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Tony McMichael National Centre for Epidemiology and Population Health

Global Climate Change: Health Risks – and Preventive Strategies. Tony McMichael National Centre for Epidemiology and Population Health The Australian National University. Climate Change 101. The world’s climate is an integrated system

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Tony McMichael National Centre for Epidemiology and Population Health

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  1. Global Climate Change:Health Risks – and Preventive Strategies Tony McMichael National Centre for Epidemiology and Population Health The Australian National University

  2. Climate Change 101 • The world’s climate is an integrated system • Many factors (‘forcings’) influence the atmosphere’s uptake and distribution of energy (heat) • Energy-trapping gases (esp CO2, water vapour, CH4) absorb outgoing re-radiated infrared radiation • This raises Earth’s surface temperature • Human activity is increasing the concentration of these ‘greenhouse’ gases • CO2 concentration has increased from 275 ppm to 380 ppm over past century • Current trend: 450 ppm by ~2030 (= + 2oC)

  3. As humanity’s resource consumption increases, World Overshoot Day occurs earlier each year. The first Overshoot Day was Dec 19, 1987. Today, it is on October 9 – i.e., our Ecological Footprint is almost 30% larger than the planet’s biocapacity. World Overshoot Day = [World biocapacity /World Ecological Footprint ] x 365 This year, in just 282 days, we consume the biosphere’s entire capacity for 2006. 1987 2000 2006 www.footprintnetwork.org/gfn_subphp?content=overshoot October 9, 2006

  4. Estimated deaths and DALYs attributable to climate change Selected health outcomes in developing countries Total = 150,000 deaths/yr Now (2000) Future (2030) Deaths (thousands) DALYs (millions) 2000 2030 WHO, 2004: Global Burden of Disease

  5. Climate Change: Relevance to Med Students • Professional • Advice to patients and families • Awareness of shifts in differential diagnosis • Contribution to organisational policy/advocacy • Participation in research • Health sector: energy efficiency, technology choices • Citizen • Participation in public debate and political decisions • Community, family and personal decisions/behaviours

  6. Doctors for the Environment Australiahttp://www.dea.org.au/Poster Campaign 2005-2006

  7. Recent Review Articles McMichael AJ, Woodruff R, Hales S. Climate change and human health: present and future. Lancet, 2006; 367: 859-69. Website of Intergovernmental Panel on Climate Change (IPCC) – Working Gp 2: chapter on Health Impacts (McMichael & Githeko) http://www.grida.no/climate/ipcc_tar/wg2/347.htm

  8. Summary of Direction, Magnitude, and Certainty of Projected Health Impacts [IPCC: draft only]

  9. Research at NCEPH • Daily temperature + air pollution  mortality & hospital admissions • Weather patterns and asthma occurrence • Daily/weekly temp and food poisoning • Climatic and environmental influences on Ross River Virus disease • Drought severity and mental health (suicides) • Modelling future changes in health risks w.r.t. climate-change scenarios

  10. Variations of the Earth’s surface temperature for the past 1,000 years: 1000-2000 AD 2000 Grey area shows statistical uncertainty range IPCC (2001): SPM 1b

  11. Past ClimateMean surface temperature, 1855-2004 Temperature variation from 1961-90 average oC Climate Research Unit, UEA, 2005

  12. Causes of Global Climate Change • Natural variability: wobbles of Earth’s axis and changes in orbit (20K-100K yrs), solar activity, volcanoes, ENSO cycle • Human activities: increases in greenhouse gases & aerosols, ozone depletion, land clearing • IPCC: Most global warming since 1950 due to human activities (incr. greenhouse gas emissions) • Evidence for this: • land-ocean temperature contrasts • annual cycle of terrestrial temperature • hemispheric temperature contrast • regional warming • height of tropopause (between troposphere/stratosphere) • pattern of oceanheating

  13. Australia: Recent climate change[CSIRO] • Warming of 0.9oC since 1910, mostly since 1950 • Minimum temperatures have risen twice as fast as maximum temperatures • 2005 was Australia’s warmest year on record • More heatwaves, fewer frosts • More rain in north-west since 1950; less in south and east Trend in mean temp, 1950-2005 (oC/10 yrs) Annual total rainfall, 1950-2005 (mm/10 yrs)

  14. Causes of climate change in Australia • Warming since 1950 mostly due to global increases in greenhouse gases • Rainfall trends: uncertain causes: • Increases in northwest: ? natural variability and shift in weather patterns due to increases in northern hemisphere aerosols • Decreases in south: ? natural variability plus greenhouse gas increases • Decreases in east: ? increase in El Niño events since 1975 (uncertain cause)

  15. 20 IPCC (2001) estimate: + 1.4-5.8 oC by 2100 19 18 17 Central estimate: 2.5 oC increase 16 15 14 Band of 1200-yr historical climatic variability Earth’s Average Surface Temp (OC) Most of warming since 1950 is due to human actions (IPCC, 2001) 13 2050 2100 1860 1900 1950 2000 Year

  16. Climate Change Projections Instead of simple extrapolation, CSIRO uses computer models of the climate system, driven by future emissions scenarios for greenhouse gas and aerosols (and ozone depletion) Emission scenarios (e.g. IPCC ‘SRES’) make assumptions about future demographic, economic & technology changes Global CO2 Emissions Atmospheric CO2 Concentrations

  17. Changes in Earth’s temperature over past 80 m years, and upper/lower estimates for next several centuries 2100 Hundreds of years FUTURE Now Homo genus Hominins appear PAST Millions of years Barrett, Nature, 2003

  18. Greenland Ice Sheet:Increase in Area Melted in Summer, from 1992 to 2002 (Arctic Climate Impact Assessment, 2004) 2002 1992 Orange area = melt-zone

  19. Great Barrier Reef Annual bleaching by 2030-50 (CSIRO, 2006)

  20. Two Important Perspectives • Health risks are influenced by both ‘natural climate variability’ and by (human-induced) climate change • Climate change typically acts in concert with other environmental changes

  21. Worldwide Capture-Fisheries Fish account for a high proportion of animal protein in the world’s diet – especially in many developing-country coastal communities. Global fisheries 25% of commercially exploited marine fish stocks are now seriously over-harvested (Millennium Ecosystem Assessment, 2005) Global marine fish harvest Grand Banks cod fishery Global fisheries harvest has declined since late ’80s

  22. “… the distributions of both exploited and non-exploited North Sea fishes have responded markedly to recent increases in sea temperature…over 25 years. … Further temperature rises are likely to have profound impacts on commercial fisheries…”

  23. Climate Change and Ocean Acidity Report by (UK) Royal Society, 30 June 2005 Increase in atmospheric carbon dioxide has significantly increased ocean acidity. Report chairman: "Failure to cut CO2 emissions may mean that there is no place in the oceans of the future for many of the species and ecosystems that we know today.“ (Calcification – zooplankton, crustaceans, shellfish – is very sensitive to pH. These species are base of marine food web. )

  24. That is, in combination: • Over-fishing • Ocean warming • Ocean acidification … are all impairing the food web and the future productivity of ocean fisheries Illustrates problem of emerging global non-sustainability

  25. Climate Change and Health: Pathways 1 Direct impact e.g. heatwaves, floods, fires Changes to physical systems/processes 3 Climate change Social, economic, demographic disruptions e.g. urban air pollution Health impacts Biological changes: processes, timing 2 e.g.mosquito numbers,range; photosynthesis  crop yields Mediating processes (indirect) Changes to ecosystem structure and function e.g. fisheries; constraints on microbes; nutrient cycles; forest productivity

  26. Empirical studies Estimation, modelling Learn Detect Past Present Future Natural climate variation: - identify ‘effect’ - quantify risks Current climate change: - detect effects - quantify effects - attribute burden Future climate change: - estimate risks - est. attrib burden Three Types of Study

  27. Perth Brisbane Adelaide Melbourne Sydney Monthly cases of Salmonella food-poisoning in relation to monthly temperatureAustralian cities, 1991-2001(modelled best-fit graphs) 100 90 Salmonella cases / month 80 70 60 50 40 30 20 10 0 10 15 20 25 28 Temperature oC D’Souza, Hall, et al., NCEPH/ANU, 2003

  28. 12-day Heatwave, 3-14 Aug, 2003Maximum Temperature, Aug 10 Excess Mortality: France: 14,800 Italy: 10,000 Spain & Portugal: 5,000 Etc. Total = 30,000+

  29. Paris, Heatwave (Aug 2003): Daily Mean Temps and Deaths 35oC 350 300 30 Mean daily temp, 2003 +12oC ~12oC above season norm 250 25 +8oC 200 20 150 Mean daily temp 1999-2002 15oC Daily deaths 100 50 0 ~900 extra deaths during heatwave Based on: Vandentorren S, et al. AJPH 2004;94:1518-20.

  30. Daily temperature and deaths: what happens at temperature extremes? Impact of Europe 2003 heat-wave suggests graph c, not b, applies at unusually hot temperatures c b We already have sufficient observations within this ‘normal’ temperature range ? Daily death rate a Old adults Young adults Average Warm Hot Extremely hot Daily temperature

  31. Tick-borne (viral) Encephalitis, Sweden: 1990s v 1980s (winter warming) Changing Distribution of the Tick Vector Early 1980s Mid-1990s White dots indicate locations where ticks were reported. Black line indicates study region. Lindgren et al., 2000, 2001

  32. Schistosomiasis: Potential transmission of S japonicum in Jiangsu province due to raised avg January temperature.[Red lines = part of planned Sth-Nth water canal.] Temperature change in China from 1960s to1990s 0.6-1.2 oC 1.2-1.8 oC Freezing zone 1970-2000 Freezing zone 1960-1990 Baima lake Hongze lake Yangtze River Recent studies in China indicate that the increase in recorded incidence of schistosomiasis over the past decade may in part reflect recent warming. The “freeze line” limits survival of the intermediate host (Oncomelania water snails) and hence limits transmission of Schistosomiasis japonica. This parasite has moved northwards, putting 20.7 million extra people at risk (Yang, Vounatsou, et al. 2005). Shanghai

  33. Hurricane Katrina crossing Gulf of Mexico Yellow/orange/red areas at or above 82°F (27.8°C) – the temperature needed for hurricanes to strengthen. (NASA, 2005)

  34. Estimating Future Influences of Climate Change on Health and Health Risks

  35. Drought CSIRO Mk2 model: 2030 (high) % change in drought frequency CSIRO estimates: • By 2030, drought frequency increases by up to 20% over most of Australia • By 2070, drought frequency increases by 20-80% in south, 20-40% in Qld, 0-20% elsewhere (except central WA) +80 +60 +40 +20 0 -20 -40 +80 +60 +40 +20 0 -20 -40 Mpelasoka et al. (in preparation)

  36. Evidence of El Niño: 1997, 2006 Sept 15 2006 Sept 20 1997 Sept 20 1997 Note: Warm surface equatorial waters are flowing east across the Pacific, brining rain to Central and South America coasts, and leaving drought in Australia (and beyond)

  37. P.vivax P.falciparum Malaria Transmissibility: Temperature and Biology Survival probability Plasmodium Incubation period Biting frequency 1 50 0.3 0.8 40 0.6 (per day) 30 0.2 (days) (per day) 0.4 20 0.1 0.2 10 0 0 0 15 20 25 30 35 40 10 15 20 25 30 35 40 10 15 20 25 30 35 40 Temp (°C) Temp (°C) Temp (°C) TRANSMISSION POTENTIAL 1 0.8 0.6 Also: Pascual et al 2006 0.4 0.2 0 14 17 20 23 26 29 32 35 38 41 Temperature (°C)

  38. Climate Change & Malaria (potential transmission) in Zimbabwe Baseline20002025 2050 Harare Ebi et al., 2005

  39. Climate Change & Malaria (potential transmission) in Zimbabwe Baseline 2000 20252050 Ebi et al., 2005

  40. Climate Change & Malaria (potential transmission) in Zimbabwe Baseline 2000 2025 2050 Ebi et al., 2005

  41. Dengue Fever: Modelling of receptive geographic region for Ae. Aegyptiimosquito, under alternative climate-change scenarios for 2050 . . Darwin . Katherine . . Cairns . . . Darwin Broome Townsville . . Katherine Port Hedland . . . Mackay Cairns . Risk region for medium emissions scenario, 2050 . Broome Rockhampton Townsville . Carnarvon Port Hedland . Mackay Rockhampton Current risk region for dengue transmission . . . Darwin Brisbane . Katherine . Cairns . . Broome Townsville . Port Hedland . Mackay . Risk region for high emissions scenario, 2050 Rockhampton Carnarvon NCEPH/CSIRO/BoM, 2003

  42. Environmental Refugees UN projection (2006) • By 2020: up to 50 million people escaping effects of environmental deterioration. • order-of-magnitude increase vs. 2005 • Inevitable spectrum of health risks – physical, nutritional, infectious, mental, and conflict situations

  43. CO2 Stabilisation & Global Warming 5.8 2.9 2.3 1.5 1.4 1.2 Stabilising CO2 at: 550 ppm by 2150 could limit warming to 1.5-2.9°C by 2100. 450 ppm by 2090 could limit warming to 1.2-2.3°C by 2100. Note: Current level = 380 ppm (vs 275 pre-industrial)

  44. Major Domains of Adaptation • Strengthening natural and infrastructural defences against physical disasters • Institutional disaster preparedness • Advance warning of epidemic outbreaks (Colombia, Indonesia, etc.) • Managing water resources • Safety/quality and access • Mosquito breeding • Reducing urban vulnerability • Protecting energy systems (decentralisation?) • Minimising heat islands • Protecting food-producing systems and food access • Data systems: Monitoring, surveillance, analysis, dissemination • Health-care system: structure, staffing, connectedness

  45. Tasks for formal health sector 1. Disease prevention 2. Public education 3. Disaster Preparedness 4. Early warning systems 5. Surveillance of disease occurrence and risk factors 6. Forecasting of likely future health risks 7. Engage in inter-sectoral discussions & policy devt 8. Minimise greenhouse gas emissions by health system infrastructure -Resource-intensive hospitals: ~60% of public consumption - Vic DHS: “HERO”; green hospitals

  46. That’s all

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