Climate Change Prolonged Drought Conditions and Health Implications

Climate Change, Prolonged Drought Conditions, and Health Implications for Rural Australia A. J Mc. Michael 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

Modelled projections of warming, for six future greenhouse emissions scenarios IPCC, 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. 5 o. C) A 1 F 1 A 2 1. 8 - 4. 0 o. C A 1 B B 1 1980 -99 baseline models 16 -21 models No. of used for each models scenario used 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: Primary Research Response, Evaluation Observed impacts Predicted impacts Prevent/slow climate change (mitigation) Modify impacts (adaptation)

Climate Change and Health: Pathways 1 Direct impact e. g. heatwaves, floods, bushfires Changes to physical systems/processes e. g. urban air pollution; freshwater supply Climate change 2 Mediating processes (indirect) Changes to biological processes, timing e. g. mosquito numbers, range; photosynthesis, crop damage reduced food yields 3 Social, Health economic, demographic impacts disruptions Changes to ecosystem structure and function e. g. fisheries; nutrient cycles; forest productivity (Mc. Michael, 2005)

Sydney, Heatwave-related Death Rates: Now and in 2100 For persons aged over 65: • Now: 40 per 100, 000 • 2100: → Low emissions scenario: 79/100, 000 → High emissions scenario: 239/100, 000 450 ppm and SRES A 2 scenarios: CSIROMK 2 & HADCM 2 NCEPH/CSIRO, 2005 (ACF/AMA Report)

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

Australia’s Drought, 2001 -2007

Trend in Mean Temperature, 1950 -2005, Australia Bureau of Meteorology (2006)

Trend in Annual Rainfall, 1950 -2005, Australia Bureau of Meteorology (2006)

Rainfall in Dry Period: 2001 -2006 Rainfall Decile Ranges Highest on record Very much > average Above average Average Below average Very much < average Lowest on record

Sources of Rainfall Variability Known major causes Approximate time scale Weather patterns Day/week Southern Annular Mode Weeks Madden-Julian Oscillation Month/s Seasonal shifts in circulations Seasonal El Niño (Southern Oscillation) Inter-annual Indian Ocean Dipole Inter-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 And here? Are the zones being pushed south, by warming? Summer dominant Marked wet summer and dry winter Wet winter and low summer rainfall Summer Wet summer and low winter rainfall Winter dominant Marked wet winter and dry summer Uniform rainfall Arid Low rainfall

Drought: Recent expansion and likely future expansion under climate change Percentage of world’s land area in drought 50 Severe drought (5% circa 2000) Extreme drought (1% circa 2000) 40 % in drought 30 20 10 0 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 Deaths per 100, 000 Nicholls et al. Int J Biometeorol 2005 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 End …The future will depend on the nature of human aspirations, values, preferences and choices…