Climate Change, Prolonged Drought Conditions, and Health
Implications for Rural Australia
A.J McMichael
National Centre forEpidemiology 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 modelsusedmodels
A2
B1
A1F1
1.8 - 4.0 oC
Modelled projections of warming, for six future greenhouse emissions scenarios
IPCC, Feb 2007: Wkg Gp I, Summary for Policy Makers
A1B
1980-99 baseline
Warming in ‘pipeline’ from current GHG levels (~0.5oC)
16-21 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 disruptionsChanges 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: Pathways1
2
3
(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 100,000• 2100:
→ 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 mediumemissions 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, 2001-2007
Trend in Mean Temperature, 1950-2005, Australia
Trend in Mean Temperature 1950-2005 (oC/10yrs)Trend in Mean Temperature 1950-2005 (oC/10yrs)Trend in Mean Temperature 1950-2005 (oC/10yrs)
Bureau of Meteorology (2006)
Trend in Annual Total Rainfall 1950-2005 (mm/10yrs)Trend in Annual Total Rainfall 1950-2005 (mm/10yrs)Trend in Annual Total Rainfall 1950-2005 (mm/10yrs)
Bureau of Meteorology (2006)
Trend in Annual Rainfall, 1950-2005, Australia
Rainfall in Dry Period: 2001-2006
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 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
Marked wet summer and dry winter
Wet summer and low winter rainfall
Uniform rainfall
Marked wet winter and dry summer
Low rainfallWet winter and low summer rainfall
AridWinter dominantWinter
Summer dominant Summer Uniform
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. 2006. Journal of Hydrometeorology
1960 1980 2000 2020 2040 2060 2080 2100
50
40
30
20
10
0
% 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, 1964-2001
Nicholls et al. Int J Biometeorol 2005
Low Annual rainfall High
Dea
ths
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
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