Global Climate Change and Extreme Weather Events: Understanding the Contributions to Infectious Disease Emergence: Workshop Summary (2008)

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

4 Policy Implications of the Health Effects of Climate Change and Extreme Weather Events OVERVIEW The urgent question of how to act on what is known—or even suspected— about the potential health consequences of climate change, which underscored discussion throughout the workshop, is taken up explicitly in this chapter. The first paper, coauthored by speaker Douglas MacPherson of McMaster Univer- sity and Migration Health Consultants, Incorporated, focuses on the complex, two-way association between climate change and human mobility and its role in infectious disease emergence. The authors discuss the burgeoning influence of human mobility and migration on infectious disease emergence and describe a variety of ways in which interactions between climate and human behavior shape infectious disease dynamics, from the cataclysmic repercussions of extreme weather events to the slowly evolving impacts of increasing temperatures, sea level rise, and decreasing freshwater availability. If, as expected, climate change drives the simultaneous emergence of multiple infectious diseases along many possible pathways, the authors observe, preventing the global spread of individual pathogens is unlikely to be feasible. Therefore, they argue, “mitigation efforts and the policies that guide them will need to become more process-related and anticipatory rather than outcome-based and reactive.” The development of such policies is fraught with challenges, as described in the chapter’s second paper by Diarmid Campbell-Lendrum of the World Health Organization (WHO). He notes that some of the obstacles to creating international public health policies to address the implications of climate change are intrinsic to the health sector and its long-standing focus on single-disease threats, rather than “systemic and long-term stresses” that produce a broad range of health effects. 219 

220 GLOBAL CLIMATE CHANGE AND EXTREME WEATHER EVENTS Within this spectrum of potential impacts, Campbell-Lendrum emphasizes “rou- tine” health threats such as diarrhea, malnutrition, and malaria that are known to be climate sensitive, and the value of basic public health interventions (e.g., providing clean water and sanitation services, improving hygiene) as a means to reduce overall disease rates and to moderate the potential effects of climate change. This is the position taken by WHO, which has evolved from assessing the health risks associated with climate change to an increasingly operational role in addressing these risks; Campbell-Lendrum discusses the organization’s primary objectives in this area, which include raising public and political aware- ness of climate change, promoting health through climate change mitigation, and strengthening health systems to manage the additional burden imposed by climate change. Due in large part to its predicted far-reaching effects on health, climate change is viewed as a potentially powerful agent of geopolitical upheaval. At its summit in March 2008, a paper presented to the European Union included a grim catalog of threats to international security posed by climate change: conflicts over water, energy, and other increasingly scarce resources; loss of infrastructure and territory; border disputes; environmentally-induced migration; and political tension at all levels of governance (European Commission, 2008). These themes were taken up by Major General Richard Engel (U.S. Air Force, retired), National Intelligence Council (NIC) deputy national intelligence officer for science and technology, in his workshop presentation, which described efforts under way to conduct a National Intelligence Assessment (NIA) concerning the challenges posed to national security by global climate change over the next two decades. Although NIAs inform decision making at the highest levels of the U.S. government, Engel noted that the NIC intends to prepare this assessment as an unclassified document—a goal that he characterized as “increasingly chal- lenging” to meet. The classified NIA entitled National Security Implications of Global Climate Change Through 2030 was delivered to Congressional requestors in mid-June 2008. The NIC has chosen to evaluate the potential impacts of climate change on the four classical elements that comprise national power: geopolitical power, military power, economic power, and social cohesion. To date, the NIC has received considerable nongovernmental expert opinion on this issue from a vari- ety of sources including the Joint Global Change Research Institute, a partnership between the University of Maryland and Pacific Northwest National Laboratories; the U.S. Climate Change Research Program, an interagency group within the U.S. government; the Center for Naval Analysis; the Center for International Earth Sci- ence Information Network at Columbia University; Arizona State University; the RAND Corporation; the Global Business Network; and the Center for Strategic and International Studies. Engel emphasized that he had crafted his remarks from these “outside views” as they have been received—but not fully evaluated—by 

POLICY IMPLICATIONS 221 the NIC. The NIC and the intelligence community have yet to complete their own analysis and interpretation of these contributions. Inherent uncertainties in predicting the course of climate change prompted the NIC to consider a “system vulnerability approach” for this assessment, which identifies existing internal vulnerability of states or regions of interest to U.S. security, then examines how the added stress of climate change could affect these states or regions. This process, with input from outside experts, has identified Africa as particularly vulnerable to the effects of climate change, Engel noted. Most immediately, the region is ill-equipped to deal with water shortages due to persistent poverty and to the number of agriculture-dependent states with weak governments. Experts advising the NIC have predicted that climate change will produce water issues and damaging weather extremes, such as the flooding of major coastal cities, in North America and Asia; stress on marine ecosystems in Asia and Australia; flooding and heat waves in Europe; both flooding and drought in South America; intensification of drought in Australia; and increas- ingly extreme environmental changes at the world’s poles. In addition to these climate change scenarios, which Engel characterized as “middle of the road,” the NIC is considering the implications of unlikely but disastrous “threshold” events, such as the collapse of major ice sheets in Antarc- tica and Greenland or the stopping, slowing, or reversal of patterns of circula- tion in the North Atlantic current of the Gulf Stream, which provides warmth to Europe. There may also be yet-unidentified feedbacks within the climate system that could amplify the changes caused by greenhouse gasses alone. On the other hand, Engel noted, experts have identified a few sources of potential overesti- mates of the effects of climate change, including assumptions that interventions will not be introduced to mitigate the process or its consequences. He concluded that while the best estimates of future warming represent an average, the potential for greater-than-expected warming has not been well defined. Climate change has the potential to create geopolitical divisions, several of which have already been reported in the global press. “Developed countries want the developing countries to participate so they don’t bear the full burden [of the cost of addressing climate change], and the developing countries want the developed countries to pay for it,” Engel observed. Experts have reported to the NIC that a north-south division even exists within Europe, resulting from the varied effects of climate change along this axis. The differential effects of climate change in regions of Asia—where some areas may suffer droughts, while others flood—may also prove a source of tension, particularly where water is concerned. Such situations, although removed from the United States, have the potential to compromise national security due to their influence on economic partners or security allies or by creating chaos that requires a U.S. response, thereby con- suming national resources. The NIC’s expert consultants agree that actions taken by the United States will profoundly influence the fate of a global consensus on 

222 GLOBAL CLIMATE CHANGE AND EXTREME WEATHER EVENTS climate change and, thereby, the nature and location of geopolitical fault lines in the coming decades. INFLUENCES OF MIGRATION AND POPULATION MOBILITY Douglas W. MacPherson, M.D., M.Sc. (CTM), F.R.C.P.C., McMaster University and Migration Health Consultants, Inc. Brian D. Gushulak, M.D.2 Migration Health Consultants, Inc. Introduction The slow and evolutionary migration of the human race out of Africa (Mayell, 2003; Read, 2003) was associated with a parallel movement of hominoid diseases, including those associated with or produced by human interaction with microbial life. The infectious diseases we carried and the new microbial agents that were encountered during this primordial migration have very much contributed to the evolutionary development of the human race. The slow and evolutionary process of population mobility driven by expedient “push” forces of available food and water supply, environmental events, physical hazards, and predation, were com- bined with corresponding “pull” factors of exploration, conquest, environmental suitability, and human curiosity. During the last 50 years the greater availability of inexpensive local and international transportation has taken place in an environment of increased trade, expanding global economies, and greater use of telecommunications systems. Together they have heralded a new era of population mobility. The modern era of mobility is associated with several factors that affect the international disper- sion of human disease events, the diversity of populations, and disparities across the determinants of health. These factors include the magnitude of populations, associated goods, and conveyances on the move; the range of the population demographics and biometric characteristics of those moving (often across signifi- cant historical boundaries of disease prevalence); and the continuity (from local to international) of processes associated with these movements (MacPherson and Gushulak, 2001). The categorization and quantification of modern mobile popula- tions provides insight regarding the significance of human movements across the sociological aspects of health and disease (see Table 4-1; DoJ, 2005; Hinrichsen, 1999; ILO, 2006; UNHCR, 2007).   Department of Pathology and Molecular Medicine, Faculty of Health Sciences, Hamilton, Ontario, Canada.   Cheltenham, Ontario, Canada/Singapore. 

POLICY IMPLICATIONS 223 TABLE 4-1 Mobile Population Characteristics and Estimated Annual Magnitudes Magnitude (annual Place Process Population estimates) Local to regional Temporary Commuters Billions Bombay: 6.5 million commuters daily Internally displaced 24.5 million persons Permanent Rural to urban 50% (developing nations) to 70% (developed nations) world population Inland to coastal 3.2 billion (<200 km) 4.0 billion (<400 km) Regional to Temporary Tourists, VFR 802 million international Business travel (Included in 802 million) Workers 86 million globally 49% international work- ers are women Permanent—regular Immigrants 191 million Refugees 9.9 million Humanitarian 100,000 (est.) Permanent—irregular Refugee claimants or 596,000 (plus asylum seekers 740,000 pending determination) Trafficked 900,000 (est.) Smuggled Unknown Stateless people 5.8 million NOTE: VFR = visiting family and friends. The association of human population mobility with global climate change and adaptation can be viewed through two lenses. The first is related to the total population number and spatial density of human beings on the planet and the associated energy requirements necessary for individual-to-communal growth and development. This association is supported by the Third Assessment Report (2001) of the UN’s Intergovernmental Panel on Climate Change (IPCC), which noted, “There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities” (IPCC, 2001). Atmo- spheric concentrations of energy-trapping gases are an essential part of the natural greenhouse effect that makes the Earth habitable. Global warming is arguably a consequence of increasing accumulation of human-generated atmospheric green- house gases (GHGs). The excess amounts of GHG observed today consist prin- cipally of carbon dioxide generated from fossil fuel combustion and the burning 

224 GLOBAL CLIMATE CHANGE AND EXTREME WEATHER EVENTS of forests. There are other heat-trapping gases associated with human activities, including methane associated with irrigated agriculture, animal husbandry, and oil extraction; nitrous oxide; and human-made halocarbons. Sustained population growth and development are accompanied by parallel growth in several of these activities, and increased population mobility supports their concomitant move- ment to new geographic areas. The magnitude of “what” the world’s human population is doing is com- plicated by “how” we are doing it. The linkages between and among human energy requirements and the global census accompanied by the push-pull factors behind human movement reflect the development of modern transportation and transportation systems. As surrogate markers of the impact of human activities on global climate change, the rate of change of population movements, the changing nature of human activities during the last 50 years, mobility, and transportation can all be linked to the creation of GHGs that contribute to global climate change. At the same time, those three factors also generate secondary influences on the distribution and epidemiology of infections through ecological change, contigu- ous extension of microbial and vector geographic patterns, and the incidental introduction of infectious diseases as a consequence of the movement of goods, conveyances, and people. The second lens through which to view global climate change and population mobility is provided by examination of the changing physical environment and the potential for extreme weather events to provoke or generate secondary adap- tive population movements. It is through this latter lens that this paper outlines the links between population mobility and the nature of emerging and reemerg- ing infectious diseases that are associated with or result from climate change or extreme weather events. This dynamic interaction between population mobility, infectious diseases, and climate change or extreme weather events is approached by reviewing the factors and forces in the following framework: 1. The establishment of new, noncontiguous prevalence zones of infectious diseases, or the “skip” pattern of diseases, introduced by population mobility 2. The temporary movement of populations from low to higher infectious disease prevalence zones for humanitarian, business, or recreational purposes 3. The slowly evolving ecological impacts of environmental change that either force or attract population movement and the classical determinants of health 4. The precipitous and forced movement of people due to extreme and sud- den weather events that result in new ecological niches that support newly arrived populations with diverse infectious disease conditions 

POLICY IMPLICATIONS 225 Evidence-Based Approach to the Adaptive Features of Population Mobility and Changes in Prevalence of Infectious Diseases Due to Climate Change or Extreme Weather Events It has been suggested that there are three categories of research into the association between climatic conditions and infectious disease transmission. The first link examines evidence from the recent past of associations between climate variability and infectious disease occurrence. The next looks at early indicators of already-emerging infectious disease impacts of long-term climate change. The third link uses the above evidence to create predictive models to estimate the future burden of infectious disease under projected climate change scenarios (WHO, 2003a). A fourth perspective on research in this area involves the linkage between human determinants of health (socioeconomic status, biology and genetics, envi- ronment, and behavior) and considers their contribution to global climate change and the impact on infectious diseases. Approaching the issues in this context allows human mobility and migration to be considered as a determinant of health that is directly linked to the globalization of microbial disease threats and risks. Transportation and transportation systems have been identified in the Fourth Assessment Report of the IPCC, released on November 16, 2007, as an impor- tant contributor to global climate change (IPCC, 2007). Frameworks similar to those that frame the processes and associated policies on transportation—for example, agreements, regulations, inspections, or data sharing between regional authorities—are mirrored in the modern approaches to international trade, eco- nomics, environment, and health. The modern relationships between global transportation, trade, travel, and migration also provide opportunities for the introduction of transmissible disease risks between previously separated preva- lence zones. Disease prevalence zones can be defined as regions of disparate epidemiological prevalence demarcated by geophysical, sociopolitical, environ- mental, biological or genetic, or behavioral characteristics, either alone or in combination. Relationships Between Population Mobility and Global Infectious Disease Epidemiology Human population mobility can affect the global distribution of infections through either chronic, sustained, or acute short-term processes. Either of these situations allows for or supports the establishment of new, noncontiguous preva- lence zones of infectious diseases—what in this paper are called “skip” patterns of disease extension. This is often associated with what can be conceived as sustained, chronic mobility. The association between the international move- ment of infectious diseases and the risk of transmission or introduction of novel infectious diseases in nations or global regions where the diseases have been non- 

226 GLOBAL CLIMATE CHANGE AND EXTREME WEATHER EVENTS endemic or of very low prevalence is an issue of increasing importance in both public health and clinical care settings (Gushulak and MacPherson, 2000). The contribution of global warming and climate change to these events may be more indirect than in the past, but the relationship between population movement and disease introduction is an important aspect of human history. Examples originate with the beginning of historical records and include descriptions of the Athenian plague of 430 B.C.E. and the Justinian plague of 542 A.D. (Smith, 1996). The threat of newly introduced infections and the risks associated with those introduc- tions provided the foundation for the traditional, quarantine-based approach to international travel and public health associated with human development until the last century (Yew, 1980). From an international health policy perspective (MacPherson et al., 2007), there is continued attention to the risks posed by the acute arrival of some regu- lated infectious diseases, in a manner similar to public health control programs of the mid-nineteenth century (WHA, 2005; see next section). Additionally, greater attention is paid to the broader global epidemiological implications of popula- tion mobility and infectious diseases of importance to the health of the public. Several health authorities in regions where diseases have been of low or very low incidence report increasing burdens of infectious diseases related to foreign-born or foreign residents. Examples include tuberculosis (Health Protection Agency, 2007), syphilis (MacPherson and Gushulak, 2008), HIV/AIDS (MacPherson et al., 2006; Zencovich et al., 2006), and multidrug-resistant organisms (Maurer and Sneider, 1969; WHO, 2006). The Temporary Movement of Populations from Low-Prevalence to Higher Infectious Disease Prevalence Zones for Humanitarian, Business, or Recreational Purposes Can Acutely Affect Infectious Disease Epidemiology Examples, including cholera in Peru arriving in the United States (Eberhart- Phillips et al., 1996), plague in India (Mittal et al., 2006), falciparum malaria in India (Das et al., 2007), severe acute respiratory syndrome (SARS) in Asia and Canada (WHO, 2003b), and avian influenza spreading from Asia to Europe and Africa (WHO, 2008), link the risks of regional events or outbreaks to the potential for international spread via the movement of people, goods, and conveyances. For the majority of these examples, the focus is on the microbial agent rather than the human factors. For each of the above noted situations through which population mobility can affect the global spread of infectious diseases, the role of environmental factors in relation to the events has often not been examined explicitly. More recently pub- lished explorations discussing the globalization of infectious diseases have made the components of international movement of infectious diseases part of the study design (Angell and Behrens, 2005; Leder et al., 2006), but there is still limited focus on the relationship between the environment and human mobility in this context. This relationship is an issue that requires study because the local environ- 

POLICY IMPLICATIONS 227 ment, itself a product of climatic features, is a contributing factor influencing both the mobility of populations and the infectious diseases that afflict them. The Relationship Between Slowly Evolving Ecological Impacts of Environmental Change and the Forces That Create the Push or Pull of Population Movements The ends of the population distribution, representing economically advan- taged populations and highly vulnerable populations, are often most directly affected by local environmental impacts related to climate change. As noted above, tourism and other voluntary and usually temporary population movements, all associated with economic capacity, have the potential to bring individuals from low-risk regions into diverse environments that may also represent greatly enhanced risks for acquired infectious diseases (Fenner et al., 2007; Pistone et al., 2007; Sejvar et al., 2003). Climate change has the potential to significantly affect travel and mobility of this type. At the other end of the population distribution are the most vulnerable populations, where the concept of being an environmental refugee is emerging as a driver for displacement (Meyers, 2002). Most extremely, desertification and coastal flooding are examples of climate change impacts on local environments that will affect the most disparate and at-risk populations of the world (Black and Sessay, 1998; Rashid et al., 2007). The choices for local populations under these circumstances are very limited and are associated with internal displacement, international displacement as refugees, or refugee claimants/asylum seekers; complex humanitarian emergency evacuations (Coninx, 2007); or nefariously trafficked or smuggled persons. As the global distribution of populations moves from rural to urban settings, where the majority of the world’s largest cities are found in lowland coastal environments, the potential for environmental shifts—whether slowly evolving or as a result of disastrous events—is likely to result in the displacement of large numbers of people. Disease risks resulting from environmentally triggered or mediated move- ments can be either acute or chronic. Acute consequences of infectious disease exposure and the clinical presentation of short-incubation diseases in areas where they are of low prevalence are often the subject of study, given the proximity of infection to the time of travel. Examples include malaria, influenza, cholera, and yellow fever, among others. Additionally, diseases with long incubation or latency periods are imported by mobile populations into low-incidence locations. Due to the natural history of these infections, they may have been acquired long before the time of the environmental event related to population movement. Examples include tuberculosis, HIV, and the nontransmissible sequelae of chronic infec- tions, such as human papilloma virus (HPV) associated cervical and esophageal cancer. 

228 GLOBAL CLIMATE CHANGE AND EXTREME WEATHER EVENTS The Precipitous and Forced Movement of People Due to Extreme and Sudden Weather Events The link between global climate change and extreme weather events, such as high winds, extremes of temperature or precipitation, or such events occurring in combination, may be questioned, but the consequences of extreme weather events on human health can be measured. It has been common to measure the health consequences of severe environ- mental events using the residual health infrastructure that has survived the event. This is frequently the case for the public health surveillance of diseases. As a consequence, the situations producing the most information are those that have resulted in areas where the infrastructure is most robust. This explains in part why the health impacts of Hurricanes Katrina and Rita on the southeastern United States (CDC, 2006a,b; Elledge et al., 2007) cannot be compared to Hurricane Georges’s (O’Leary et al., 2002; Sanders et al., 1999) effects in Central America and the Caribbean. Almost certainly because the direct physical consequences of Hurricane Katrina affected a major urban center in the United States, the existence of a highly sophisticated social environment with considerable robust- ness and response capacity during emergencies was more permissive of several measurements of infectious disease outcomes being sought in both the displaced persons and the responders (CDC, 2005, 2006c; Corbin et al., 2007; Rao et al., 2007; Sevbold et al., 2007; Yee et al., 2007) compared to other weather-related catastrophes in the region. The long-term health consequences of extreme weather events, particularly the infectious disease outcomes in affected or dispersed persons, are much more difficult to quantify. Tracking an individual over time and place, recording the changing administrative status from displaced person to returnee or from refugee to permanent resident, poses significant challenges to the way surveillance data are currently managed. As rural to urban migration increases globally and as many of the mega- cities of the world are located at or near coastal regions, the impact on population placement due to global climate change and extreme weather events can only be expected to be of greater magnitude and associated with a higher risk of disease outcomes. Policy Implications Related to Population Mobility, Climate Change, and Infectious Diseases Recognizing the relevant linkages between population mobility, climate change, and infectious diseases, and being able to address them at a program- matic level, require policy responses that are informed, robust, and feasible and extend across a spectrum from local to international scope. Existing methodologies used by some nations, such as the medical screening 

POLICY IMPLICATIONS 229 and health assessment of immigrants and refugees for transmissible infectious diseases of public health significance, are feasible in some situations. They may not be transferable between health jurisdictions or applicable in situations involv- ing other types of mobile populations. For example, climatic events precipitating large population movements may themselves be of magnitudes that exceed the capacity to mitigate or prevent the introduction of infectious diseases. Very large movements, such as seen in the Americas during school winter breaks, when thousands of people move to warmer regions for vacations, may overwhelm the existing local public health detection systems originally designed for the host population. This can be particularly true for diseases that are not part of routine or anticipated surveillance designs, such as mumps in what is believed to be an immunized population (Peltola et al., 2007). Lack of anticipatory capacity is much greater with other types of population mobility. Humanitarian movements by nature include a balance between the expected benefit and potential risk result- ing from the movement. Depending on the characteristics of the population itself, the local environment, and the nature of the physical journey, the potential for novel disease introductions related to the movement may fall into the “unknown unknowns” category of impossible planning challenges. Further complicating policies to mitigate the infectious disease risk associated with mobile populations are the indirect associations with other disease-related processes. Food production environments, the processes of food management and safety, may all be subject to local influences that can affect the risk of disease. The increasing dispersion both regionally and internationally of nutrition also has disease implications (FDA, 2007a,b). Bio-adaptive responses to climate change, particularly those that involve the movement of conveyances, goods, and people, have implications for infectious disease management, including training, education, maintenance of competence, surveillance, notification, reporting systems, and consideration of multiple ­layers of service providers from border inspectors to traditional and nontraditional health services providers such as doctors, nurses, pharmacists, and linguistically or culturally aligned healers. The resulting challenges will be particularly daunting for policy and deci- sion makers. Increasing global mobility across all sectors involving people, goods, and the conveyances themselves is increasingly associated with movement across gradients of individual, population, and public health determinants. These determinants, represented by biological, genetic, environmental, socioeconomic, and behavioral characteristics of the populations on the move, are themselves dynamic and interactive. While many health prevention and mitigation strategies recognize that there are disease risks associated with travel across these gradients, they tend to con- sider the mitigation of these risks through historically conceived disease control and prevention policies. Given the scope, diversity, and growing integration of current global mobility, preventing disease introduction and spread may be less 

230 GLOBAL CLIMATE CHANGE AND EXTREME WEATHER EVENTS manageable. Mitigation efforts and the policies that guide them will need to become more process-related and anticipatory rather than outcome based and reactive. Not all of the climatic implications for population mobility will be negative in context. Some positive consequences of climate change already measured include longer growing seasons and increased rains that boost yields in many temperate regions (CCSP and the Subcommittee on Global Change Research, 2008). Records show that the crop-growing season has already lengthened in the United Kingdom, Scandinavia, Europe, and North America (UNFCCC, 2008). Young forest growth is also expected to occur more productively in these regions. There is expected to be a reduction in cold weather-associated mortality that will benefit the most vulnerable populations such as the elderly, under-housed/home- less, and displaced persons (Patz et al., 2000). In addition, economic benefits are expected from increasingly accessible shipping lanes in the Northwest Passage due to longer ice-free seasons. This will reduce the human and economic costs of international shipping and trade (Environment Canada, 1999; Nickerson, 2000). These regional environmental outcomes will also be associated with increased mobility of human populations, goods, and conveyances that move to take advan- tage of new opportunities in food security, labor markets, and other forms of trade. Global climate change, extreme weather events, and infectious diseases are a complicated and complex interface involving several factors. Humans contribute to the issue, experience both the benefits and the deleterious consequences, and are the potential stewards of this dynamic interaction. How the management of global environmental systems proceeds will influence migration and population mobility and can be expected to raise new challenges to human endeavors on this planet (UNFCCC, 2007). CLIMATE CHANGE, INFECTIOUS DISEASE, AND INTERNATIONAL PUBLIC HEALTH POLICY Diarmid Campbell-Lendrum, D.Phil. World Health Organization Climate Change as a Challenge to Public Health Policy Health concerns are increasingly evident in policy discussions and media reporting on climate change. In recent years, there has also been a corresponding   The views expressed in this article are those of the author and do not necessarily reflect the posi- tion of the World Health Organization.   Department of Public Health and Environment, CH-1211 Geneva 27, Switzerland. 

POLICY IMPLICATIONS 231 increase in the engagement of national and international health agencies. For all of this emerging interest, the issue combines a range of characteristics that render policy making particularly difficult. Some of these challenges arise within the health sector. As a generalization, the traditional assessment methods used in the health sciences are designed to deal with direct, compartmentalized, cause-effect relationships resulting in indi- vidual diseases, rather than systemic and long-term stresses leading to a range of health effects. This makes it difficult both to assess and to communicate the evi- dence for either health effects that can already be attributed to climate change or the risks of health impacts that may occur as the process continues. For example, it is often difficult to make clear that for well-described methodological reasons (Kovats et al., 2001; Wilkinson et al., 2003), the empirical evidence that gradual climate change is already affecting health is limited to a few specific examples,  but at the same time, the evidence that important diseases are climate sensitive, and therefore likely to be affected either now or in the future, is overwhelm- ingly strong. Related to this, much of the effort of the health sector is applied to addressing individual diseases with specific, often curative, interventions. This tends to lead to a focus on identifying single technological tools to address new risks, with a relative hesitancy to work across sectors to address the root causes of multiple health exposures, including environmental and social determinants (Commission on Social Determinants of Health, 2007; McMichael et al., 2008). Challenges in the health sector are further amplified because the health effects of climate change lie within a broader and very complex policy debate. As an international policy issue, climate change touches on many highly conten- tious fields, including the speed and nature of economic development, energy production and security, division of obligations between rich and poor countries, population growth, and individual lifestyle choices, to name but a few. Within this policy discussion, risks to health tend to attract particular attention because they present a tangible “human dimension” of the climate change debate. Evidence for or against health risks from climate change is therefore often used selectively by parties to promote political agendas that have little to do with the health risk itself. Related to this, the public perception of health risks from climate change is filtered through media that can often tend to sensationalize stories and amplify disagreements to present polarized positions (Boykoff and Boykoff, 2004). For an example of the former, take the following headline from a recent edition of the Daily Telegraph newspaper following the release of a U.K. government report on health risks arising from climate change in Britain (Prince, 2008):   See Bouma et al. (1996); Pascual et al. (2006, 2008); Stott et al. (2004).   See reviews such as Confalonieri et al. (2007); ������������������������ McMichael et al. (2003). 

232 GLOBAL CLIMATE CHANGE AND EXTREME WEATHER EVENTS Malaria warning as UK becomes warmer: The UK is to be hit by regular malaria outbreaks, fatal heatwaves and contaminated drinking water within five years because of global warming, the Government has warned the NHS. The cited U.K. report, however, actually stated (Department of Health/Health Protection Agency, 2008): We would therefore not expect more than a very few cases of autochthonous malaria in the UK over the next 50 years. Indeed one is more likely to be struck by lightning than to get malaria from an English mosquito. In this environment, the production and clear communication of impartial, evidence-based, policy-relevant assessments becomes particularly important. Placing Climatic Influences on Infectious Diseases in Context The focus of this particular meeting of the Forum on Microbial Threats is on the potential effect of climate change on the emergence, reemergence, and spread of infectious disease. Such processes, bringing infections to new populations, have important public health implications. These include exposure of nonimmune populations that may suffer particularly high morbidity and mortality rates, as well as diversion of resources from routine endemic disease problems and, in some cases, more indirect effects, including disruption of important economic sectors such as tourism. However, it is important to place these “novel” disease threats within the context of a range of public health implications of climate change. Many diseases that are well known and not necessarily spreading rapidly are also highly sensi- tive to climate conditions. For example, time-series and cross-sectional studies in Lima, Peru, and in the South Pacific Islands have shown that rates of diarrhea morbidity are influenced by both temperature and precipitation, higher rates being associated with higher temperatures in both studies and with either particularly high or low rainfall in the South Pacific (Checkley et al., 2000; Singh et al., 2001). Even small variations in meteorological conditions can have a marked effect on such diseases. In Lima, rates of admission for acute diarrhea at a pediatric clinic were 3 to 4 times higher in the summer than in the winter and increased by 8 percent for every 1°C increase in temperature, with an additional increase during the sustained high temperatures associated with the 1997-1998 El Niño event. Such “routine” climate-sensitive diseases may attract less attention than emerging, reemerging, and spreading infections, but they are nonetheless of major importance, particularly in the developing world. For example, diarrhea kills more than 1.8 million people annually; malaria kills almost 1 million; and undernutrition (partly compounded by infections) kills approximately 3.5 million (Black et al., 2008; WHO, 2006a). These burdens are overwhelmingly concen- trated on children in developing countries. The current trend toward a warmer 

POLICY IMPLICATIONS 233 and more variable climate, with reduced agricultural production at low latitudes, is expected to increase the difficulties of combating these and other persistent health problems (WHO, 2008a). It is also essential to place the effect of climate change and climate variability in the context of other health determinants. While the evidence for meteorological effects on diarrhea is clear, other factors—most importantly, water, sanitation, and hygiene—have a very strong effect on diarrhea mortality and morbidity (Prüss- Üstün et al., 2004). Such factors not only influence the overall rate of disease, but can also moderate climate effects. There is evidence that improvements in water, sanitation, and hygiene services have a relatively greater effect on reduc- ing infections with bacterial and protozoan pathogens that tend to be favored by high temperatures, than with viral pathogens that often survive better in colder conditions. This is a likely explanation for the occurrence of winter rather than summer peaks in diarrhea incidence in more developed countries with improved infrastructure. For these reasons, separating the effects of climate variability and change from the context of other determinants, or assessing the influence of climate versus other factors as a mutually exclusive “either/or” debate, is unproductive. Instead, considering climate as one important determinant of health risks, medi- ated by other contextual determinants, is more likely to lead to sound health policy. International Developments in Health and Climate Policy Since climate change began to emerge as a major issue at the end of the 1980s, research output has steadily increased (see Figure 4-1). The WHO has been involved throughout this process. Beginning in 1990, WHO released a series of reports on the health implications of climate change regionally and globally; published methods for qualitative and quantitative assessment of health vulner- ability; and participated in major review processes, such as the production of the assessment reports of the IPCC (WHO, 2008b). In recent months, there has been rapid change in the scale and nature of the engagement of health agencies in climate change. This has included strong state- ments and dedicated policy speeches by the WHO director-general (Chan, 2007) and the selection of “Health Protection from Climate Change” as the theme for World Health Day 2008 (WHO, 2008a). This has been mirrored by similar high- lighting of the issue by major U.S. organizations, such as the American Public Health Association, the American Institute of Biological Sciences, and the U.S. Centers for Disease Control and Prevention, as well as many others internation- ally. The Member States of the Executive Board of WHO have also proposed a resolution on climate change and health to be discussed at the 2008 World Health Assembly—the first on this subject for 10 years (Box 4-1). Climate change has therefore moved firmly to the center of the international public health agenda. 

234 GLOBAL CLIMATE CHANGE AND EXTREME WEATHER EVENTS 160 140 Number of publications 120 100 80 60 40 20 0 1990 1995 2000 2005 Year FIGURE 4-1  Number of publications in PubMed referring to “health” and either “climate change” or “global warming” from 1990 to 2007. Putting Together a Coherent4-1 Figure Response to Health Risks from Climate Change This has called for a development of the field away from only describing health risks from climate change to a more serious consideration of how best to support public health policy and disease control programs to cope with this emerging threat. In line with the Executive Board resolution, WHO is reframing its support to Member States on health and climate change around three main objectives: (1) raising awareness, (2) promoting health through climate change mitigation, and (3) strengthening health systems to address the additional health risks from climate change. In terms of raising awareness, there is growing appreciation that climate change can no longer be considered simply an environmental or a developmental issue. More importantly, it puts at risk the protection and improvement of human health and well-being. A greater appreciation of the human health dimensions of climate change is necessary for both the development of effective policy and the mobilization of public engagement. A range of health agencies are now making clear that the ultimate aim of mitigation and adaptation, and related development 

POLICY IMPLICATIONS 235 BOX 4-1 The International Mandate for Stronger Action on Health and Climate Change In January 2008, the 34 Member States of the Executive Board of WHO drafted a resolution on “Climate change and health,” for consideration by the World Health Assembly, comprising the 193 WHO Member States. The draft resolution places on record the shared concern of the Member States regarding the strength- ening evidence of the effect of atmospheric greenhouse gases, and the potential negative consequences for human health, including risks to the achievement of the Millennium Development Goals and undermining of efforts to improve public health and reduce health inequalities globally. The resolution recognizes the joint responsibility of all Member States to sup- port solutions to address the health impacts of climate change. It calls on WHO to work with its partners to strengthen support to Member States, through four main areas of work. These can be summarized as follows: 1. Drawing attention to the serious risk of climate change to global health secu- rity and to the achievement of the health-related Millennium Development Goals, to ensure that health concerns are taken into account in national and international responses. 2. Engaging in the UN cross-sectoral program on adaptation to climate change, to ensure its relevance to health and to facilitate participation by Member States. 3. Developing capacity to assess the risks from climate change for human health and to implement effective response measures, through further research and pilot projects, including on • the scale and nature of health vulnerability to climate change; • assessment of protection strategies and measures; • the health impacts of potential adaptation and mitigation measures in other sectors such as water resources, land use, and transport; • decision support and other tools, such as surveillance and monitoring, for assessing vulnerability and targeting protection measures appropriately; and • assessment of the likely financial costs and other resources necessary for health protection from climate change. 4. Consultation with Member States on scaling up WHO’s technical support for assessing and addressing the implications of climate change for health and health systems. SOURCE: The full text of the resolution and background documentation can be found in WHO (2008c). 

236 GLOBAL CLIMATE CHANGE AND EXTREME WEATHER EVENTS decisions, should be the protection and improvement of human well-being (i.e., health should be at the heart of climate policy). On promoting health through climate change mitigation, it is clear that in the long term, sustainable development and protection of ecosystem services are fundamentally necessary for human health (Millennium Ecosystem Assessment, 2005). However, even in the short term, development choices that protect the climate have the potential for important public health benefits. The intersection of energy, transport, climate, and health provides a clear example. It is widely appre- ciated that both modes of transport (i.e., relative use of active, public, and private modes) and choice of fuels have an important influence on greenhouse gas emis- sions. It is less widely appreciated that these decisions also have an effect on the 800,000 annual global deaths from outdoor air pollution; the 1.2 million annual deaths from traffic accidents; and the 1.9 million annual deaths from physical inactivity (Ezzati et al., 2004; WHO, 2002). Providing the poorest communities with access to cleaner domestic energy technologies could reduce the 1.5 mil- lion annual indoor air pollution deaths, as well as slow the growth in greenhouse gas emissions (Bailis et al., 2005; Smith et al., 2004; WHO, 2006b). There is, therefore, the potential for important public health improvements through a closer engagement with relevant environmental and economic sectors. The most obvious and immediate area of engagement, however, is in strength- ening public health systems to protect populations against emerging health risks. In climate change policy, this corresponds to “adaptation” (i.e., minimizing the damages caused by climate change that is now inevitable). To some extent, plan- ning of interventions may be less complex than assessing and communicating the health risks from climate change. While there is vocal disagreement over some aspects of the evidence for effects of climate change on health, many of these disagreements are of little relevance to identifying effective interventions. The fundamental principle put forward by WHO and others is that protec- tion from climate change is part of a basic, preventive approach to public health, not a separate or competing demand (Campbell-Lendrum et al., 2007; WHO, 2008a). Many of the most important actions are public health interventions of proven effectiveness—from controlling vector-borne disease, to providing clean water and sanitation. All would improve health now, as well as reducing vulner- ability to climate change in the future. This can be illustrated by examples of two broad areas: preventive environmental health interventions and infectious disease surveillance and response. Preventive Environmental Health Interventions One example of an emerging health threat associated with climate change is the decline in global freshwater resources, caused mainly by increasing rates of water extraction and contamination. A warmer and more variable climate is expected to further worsen the decline in water quantity and quality in many 

POLICY IMPLICATIONS 237 regions through the retreat of glaciers that supply freshwater in summer to much of the global population, greater surface evaporation, and shifting and more extreme precipitation (IPCC, 2007). Scaling-up water and sanitation services and providing point-of-use disinfection are highly cost-effective interventions (Hutton and Haller, 2004) that should both reduce the current burden of disease and ameliorate the health impacts of decreasing water supplies. As water stresses intensify, governments could protect health by strengthening and enforcing their regulatory frameworks to ensure that increasing use of new water sources, such as wastewater, excreta, and graywater in agriculture and aquaculture, does not bring increases in infectious or chemical risks (WHO, 2006c). Infectious Disease Surveillance and Response Effective surveillance and response systems are essential in managing any infectious disease. However, they become even more important under conditions of rapid change, including climatic shifts as well as increasing rates of movement of and contact between humans, pathogens, and reservoirs. This requires improved human health surveillance integrated with monitoring of climate and other envi- ronmental conditions that favor disease outbreaks, including disease in wildlife and agricultural animals. Climate change also strengthens the case for reinforcing response systems for infectious disease outbreaks, including predefined action plans and maintenance of the control resources and personnel capacity neces- sary to implement disease control. There is already a great deal of institutional infrastructure in place that can help to control these risks. Most importantly at the global level, the newly revised International Health Regulations define operating procedures for detection, notification, and control of disease risks, including but not restricted to preventing the spread of infections across international borders (WHO, 2007). New investments to meet the additional risks of climate change should build on, rather than replicate, these existing mechanisms. A great deal of the scientific discussion in this field relates to the develop- ment of early warning systems, often based on new technologies, such as satel- lite-based remote sensing. Such tools have the potential to improve lead times and, therefore, improve control. However, one should not assume that advances in this area will by themselves have a major impact on cutting disease rates, par- ticularly in developing countries. It is essential that future work in this area takes note of the warning that “forecasts based entirely on scientific objectives have little impact on policy because there is no stakeholder” (Clark et al., 2001) and follows the recommendation provided by a previous National Research Council (NRC) report that “development of early warning systems should involve active participation of the system’s end users” (NRC, 2001). In many cases, the weak link is not the lead time of a warning but the capacity to respond effectively. A recent WHO literature review identified numerous examples of scientific studies linking climate variability and infectious disease, but could not locate any full 

238 GLOBAL CLIMATE CHANGE AND EXTREME WEATHER EVENTS descriptions of climate-based early warning systems being used to influence control decisions (WHO, 2005). Conclusions Health threats arising from climate change understandably attract widespread policy and public attention. Climate change does not act in isolation, but is likely to interact with other rapid changes to strain existing weak points in public health systems. The most effective responses are likely to be strengthening of key functions, such as environmental management, and surveillance and response to safeguard changes in infectious disease patterns and other hazards. The NRC (2001) reported that there will always be some element of unpredictability in climate variations and infectious disease outbreaks. Therefore, a prudent strategy is to set a high priority on reducing people’s overall vulnerability to infectious disease through strong public health measures such as vector control efforts, water treatment systems, and vaccination programs. As climate change continues to rise up the scientific and political agenda, this guidance remains as relevant as ever. REFERENCES Overview Reference European Commission. 2008. Climate change and international security. Paper presented at European Union Summit, Brussels. MacPherson and Gushulak References Angell, S. Y., and R. H. Behrens. 2005. Risk assessment and disease prevention in travelers visiting friends and relatives. Infectious Disease Clinics of North America 19(1):49-65. Black, R., and M. Sessay. 1998. Forced migration, natural resource use and environmental change: the case of the Senegal River Valley. International Journal of Popular Geography 4(1):31-47. CCSP (U.S. Climate Change Science Program) and the Subcommittee on Global Change Research. 2008. The effects of climate change on agriculture, land resources, water resources, and biodi- versity in the United States. Washington, DC: U.S. Environmental Protection Agency. CDC (Centers for Disease Control and Prevention). 2005. Infectious disease and dermatologic conditions in evacuees and rescue workers after Hurricane Katrina—multiple states, August- September, 2005. Morbidity and Mortality Weekly Report 54(38):961-964. ———. 2006a. Surveillance for illness and injury after Hurricane Katrina—three counties, Missis- sippi, September 5-October 11, 2005. Morbidity and Mortality Weekly Report 55(9):231-234. ———. 2006b. Illness surveillance and rapid needs assessment among Hurricane Katrina evacuees— Colorado, September 1-23, 2005. Morbidity and Mortality Weekly Report 55(9):244-247. ———. 2006c. Two cases of toxigenic Vibrio cholerae O1 infection after Hurricanes Katrina and Rita—Louisiana, October 2005. Morbidity and Mortality Weekly Report 55(2):31-32. 

POLICY IMPLICATIONS 239 Coninx, R. 2007. Tuberculosis in complex emergencies. Bulletin of the World Health Organization 85(8):637-640. Corbin, A., C. Delatte, S. Besson, A. Guidry, A. H. Hoffmann III, P. Monier, and R. Nathaniel. 2007. Budvicia aquatica sepsis in an immunocompromised patient following exposure to the aftermath of Hurricane Katrina. Journal of Medical Microbiology 56(Pt 8):1124-1125. Das, N. G., P. K. Talukdar, J. Kalita, I. Baruah, and R. B. Sribastave. 2007. Malaria situation in forest-fringed villages of Sonitpur district (Assam), India bordering Arunachal Pradesh during an outbreak. Journal of Vector-Borne Diseases 44(3):213-218. DoJ (Department of Justice). 2005. The human smuggling and trafficking centre. Fact sheet: dis- tinctions between human smuggling and human trafficking, http://www.usdoj.gov/crt/crim/ smuggling_trafficking_facts.pdf (accessed December 29, 2007). Eberhart-Phillips, J., R. E. Besser, M. P. Tormey, D. Koo, D. Feikin, M. R. Araneta, J. Wells, I. Kilman, G. W. Rutherford, P. M. Griffin, R. Baron, and L. Mascola. 1996. An outbreak of cholera from food served on an international aircraft. Epidemiology and Infection 116(1):9-13. Elledge, B. L., D. T. Boatright, P. Woodson, R. E. Clinkenbeard, and M. W. Brand. 2007. Learning from Katrina: environmental health observations from the SWCPHP response team in Houston. Journal of Environmental Health 70(2):22-26. Environment Canada. 1999. Responding to global climate change in the Arctic. In The Canada Coun- try Study. Toronto, Ontario: Environmental Adaptation Research Group. FDA (Food and Drug Administration). 2007a. Pet food recall (melamine) tainted animal feed, http:// www.fda.gov/oc/opacom/hottopics/petfood.html (accessed December 31, 2007). ———. 2007b. FDA warns consumers not to eat certain jars of Peter Pan peanut butter and Great Value peanut butter, http://www.fda.gov/bbs/topics/NEWS/2007/NEW01563.html (accessed December 31, 2007). Fenner, L., R. Weber, R. Steffen, and P. Schlagenhauf. 2007. Imported infectious disease and purpose ���������������������������������������������� of travel, Switzerland. Emerging Infectious Diseases 13(2):217-222. Gushulak, B. D., and D. W. MacPherson. 2000. Population mobility and infectious diseases: the diminishing impact of classical infectious diseases and new approaches for the 21st century. Clinical Infectious Diseases 31(3):776-780. �������������� Health Protection Agency. 2007. Epidemiology data: tables and figures. Case reports (enhanced TB surveillance and national TB surveys), http://www.hpa.org.uk/infections/topics_az/tb/ epidemiology/tables.htm#ets (accessed December 31, 2007). Hinrichsen, D. 1999. The coastal population explosion. In Trends and future challenges for U.S. national ocean and coastal policy, edited by B. Cicin-Sain, R.W. Knecht, and H. Foster. Wash- ington, DC: NOAA. Pp. 27-30. http://oceanservice.noaa.gov/websites/retiredsites/natdia_pdf/ 3hinrichsen.pdf (accessed December 29, 2007). ILO (International Labour Organization). 2006. Facts on labour migration, http://www.ilo.org/public/ english/bureau/inf/download/ecosoc/migration.pdf (accessed August 19, 2008). IPCC (Intergovernmental Panel on Climate Change). 2001. Climate change 2001: third assessment report (vol. I). Cambridge, UK: Cambridge University Press. ———. 2007. Summary for policymakers of the synthesis of the IPCC fourth assessment report. Cambridge, UK: Cambridge University Press. Leder, K., S. Tong, I. Weld, K. C. Kain, A. Wilder-Smith, F. von Sonnenburg, J. Black, V. Brown, J. Torresi, and GeoSentinel Surveillance Network. 2006. Illness in travelers visiting friends and relatives: a review of the GeoSentinel Surveillance Network. Clinical Infectious Diseases 43(9):1185-1193. MacPherson, D. W., and B. D. Gushulak. 2001. Human mobility and population health. New ap- proaches in a globalizing world. Perspectives in Biology and Medicine 44(3):390-401. ———. 2008. Syphilis in immigrants, public health, and the Canadian immigration medical examina- tion. Journal of Immigrant and Minority Health 10(1):1-6. 

240 GLOBAL CLIMATE CHANGE AND EXTREME WEATHER EVENTS MacPherson, D. W., M. Zencovich, and B. D. Gushulak. 2006. Emerging pediatric HIV epidemic related to migration. Emerging Infectious Diseases 12(4):612-617. MacPherson, D. W., B. D. Gushulak, and L. Macdonald. 2007. Health and foreign policy: influences of migration and population mobility. Bulletin of the World Health Organization 85(3):200-206. Maurer, L. H., and T. J. Sneider. 1969. Gonococcal urethritis in males in Vietnam: three peni- cillin regimens and one tetracycline regimen. Journal of the American Medical Association 207(5):946-948. Mayell, H. 2003. Documentary redraws humans’ family tree. National Geographic News, http://news. nationalgeographic.com/news/2002/12/1212_021213_journeyofman.html (accessed February 26, 2008). Meyers, N. 2002. Environmental refugees: a growing phenomenon of the 21st century. Philosophi- cal Transactions of the Royal Society of London. Series B, Biological Sciences 357(1420): 609-613. Mittal, V., D. Bhattacharya, U. V. Rana, A. Rai, S. T. Pasha, A. Kumar, A. K. Hart, R. L. Ishpujani, U. K. Baveia, S. Lal, and S. P. Agarwal. 2006. Prompt laboratory diagnosis in timely containment of a plague outbreak in India. Journal of Communicable Diseases 38(4):317-324. Nickerson, C. 2000 (March 21). Girding for a sea change: with ice thinning, Canada claims a North- west Passage. Boston Globe. O’Leary, D. R., J. G. Rigau-Pérez, E. B. Hayes, A. V. Vonrdam, G. G. Clark, and D. J. Gubler. 2002. Assessment of dengue risk in relief workers in Puerto Rico after Hurricane Georges, 1998. American Journal of Tropical Medicine and Hygiene 66(1):35-39. Patz, J. A., M. A. McGeehin, S. M. Bernard, K. L. Ebi, P. R. Epstein, A. Grambsch, D. J. Gubler, P. Reither, I. Romieu, J. B. Rose, J. M. Samet, and J. Trtanj. 2000. The potential health impacts of climate variability and change for the United States: executive summary of the report of the health sector of the U.S. National Assessment. Environmental Health Perspectives 108(4):367-376. Peltola, H., P. S. Kulkarni, S. V. Kapre, M. Paunio, S. S. Jadhav, and R. M. Dhere. 2007. Mumps outbreaks in Canada and the United States: time for new thinking on mumps vaccines. Clinical Infectious Diseases 45(4):459-466. Pistone, T., P. Guibert, F. Gay, D. Malvy, K. Ezzedine, M. C. Receveur, M. Siriwardana, B. Larouzé, and O. Bouchard. 2007. Malaria risk perception, knowledge and prophylaxis practices among travellers of African ethnicity living in Paris and visiting their country of origin in sub-Saharan Africa. Transactions of the Royal Society of Tropical Medicine and Hygiene 101(10):990-995. Rao, C. Y., C. Kurukularatne, J. B. Garcia-Diaz, S. A. Kemmerly, D. Reed, S. K. Frickin, and J. Morgan. 2007. Implications of detecting the mold Syncephalastrum in clinical specimens of New Orleans residents after Hurricanes Katrina and Rita. Journal of Occupational and Envi- ronmental Health 49(4):411-416. Rashid, H., I. M. Hunt, and W. Haider. 2007. Urban flood problems in Dhaka, Bangladesh: slum resi- dents’ choices for relocation to flood-free areas. Environmental Management 40(1):95-104. Read, M. 2003. Journey of man. National Geographic News, http://news.nationalgeographic.com/ news/2002/12/photogalleries/journey_of_man/photo2.html (accessed December 29, 2007). Sanders, E. J., J. G. Rigau-Pérez, H. L. Smits, C. C. Deseda, V. A. Vorndam, T. Aye, R. A. Spiegel, R. S. Weyant, and S. L. Bragg. 1999. Increase of leptospirosis in dengue-negative patients after a hurricane in Puerto Rico in 1996 [correction of 1966]. American Journal of Tropical Medicine and Hygiene 61(3):399-404. Sejvar, J., E. Bancroft, K. Winthrop, J. Bettinger, M. Bajani, S. Bragg, K. Shutt, R. Kaiser, N. Marano, T. Popovic, J. Tappero, D. Ashford, I. Mascola, D. Vugia, B. Perkins, N. Rosenstein, and Eco- Challenge Investigation Team. 2003. Leptospirosis in “Eco-Challenge” athletes, Malaysian Borneo, 2000. Emerging Infectious Diseases 9(6):702-707. 

POLICY IMPLICATIONS 241 Sevbold, U., N. White, Y. F. Wang, J. S. Halvosa, and H. M. Blumberg. 2007. Colonization with multidrug-resistant organisms in evacuees after Hurricane Katrina. Infection Control and Hos- pital Epidemiology 28(6):726-729. Smith, C. A. 1996. Plague in the ancient world: a study from Thucydides to Justinian. In The Student Historical Journal, vol. 28. Loyola University: New Orleans. UNFCCC (United Nations Framework Convention on Climate Change). 2007. Decision-/CP.13. Bali Action Plan. United Nations Climate Change Conference, Bali, December 3-14, 2007, http://unfccc.int/files/meetings/cop_13/application/pdf/cp_bali_action.pdf (accessed December 31, 2007). ———. 2008. Climate change information sheet 10: agriculture and food security, http://unfccc. int/essential_background/background_publications_htmlpdf/climate_change_information_kit/ items/288.php (accessed June 24, 2008). UNHCR (United Nations High Commissioner for Refugees). 2007. Protecting refugees and the role of the UNHCR, http://www.unhcr.org/basics/BASICS/4034b6a34.pdf (accessed February 1, 2008). WHA (World Health Assembly). 2005. WHA 58.3 Revision of the International Health Regulations, http://www.who.int/gb/ebwha/pdf_files/WHA58/WHA58_3-en.pdf (accessed November 25, 2007). WHO (World Health Organization). 2003a. Climate change and human health: risks and responses, edited by A. J. McMichael, D. H. Campbell-Lendrum, C. F. Corvalán, K. L. Ebi, A. Githeko, J. D. Scheraga, and A. Woodward. Geneva, Switzerland: World Health Organization. ———. 2003b. Areas with recent local transmission of SARS, http://www.who.int/csr/sars/areas/en/ (accessed December 31, 2007). ———. 2006. Addressing the threat of tuberculosis caused by extensively drug-resistant Mycobac- terium tuberculosis. Weekly Epidemiological Record 81(41):385-390, www.who.int/wer/2006/ wer8141.pdf (accessed December 31, 2007). ———. 2008. Situation updates—avian influenza, http://www.who.int/csr/disease/avian_influenza/ updates/en/ (accessed December 31, 2007). Yee, E. L., H. Palacio, R. I. Almar, U. Shah, C. Kilborn, M. Faul, T. E. Gavagan, R. D. Feigin, J. Versalovic, F. H. Neil, A. L. Panililo, M. Miller, J. Spahr, and R. L. Glass. 2007. Widespread outbreak of norovirus gastroenteritis among evacuees of Hurricane Katrina residing in a large “megashelter” in Houston, Texas: lessons learned for prevention. Clinical Infectious Diseases 44(8):1032-1039. Yew, E. 1980. Medical inspection of immigrants at Ellis Island, 1891-1924. Bulletin of the New York Academy of Medicine 56(5):488-510. Zencovich, M., K. Kennedy, D. W. MacPherson, and B. D. Gushulak. 2006. Immigration medi- cal screening and HIV infection in Canada. International Journal of STDs and AIDS 17(12):813-816. Campbell-Lendrum References Bailis, R., M. Ezzati, and D. M. Kammen. 2005. Mortality and greenhouse gas impacts of biomass and petroleum energy futures in Africa. Science 308(5718):98-103. Black, R. E., L. H. Allen, Z. A. Bhutta, L. E. Caulfield, M. de Onis, M. Ezzati, C. Mathers, and J. Rivera. 2008. Maternal and child undernutrition: global and regional exposures and health consequences. Lancet 371(9608):243-260. Bouma, M. J., C. Dye, and H. J. vanderKaay. ��������������������������������������������������� 1996. Falciparum malaria and climate change in the Northwest Frontier Province of Pakistan. American Journal of Tropical Medicine and Hygiene 55(2):131-137. 

242 GLOBAL CLIMATE CHANGE AND EXTREME WEATHER EVENTS Boykoff, M. T., and J. M. Boykoff. 2004. Balance as bias: global warming and the U.S. prestige press. Global Environmental Change-Human and Policy Dimensions 14(2):125-136. Campbell-Lendrum, D., C. Corvalán, and M. Neira. 2007. Global climate change: implications for international public health policy. Bulletin of the World Health Organization 85(3):235-237. Chan, M. 2007. Climate change and health: preparing for unprecedented challenges. The 2007 David E. Barmes Global Health Lecture. Bethesda, MD, December 10. Checkley, W., L. D. Epstein, R. H. Gilman, D. Figueroa, R. I. Cama, J. A. Patz, and R. E. Black. 2000. Effects of El Niño and ambient temperature on hospital admissions for diarrhoeal diseases in Peruvian children. Lancet 355(9202):442-450. Clark, J. S., S. R. Carpenter, M. Barber, S. Collins, A. Dobson, J. A. Foley, D. M. Lodge, M. Pascual, R. Pielke, W. Pizer, C. Pringle, W. V. Reid, K. A. Rose, O. Sala, W. H. Schlesinger, D. H. Wall, and D. Wear. 2001. Ecological forecasts: an emerging imperative. Science 293(5530):657-660. Commission on Social Determinants of Health. 2007. Achieving health equity: from root causes to fair outcomes. Geneva, Switzerland: World Health Organization. Confalonieri, U., B. Menne, R. Akhtar, K. L. Ebi, M. Hauengue, R. S. Kovats, B. Revich, and A. Woodward. 2007. Human health. In Climate change 2007: impacts, adaptation and vulner- ability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovern- mental Panel on Climate Change, edited by M. L. Parry, O. F. Canziani, J. P. Palutikof, P. J. van der Linden, and C. E. Hanson. Cambridge, UK: Cambridge University Press. Department of Health/Health Protection Agency. 2008. Health effects of climate change in the UK 2008: an update of the Department of Health Report 2001/2002. London, UK: Department of Health/Health Protection Agency. Ezzati, M., A. D. Lopez, A. Rodgers, and C. J. L. Murray, eds. 2004. Comparative quantification of health risks: global and regional burden of disease due to selected major risk factors. Geneva, Switzerland: World Health Organization. Hutton, G., and L. Haller. 2004. Evaluation of the costs and benefits of water and sanitation improve- ments at the global level. Geneva, Switzerland: World Health Organization. IPCC (Intergovernmental Panel on Climate Change). 2007. Climate change 2007: climate change impacts, adaptation and vulnerability. Contribution of Working Group II to the Intergovern- mental Panel on Climate Change Fourth Assessment Report. Cambridge, UK: Cambridge University Press. Kovats, R. S., D. H. Campbell-Lendrum, A. J. McMichael, A. Woodward, and J. S. Cox. 2001. Early effects of climate change: do they include changes in vector-borne disease? Philosophical Transactions of the Royal Society Series B 356(1411):1057-1068. McMichael, A., D. H. Campbell-Lendrum, C. Corvalán, K. Ebi, A. Githeko, J. Scheraga, and A. Woodward, eds. 2003. Climate change and human health: risks and responses. Geneva, Switzerland: World Health Organization. McMichael, A. J., S. Friel, A. Nyong, and C. Corvalan. 2008. Global environmental change and health: impacts, inequalities, and the health sector. British Medical Journal 336(7637):191-194. Millennium Ecosystem Assessment. 2005. Ecosystems and human well being: health synthesis. Ge- neva, Switzerland: World Health Organization. NRC (National Research Council). 2001. Under the weather: climate, ecosystems, and infectious disease. Washington, DC: National Academy Press. Pascual, M., J. A. Ahumada, L. F. Chaves, X. Rodo, and M. Bouma. 2006. Malaria resurgence in the East African highlands: temperature trends revisited. Proceedings of the National Academy of Sciences 103(15):5829-5834. Pascual, M., B. Cazelles, M. J. Bouma, L. F. Chaves, and K. Koelle. 2008. Shifting patterns: malaria dynamics and rainfall variability in an African highland. Proceedings. Biological Sciences 275(1631):123-132. Prince, R. 2008. Malaria warning as UK becomes warmer. Daily Telegraph, December 2. 

POLICY IMPLICATIONS 243 Prüss-Üstün, A., D. Kay, F. Fewtrell, and J. Bartram. 2004. Unsafe water, sanitation and hygiene. In Comparative quantification of health risks: global and regional burden of disease attributable to selected major risk factors, edited by M. Ezzati, A. Lopez, A. Rodgers, and C. Murray. Geneva, Switzerland: World Health Organization. Singh, R. B., S. Hales, N. de Wet, R. Raj, M. Hearnden, and P. Weinstein. 2001. The influence of climate variation and change on diarrheal disease in the Pacific Islands. Environmental Health Perspectives 109(2):155-159. Smith, K. R., S. Mehta, and M. Meausezahl-Feuz. 2004. Indoor air pollution from household use of solid fuels. In Comparative quantification of health risks: global and regional burden of disease due to selected major risk factors, edited by M. Ezzati, A. Lopez, A. Rodgers, and C. Murray. Geneva, Switzerland: World Health Organization. Stott, P. A., D. A. Stone, and M. R. Allen. 2004. Human contribution to the European heatwave of 2003. Nature 432(7017):610-614. WHO (World Health Organization). 2002. The world health report 2002. Geneva, Switzerland: World Health Organization. ———. 2005. Using climate to predict infectious disease epidemics. Geneva, Switzerland: World Health Organization. ———. 2006a. Burden of disease statistics, http://www.who.int/healthinfo/bod/en/index.html (ac- cessed April 18, 2008). ———. 2006b. Fuel for life: household energy and health. Geneva, Switzerland: World Health Organization. ———. 2006c. WHO guidelines for the safe use of wastewater, excreta and greywater, 3rd edition. Geneva, Switzerland: World Health Organization. ———. 2007. International Health Regulations (IHR), http://www.who.int/csr/ihr/en/ (accessed April 18, 2008). ———. 2008a. Protecting health from climate change: World Health Day 2008. Geneva, Switzerland: World Health Organization. ———. 2008b. Climate change and health: WHO publications 1990-2008, http://www.who.int/ globalchange/climate/publications/en/index.html (accessed April 18, 2008). ———. 2008c. Documentation of the 122nd session of the executive board of the World Health Or- ganization, http://www.who.int/gb/e/e_eb122.html (accessed April 18, 2008). Wilkinson, P., D. H. Campbell-Lendrum, and C. L. Bartlett. 2003. Monitoring the health effects of climate change. In Climate change and human health: risks and responses, edited by A. McMichael, D. H. Campbell-Lendrum, C. Corvalán, K. Ebi, A. Githeko, J. Scheraga, and A. Woodward. Geneva, Switzerland: World Health Organization.