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AJ McMichael National Centre for Epidemiology and Population Health The Australian National University Canberra

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  1. Global Warming and Climate Change: Why the Health Sector Should be Engaged SEARO Office, New Delhi, March 2008 AJ McMichael National Centre for Epidemiology and Population Health The Australian National University Canberra

  2. Should the Health Sector Engage? • Health risks are real … and are increasing. • Extreme weather events likely to increase: Could overwhelm health sector’s capacity. • CC jeopardises other ongoing health gains – esp. in low-income/vulnerable populations • (e.g. Millennium Devt Goals; HIV/AIDS pandemic; etc.) • 4. Health sector has, generally, been slow to recognise and respond to risk. Consequently: • Inadequate capacity-building (research, prevention, policy) • Deficient contact/engagement with other sectors • 5. Society has been slow to understand that threat to health is the most serious, fundamental, risk. • Population health is ultimate marker of ‘sustainability’

  3. Climate Change: Health Impacts and Policy Responses Adaptation:Reduce impacts Natural processes and forcings • Global Environmental Changes, affecting: • Climate • Water • Food yields • Other materials • Physical envtl. safety • Microbial patterns • Cultural assets • Impacts on human society: • livelihoods • economic productivity • social stability • health Human pressure on environment • Human society: • culture, institutions • economic activity • demography Feedback Mitigation: Reduce pressure on environment

  4. Overview of Recent CC Science • Together, the reported GCM model runs for the 6 IPCC emissions scenarios forecast, for 2100, increases in temperature (central estimate per scenario) of 1.4-5.8 oC. • Most of the uncertainty reflects unknowable human futures (the scenarios); the rest is due to model uncertainties. • A further ~0.7 oC is ‘committed’ (on top of the 0.6oC already realised) • IPCC Fourth Assessment Report (2007) already looks conservative. Recent studies indicate accelerating change. • Political discourse in high-income countries is now starting to acknowledge need for 80+% reduction in emissions relative 2000.

  5. CO2 Concentration Av Surface Temp Sea Level Rise (cm) Climate Change: Faster than expected in 1990s Solid lines = observed • IPCC 4 (2007) was limited to science published by early 2006 • Subsequent research shows increasing rates of: • Global GHG emissions 3.3% p.a. in 2000s, vs 1.3% p.a. in 1990s • Temperature rise especially in polar regions • Ice melt (Arctic: 40% loss since 1980, accelerating 2006-07) • Sea-level rise Dashed lines = 1990s projections Rahmstorf, Church, et al., Science 2007 1975 1985 1995 2005

  6. Intergovernmental Panel on Climate Change, WkGp2 Report(2007):SomeKey Findings • Water:75-250m Africans may face water-shortage by 2020. • Crops: • Rain-fed agriculture could decline by 50% in • some African countries by 2020. • Crop yields could: • increase by 20% in some parts of Southeast Asia … but • decrease by up to 30% in Central/South Asia. • Glaciers and snow cover: Expected to decline, reducing supply of melt water to major regions, cities. • Species: 20-30% of all plant and animal species face increased risk of extinction if 1.5-2.5 oC rise.* • Scientific literature review of >29,000 studies of physical and biological changes in natural world: 89% consistent with accompanying warming.

  7. Excerpt from UNDP Press Release, Nov 27

  8. Indirect impacts Direct health impacts (heat, extreme events, etc.) • Human Health: • Injuries/deaths • Thermal stress • Infectious diseases • Malnutrition • Mental stresses • Conflict, drugs, etc. Climate Change & Health Physical systems (ice, rivers, etc.) e.g. prime focus of Stern Report (UK, 2006) Economy: infrastructure, output, growth Climate Change Impacts Food yields Biological & seasonal cycles Wealth (and distribution); local environment; etc.

  9. Cartogram:Emissions of greenhouse gases Density-equalling cartogram. Countries scaled according to cumulative emissions in billion tonnes carbon equivalent in 2002. Patz, Gibbs, et al, 2007

  10. Cartogram: (Selected) health impacts of climate change Malnutrition > diarrhoea > malaria > floods Density-equalling cartogram: Patz, Gibbs, et al, 2007. WHO regions scaled according to estimated mortality (per million people) in the year 2000. Based on burden-of-disease attribution to the climate change that occurred from 1970s to 2000 (McMichael et al., 2003).

  11. Health Impacts Summary: IPCC AR4 (2007) (IPCC, 2007)

  12. Health Impacts: Examples • Thermal stress (esp. heat-waves) • Diarrhoeal disease • Vector-borne infectious disease • Dengue fever • Food yields: nutrition, child development • Disasters: damage, dislocation, displacement

  13. Heatwave: August 2003 Land surface temperatures, summer of 2003, vs. summers of 2000-04. NASA satellite spectrometry 35,000-50,000 extra deaths over a 2-week period

  14. Seasonal variation in daily mortality pattern, Delhi, 1991-94 60 40 Daily deaths 20 0 1jan,1991 1jan,1993 1jan,1995

  15. Heat-related mortality, Delhi, 1991-94: Generalised additive model, with cubic-spline smoothing Relative mortality (% of daily average) 140 120 100 Uncertainty range: 95% CI 80 0 10 20 30 40 Daily mean temperature (oC) McMichael et al, ISOTHURM Study

  16. Diagram of Typical Influence of Seasonal Rainfall, Surface Water, and Crowding on Cholera Occurrence, Madras region Based on Ruiz-Moreno, Pascual, Bouma, et al, EcoHealth 2007; 4: 52-62. Study of 26 districts, Madras Presidency, south-east India, 1901-1940. Ro = ‘reproductive number’ Roprimary (water-borne) transmission Rosecondary (human-to-human) transmission human crowding effect water dilution effect 1.0 1.0 Flood Shallow Water Depth

  17. Domestic bamboo pole holders Found in public housing estates KT Goh, Singapore Ministry of Health

  18. Dengue’s principal vector: Aedes aegypti Principal vector is female Aedes aegypti mosquito. Infected mosquito remains infective for life. Indonesia: reported dengue cases doubled in 2007 vs. 2005.

  19. Effects of Temperature Rise on Dengue Transmission Shorten viral incubation period in mosquito Shorten breeding cycle of mosquito Increase frequency of mosquito feeding More efficient transmission of dengue virus from mosquito to human

  20. Global Dengue Epidemiology 1960s Thousand-fold increase in reported incidence 1990s Dengue fever only DHF/DSS Dengue007/CMH/260302

  21. 1990 2085 Estimated regional probability of dengue occurrence under medium climate change scenario:2085 vs 1990Using statistical equation derived from observations of recent distribution of disease in relation to meterological variables Source: Hales et al. Lancet, 2002. http://image.thelancet.com/extras/01art11175web.pdf Probability

  22. Schistosomiasis: Northwards extension ofpotential transmission (limited by ‘freezing zone’), in Jiangsu province, due to rise in average January temperature since 1960 Freezing zone 1970-2000 Temperature change from 1960s to 1990s 0.6-1.2 oC 1.2-1.8 oC Freezing zone 1960-1990 Baima lake Hongze lake planned Sth-to-Nth water canal Yang et al, 2005: Increase in reported incidence of schistosomiasis over past decade. May reflect recent warming? Northwards extension of “freeze line” (which limits survival of water snails) puts 21 million extra people at risk. Yangtze River Shanghai

  23. Now 2030: + 0.9oC 2050: + 1.6oC Zhou X-N, Yang G-J, et al. Potential Impact of Climate Change on Schistosomiasis Transmission in China “Recent data suggest that schisto-somiasis is re-emerging in some settings that had previously reached the [successful disease control] criteria of either transmission control or transmission interruption. …. Along with other reasons, climate change and ecologic transformations have been suggested as the underlying causes.”

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

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

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

  27. General Relationship of Temperature and Photosynthesis 100% Photo-synthetic activity 2oC  2oC  0% 20o C 30o C 40o C C Field & D Lobell. Environmental Research Letters, 2007: A 1oC increase reduces global cereal grain crop yields by 6-10%. So, a rise of 2oC could mean 12-20% fall in global production. [Note: this estimate is higher than most others.]

  28. Climate change impacts on rain-fed cereal production, 2080 (IIASA: Fischer et al, 2001)

  29. Vietnam Bangladesh Population

  30. Climate Change: Health Impacts and Policy Responses Adaptation:Reduce impacts Natural processes and forcings • Global Environmental Changes, affecting: • Climate • Water • Food yields • Other materials • Physical envtl. safety • Microbial patterns • Cultural assets • Impacts on human society: • livelihoods • economic productivity • social stability • health Human pressure on environment • Human society: • culture, institutions • economic activity • demography Feedback Mitigation: Reduce pressure on environment

  31. CC and Health: Main Types of Adaptive Strategies Public education and awareness Early-alert systems: heatwaves, other impending weather extremes, infectious disease outbreaks Community-based neighbourhood support/watch schemes Climate-proofed housing design, and ‘cooler’ urban layout Disaster preparedness, incl. health-system ‘surge’ capacity Enhanced infectious disease control programs vaccines, vector control, case detection and treatment Improved surveillance: Risk indicators (e.g. mosquito numbers, aeroallergen concentration) Health outcomes (e.g. inf dis outbreaks, rural suicide rates, seasonal asthma peaks) Appropriate workforce training and mid-career development

  32. Use of climate-health time-series data to develop a Malaria Early Warning System (Botswana) Observed summer (Dec-Feb) rain Forecast (advance- modelled) summer rain • Thomson M, et al. Summer rain and subsequent malaria annual incidence in Botswana.Nature 2006; 439: 576-9 Highest malaria incidence years (versus) Log malaria incidence Relationship between summer rainfall and subsequent annual malaria incidence … Lowest malaria incidence years Summer Precipitation (mm / day) Precipitation anomaly (mm / day)

  33. Climate Change and Health Dual Purpose of Research • Enhance Health Protection, at two levels: • 1. Recognition of health risks will potentiate true primaryprevention – i.e. the reduction of GHG emissions. (Which may also revitalise Health Promotion) Meanwhile …. • 2. Health risks already exist and more are unavoidable. So, we must develop and evaluate adaptive (secondary prevention) strategies.

  34. Conclusion Plenty to be worried about – but big chance to play a key role in achieving a global solution, revitalised health promotion – and true Sustainability

  35. Climate Change & Health: ‘Core’ Categories of Research Empirical data-based studies Scenario-based future-health risk assessment 2.Detect impacts 3.Estimate current burden 4. Predictive estimation (eg, modelling) 1.Learn: CC-health relations Past Present Future Adaptive strategies

  36. Climate Change and Geopolitical Security • “Climate change of the order and time frames predicted by climate scientists poses fundamental questions of human security, survival and the stability of nation states which necessitate judgments about political and strategic risks as well as economic cost.” • Heating Up the Planet: Climate Change and Security. • Dupont A, Pearman G, Lowy Institute Paper 12, 2006

  37. Deaths and DALYs attributable to Climate Change, 2000 & 2030 Selected conditions in developing countries Deaths Total Burden Now (2000) Future (2030) Deaths (thousands) DALYs (millions) McMichael et al/WHO, 2004 2000 2030

  38. Impacts, Vulnerability, Adaptations Characteristics of exposed group (location, wealth, resources, health status, culture, etc.) Adaptations Vulnerability of group Learning Actions in response to impact Health Impact Exposure Mitigation: Reduced exposure

  39. Projected warming, to 2100: for six future global greenhouse gas emissions scenariosIntergovernmental Panel on Climate Change (IPCC), 2007 3 of the 6 emissions scenarios Uncertainty range: 1 standard deviation Warming already in ‘pipeline’ from existing GHG levels (~0.6oC) A1FI + 4oC A2 1.8-4.0 oC A1B Warming (oC) + 2oC B1 23 models (tested against recent record) 1980-99 baseline temperature A1T B2 A1FI 16-21 models used for each scenario Range of estimates for all GCM model runs of B1 scenarios emissions No. of models used 1900 2000 2100 6 different GHG emissions scenarios Year

  40. Malaria in Tawau, Sabah Source: VBDCP, MOH

  41. Global rise in dengue cases reported annually to WHO, 1955-2005 925,896 1,000,000 One thousand-fold increase 800,000 479,848 600,000 295,554 400,000 122,174 200,000 15,497 908 0 1955-59 1960-69 1970-79 1980-89 1990-99 2000- 2005 Lancet 2006;368:2194

  42. Health Co-Benefits from GHG Emissions Mitigation Actions: Revitalised Health Promotion? • Reduce fossil fuel combustion: • Reduce cardio-respiratory deaths/hospitalisations from local air pollution (esp. fine particulates). • Low-emission urban (public) transport system: • Increase physical activity (walking, cycling)  reduce over-weight, improve lipid/endocrine profiles, increase social contact and wellbeing. • Road trauma should decline. • Reduce red (ruminant) meat consumption(livestock sector is major source of GHG emissions, esp. methane) • Reduce risks of some disease: large bowel cancer, ?breast cancer; also heart disease (meat fat content). • More energy-efficient housing • Reduce family costs, and (especially for lower-income households) reduce thermal stress – and debt-related mental stress.

  43. Tasks for policy-makers • Integrate health risk assessment into impact assessments carried out by non-health sectors • Understand the intrinsic uncertainties in this topic, including unavoidable uncertainties about projected future risks • Identify vulnerable communities and sub-populations • Develop and evaluate adaptive strategies/interventions to reduce both present and likely future risks to health from climate change • Coordinate development of policy and programs at local, national and international levels • Recognise need for governmental regulatory involvement as basis of societal response to this (and other) global environmental problem(s)

  44. Achieving Sustainability: Citizens, or Society – or Global Governance? • Individual citizen/consumer actions can solve ~5% of problem. (But useful contribution, and good for engagement.) • Large-scale (global) environmental changes need large-scale (governmental) policy changes • We need a Cultural Transformation (‘Third Industrial Revolution’; Sustainability Transition) • Global climate/envtl changes arise from systemic market failures. Government’s role is to remedy these (Adam Smith also recognised that!) …………….. • ‘mutually-agreed mutual coercion’