AJ McMichael

National Centre forEpidemiology and Population Health The Australian National University Canberra

Global Warming and Climate Change: Why the Health Sector Should be Engaged

SEARO Office, New Delhi, March 2008

Should the Health Sector Engage?Health risks are real and are increasing.Extreme weather events likely to increase: Could overwhelm health sectors 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 sectors5.Society has been slow to understand that threat to health is the most serious, fundamental, risk. Population health is ultimate marker of sustainability

Climate Change: Health Impacts and Policy ResponsesGlobal Environmental Changes, affecting:

Climate Water Food yields Other materials Physical envtl. safety Microbial patterns Cultural assetsNatural processes and forcingsImpacts on human society: livelihoods economic productivity social stability healthHuman society: culture, institutions economic activity demographyFeedbackAdaptation: Reduce impactsHuman pressure on environmentMitigation: Reduce pressure on environment

Overview of Recent CC ScienceTogether, 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.

Projected warming, to 2100: for six future global greenhouse gas emissions scenarios

Intergovernmental Panel on Climate Change (IPCC), 2007: Wkg Gp I6 different GHG emissions scenarios3 of the 6 emissions scenariosUncertainty range: 1 standard deviationNo. of modelsused

A2

B1

A1F1

1.8 - 4.0 oC

A1BWarming already in pipeline from existing GHG levels (~0.6oC)Warming (oC)Year+ 2oC+ 4oC

23 models (tested against recent record)

1980-99 baselinetemperature

16-21 models used for each scenarioA1TB2A1F11900 2000 2100

Climate Change: Faster than expected in 1990s 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 1990sTemperature rise especially in polar regionsIce melt (Arctic: 40% loss since 1980, accelerating 2006-07)Sea-level rise

Dashed lines = 1990s projectionsRahmstorf, Church, et al., Science 2007Solid lines = observed1975 1985 1995 2005

Intergovernmental Panel on Climate Change, WkGp2 Report (2007): Some Key FindingsWater: 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.

Excerpt from UNDP Press Release, Nov 27

Climate Change & HealthClimate ChangeImpactsPhysical systems(ice, rivers, etc.)Biological & seasonal cyclesEconomy: infrastructure, output, growthe.g. prime focus of Stern Report (UK, 2006)Wealth (and distribution); local environment; etc.Food yields

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

Cartogram: (Selected) health impacts of climate change

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). Malnutrition > diarrhoea > malaria > floods

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

Health Impacts: ExamplesThermal stress (esp. heat-waves)Diarrhoeal diseaseVector-borne infectious diseaseDengue feverFood yields: nutrition, child developmentDisasters: damage, dislocation, displacement

Heatwave: August 200335,000-50,000 extra deaths over a 2-week periodLand surface temperatures, summer of 2003, vs. summers of 2000-04. NASA satellite spectrometry

Seasonal variation in daily mortality pattern, Delhi, 1991-94Daily deaths 1jan,19911jan,199302040601jan,1995

Daily mean temperature (oC)Heat-related mortality, Delhi, 1991-94: Generalised additive model, with cubic-spline smoothing 01020304080100120140Uncertainty range: 95% CIMcMichael et al, ISOTHURM StudyRelative mortality (% of daily average)

Diagram of Typical Influence of Seasonal Rainfall, Surface Water, and Crowding on Cholera Occurrence, Madras region Water DepthShallowFloodRo primary (water-borne) transmissionRo secondary (human-to-human) transmission1.01.0Based on Ruiz-Moreno, Pascual, Bouma, et al, EcoHealth 2007; 4: 52-62.Study of 26 districts, Madras Presidency, south-east India, 1901-1940. waterdilution effecthuman crowding effectRo = reproductive number

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

Dengues principal vector: Aedes aegyptiPrincipal vector is female Aedes aegypti mosquito. Infected mosquito remains infective for life.Indonesia: reported dengue cases doubled in 2007 vs. 2005.

Effects of Temperature Rise on Dengue Transmission Shorten viral incubation period in mosquitoShorten breeding cycle of mosquitoIncrease frequency of mosquito feedingMore efficient transmission of dengue virus from mosquito to human

Global Dengue EpidemiologyDengue007/CMH/2603021960s1990s Dengue fever only DHF/DSSThousand-fold increase in reported incidence

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 variablesSource: Hales et al. Lancet, 2002. http://image.thelancet.com/extras/01art11175web.pdf Probability

Baima lake Hongze lakeSchistosomiasis: Northwards extension of potential transmission (limited by freezing zone), in Jiangsu province, due to rise in average January temperature since 1960Yang 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 RiverShanghaiTemperature change from 1960s to 1990s

0.6-1.2 oC

1.2-1.8 oCFreezing zone 1960-1990Freezing zone 1970-2000planned Sth-to-Nth water canal

Zhou X-N, Yang G-J, et al. Potential Impact of Climate Change on Schistosomiasis Transmission in ChinaRecent 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.

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

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

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

Photo-synthetic activity20o C30o C40o CGeneral Relationship of Temperature and Photosynthesis0%100%2oC 2oC 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.]

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

Population

Climate Change: Health Impacts and Policy ResponsesGlobal Environmental Changes, affecting:

Climate Water Food yields Other materials Physical envtl. safety Microbial patterns Cultural assetsNatural processes and forcingsImpacts on human society: livelihoods economic productivity social stability healthHuman society: culture, institutions economic activity demographyFeedbackAdaptation: Reduce impactsHuman pressure on environmentMitigation: Reduce pressure on environment

CC and Health: Main Types of Adaptive StrategiesPublic education and awarenessEarly-alert systems: heatwaves, other impending weather extremes, infectious disease outbreaksCommunity-based neighbourhood support/watch schemesClimate-proofed housing design, and cooler urban layoutDisaster preparedness, incl. health-system surge capacityEnhanced infectious disease control programs vaccines, vector control, case detection and treatmentImproved 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

Use of climate-health time-series data to develop a Malaria Early Warning System (Botswana)Thomson M, et al. Summer rain and subsequent malaria annual incidence in Botswana. Nature 2006; 439: 576-9 Highest malaria incidence years

(versus)Lowest malaria incidence yearsPrecipitation anomaly (mm / day)Observed summer (Dec-Feb) rainForecast (advance- modelled) summer rainRelationship between summer rainfall and subsequent annual malaria incidence Log malaria incidenceSummer Precipitation (mm / day)

Climate Change and Health Dual Purpose of ResearchEnhance Health Protection, at two levels: 1. Recognition of health risks will potentiate true primary prevention 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.

ConclusionPlenty to be worried about but big chance to play a key role in achieving a global solution, revitalised health promotion and true Sustainability

Climate Change & Health: Core Categories of Research1. Learn: CC-health relations2. Detect impacts3. Estimate current burden4. Predictive estimation (eg, modelling)Empirical data-based studiesScenario-based future-health risk assessmentPastFuturePresentAdaptive strategies

Climate Change and Geopolitical SecurityClimate 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

Deaths (thousands)DALYs (millions)20002030Deaths and DALYs attributable to Climate Change, 2000 & 2030Selected conditions in developing countries

McMichael et al/WHO, 2004

Now (2000)Future (2030)DeathsTotal Burden

ExposureHealth Impact Actions in response to impact

Characteristics of exposed group (location, wealth, resources, health status, culture, etc.)Vulnerability of groupAdaptationsImpacts, Vulnerability, AdaptationsMitigation: Reduced exposureLearning

Projected warming, to 2100: for six future global greenhouse gas emissions scenarios

Intergovernmental Panel on Climate Change (IPCC), 20076 different GHG emissions scenarios3 of the 6 emissions scenariosUncertainty range: 1 standard deviationNo. of modelsused

A2

B1

A1FI

1.8 - 4.0 oC

A1BWarming already in pipeline from existing GHG levels (~0.6oC)Warming (oC)Year+ 2oC+ 4oC

23 models (tested against recent record)

1980-99 baselinetemperature

16-21 models used for each scenarioA1TB2A1FI1900 2000 2100Range of estimates for all GCM model runs of B1 scenarios emissions

Malaria in Tawau, SabahSource: VBDCP, MOH

Global rise in dengue cases reported annually to WHO, 1955-2005Lancet 2006;368:2194925,896479,848295,554122,17490815,4970200,000400,000600,000800,0001,000,0001955-591960-691970-791980-891990-992000-2005One thousand-fold increase

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.

Tasks for policy-makersIntegrate 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 risksIdentify 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 levelsRecognise need for governmental regulatory involvement as basis of societal response to this (and other) global environmental problem(s)

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 changesWe need a Cultural Transformation (Third Industrial Revolution; Sustainability Transition)Global climate/envtl changes arise from systemic market failures. Governments role is to remedy these (Adam Smith also recognised that!) .. mutually-agreed mutual coercion

Linking these projections to a series of climate-health models, take conservative simplistic account of csocioeconomic factors, come up with the following projections.

Insights:

Small changes in big burdens may be more important than large relative changes in small burden s (floods vs. diarrheoa)

Of course, climate is not the only influence on these disease, we need to take account of changes in socioeconomic conditions etc.

We address this in several ways. Firstly, we apply our proportional changes to disease burdens, and future projections, that already take account of socioeconomic influences over time, and between different WHO regions.. Small proportional changes in areas with a large disease burden therefore weigh much heavier than changes in areas where socioeconomic conditions and health services keep diseases in check.

Secondly, we make a series of reasonable conservative assumptions on SE effects. For example, based on previous analyses carried out at LSHTM we think it is unlikely that climate change will lead to re-establishment of malaria in Western Europe.

Finally, we make conservative assumptions about the climate sensitivity of these diseases. In the diarrhoea example, we have no evidence on the effect of temp on all cause DD in developed countries

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