tony mcmichael, ao emeritus professor (population health) national centre for epidemiology and...
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Tony McMichael, AOEmeritus Professor (Population Health)
National Centre for Epidemiology and Population Health The Australian National University
Climate Change and Human Population Health: Past, Present, Future
Department of Defence, June 2013
Deaths Attributable to Climate Change: Year 2000
14 WHO statistical regions scaled by estimated annual mortality (selected causes, in 2000) due to change in climate during 1970-2000.
(Patz et al, 2007: based on McMichael, et al, 2004)
Estimated annual deaths attributable to climate change from: malnutrition (~80K), diarrhoea (~50K), malaria (~20K), flooding (~3K)
Physical systems(river flow, vegetation, soils, ocean temp, etc.)
Biological &ecological processes
Economic/social impacts: infrastructure, economic productivity, jobs, coastal displacement, resource-related conflict/warfare
Human Health• Injuries/deaths; mental stress• Thermal stress impacts
Indirect (‘secondary’) impacts, ecologically-mediated: changes in food, water, mosquitoes
Indirect (‘tertiary’) health impacts – socially & politically mediated
Direct (‘primary’) impacts (extreme weather, heatwaves, air pollution)
• Infectious diseases• Under-nutrition
• Mental stresses• Trauma/deaths
Climate Change:
Impacts
Climate Change: Health Impact Pathways
Relationship between Rainfall Index (combines rainfall and temperature) in Spring (April-June) and Barley Yields in Czech Republic since 1940s.
Dry WetNormal Range
Spring Barley Yield (deviation, %)
Rainfall Index, April-June
Brazdil et al, 2008
5-year running mean yield deviation
64
36
20
80
Percentage change in yields to 2050
-50 -20 0 +20 +50 +100
UN Devt Prog, 2009
Not including climate-related:
•Flood/storm/fire damage•Droughts – range,
severity•Pests (climate-sensitive)•Infectious diseases
(ditto)
CLIMATE CHANGE to 2050: MODELLED CHANGES IN CEREAL GRAIN YIELDS (due to temperature and soil moisture)
Poor Countries are Projected to Fare Worst
eg. dengue, malaria;Ross River virus, Lyme disease
eg. nutrition-related immune function
Climate Change: Diverse Influence Paths on Infectious Diseases
Social-demographic influences
NCEPH/CSIRO/BoM/UnivOtago, 2003
Dengue Fever: Estimated ‘receptive’ region for Ae. aegypti
mosquito vector, under alternative climate-change
scenarios for 2050
Risk region for mediumemissions scenario, 2050
Darwin
Katherine
Cairns
Mackay
Rockhampton
Townsville
Port Hedland
Broome..
....
..Carnarvon.
Katherine
Cairns
Mackay
Rockhampton
Townsville
Port Hedland
Broome..
...
..Brisbane.
Current risk region for dengue transmission
Darwin
Katherine
Cairns
Mackay
Rockhampton
Townsville
Port Hedland
Broome..
....
..Carnarvon. Risk region for high
emissions scenario, 2050
Climate Change Influences on Health in Australia
Already apparent: baseline risks amplified by underlying climate change Uptrend in av annual no. of heat-days deaths, hospitalisations
Increases in no./severity bushfires injury/death, resp. hazard, mental health
Severe flooding (due to increased sea-surface temp, increased rainfall?)
Probable current health impacts: but not yet clearly identified Rising rates of some food-borne enteritis (diarrhoeal) diseases Altered (urban) air quality: ozone formation, aeroallergens Mental health impacts, esp. in some (drying) rural regions: e.g. MD Basin
Predicted future health impacts More extreme weather events trauma/deaths, infectious disease, depression Water shortages, affecting food yields, domestic hygiene Mosquito-borne infections – shifts in range and seasonality:
Dengue, Ross River virus, Barmah Forest virus, Japanese encephalitis, etc. Increased thermal stress at work, esp. in outdoor workers and under-ventilated
factories: accidents/injuries, organ damage; reduced work capacity
Sahara dries
Acute cooling: 536 CE ‘Event’
Mediaeval Warm Period,
Europe
Roman Warm Period
Holocene Climatic
Optimum I, II
Drought & cooling in East Mediterranean
region
11 10 9 8 7 6 5 4 3 2 1 0 2 4 6 8 10 12 14 16 18 20 22
Millennia BCE (1000s of yrs) Centuries CE (100s of yrs)
Variations in NH Temp, oC (rel. to Holocene average)
+4
+3
+2
+1
0
-1
-2
-3
BCE/CE
Post-glacial warming following Younger Dryas cooling, 12.8-11.6K BP
Modelled range of projected global
temperature rise to 2100 (vs.1990) = + 2-5oC
Little Ice Age: Europe, China
Holocene
Changes in Average Northern Hemisphere Temperature over the Past 11,000 Years
Early agrarian societies begin to
form: Egypt, Sumer, southern China
Faster warming
since 1975
Acute cooling: Tambora
eruption 1815
AJ McMichael, 2012)
1500 1550 1600 1650 1700 1750 1800
War Fatality Index, Europe
Nth Hemi-sphere
Temperature Variation
oC
Rate of Migrations,
Europe
European Temperature
Variationstandardised units
Cold Period1570-1660
Zhang et al., PNAS, 2011
Europe’s coldest period, 1570-1660, during Little Ice Age Food yields down, grain prices tripled … conflict , war, displacement
Famine-years/decade x 2Epidemic rate x 3Adult height ↓1.5cm
Northern (> 20oN)
Hemisphere temperature
variations, o
( cf 1961- 90 av.)
No. of internal wars (per decade)
Populationsize
(millions)
1000 1200 1400 1600 1800 2000
WarsRebellions
1000 1200 1400 1600 1800 2000
C
N. Song S. Song Yuan Ming Qing
Five (grey) periods of cold in China
Temperature, Conflict, Warfare within China, 1000-1940: Relationship to Fall of Dynasties
Adapted from Zhang et al, 2009
The ‘Little Ice Age’
Hsiang et al., Nature 2011
Affected (n= 93 countries)
(n= 82 countries)
Probability of new civil conflicts breaking out in El Niño years is double that seen in cooler La Niña years
Annual Civil
Conflict Rate
(% of countries
embroiled)
El Niño Index (NINO3: May-Dec average Sea-Surface Temperature)
Civil Conflicts, 1950-2004, in Countries Affected or Not/Little Affected by ENSO
StrongerWeaker