extending the environment-health research and policy...
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Climate Change, Environmental Change and Health:
Extending the Environment-Health Research and Policy Agenda
Tony McMichael
National Centre for Epidemiology and Population HealthThe Australian National University
Canberra
Environmental Health Risks Scale and Type
Acid rain (regional)
Global Climate-Environmental
changes
Direct, toxic, hazard
Disruption of life/health-support systems
Environmental tobacco smoke
Ambient air pollution
Environment & Health: Background
• Industrialization and urbanization continuation of ‘classic’ direct-acting environmental exposures: → chemicals, physical hazards and microbes (food/water)
• WHO: one-quarter of global disease burden (and one-third of burden in children) due to modifiable environmental factors (Pruss-Ustun & Corvalan, 2006)
→ main contributors: diarrhoea, lower respiratory infections, unintentional injuries, malaria
→ burden much higher in low-income than in high-income countries (25% of all deaths, versus 17%)
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2
4
3
- 1
- 2
- 3
0
MediumLow
Postnatal blood lead up to age 2 years
Gen. CognitiveIndex (McCarthy)IQ (WISC)
IQ (WISC)
2 yrs
11-13 yrs
7 yrs
4 yrsVariation in confounder-adjusted score(one pointapproximates to a one percent change in IQ)
Environmental Lead Exposure and Early Childhood Cognitive Development (McMichael et al)
5 IQ points per 20 ug/dl PbB
Age:
c. 5 ug/dl c. 25 ug/dlc. 15 ug/dlHigh
Motor DevtIndex (Bayley)
Globalisation
Mental hlth and psych disorders
Industrialisation Modernisation Future19001800 2000
Infectious diseases
Obesity
Urban air pollution
Road trauma
Greenhouse gas emissions climate change
Rise and Fall of Urban Health Penalties
Globalisation
Mental hlth and psych disorders
Industrialisation Modernisation Future
1900
1800 2000
Infectious diseases
Obesity
Urban air pollution
Road trauma
Greenhouse gas emissions climate change
Rise and Fall of Urban Health Penalties
Sanitation (infrastructure)
Food safety: laws/regs
Clean air laws
Road/car design
Seat-belt laws Drink/drive
laws
??? Displace responsibility to individuals
Delay, myopia, techo-optimism?
Garden City movementGerm Theory New Towns
WHO Healthy Cities
Education: domestic hygiene
Smoke control: Zoning, best-practice, etc.
Populations
Sub-groups
Individuals
1800 1850 1900 1950 2000
Esp. occupational groupings, industries
Epidemiology since ~1850: Changes in emphasis on different levels/units of analysis
Germ Theory,Micronutrients
Non-Infectious Dis:Esp. individual-level exposures, risk factors
Molecules and genes
Social epi
Sustaining population health: Understanding the effects of systemicchanges
Specific (measured) exposures
Urban v rural
Rich v poor
As humanity’s resource consumption increases, World Overshoot Day occurs earlier each year. The first Overshoot Day was Dec 19, 1987. Today, it is on October 9 – i.e., our Ecological Footprint is almost 30% larger than the planet’s biocapacity.
World Overshoot Day = [World biocapacity / World Ecological Footprint ] x 365 This year, in just 282 days, we consumed the biosphere’s entire capacity for 2006.www.footprintnetwork.org/gfn_sub
php?content=overshoot
1987
2006
2000
October 9, 2006
Global Environmental Changes: Health Impacts, Social Responses
Global Environmental Changes, affecting:• Climate• Water• Food• Useful materials• Physical envtl. safety• Microbial patterns• Cultural assets• Aesthetics
Natural processes and forcings Impacts on human
society: • livelihoods• economic productivity• social stability• wellbeing• health
Mitigation: changes in social priorities, technology, culture
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2
3
Human society: • culture, institutions• economic activity• demography
Feedback change
Feedback change
Adaptation: risk management
Variations in Earth’s surface temperature for past 1,000 years: Northern hemisphere
IPCC (2001): SPM 1b
Grey area shows statistical uncertainty range
2000
131900 21002000
20
15
14
16
17
18
19Earth’s Average Surface Temp (oC)
Year205019501860
Band of long-term historical climatic variability
IPCC (2001) estimate:+ 1.4-5.8 oC by 2100
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20
15
14
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Changes in Earth’s temperature over past 80 million years, and upper/lower estimates for
next several centuries
Millions of years
2100Hundreds of years
Homininsappear
Homo genus
PAST
FUTURE
Barrett, Nature, 2003
Warmest IPCC scenario
Coolest IPCC scenario
Now
Greenland Ice Sheet: Increase in Area Melted in Summer, from 1992 to 2002
(Arctic Climate Impact Assessment, 2004)
Orange area = melt-zone
1992 2002
Climate change
Warming
Warming, plus rainfall changes, etc.
Glaciers meltingSea-ice recedingCoral reefs bleached/dying? More variable weather patterns
Birds, bugs and buds:Nesting timeMigration time/pathsBuds openingEtc.
Direct/indirect impacts on human biology and health
Many other factors
Difficulties with causal attribution
Simplepathways
Complexpathways
Climate Change Impacts on Natural Environment and Biological Systems
Rain Forest, with seasonal fruiting – bat diet
Forest clearing
Fruit orchards
Pig farming
Virus-contaminated fruit, bat droppings
Eaten by pigsInfected (sick) pigs
265 humans infected:JE-like illness~40% fatal~105 deaths
Nipah Virus Disease: Outbreak in Malaysian Pig Farmers, 1997-1999
El Niño drying
Forest-fire smoke (?)
i.e., ?? influencesDeforestation, El Niño conditions, Smoke haze:Decline in fruit
Fruit bats (with “their”virus: ~40% positive)
Climate change
Social, economic, demographic disruptions
Biological changes: processes, timing
Changes to ecosystem structure and function
Direct impact
Mediating processes(indirect)
Health impacts
e.g. heatwaves, floods, fires
e.g. fisheries; constraints on microbes; nutrient cycles; forest productivity
Changes to physical systems/processes
e.g. urban air pollution
e.g. mosquito numbers,range; photosynthesis crop yields
Climate Change and Health: Pathways1
2
3
Three Types of Study
Past FuturePresent
Learn DetectEstimation, modelling
Empirical studies
Paris, Heatwave (Aug 2003): Daily Mean Temps and Deaths
30Mean daily temp, 2003
Mean daily temp 1999-2002
~12 oC above season norm25
15 oC
20
35 oC
~900 extra deaths during heatwave
350
300
250
200
150
100
0
Daily deaths
50
Kalkstein et al, in press
+8oC
+12oC
Daily death rate
Average Warm Hot Extremely hot
We already have sufficient observations within this ‘normal’ temperature range
Daily temperature
?
c
b
a
Young adults
Old adults
Impact of Europe 2003 heat-wave suggests graph c, not b, applies at unusually hot
temperatures
Daily temperature and deaths: what happens at temperature extremes?
Estimated deaths due to hot days
in 2100
Deaths due to hot days in
2000
Independent effect of ageing
Combined (additive) effect of
temperature+ ageing
Possible synergistic
effect of temperature
& ageing (esp. at higher temperatures
than previously encountered)
Independent effect of highertemperature
+ ???
+ 6,900
+ 600
+ 6,300
Baseline (current) no. of annual deaths due to heat = 1,100
+ 11,900
+ 14,000
+ 2,100
+ ???
Forecast heat-related deaths in people aged 65+, due to higher mean annual temperatures:
Australian capital cities, 2100
Woodruff et al. (2005) Climate Change Health Impacts by 2100
High GHG emissionsLow GHG emissions
‘Heat Island’ effect: Comparison of annual mean temperature in urban vs rural Shanghai
Tan Jianguo, 2005 (Beijing)
urban rural
Temperature (oC)
Urban
1.5 oC
Since mid-70s (as world has warmed by 0.5oC),
urban Shanghai has warmed by 2.5 oC,
versus 1.0 oC in rural
Rural
Food Systems: Yields, Access, Health
FAO data: ~840 million under-nourished personsAbsolute increase since 2000
• Over-worked soils (organic matter, etc.)• Chemicalisation (fertilisers)• Irrigation (water-logging, salination) • Climate change → temperature, soil moisture, monsoon systems, floods/droughts, etc.
• Ecosystem disruption (e.g. weeds, pollinators)• Mono-culture vulnerability to pests/infections• Livestock: pests/infections (CC and blue-tongue virus?)
• Access ‘(entitlement’) – social institutions, policies
Worldwide Capture-Fisheries
Global fisheries
Grand Banks cod fishery
Fish account for high proportion of animal protein in world diet –especially in developing-country coastal communities.
25% of commercial marine fish stocks now seriously over-harvested
(Millennium Assessment, 2005)
Global fisheries harvest has declined
since late ’80s
“… the distributions of both exploited and non-exploited North Sea fishes have responded markedly to recent increases in sea temperature…over 25 years. … Further temperature rises are likely to have profound impacts on commercial fisheries.”
Increase in atmospheric carbon dioxide has increased ocean acidity (pH 0.1 units).
Chair: “Failure to cut CO2 emissions may mean that there is no place in the oceans of the future for many of the species and ecosystems that we know today.”
Calcification – in zooplankton, crustaceans, shellfish – is very sensitive to pH.These species are base of marine food web.
Climate Change and Ocean AcidityReport by (UK) Royal Society, June 2005
That is, in combination:
• Over-fishing• Ocean warming• Ocean acidification…all impair productivity of ocean fisheries
Illustrates well the (often) multi-causal nature of environmental non-sustainability
Baima lake Hongze lake
Freezing zone 1960-1990
Freezing zone 1970-2000
Schistosomiasis: Potential transmission of S. japonicum in Jiangsu province due to raised avg January temperature. [Red lines = part of planned Sth-Nth water canal.]
Recent studies indicate that recent increase in recorded incidence of schistosomiasis may in part reflect warming. “Freeze line” limits survival of intermediate host (Oncomelania water snails), limiting transmission of Schistosomiasis japonica. Parasite has moved northwards, putting 20.7 million extra people at risk (Yang et al. 2005).
Temperature change in China from 1960s to1990s
0.6-1.2 oC
1.2-1.8 oC
Yangtze River
Shanghai
Risk Map (current) for Dengue: average of 100 bootstrap models
Green (prob < 0.5) = not suitable. Yellow Red = increasing suitability
For comparison: WHO map for dengue, 2003, is shown
with black linesRogers D, et al. Advances in Parasitology 2006
NCEPH/CSIRO/BoM, 2003
Dengue Fever: Modelling of receptive geographic region for Ae. Aegyptii mosquito, under alternative
climate-change scenarios for 2050
Risk region for mediumemissions scenario, 2050
Darwin
Katherine
Cairns
Mackay
Rockhampton
Townsville
Port Hedland
Broome ..
.... ..
Carnarvon.
Darwin
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 highemissions scenario, 2050
1990
2085
Estimated population at risk of Dengue Fever (i.e. vector climate envelope) under mid-range climate change scenario: 2085 (vs 1990)
Source. Hales, Woodward, et al. Lancet (online) 6 Aug 2002. http://image.thelancet.com/extras/01art11175web.pdf
TRANSMISSION POTENTIAL
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0.8
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Temperature (°C)
Plasmodium Incubation period
0
10
20
30
40
50
15 20 25 30 35 40
(day
s)
Biting frequency
0
0.1
0.2
0.3
10 15 20 25 30 35 40Temp (°C)
(per
day
)
Survival probability
0
0.2
0.4
0.6
0.8
1
10 15 20 25 30 35 40
(per
day
)
Temp (°C) Temp (°C)
Malaria Transmissibility: Temperature and Biology
P.vivaxP.falciparum
See also: Pascual et al 2006
Ebi et al., 2005
Climate Change & Malaria (potential transmission) in Zimbabwe
Baseline 2000 2025 2050
Harare
Ebi et al., 2005
Climate Change & Malaria (potential transmission) in Zimbabwe
Baseline 2000 2025 2050
Ebi et al., 2005
Climate Change & Malaria (potential transmission) in Zimbabwe
Baseline 2000 2025 2050
Environmental RefugeesUN projection (2006)
• By 2020: up to 50 million people escaping effects of environmental deterioration. → order-of-magnitude increase vs. 2005
• Inevitable spectrum of health risks –infectious, nutritional, physical, mental, and conflict situations
Global warming: scenarios
1.21.41.5
2.3
2.9
5.8
Stabilising CO2 at 550 ppm by 2150 could limit warming to 1.5-2.9°C by 2100. Stabilising CO2 at 450 ppm by 2090 could limit warming to 1.2-2.3°C by 2100. Pre-industrial CO2 = 275 ppm; Current level = 385 ppm
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1980 2000 2020 2040 2060 2080 2100Year
Tem
pera
ture
cha
nge
(o C) IPCC (SRES) high
IPCC (SRES) lowIPCC 450 ppm lowIPCC 450 ppm highIPCC 550 ppm lowIPCC 550 ppm high
Now
Low-high range
Human pressures on environment
Impact on local envt:ContaminationResource depletion
Long-term impacts on human wellbeing, health and survival
The real reason for seekingSustainability
Near-term direct health impacts
Regional/Global environment:Disruption of natural systems
Impaired life-support processes(soil regeneration, climate stability; flood control; microbe constraints; nutrient cycling; etc.)
“Triple Bottom Line” – the focus of much current discussion
Reducedenvironmental assets: recreational, aesthetic, spiritual losses
Social disruption:jobs, institutions, etc.
Impaired economic productivity
Population Health as Key Criterion of Sustainability
…The future will depend on the nature of human aspirations, values, preferences and choices…The End
Health and Sustainability
Population health is both: • input to sustainable development, and• criterion (especially in the long term) for
the achievement of sustainability
i.e. Population health is the real bottom line (i.e., the purpose) of Sustainability
Tick-borne (viral) Encephalitis, Sweden: 1990s v 1980s (winter warming)Northward Trend in Distribution of Tick Vector
Early 1980s
Mid-1990s
Lindgren et al., 2000, 2001
White dots indicate locations where ticks were reported. Black line indicates study region.
Global Environmental Change & Health: causes, impacts, linkages
Immune suppressionEyes (cataracts, etc.)Skin damage/cancer
Land cover change
Direct impactsThermal stress: death, disease events, injuryStorms, cyclones, floods, firesSea-level rise: phys hazards, displacement
Changes in vector species (mosquitoes, etc.)
Infectious disease risks (emerging and resurging/spreading)
Food yields: nutrition and health
Predation by humans
Slums, hygiene; physical hazards; infectious disease risks (mobility, contact networks, density)
e.g. pollination
Avian ‘flu, Nipahvirus, BSE, etc.
Land use
Carbon cycle & Climate Change
Water systems, watersheds: management
Urbanisation; human settlements
Direct impactsStrat ozone depletion
(vulnerability)
Spread of invasive species
Food-production systems, methods (+ fisheries?)
Biodiversity changes
Climate change blamed for surge in Legionnaires' Disease
The Independent, UK, 18 October 2006
“Britain has suffered its first deaths from infectious disease attributable to global warming, official figures suggest.
“Cases of Legionnaires' disease, the bacterial lung infection which kills more than one in 10 of those it infects, reached record levels in August and September and experts say the extreme summer weather is the most likely cause of the rise.”
http://news.independent.co.uk/uk/health_medical/article1886640.ece
Monthly Salmonella food-poisoning cases in relation to monthly temperature
Australian cities, 1991-2001 (modelled best-fit graphs)
0
10
20
30
40
50
60
70
80
90
100
10 15 20 25 28Temperature oC
Salmonella cases / month Perth
Brisbane
Adelaide
MelbourneSydney
D’Souza et al., NCEPH/ANU, 2003