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

Climate Change: Getting the Science Right

6 different GHG emissions scenarios 3 of the 6 GHG emissions scenarios Potential error, to one SD No. of models used models A2 B1 A1F o C Modelled projections of warming, for six future greenhouse emissions scenarios IPCC, Feb 2007: Wkg Gp I, Summary for Policy Makers A1B baseline Warming in ‘pipeline’ from current GHG levels (~0.5 o C) models used for each scenario

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 Observed impacts Predicted impacts Primary Research Applied Research: Response, Evaluation Modify impacts (adaptation) Prevent/slow climate change (mitigation)

Climate change Social, economic, demographic disruptions Changes to biological processes, timing Changes to ecosystem structure and function Direct impact Mediating processes (indirect) Health impacts e.g. heatwaves, floods, bushfires e.g. fisheries; nutrient cycles; forest productivity Changes to physical systems/processes e.g. urban air pollution; freshwater supply e.g. mosquito numbers, range; photosynthesis, crop damage  reduced food yields Climate Change and Health: Pathways (McMichael, 2005)

Sydney, Heatwave-related Death Rates: Now and in 2100 NCEPH/CSIRO, 2005 (ACF/AMA Report) 450 ppm and SRES A2 scenarios: CSIROMK2 & HADCM2 For persons aged over 65: Now: 40 per 100, : → Low emissions scenario: 79/100,000 → High emissions scenario: 239/100,000

NCEPH/CSIRO/BoM/UnivOtago, 2003 Dengue Fever: Estimated region suitable for Ae. Aegypti mosquito, under alternative climate-change scenarios for 2050 Risk region for medium emissions scenario, 2050 Darwin Katherine Cairns Mackay Rockhampton Townsville Port Headland Broome Carnarvon. Darwin Katherine Cairns Mackay Rockhampton Townsville Port Headland Broome Brisbane. Current risk region for dengue transmission Darwin Katherine Cairns Mackay Rockhampton Townsville Port Headland Broome Carnarvon. Risk region for high emissions scenario, 2050

Australia’s Drought,

Trend in Mean Temperature, , Australia Bureau of Meteorology (2006)

Trend in Annual Rainfall, , Australia

Rainfall in Dry Period: Very much > average Above average Average Below average Very much < average Lowest on record Rainfall Decile Ranges Highest on record

Sources of Rainfall Variability Known major causesApproximate time scale Weather patternsDay/week Southern Annular ModeWeeks Madden-Julian OscillationMonth/s Seasonal shifts in circulationsSeasonal El Niño (Southern Oscillation) Inter-annual Indian Ocean DipoleInter-annual Inter-decadal Pacific Oscillation Inter-decadal

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 Marked wet summer and dry winter Wet summer and low winter rainfall Uniform rainfall Marked wet winter and dry summer Low rainfall Wet winter and low summer rainfall Arid Winter dominantWinter Summer dominantSummerUniform Are the zones being pushed south, by warming? And here?

Drought: Recent expansion and likely future expansion under climate change Percentage of world’s land area in drought Extreme drought (1% circa 2000) Severe drought (5% circa 2000) Burke EJ, Brown SJ, Christidis N Journal of Hydrometeorology % in drought

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, Nicholls et al. Int J Biometeorol 2005 Low Annual rainfall High Deaths per 100,000

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