy may be required to make a forecast useful. This may be the case for small farmers who may be unwilling to change their past successful practices on the basis of a forecast of uncertain or unproved accuracy. A higher threshold may also be set for actors who are held to standards of practice by oversight bodies. An example may be disaster insurers, whose regulatory authorities may not allow them to readjust their rates on the basis of climate forecasts until the forecasts have passed some test of accuracy. 2. Responses to past climate forecasts are an essential source of information for understanding responses to future ones. Before 1997, there was very little research specifically on the use of climate forecast information. However, the few rich case studies that exist suggest the value of carefully examined experience. The 1997-1998 El Niño event provides a valuable opportunity for building knowledge from experience that may be critical for improving the use of future climate forecasts. 3. Individual and organizational responses to climate forecasts are likely to conform to known generalities about responses to other kinds of new information. Thus, individuals' responses are likely to be strongly affected by the cognitive frameworks and beliefs to which they assimilate the new information. Organizational responses are strongly affected by their preexisting routines and the roles and responsibilities of those who would receive and act on the information for the organization. General knowledge about responses to new information suggest the following hypotheses:

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Page 92   • People will understand information from ENSO-based forecasts and use it more if they are first educated about the ENSO mechanism and how it affects local climate.   • Such learning will be best accomplished soon after extreme climatic events, such as those associated with the 1997-1998 El Niño.   • Those who learn to use a mental model of ENSO may treat ENSO-based forecasts as having more certainty attached to them than the scientific evidence warrants.   • Overconfident predictions and forecasts not borne out by actual events are likely to have an especially strong influence on the future use of forecast information. Forecasts presented without mentioning uncertainty are likely to be interpreted as if the forecasters have high confidence.   • Because people often stop after making one appropriate response to a situation, it may be useful to provide the users of climate forecasts with checklists or other external aids that identify a full complement of beneficial responses they could make. 4. The effectiveness of new information depends strongly on the systems that distribute the information (e.g., scientific organizations, mass media), the channels of distribution (e.g., print or visual media, word of mouth), recipients' judgments about the information sources, and the ways in which the informational messages are presented. Knowledge about information delivery systems and information use in situations that partly resemble the situation of delivering climate forecasts suggests some working hypotheses about how to improve delivery of this kind of information.   a. At the present stage of development of climate forecasting, participatory strategies are likely to be most useful for designing effective information systems. These strategies typically involve recipients, their representatives, or their proxies in identifying the needed climatic information and designing the information delivery system. Participatory strategies are important at this stage because the accuracy and importance of climate forecast information is not yet obvious to the potential users and because climate scientists do not yet understand which attributes of forecast information would make it most useful to recipients. Although general principles have been stated for broad participation in informing environmental decisions, the most effective methods for each situation must be determined empirically.   b. When delivering climate forecast information requires the involvement of new organizations or organizational roles, a period of learning is likely to be required to achieve effective information delivery. Learning is likely to be important both within organizations and in terms of coordination of the parts of the information delivery system.

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Page 93   c. General principles of persuasive communication can be applied to climate forecast information within the bounds of audience acceptance of deliberate influence. Among the principles likely to make an important difference in this field include presenting short and simple information, giving guidance on what to do to take advantage of a forecast, informing people about lead time, using frequent repetition over multiple channels, and getting information to people from sources they use and trust. These principles are likely to come increasingly into play as climate forecasts gain credibility and produce information that is accepted as beneficial to recipients and society.   d. The usefulness of forecast information for a particular recipient will depend on how it is presented. For example, the same forecast information can be presented with or without estimates of its level of uncertainty; the forecast means and variances can be presented in words, numbers, or graphs; the information can be distributed in one-way communication style, or it can be discussed. The manner of presentation may make a considerable difference in whether or not a climate forecast changes the behavior of those who might benefit from it. Little is known about the specifics for climate forecast information and particular types of recipients.   e. Useful information is likely to flow first to those with the most education and money. This is likely to be particularly true for highly technical information about future climate. For such information to be used by less-educated and less-affluent actors will probably require special efforts to process the information to make it easier to know how to use it and to reach these audiences through sources they trust, including their personal social networks. 5. Climate forecasts are likely to have different effects on different regions, sectors, and actors; in particular, if the typical strategies are used for delivering information, the benefits of improved forecasts are likely to go disproportionately to better-off individuals, groups, and societies. Differential effects arise because particular items of forecast information provide more value to some than to others; because the costs of getting, interpreting, and acting on forecast information weigh more heavily on those with fewest resources to pay them; because of differential distribution of information typically, favoring the educated, the literate, and members of dominant cultural groups; and because of institutional and other factors that leave some people able to benefit more than others from the information. Some actors may benefit from forecasts at the expense of others. The effects on any specific actor depend strongly on the coping mechanisms available that allow the actor to take advantage of the new information and on the cost of the information in money, time, and effort to make it usable. Economic principles suggest that, when a forecast has a fixed cost, it is more

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Page 94   likely to be used by large actors because the benefit is likely to be proportional to the magnitude of the decision that benefits from the forecast. However, the actual cost threshold is likely to vary also with the type of activity, with various attributes of the forecast (accuracy, timeliness, etc.), and with the situations and institutional contexts of affected actors. In sum, climate forecasts are useful only in relation to the actions people can take, given forecast information, to improve their outcomes. Many factors specific to forecasts and to the recipients' decision situations affect the potential usefulness of forecast information. To improve the usefulness of climate forecasts, it is important to identify the decision-relevant attributes of forecast information for particular activities and actors and to encourage forecasters to provide information with those attributes when possible. It is also important to consider what the recipients of climate forecasts are likely to do in practice, given the coping strategies they actually use, their ability to modify those strategies in response to forecast information, the normal routines of their activities, their usual practice in dealing with new information that is offered to them as helpful, their level of trust in the forecast and its source, and other realities of their situations. Available evidence suggests that the benefits from improved information typically go disproportionately to the wealthy and better educated. Closing the gap between the potential value of climate forecast information and its actual value will depend on developing focused knowledge about which forecast information is potentially useful for which recipients, about how these recipients process the information, and about the characteristics of effective information delivery systems and messages for meeting the needs of particular types of recipients. It may also depend on improved understanding of how to design information systems that effectively reach marginalized and vulnerable groups.