Climate Change, Prolonged Drought Conditions, and Health

1

• 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

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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

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Climate Change Getting the Science Right
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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
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Increased Weather Variability?
Canberra Tues Feb 27, 2007
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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

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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)
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Climate Change and Health Pathways
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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)
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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 A2 scenarios CSIROMK2 HADCM2
NCEPH/CSIRO, 2005 (ACF/AMA Report)
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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
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• Australias Drought, 2001-2007

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Trend in Mean Temperature, 1950-2005, Australia
Bureau of Meteorology (2006)
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Trend in Annual Rainfall, 1950-2005, Australia
Bureau of Meteorology (2006)
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Rainfall in Dry Period 2001-2006
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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
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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

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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 dominant
Winter
Low rainfall
Marked wet winter and dry summer
Wet winter and low summer rainfall
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Drought Recent expansion and likely future
expansion under climate change
Percentage of worlds 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
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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

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• Drought Conditions and Long-Term Drying
• Risks to Health in Rural Australia

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NSW Annual rainfall and suicide rate, 1964-2001
Nicholls et al. Int J Biometeorol 2005
Deaths per 100,000
Low Annual rainfall
High
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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)

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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

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The future will depend on the nature of human
aspirations, values, preferences and choices
The End