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Climate Change, Prolonged Drought Conditions, and Health Implications for Rural Australia A.J McMichael National Centre for Epidemiology and Population Health The Australian National University Canberra. Outline of Presentation. Global climate change: state of knowledge
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Climate Change, Prolonged Drought Conditions, and Health Implications for Rural Australia A.J McMichael National Centre for Epidemiology and Population Health The Australian National University Canberra
Outline of Presentation • Global climate change: state of knowledge • Implications for human health • Climate change, drought conditions and rural health . . . . . . . • Need for coordinated research program, including development of adaptive strategies • Conclusion
Modelled projections of warming, for six future greenhouse emissions scenariosIPCC, Feb 2007: Wkg Gp I, Summary for Policy Makers 3 of the 6 GHG emissions scenarios Potential error, to one SD Warming in ‘pipeline’ from current GHG levels (~0.5oC) A1F1 A2 1.8-4.0 oC A1B B1 1980-99 baseline 16-21 models used for each scenario No. of models used models 6 different GHG emissions scenarios
Increased Weather Variability? Canberra: Tues Feb 27, 2007
Climate Change: Faster than Expected? • IPCC 4 (2007) is somewhat conservative • Limited to science published by late 2005 • Subsequent research* shows increasing rates of: • Global GHG emissions • Temperature rise - especially in polar regions • Ice melt • Sea-level rise * e.g. Rahmstorf, Church, et al., Science 2007
CC Impacts and Adaptation: Relationships and Rationale Applied Research: Response, Evaluation Primary Research Prevent/slow climate change (mitigation) Observed impacts Predicted impacts Modify impacts (adaptation)
Climate Change and Health: Pathways 1 Direct impact e.g. heatwaves, floods, bushfires Changes to physical systems/processes 3 Climate change Social, economic, demographic disruptions e.g. urban air pollution; freshwater supply Health impacts Changes to biological processes, timing 2 e.g. mosquito numbers, range; photosynthesis, crop damage reduced food yields Mediating processes (indirect) Changes to ecosystem structure and function e.g. fisheries; nutrient cycles; forest productivity (McMichael, 2005)
Sydney, Heatwave-related Death Rates: Now and in 2100 For persons aged over 65: • Now:40per 100,000 • 2100: • Lowemissions scenario:79/100,000 • Highemissions scenario:239/100,000 450 ppm and SRES A2 scenarios: CSIROMK2 & HADCM2 NCEPH/CSIRO, 2005 (ACF/AMA Report)
Dengue Fever:Estimated region suitable for Ae. Aegypti mosquito, under alternative climate-change scenarios for 2050 . . Darwin . Katherine . . Cairns . Darwin . . Broome Townsville . Katherine Port Headland . . Mackay . Cairns . Risk region for medium emissions scenario, 2050 . . Broome Rockhampton Townsville . Carnarvon Port Headland Mackay . Current risk region for dengue transmission Rockhampton . . . Darwin Brisbane . Katherine . Cairns . . Broome Townsville . Port Headland . Mackay . Risk region for high emissions scenario, 2050 Rockhampton Carnarvon NCEPH/CSIRO/BoM/UnivOtago, 2003
Trend in Mean Temperature, 1950-2005, Australia Bureau of Meteorology (2006)
Trend in Annual Rainfall, 1950-2005, Australia Bureau of Meteorology (2006)
Rainfall Decile Ranges Highest on record Very much > average Above average Average Below average Very much < average Lowest on record Rainfall in Dry Period: 2001-2006
Drought: Related to Climate Change? • CC is causing a decline in winter rainfall • Latitude (southwards) shift in rainfall system • Higher temperature affects evaporation – but complex relationship: • Drier soils (?) • Reduced capture/storage of water • Higher sea-surface temp may cause intensified El Niño events
Seasonal rainfall zones And here? Are the zones being pushed south, by warming? Summer dominant Summer Uniform Marked wet summer and dry winter Wet summer and low winter rainfall Uniform rainfall Arid Winter Winter dominant Low rainfall Wet winter and low summer rainfall Marked wet winter and dry summer
Drought: Recent expansion and likely future expansion under climate change Percentage of world’s land area in drought 50 40 30 20 10 0 Severe drought (5% circa 2000) Extreme drought (1% circa 2000) % in drought 1960 1980 2000 2020 2040 2060 2080 2100 Burke EJ, Brown SJ, Christidis N. 2006. Journal of Hydrometeorology
Climate Change: Impacts on Rural Environment • Climate conditions and food yields • Photosynthesis • Chills and frosts • Livestock health and growth • Extreme weather events: damage • Pests and diseases: plants and animals • Invasive species: “weeds” • Drought severity and duration • Due to (?) shift in rainfall systems, evaporation, and intensification of El Niño cycle • Additional impacts because of reduced irrigation
Drought Conditions and Long-Term Drying: Risks to Health in Rural Australia
NSW: Annual rainfall and suicide rate, 1964-2001 Nicholls et al. Int J Biometeorol 2005 Deaths per 100,000 Low Annual rainfall High
Prolonged Drought Conditions: Rural Health Risks • Adult mental health problems • Child emotional and material experiences: impacts on development and health • Exposures to extremes: heat, dusts, smoke • Reduced freshwater supply: hygiene • Local food production, prices: family diets, nutrition and health • Community erosion, income loss, low morale: changes in health-related behaviours • Remote indigenous communities: above, plus loss of traditional plant/animal food species • …. and benefits? (e.g. reduced mozzie numbers)
Outline of a Comprehensive National Research Program • Secondary (‘opportunistic’) analyses -- from existing, large, population-based epidemiological data sets • Survey-research in selected rural communities gathering information at individual, family and community levels • Develop/assess appropriate methods and levels of intervention (‘adaptive strategies’) -- to prevent or alleviate adverse health impacts
…The future will depend on the nature of human aspirations, values, preferences and choices… The End