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4 Health in the Context of Global Climate Change Scenarios The following chapter is a summary of a webinar on developing scenarios for global climate change. The webinar featured three speakers with extensive experience in developing scenarios: Kristie L. Ebi, ClimAdapt, LLC; Marc Levy, Columbia University; and StÃ©phane Hallegatte, the World Bank. Scenarios are important in thinking about and preparing for multiple plausible futures, from the expected to the unexpected, in an analytically coherent and creative manner. Scenarios can facilitate research and assessment of the magnitude and extent of changes in climate and associated impacts, the degree to which mitigation and adaptation policies can reduce risks, the interactions among and tradeoffs between climate change impacts and adaptation and mitigation policies, and the relationship between climate change and development. As climate change is a cross-cutting issue for future global development goals and targets, it will become increasingly important to use scenarios when developing regional and national strategies to help ensure sustainable development as climate and development pathways change. Health outcomes, social determinants, gross domestic product, and other factors can be both inputs and outputs of climate change scenarios, providing opportunities for collaboration to develop projections that can better inform global development frameworks. OPENING John Balbus, senior advisor for public health at the National Institute of Environmental Health Sciences and co-chair of the Global Environmental Health and Sustainable Development Innovation Collaborative, provided a brief overview of the webinar topic. At first glance, the topic of scenario 43
44 INCLUDING HEALTH IN GLOBAL FRAMEWORKS development for health in the context of global climate change seems focused on the health implications of climate change, but it more broadly extends to the entire health community. To understand how climate change will impact health in the future, scientists have to understand the ways in which climate change and climate variability affect health in the present, and then project how those impacts will be felt. Part of that involves understanding what the future world will look like in terms of incidence and prevalence of conditions that convey vulnerability to climate change health impacts, noting that climate change acts as a force multiplier or as an additional stressor on top of existing stressors to global populations. Balbus noted that the scientific community is engaging in international efforts to understand the impacts of climate change broadly, and the health impacts of climate change more specifically to improve existing models. In order to do this, scientists need to be able to produce rigorous scenarios of the future to support these predictive efforts and models. OVERVIEW OF THE SHARED SOCIOECONOMIC PATHWAYS FOR USE IN NEW CLIMATE CHANGE SCENARIOS Kristie L. Ebi, Ph.D., M.P.H. Independent Consultant ClimAdapt, LLC Kristie Ebiâs presentation provided a historical overview of climate change scenarios, and the process for developing new climate change scenarios. Scenarios have a long history in climate change science, often led by the integrated assessment and climate modeling community. The integrated assessment modeling community coordinates its research and analysis through the Integrated Assessment Modeling Consortium,1 1 The Integrated Assessment Modeling Consortium (IAMC) is an organization of scientific research organizations. The IAMC was created in 2007 in response to a call from the Intergovernmental Panel on Climate Change (IPCC) for a research organization to lead the integrated assessment modeling community in the development of new scenarios that could be employed by climate modelers in the development of prospective ensemble numerical experiments for both the near term and long terms. More information is available at http://www.global change.umd.edu/iamc (accessed September 3, 2013).
GLOBAL CLIMATE CHANGE SCENARIOS 45 which has fielded questions from policy makers concerning the costs of particular mitigation policies. Edmonds and Reilly developed early climate change scenarios in 1984 to provide input into the U.S. Department of Energy carbon cycle analyses. This and other developments led to the first Intergovernmental Panel on Climate Change (IPCC) scenarios released in 1990, followed by a second set in 1992. The 1992 scenarios were used to assess the costs and benefits of mitigation policies and to project impacts; they were designated âIS92â followed by A, B, C, D, E, and F to identify specific scenarios. IS92A was considered a business-as-usual scenario, said Ebi. Use of these scenarios in the IPCCâs Second Assessment Report (IPCC, 1993) led to questions about the narratives underlying these scenarios. Increasing scientific understanding of the driving forces for greenhouse gas and sulfur emissions led the IPCC to conduct the Special Report on Emissions Scenarios (SRES) (IPCC, 2000). Ebi explained that the scientists tasked with writing this special report first developed internally consistent storylines of possible future worlds. The four main storylines describe the relationships between driving forces of emissions of greenhouse gases and other radiatively active substances and their evolution during the 21st century. Each storyline presents different demographic, social, economic, technologic, and environmental development pathways, designed to produce a wide range of atmospheric concentrations of greenhouse gases. Quantification of the storylines resulted in estimated emissions of greenhouse gases and sulfur that were used as input into climate models to project changes in patterns of climate variables such as temperature and precipitation. Ebi noted that the four main storylines were developed along two axes: one axis represents the extent to which a future world is focused on economic or environmental issues, and the second axis represents the extent to which a future world is focused on global or regional issues (see Figure 4-1). To keep the scenarios neutral, names were not assigned; instead they are called A1, A2, B1, and B2. An A1 scenario describes a future world more focused on global issues, with strong international institutions, and with a strong economic drive. As a result, an A1 world has high emissions of greenhouse gases. A B2 scenario describes a world more focused regionally and environmentally, with weaker international institutions, but a stronger focus on issues related to sustainable development. This world has lower emissions. These scenarios have been used extensively by the climate change community to project what may happen as temperatures increase and precipitation patterns change.
46 INCLUDING H EALTH IN GLOBBAL FRAMEWORRKS Duuring the passt decade, kn nowledge andd understandding of climaate changee science inccreased consiiderably, saidd Ebi. Earth system modeels now in ncorporate thhe full baskett of greenhouuse gases, lannd use changge, and aeerosols (see Fiigure 4-2). FIGUR RE 4-1 Four sccenario familiees. NOTES S: Schematic illustration of the Special R Report on Emis issions Scenariios (SRES)) scenarios. Thhe four scenario o âfamiliesâ aree illustrated, veery simplisticallly, as bran nches of a two-dimensional trree. In reality, tthe four scenarrio families shaare a spacee of a much higgher dimension nality given thhe numerous asssumptions needded to defin ne any given scenario s in a particular p modeeling approachh. The schemaatic diagram m illustrates th hat the scenarioos build on thee main drivingg forces of greeen- house gas g emissions. Each scenario o family is bassed on a comm mon specificatiion of some of the main driving d forces. SOURC CE: IPCC, 200 00. Reprinted with permissioon from the Inntergovernmenntal Panel on o Climate Chaange.
GLOBALL CLIMATE CHAANGE SCENARIO OS 47 FIGUR RE 4-2 Unified d earth system model. NOTES S: Human acttivities like bu urning coal, ooil, and gas too power hom mes, factoriees, and transpo ort have releaseed huge quantiities of carbonn dioxide into tthe atmospphere, causing an enhanced greenhouse g efffect. This causses an imbalannce in the energy cyclee that, in turrn, impacts tthe water cyccle, atmospheeric circulattion, and oceann currents, leaading to changees in weather aand climate. T The unified d earth system m model also o represents m more than juust the physiccal atmosppheric and oceeanic processees, including representationns of the globbal carbon cycle, dynam mic vegetation, atmospheric cchemistry, andd ocean biologgy. SOURC CE: Met Officee, 2013. Reprintted with permisssion Â© Crownn Copyright 20113, data su upplied by the Met M Office. Inttegrated asseessment models now incoorporate conssiderably moore interacctions within the energyâeeconomyâenvvironment sysstem, including more aspects a of hum man and natu ural systems. Ebi noted thaat this providdes the op pportunity to develop d much h more compplex descriptiions of how tthe future could evolve. Further, population proojections chaanged since tthe releasee of the SRESS, when fertility rates were higher worlddwide. A growwth in undderstanding off technology changes is aanother model improvemennt, said Ebbi.
48 INCLUDING HEALTH IN GLOBAL FRAMEWORKS At the end of the process to develop the SRES, it was jointly decided by world governments and the scientific community that leadership would transfer from the IPCC to the scientific community because of the greater scientific credibility of scenarios developed by the scientific community and more control over a process free from institutional timelines. However, this also means that no single group is in charge of the process, explained Ebi. During the past several years, discussions between the integrated assessment community and climate modelers initiated the process of developing a new set of scenarios. Instead of following the kind of process used in developing the SRES, the integrated assessment modeling community and climate change modelers agreed to first determine a limited number of concentrations of greenhouse gases in the atmosphere in the year 2100. Three criteria were agreed for selecting these concentrations: they spanned a wider range of emissions than used in the SRES; climate modelers could distinguish these concentrations in their models; and at least one integrated assessment model had published results reaching that concentration. Ebi stated that the four concentrations chosen are termed the Representative Concentration Pathways (RCPs) because they are representative of the full range of possible emissions over the coming century. The RCPs incorporate the full basket of greenhouse gases, including short- and long-term species such as methane and carbon dioxide, land use, and other factors. The RCPs also offer finer-scale descriptions of emission pathways that will be useful for impact modelers. The RCPs are measured in radiative forcing in 2100, in watts per meter squared. The four RCPs are RCP 2.6, 4.5, 6.0, and 8.5. RCP 2.6 is a peak and decline pathway, with a peak in emissions by mid-century, followed by a decline that leads to negative emissions by 2100. In 2100, radiative forcing is approximately 450 parts-per-million (ppm) carbon dioxide equivalent. RCP 4.5 is a stabilization pathway, with stabilization after 2100, and with radiative forcing in 2100 of approximately 650 ppm carbon dioxide equivalent. RCP 6.0 also stabilizes after 2100, with a radiative forcing in 2100 of approximately 850 ppm carbon dioxide equivalent. RCP 8.5 has the steepest increase in emissions, with radiative forcing of approximately 1370 ppm carbon dioxide equivalent in 2100 and no stabilization. Some earth system models extended these emissions to 2300, leading to an improved understanding of the speed at which a decline in emissions would affect global mean surface temperature. One of the insights gained is how slowly radiative forcing would change over hundreds of years once emissions are reduced.
GLOBAL CLIMATE CHANGE SCENARIOS 49 An insight gained from the SRES and confirmed in the work developing the RCPs is that any particular emission concentration can be reached from a wide variety of socioeconomic development pathways, said Ebi. Population and gross domestic product (GDP) are not strong predictors of emissions. A world with a small population that burns large amounts of coal could have high emissions, while a world with a large population that uses strictly green technology could have low emissions. With that in mind, it was decided that the new scenarios would be developed using a matrix approach. The matrix includes the RCPs and shared socioeconomic pathways (SSPs). Combining a RCP with a SSP forms a scenario. This approach allows scientists to ask new questions, such as what would happen if a world on track for 6.0 watts per meter squared in 2100 interacts with a world that is trying to achieve sustainable development versus a world that is more regionally focused. Or, what could be the impacts in a world continuing current development trends if there is a large or smaller amount of climate change. In essence, the scientific community is being provided with a toolkit to develop scenarios focused on addressing a wide range of research questions. Ebi emphasized that although this is complicated, it is worthwhile to gain a basic understanding of the process to be able to provide more useful input to policy questions. One example provided by Ebi was a question involving malaria that could be answered using the new scenarios: if the world is making progress toward sustainable development, then what might be the burden of malaria attributable to climate change under different RCPs? SSPs are situated along two axesâone axis focuses on worlds with increasing challenges to adaptation to climate change. The second axis describes worlds with increasing challenges to climate change mitigation. Ebi noted that these axes were chosen because adaptation and mitigation are the two main policy responses to climate change. Challenges to mitigation include high demand for energy resources, a fossil-dominated supply, and slow technology change. Adaptation challenges are concerned with development, and include low economic growth, poorly engineered infrastructure, and barriers to trade. Five SSPs are being developed, currently unnamed. As shown in Figure 4-3, SSP 1 describes a future world with low challenges for mitiga- tion and adaptation; this represents a world working toward sustainable development. SSP 3 describes a future world with high challenges to adaptation and mitigation; this world would have weak international institutions and potential conflict, said Ebi.
50 INCLUDING H EALTH IN GLOBBAL FRAMEWORRKS FIGURRE 4-3 Shared d socioeconomiic pathways (S SPs). SOURC CE: OâNeill et al., 2013. Rep printed with per ermission from Springer Sciennce and Business Media. Eaach SSP inclu udes a brief narrative n that offers a broaad vision of tthe future,, including lim mited inform mation about hhealth, and quuantification of populaation, urbanizzation, rates of o technologiical change, iincome, hum man develoopment index x, income disttribution, andd more. Ebi eexpressed hoope that this toolkit can be extended to t provide infformation neccessary to creaate scenarrios focused ono regions and d sectors. urther information on the new scenarioo approach aand the SSPs is Fu forthcooming in two o academic jou urnals. An isssue of Climattic Change w will featuree 4 papers thaat lay out the framework f deescribed in thhis presentatioon, plus 10 additional papers p discusssing variouss aspects of thhe approach. A special issue of Glo obal Environmental Channge will incluude a paper thhat detailss the full narraatives for shared socioeconnomic pathwaays. Ebbi discussed how the SSP Ps and new scenarios couuld be used to project the impacts of climate ch hange on heallth. For exam mple, in SSP1 (a world working tow ward sustainaable developm ment), more children wouuld survivee to the age of 5, and majorr public healthh problems likke malnutritioon, diarrheeal disease, and malaria would be bbetter controllled. However, chroniic diseases would w be morre prevalent, although beetter control of
GLOBAL CLIMATE CHANGE SCENARIOS 51 various air pollutants would reduce the burden of air pollutionârelated mortality and morbidity. SSP 3 (high challenges to adaptation and mitigation) would be a regionalized world with weak international institutions, said Ebi. The burden of climate-sensitive health outcomes would be expected to rise, with greater challenges to controlling malaria, diarrheal disease, and other public health problems that require global collaboration through international bodies like the World Health Organization. The International Committee on New Integrated Climate change assessment Scenarios (ICONICS) is the group of scientists working on developing these scenarios, of which Ebi is a co-chair. Within ICONICS are six working groups developing aspects of the SSPs and new scenarios (e.g., narratives, nested scenarios across geography and time). Their website offers further information on these new climate change scenarios and will provide information on accessing relevant scientific papers when available (https://www.isp.ucar.edu/iconics [accessed October 7, 2013]). REFLECTIONS ON SCENARIO PLANNING Marc Levy Deputy Director, Center for International Earth Science Information Network, The Earth Institute Columbia University Marc Levyâs presentation focused on the quantitative challenges to implementing the scenarios outlined by Ebi. Levy articulated three difficult questions the community encounters in developing quantitative indicators for climate change scenarios: 1. What needs to be included? 2. How to get the variance right? 3. How to get the dependencies right? These questions provide a sense of what has to happen in order to better characterize future vulnerability to climate change, said Levy. In regard to the first question, the scenarios developed earlier in the SRES do not adequately specify the kinds of conditions that will shape the degree to which future societies are vulnerable to climate change. The relationship between climate change and various health outcomes is
52 INCLUDING HEALTH IN GLOBAL FRAMEWORKS not simple and one-to-one; thus, a model in which physical aspects of climate change (e.g., temperature and precipitation change) lead to human impacts such as changes to food security or health outcomes would not be sufficient. Socioeconomic conditions mediate the outcomes between the physical drivers of climate change and human society, said Levy. The goal in developing a model is to identify the most important set of measurable socioeconomic parameters that will play the biggest role in discriminating between areas of high vulnerability and low vulnerability, given a common set of physical stressors. One step in doing this would be to narrow down the set of highest-priority socioeconomic variables. In an effort to identify these variables, an expert survey was conducted within the climate change community. The results yielded a high-priority list of variables considered to be the most important for understanding climate impacts: per capita income, quality of governance, extreme poverty, coastal population, water availability, urbanization, educational attainment, and innovation capacity. More specific and focused scenarios may require additional elements. Levy acknowledged that very few of these socioeconomic variables have been specified in any satisfactory manner in the existing family of climate scenarios, which presents a significant challenge. Past analyses have had to resort to assumptions that these socioeconomic variables would remain constant into the future. Levy stated that processes are under way to populate quantitative databases over time and space with most of these additional socioeconomic indicators. Some indicators are more simple to quantify than others; for example, innovation capacity has proven more difficult to quantify than something like water availability. Innovation capacity may be an example of an indicator that is evaluated purely in a narrative form. The second big question is how to get the variance right. In the past, analyses have tended to degrade the specification and the variance over time and space. Over time, linear or monotonically increasing trends tend to be forgotten. Variations from country to country, region to region, and city to city are often dampened, and the differences may be lost in socioeconomic scenarios, said Levy. The scenarios community, however, seeks to evaluate what kind of spatial and temporal variability is appro- priate for the kinds of questions that climate change scenarios hope to answer. The process of generating quantitative indicators now is different from how the SRES was carried out. SRES scenarios all assumed rapid
GLOBAL CLIMATE CHANGE SCENARIOS 53 reduction in cross-national income inequality; however, the variance based on historical data does not predict such a trend. Health researchers in poorer regions have rejected the SRES scenarios because in them is embedded an artificial and unrealistic assumption of rapid growth in per capita income, stated Levy. Current efforts attempt to be more sensitive to the variance that matters in scenarios, which remains a challenge. When a group of mainstream economic modelers from the Organisation for Economic Co- operation and Development (OECD) projected future income based on observed data for inequality of per capita income across countries, the models persisted in showing a rapid reduction of inequality across countries in these scenarios (see Figure 4-4a). The models used economic theory and data to project future income, but a problem is that the economic models often assume that investment flows to the areas in which capital is scarce and hence (according the models) the return on investment is highest. However, that is not the way the world has worked, so the yielded results are not fit for the purpose of these scenarios. Other methods have been able to develop the right kind of spread. Summary indicators developed by the International Institute for Applied Systems Analysis (IIASA) have been able to show a continuation in one scenario of high levels of inequality, which allows one to use the scenario for examining the impact of climate change on societies in a world that is assumed to maintain high income inequality (see Figure 4-4b). The third big question from Levy is how to correctly specify the dependencies across the quantitative elements in a scenario. A review of past practices has revealed that this results in challenging tensions. Although scientists want the quantitative relationship among the elements to represent as accurately as possible the state of knowledge about how these things get together, new vulnerabilities may emerge that could impose unwanted determinism in those dependencies. For example, if urbanization rises with income, it would be desired to have indicators that reflect that. However, if infrastructure also increases with income and that is reflected, it may not be possible to have scenarios where rich countries have deteriorating infrastructure to understand the implications for that vulnerability. If there are too many assumptions, these critical vulnerabilities may be missed, said Levy. The best recommended practice is to make these tradeoffs explicitly and transparently, with careful attention to relevant risks. Scenario exercises at the local level tend to do a better job of this, stated Levy,
54 INCLUDING H EALTH IN GLOBBAL FRAMEWORRKS a b FIGUR RE 4-4 Future income i scenarios based on obbserved data forr inequality of pper capita gross g domestic product (GDP)) across countriies from the (a)) Organisation for Econom mic Co-operatio on and Develop pment (OECD) and (b) Internattional Institute for Appliedd Systems Anallysis (IIASA). SOURC CE: Levy, 20133.
GLOBAL CLIMATE CHANGE SCENARIOS 55 because they are more sensitive to the many ways that different factors could interact to generate risk. In summary, Levy reported that the baseline condition for incorporating new quantitative indicators is not ideal. There are currently no quantitative scenarios that reflect the phenomena that matter the most for climate change projections, but hard work is being done to implement them. Over the next few years, Levy expects to see high-quality, usable quantitative indicators on income, spatial population, inequality, governance, and health. Variance, which has previously been ignored, is now being considered. Dependencies are being better represented, and there are good examples that exist on a local scale, where communities are carrying out scenario exercises that show intelligent ways to handle the tensions described above. Globally, however, this is not yet being done well, and requires new experiments. Getting these dependencies right is important for bringing together the climate and health communities, said Levy. Health is a background condition that could shape the relationship between climate and other dependencies, such as poverty. In turn, health impacts from climate change will differ based on characteristics of the population. Levy stated it is especially important to understand the intents of actions in response to climate change, and to consider these dependencies in future scenarios. ENGAGING KEY PARTNERS AND INSTITUTIONS IN DEVELOPMENT AND DISSEMINATING CLIMATE CHANGE SCENARIOS StÃ©phane Hallegatte, Ph.D. Senior Economist, The World Bank The process of developing scenarios for climate change is ongoing and will not end in the near future, said Hallegatte. As scenarios are improved, communities will hopefully get engaged and will help develop their scenarios from a user point of view. Hallegatteâs presentation focused on the future of climate change scenarios, and who will need to be engaged to improve their utility. Three issues need to be addressed in developing new SSPs for climate change scenarios. The first issue is scale. Many existing scenarios are on a global scale, although issues of interest exist on a local
56 INCLUDING HEALTH IN GLOBAL FRAMEWORKS scale. Local scenarios will need to be developed based on existing global ones to be used in analyzing policy decisions. Most policy decisions will require local-scale scenarios, and even the well-designed global scenarios cannot address all needs, said Hallegatte. The link between global and local scenarios exists but is not a deterministic one. For example, the health impact of local pollution depends partly on global choices described in scenarios, such as oil price, availability of electric cars. But it also depends on local choices such as urban forms and availability of public transport. The impacts of natural disasters also depend on things that occur on a global scale, such as foreign aid, but also on many local choices, like the decision to build dikes. A great improvement in global governance, however, does not connect strongly to local scenarios. The hope is that in the next few years, people will take newly developed global scenarios and downscale them to the local level for their use, said Hallegatte. Eventually, it may be possible to aggregate many local scenarios into new global scenarios and compare them to global scenarios that were chosen earlier. The second issue concerns the content of scenarios, which needs to be appropriate for analyzing various policy decisions. Past scenarios were lacking necessary health information and had very little content on inequality within countries; for example, there were no details on govern- ance or the development of health care insurance. The new generation of scenarios will make progress in that direction, but Hallegatte expressed doubt that the supply side of the scenario would be able to provide the health community with all it needs to do its work. Engagement from users will be needed to identify what is required in these scenarios, which could lead to analyses beyond climate change and opportunities for the scientific community to introduce more health considerations than the scenarios currently have. Lastly, the third issue is relevance, and determining which scenarios are most relevant for a given question. Hallegatte stated that the problem is that there are many possible futures, but there can only be a small set of scenarios. In this generation of scenarios, there will be five SSPs that need to be able to be used for many research questions and policy analyses. Ideally, it would be possible to have a different set of scenarios for each research question and each policy analysis. One possible option for that is to have a dataset with many scenarios in addition to the five primary scenarios. A set of scenarios created to inform decisions on waterborne illnesses would be different in terms of land use and agricultural practices from a set of scenarios created to inform decisions
GLOBAL CLIMATE CHANGE SCENARIOS 57 on local air pollution. To answer questions about various health issues, scenarios will differ based on variables like demographics, economic conditions, or access to services, and maybe not so much in terms of availability of renewable energy. Hallegatte concluded by reiterating that there is a great possibility for various communities to engage in the scenario development process and to make sure that the process is driven by not just the producers of scenarios, but also the users. He echoed the sentiments of Ebi and Levy that the webinar provided an important opportunity for future engagement. DISCUSSION A brief discussion among the speakers and participants followed the presentations. Their remarks are summarized in this section. Mechanisms to Address the Governance of the Selection Process Balbus noted that the presentations highlighted the need to consider many different variables in a limited number of scenarios, which results in a certain amount of arbitrariness. At the same time, scientific work on climate change seeks to be as solidly based and widely accepted by the broad scientific community as possible. Given the challenge of dealing with some amount of subjectivity, Balbus asked what are the intended mechanisms within the IPCC or ICONICS to address the governance of the selection process? Ebi replied first, reminding the audience that the scientific community is leading the effort, which means that no particular body is in charge and core funding is lacking to move this process forward. The IPCC has facilitated some meetings that require at least 40 percent participation from developing countries; however, it has been a challenge to keep people engaged without sustained funding. One option going forward is called Future Earth, said Ebi, and seeing if this process could take on governance issues as a core activity. Future Earth is an organization that is replacing others moving forward, including the International Human Dimension Program, the International Geosphere-Biosphere Programme, and others that have focused on various aspects of what needs to be understood about how the future will evolve and interact with global environmental change.
58 INCLUDING HEALTH IN GLOBAL FRAMEWORKS Levy added two additional points. The first is that the simple act of generating five SSPs means that it will be possible to do scenario analysis on climate impacts using a set of five reference scenarios, which will make the results comparable in a meaningful way. The second point is that nobody is going to be satisfied with only using those reference scenarios, and people will likely tinker with them as desired. In addition to the reference scenarios, the community needs a set of methods for documenting deviations from the scenarios in a simple and transparent manner so that users can understand how the scenarios differ. Hallegatte noted that the community is trying to achieve a lot with these scenarios, but at the same time, trying to tailor scenarios to certain questions. He acknowledged that the five scenarios will not be able to meet all the needs and will probably need to be complemented by other models and narratives. The scenarios will only be one piece of the puzzle, and what is needed right now is more engagement. Potential Use of Climate Change Scenarios in the Health Community Carlos Santos-Burgoa thanked the speakers and commented on the potential use of scenarios in the health community. He suggested other assumptions about health that could be included in a scenario, such as the prevalence of chronic diseases and access to universal health coverage. Assumptions of risk from disease or lack of coverage would be desired in a scenario for health. Ebi responded by saying that she was excited for the opportunity to engage the health community through this webinar, and that trying to quantify the health sector remains a challenge. Although the health community has struggled to develop future projects, the SSPs may be useful for examining health issues, like the burden of childhood mortality or chronic disease in the future. Ebi noted that the agricultural sector is developing scenarios as well, and there could be an opportunity in working with them on issues like food security. Linking Social Determinants of Health and Climate Change Scenarios A member of the audience asked how the social determinants of health should be approached around or within climate change scenarios, and to what extent are the social determinants of health assumed in the scenarios (versus something that is an output of the models).
GLOBAL CLIMATE CHANGE SCENARIOS 59 Ebi responded that the variables placed in SSPs are those that will be important for projections of impacts or for looking at adaptation and mitigation policies. As an input, the social determinants of health would need to be quantified. She noted that it is important to have projections for them out to at least the year 2050 to better inform the modeling work that will provide information on the impacts of climate change. Hallegatte commented that everything in the SSPs is an input or an output. Health and other factors, such as GDP, can be both inputs and outputs, which makes collaboration among sectors vital. Predicted Health Impacts of Climate Mitigation Initiatives The final question from the audience asked if models can predict the health impacts of major kinds of climate mitigation initiatives, policies, or movements; e.g., if the United States stopped using gasoline to power vehicles in favor of hydrogen fuel. Balbus replied that these are exactly the kinds of questions that the integrated assessment models were created to explore. He noted that the webinar focused on how to provide the scientists working with these models with the best information about global health in the future, which can be incorporated into the models and be used to create more accurate assessments of climate change mitigation and adaptation efforts. REFERENCES IPCC (Intergovernmental Panel on Climate Change). 1993. Climate change 1992: The supplemental report to the IPCC impacts assessment. Canberra, Australia: Australian Government Publishing Service. IPCC. 2000. Special report on emissions scenarios. Prepared by Working Group III of the Intergovernmental Panel on Climate Change. Cambridge, UK: Cambridge University Press. Levy, M. 2013. Incorporating quantitative elements into socioeconomic narratives and scenarios. Presentation at the Institute of Medicine Webinar on Health in the Context of Global Climate Change, Washington, DC. Met Office. 2013. Met Office delivers new climate simulations to international modeling activity. Available at http://www.metoffice.gov.uk/research/news/ cmip5 (accessed October 7, 2013).
60 INCLUDING HEALTH IN GLOBAL FRAMEWORKS OâNeill, B. C., E. Kriegler, K. Riahl, K. L. Ebi, S. Hallegatte, T. R. Carter, R. Mathur, and D. P. van Vurren. 2013. A new scenario framework for climate change research: The concept of shared socio-economic pathways. Climatic Change. doi:10.1007/s10584-013-0905-2.