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