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Addressing the Urgent Threat of Global Climate Change to Public Health and the Environment

Policy Date: 11/6/2007
Policy Number: 20078

Scientific certainty regarding the role of human activities in changing the world’s climate has greatly increased since adoption of American Public Health Association (APHA) Policy Statement 95-10, “Global Climate Change,”1 as reflected by the fourth Intergovernmental Panel on Climate Change (IPCC) report.2 This report states that warming of the earth over the past century is “unequivocal” and that warming can be attributed to humans with a greater than 90% level of certainty.

Warming will occur through the next century even with significant reductions in new emissions, due to the prolonged residence time in the atmosphere of anthropogenic greenhouse gases (GHGs, e.g., carbon dioxide, methane, and ozone), and the slow response time of the ocean.3,5 Public health impacts associated with moderate degrees of global warming include increases in (1) heat-related morbidity and mortality,4–7 (2) the health consequences of increases in the frequency of strong typhoons, hurricanes, and other extreme weather events,8–10 (3) increases in the intensity and range of transmission of vector-borne and other infectious diseases,11–19; (4) respiratory and cardiovascular illness associated with increases in ozone air pollution related to higher ambient temperatures20,21, and (5) malnutrition from threatened agriculture and fisheries, especially in developing countries.22,23

These climate-related impacts on public health—including deaths from heat stress and extreme events, air pollution, and infectious diseases—are already occurring around the world, as noted by the World Health Organization.24 Documented changes in natural systems are likely to accelerate, including increases in extreme weather,2 rise in sea level,2 shrinkage of the snow pack,25 retreat of Arctic sea ice and glaciers and ice caps around the world,2 melting of the Greenland and Antarctic ice sheets, and the melting of permafrost.2

Biological responses to climate change also have negative implications for human health, due to loss of ecosystem services (such as water purification), loss of species for medical research (such as marine and rainforest species for cancer therapies), altered infectious disease dynamics due to changes in temperature and precipitation patterns and ecosystem disruption, and disruption of food supplies due to desertification, changes in distribution of cultivatable land, and collapse of marine fisheries.26–31 The adverse public health and environmental impacts of projected changes in global climate are likely to be especially severe among populations already living in extreme poverty throughout the developing world, and, as the World Health Organization has concluded, most of the contemporaneous health-related impacts associated with global climate change are occurring in developing countries, with adverse impacts in 2000 estimated at approximately 5.5 million disability-adjusted life years.32 The adverse public health impacts of projected changes in global climate also are anticipated to be especially severe among susceptible subpopulations, especially children, the elderly, those with underlying chronic diseases, and those in impoverished communities, particularly the urban poor, within the United States.33

Current best estimates project that global temperatures will increase by 1.8 to 4.0°C by 2100, and sea levels may rise 0.18 to 0.59 m or more this century, depending on ice sheet dynamics.2 Scientists calculate that significant reductions in GHG emissions must begin to take place within 10 years for humans to have a chance at averting dangerous climate change (as the term has been developed under the 1992 United Nations Framework Convention on Climate Change), a definition that concedes significant damages to coral reef and Arctic ecosystems, large-scale species extinction, as well as regional decreases in food production, and that minimizes, but does not eliminate, the chance that the Greenland ice sheet will disintegrate.34,35 These manifestations of rapid anthropogenic climate change pose an unprecedented threat to human health and well-being. There will be severe limitations in the ability to adapt to or provide “secondary prevention“ for many of the health manifestations of rapid and severe climate change, such as the consequences of population displacement and increasingly severe weather extremes. For this reason, the public health community must communicate the critical importance of primary prevention, namely the mitigation of climate change, in addition to preparing to provide secondary and tertiary prevention of climate change health effects.

Policies that reduce GHGs through reduced usage of energy, fossil fuel combustion, and personal motor vehicle use may provide substantial public health cobenefits through reductions in ambient air pollution36–38 and increases in personal physical activity.39

American Public Health Association (APHA) therefore resolves the following:
1. The long-term threat of global climate change to global health is extremely serious and the fourth IPCC report and other scientific literature demonstrate convincingly that anthropogenic GHG emissions are primarily responsible for this threat.
2. The public health community should advocate for mitigation and avoidance of climate change, track the impacts of climate change on human health, and assist with adaptation, to the degree possible, to those health effects caused by changes in climate that can not be prevented. The public health community also should assess and communicate the potential short-term public health benefits, as well as the potential adverse public health impacts, of GHG mitigation strategies.
3. US policy makers should immediately take necessary steps to reduce US emissions of GHGs, including carbon dioxide, to avert dangerous climate change. The key component of such an effort is establishing a mandatory economywide cap on emissions with successive reductions over time. Such a cap will create incentives for residential and industrial energy efficiency and increased use of alternative energy production, such as wind and solar power. It also will promote advanced technologies to reduce or capture carbon emissions from energy production; changes in transportation and land-use policy to promote conservation and reduce consumption of fossil fuels; increases in fuel economy; changes in agriculture; and extensive investment in research and development in low-carbon energy, transportation, agriculture, and manufacturing technologies. US companies also should employ technologies to reduce GHG emissions from their facilities located outside of the United States.
4. Acknowledge that freedom from serious adverse effects of global climate change qualifies as a basic human right as the APHA understands that term. Individuals living in extreme poverty, in particular, must be protected from the adverse effects of changes in global climate, and the United States, as the largest global contributor of GHGs40 to the atmosphere over the past 150 years, should substantially increase funding for both traditional development projects that reduce or minimize GHG emissions and build public health capacity and infrastructure in developing countries as well as specific climate change adaptation projects.
5. The United States and international public health agencies should promote strategies (e.g., family planning) to address population growth, which, if not addressed, will make GHG reductions extremely difficult.
6. The public health workforce should be better educated about the impacts of global climate change, as well as mitigation and adaptation strategies. Federal, state, and local public health agencies should receive adequate resources to support education, outreach, surveillance and monitoring, needs assessment, and prevention activities related to climate change.
7. The curricula for students in atmospheric chemistry, meteorology, and other earth sciences relevant to the study of climate change and its geophysical effects should include instruction on the public health consequences of climate change.
8. All public health professionals and organizations should adopt practices that minimize GHG emissions related to their activities.
9. There should be ongoing research, education, prevention, monitoring, and assessment pertaining to long-term, intergenerational public health issues that will likely arise from climate and ecological change, as called for in APHA Policy 9510, but that these activities should not delay immediate and aggressive activity toward stabilization and reduction of GHG emissions.

1. American Public Health Association. APHA Policy Statement 2005-10. Global Climate Change. Washington, DC: American Public Health Association; 2006. Available at: www.apha.org/advocacy/policy/policysearch/default.htm?id=105. Accessed December 7, 2007.
2. Alley R, Berntsen A, Bindoff NL, et al. Climate Change 2007: the Physical Science Basis. Summary for Policymakers. Geneva, Switzerland: Intergovernmental Panel on Climate Change; 2007. Available at: www.aaas.org/news/press_room/climate_change/media/4th_spm2feb07.pdf. Accessed December 5, 2007.
3. Hansen J, Nazarenko L, Ruedy R, et al. Earth’s energy imbalance: confirmation and implications. Science. 2005; 308(5727):1431–1435. Epub April 28, 2005.
4. Ebi KL, Mills DM, Smith JB, Grambsch A. Climate change and human health impacts in the United States: an update on the results of the U.S. national assessment. Environ Health Perspect. 2006;114:1318–1324.
5. Dessai S. Heat stress and mortality in Lisbon Part II. An assessment of the potential impacts of climate change. Int J Biometeorol. 2003;48:37–44.
6. Schar C, Luigi-Vidale P, Luthi D, et al. The role of increasing temperature variability in European summer heatwaves. Nature. 2004;427:332–336.
7. Meehl GA, Tebaldi C. More intense, more frequent, and longer lasting heat waves in the 21st century. Science. 2004;305:994–997.
8. Milly, PCD, Wetherald RT, Dunne KA, Delworth T L. Increasing risk of great floods in a changing climate. Nature. 2002 415:514–515
9. Running SW. Is global warming causing more, larger wildfires? Science. 2006; 313:927–928.
10. Emanuel K. 2005. Increasing destructiveness of tropical cyclones over the past 30 years. Nature. 2005;436:686–688.
11. Epstein PR. Climate change and emerging infectious diseases. Microbes Infect. 2001;3:747–754.
12. Gubler DJ, Reiter P, Ebi KL, Yap W, Nasci R, Patz JA Climate variability and change in the United States: potential impacts on vector- and rodent-borne diseases. Environ Health Perspect. 2001;109(suppl 2): 223–233.
13. Rose JB, Epstein PR, Lipp EK, Sherman BH, Bernard SM, Patz JA. Climate variability and change in the United States: potential impacts on water and foodborne diseases caused by microbiologic agents. Environ Health Perspect. 2001; 109(suppl 2):211–221.
14. Fleury M, Charron DF, Holt JD, Allen OB, Maarouf AR. A time series analysis of the relationship of ambient temperature and common bacterial enteric infections in two Canadian provinces. Int J Biometeorol. 2006;60:385–391.
15. Kovats RS, Edwards SJ, Hajat S, Armstrong B, Ebi KL, Menne B, and The Collaborating Group. The effect of temperature on food poisoning: a time-series analysis of salmonellosis in ten European countries. Epidemiol Infect. 2004;132,443–453.
16. Bradshaw WE, Holzapfel CM. 2001. Genetic shift in photoperiodic response correlated to global warming. Proc Natl Acad Sci U S A. 2001; 98(25):14509-14511.
17. Epstein P, Diaz H, Elias S, et al. Biological and physical signs of climate change: focus on mosquito borne diseases. Bulletin of the American Meteorological Society. 1998;79:409–417
18. Loevinsohn ME. Climate warming and increased malaria incidence in Rwanda. Lancet. 1994;343:714–718
19. Hjelle B, GE Glass. Outbreak of hantavirus infection in the Four Corners region of the United States in the wake of the 1997–1998 El Nino-southern oscillation. J Infect Dis. 2000;181:1569–1573.
20. Knowlton K, Rosenthal J, Hogrefe C, et al. Assessing ozone-related health impacts under a changing climate. Environ Health Perspect. 2004;112:1557–1563.
21. Hogrefe C, Lynn B, Civerolo K, et al. Simulating changes in regional air pollution due to changes in global and regional climate and emissions. J Geophys Res. 2004;109:22301.
22. Gregory PJ, Ingram JS, Brklacich M. Climate Change and Food Security. Philos Trans R Soc Lond B Biol Sci. 2005;360(1463):2139–2148.
23. Parry M, Rosenzweig C, Livermore M. Climate change, global food supply and risk of hunger. Philos Trans R Soc Lond B Biol Sci. 2005;360(1463):2125–2138.
24. McMichael AJ, Woodruff RE, Hales S. Climate change and human health: present and future risks. National Centre for Epidemiology and Population Health. Lancet. 2006;367(9513):859–869.
25. Mote PW, Hamlet AF, Clark MP, Lettenmaier DP. Declining mountain snowpack in western North America. Bulletin of the American Meteorological Society. 2005;86:39–49.
26. Chivian E, ed. Biodiversity: Its Importance to Human Health. Cambridge, MA: Harvard Medical School; 2002. Available at: http://chge.med.harvard.edu/publications/documents/Biodiversity_v2_screen.pdf. Accessed March 7, 2007.
27. Parmesan C, Yohe G. A globally coherent fingerprint of climate change impacts across natural systems. Nature. 2003;421:37–42.
28. Root TL, Price JT, Hall KR, Schneider SH, Rosenzweig C, Pounds JA. Fingerprints of global warming on wild animals and plants. Nature. 2003;421:57–60
29. Bradshaw WE, Holzapfel CM. Genetic shift in photoperiodic response correlated with global warming. Proc Natl Acad Sci U S A. 2001;98:14509–14511.
30. Epstein P, Diaz H, Elias S, et al. 1998. Biological and physical signs of climate change: focus on mosquito borne diseases. Bulletin of the American Meteorological Society.79:409–417
31. Loevinsohn ME. Climate warming and increased malaria incidence in Rwanda. Lancet. 1994;343:714–718
32. Campbell-Lendrum D, Pruss-Ustun A, Corvalan C. How much disease could climate change cause? In: McMichael AJ, Campbell-Lendrum D, Corvalan C, Ebi KL, Githeko AK, Scheraga JS, eds. Climate Change and Health: Risks and Responses. Geneva, Switzerland: World Health Organization; 2003:133–155.
33. Longstreth J. Public health consequences of global climate change in the United States- some regions may suffer disproportionately. Environ Health Perspect. 1999;107(suppl 1):169–179.
34. O’Neill BC, Oppenheimer M. Climate change. Dangerous climate impacts and the Kyoto Protocol. Science. 2002;296(5575):1971–1972.
35. Schellnhuber HJ, ed. Avoiding Dangerous Climate Change. Cambridge: Cambridge University Press; 2006. Available at: www.defra.gov.uk/environment/climatechange/research/dangerous-cc/pdf/avoid-dangercc.pdf. Accessed June 16, 2007.
36. Cifuentes L, Borja-Aburto VH, Gouveia N, Thurston G, Davis DL. Assessing the health benefits of urban air pollution reductions associated with climate change mitigation (2000–2020): Santiago, Sao Paulo, Mexico City, and New York City. Environ Health Perspect. 2001;109(Suppl 3):419–425.
37. Cifuentes L, Borja-Aburto VH, Gouveia N, Thurston G, Davis DL. Climate change. Hidden health benefits of greenhouse gas mitigation. Science. 2001;17;293(5533):1257–1259.
38. West JJ, Fiore AM, Horowitz LW, Mauzerall DL. Global health benefits of mitigating ozone pollution with methane emission controls. Proc Natl Acad Sci U S A. 2006;14;103:3988–3993.
39. Besser LM, Dannenberg AL. Walking to public transit: steps to help meet physical activity recommendations. Am J Prev Med. 2005;29:273–280.
40. Baumer KA, Herzog T, Pershing J. Navigating the Numbers: Greenhouse Gas Data and International Climate Change Policy. Washington, DC: World Resources Institute; 2005.