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

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 CO 2, water vapour, CH 4 ) absorb outgoing re-radiated infrared radiation –This raises Earth’s surface temperature Human activity is increasing the concentration of these ‘greenhouse’ gases CO 2 concentration has increased from 275 ppm to 380 ppm over past century –Current trend: 450 ppm by ~2030 (= + 2 o C)

As humanity’s resource consumption increases, World Overshoot Day occurs earlier each year. The first Overshoot Day was Dec 19, 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 php?content=overshoot October 9, 2006

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

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

Doctors for the Environment Australia org.au/ Poster Campaign

Recent Review Articles McMichael AJ, Woodruff R, Hales S. Climate change and human health: present and future. Lancet, 2006; 367: Website of Intergovernmental Panel on Climate Change (IPCC) – Working Gp 2: chapter on Health Impacts (McMichael & Githeko)

Summary of Direction, Magnitude, and Certainty of Projected Health Impacts [IPCC: draft only] Negative ImpactPositive Impact Very High Confidence Effects on geographic range & incidence of malaria High Confidence Undernutrition & consequent disorders Extreme events (heatwaves, storms, floods, droughts) Illness/death due to (amplified) poor air quality Cold-related deaths Medium Confidence Diarrhoeal diseases

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

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

Past Climate Mean surface temperature, Climate Research Unit, UEA, 2005 Temperature variation from average o C

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 ocean heating

Australia: Recent climate change [ CSIRO ] Warming of 0.9 o C 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, ( o C/10 yrs) Annual total rainfall, ( mm / 10 yrs)

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)

Earth’s Average Surface Temp ( O C) Year Central estimate: 2.5 o C increase Band of 1200-yr historical climatic variability Most of warming since 1950 is due to human actions (IPCC, 2001) IPCC (2001) estimate: o C by 2100

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 CO 2 EmissionsAtmospheric CO 2 Concentrations

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

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

Great Barrier Reef Annual bleaching by (CSIRO, 2006)

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

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

“… 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…”

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 CO 2 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. )

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

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

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

Monthly cases of Salmonella food-poisoning in relation to monthly temperature Australian cities, (modelled best-fit graphs) Temperature o C Salmonella cases / month Perth Brisbane Adelaide Melbourne Sydney D’Souza, Hall, et al., NCEPH/ANU, 2003

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

Paris, Heatwave (Aug 2003): Daily Mean Temps and Deaths 30 Mean daily temp, 2003 Mean daily temp ~12 o C above season norm o C o C ~900 extra deaths during heatwave Daily deaths oC+8 oC +12 o C Based on: Vandentorren S, et al. AJPH 2004;94:

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

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

Baima lake Hongze lake Freezing zone Freezing zone Schistosomiasis: Potential transmission of S japonicum in Jiangsu province due to raised avg January temperature. [Red lines = part of planned Sth-Nth water canal.] 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). Temperature change in China from 1960s to1990s o C o C Yangtze River Shanghai

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)

Estimating Future Influences of Climate Change on Health and Health Risks

Drought 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) CSIRO Mk2 model: 2030 (high) % change in drought frequency Mpelasoka et al. (in preparation)

Evidence of El Niño: 1997, 2006 Sept Sept 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)

TRANSMISSION POTENTIAL Temperature (°C) Plasmodium Incubation period (days) Biting frequency Temp (°C) (per day) Survival probability (per day) Temp (°C) Malaria Transmissibility: Temperature and Biology P.vivax P.falciparum Also: Pascual et al 2006

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

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

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

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

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

CO 2 Stabilisation & Global Warming Stabilising CO 2 at: 550 ppm by 2150 could limit warming to °C by ppm by 2090 could limit warming to °C by Note: Current level = 380 ppm (vs 275 pre-industrial)

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

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

That’s all