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Global Climate Change: Health Risks – and Preventive Strategies. Tony McMichael National Centre for Epidemiology and Population Health The Australian National University. Climate Change 101. The world’s climate is an integrated system

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slide1
Global Climate Change:Health Risks – and Preventive Strategies

Tony McMichael

National Centre for Epidemiology and Population Health

The Australian National University

climate change 101
Climate Change 101
  • The world’s climate is an integrated system
  • Many factors (‘forcings’) influence the atmosphere’s uptake and distribution of energy (heat)
  • Energy-trapping gases (esp CO2, water vapour, CH4) absorb outgoing re-radiated infrared radiation
    • This raises Earth’s surface temperature
  • Human activity is increasing the concentration of these ‘greenhouse’ gases
  • CO2 concentration has increased from 275 ppm to 380 ppm over past century
    • Current trend: 450 ppm by ~2030 (= + 2oC)
slide3
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 consume the biosphere’s entire capacity for 2006.

1987

2000

2006

www.footprintnetwork.org/gfn_subphp?content=overshoot

October 9, 2006

slide4
Estimated deaths and DALYs attributable to climate change

Selected health outcomes in developing countries

Total = 150,000 deaths/yr

Now (2000)

Future (2030)

Deaths (thousands)

DALYs (millions)

2000

2030

WHO, 2004: Global Burden of Disease

climate change relevance to med students
Climate Change: Relevance to Med Students
  • Professional
    • Advice to patients and families
    • Awareness of shifts in differential diagnosis
    • Contribution to organisational policy/advocacy
    • Participation in research
    • Health sector: energy efficiency, technology choices
  • Citizen
    • Participation in public debate and political decisions
    • Community, family and personal decisions/behaviours
doctors for the environment australia http www dea org au poster campaign 2005 2006
Doctors for the Environment Australiahttp://www.dea.org.au/Poster Campaign 2005-2006
recent review articles
Recent Review Articles

McMichael AJ, Woodruff R, Hales S. Climate change and human health: present and future. Lancet, 2006; 367: 859-69.

Website of Intergovernmental Panel on Climate Change (IPCC) – Working Gp 2: chapter on Health Impacts (McMichael & Githeko)

http://www.grida.no/climate/ipcc_tar/wg2/347.htm

research at nceph
Research at NCEPH
  • Daily temperature + air pollution  mortality & hospital admissions
  • Weather patterns and asthma occurrence
  • Daily/weekly temp and food poisoning
  • Climatic and environmental influences on Ross River Virus disease
  • Drought severity and mental health (suicides)
  • Modelling future changes in health risks w.r.t. climate-change scenarios
slide10
Variations of the Earth’s surface temperature

for the past 1,000 years: 1000-2000 AD

2000

Grey area shows statistical uncertainty range

IPCC (2001): SPM 1b

past climate mean surface temperature 1855 2004
Past ClimateMean surface temperature, 1855-2004

Temperature variation from 1961-90 average oC

Climate Research Unit, UEA, 2005

causes of global climate change
Causes of Global Climate Change
  • Natural variability: wobbles of Earth’s axis and changes in orbit (20K-100K yrs), solar activity, volcanoes, ENSO cycle
  • Human activities: increases in greenhouse gases & aerosols, ozone depletion, land clearing
  • IPCC: Most global warming since 1950 due to human activities (incr. greenhouse gas emissions)
    • Evidence for this:
      • land-ocean temperature contrasts
      • annual cycle of terrestrial temperature
      • hemispheric temperature contrast
      • regional warming
      • height of tropopause (between troposphere/stratosphere)
      • pattern of oceanheating
australia recent climate change csiro
Australia: Recent climate change[CSIRO]
  • Warming of 0.9oC since 1910, mostly since 1950
  • Minimum temperatures have risen twice as fast as maximum temperatures
  • 2005 was Australia’s warmest year on record
  • More heatwaves, fewer frosts
  • More rain in north-west since 1950; less in south and east

Trend in mean temp, 1950-2005 (oC/10 yrs)

Annual total rainfall, 1950-2005 (mm/10 yrs)

causes of climate change in australia
Causes of climate change in Australia
  • Warming since 1950 mostly due to global increases in greenhouse gases
  • Rainfall trends: uncertain causes:
    • Increases in northwest: ? natural variability and shift in weather patterns due to increases in northern hemisphere aerosols
    • Decreases in south: ? natural variability plus greenhouse gas increases
    • Decreases in east: ? increase in El Niño events since 1975 (uncertain cause)
slide15
20

IPCC (2001) estimate:

+ 1.4-5.8 oC by 2100

19

18

17

Central estimate:

2.5 oC

increase

16

15

14

Band of 1200-yr historical

climatic variability

Earth’s Average Surface Temp (OC)

Most of warming since 1950 is due to human actions (IPCC, 2001)

13

2050

2100

1860

1900

1950

2000

Year

climate change projections
Climate Change Projections

Instead of simple extrapolation, CSIRO uses computer models of the climate system, driven by future emissions scenarios for greenhouse gas and aerosols (and ozone depletion)

Emission scenarios (e.g. IPCC ‘SRES’) make assumptions about future demographic, economic & technology changes

Global CO2 Emissions

Atmospheric CO2 Concentrations

slide17
Changes in Earth’s temperature over past 80 m years, and upper/lower estimates for next several centuries

2100

Hundreds of years

FUTURE

Now

Homo genus

Hominins appear

PAST

Millions of years

Barrett, Nature, 2003

slide18
Greenland Ice Sheet:Increase in Area Melted in Summer, from 1992 to 2002 (Arctic Climate Impact Assessment, 2004)

2002

1992

Orange area = melt-zone

slide19
Great Barrier Reef

Annual bleaching by 2030-50 (CSIRO, 2006)

two important perspectives
Two Important Perspectives
  • Health risks are influenced by both ‘natural climate variability’ and by (human-induced) climate change
  • Climate change typically acts in concert with other environmental changes
slide21
Worldwide Capture-Fisheries

Fish account for a high proportion of animal protein in the world’s diet – especially in many developing-country coastal communities.

Global fisheries

25% of commercially exploited marine fish stocks are now seriously over-harvested

(Millennium Ecosystem Assessment, 2005)

Global marine fish harvest

Grand Banks cod fishery

Global fisheries harvest has declined since late ’80s

slide22
“… 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…”
slide23
Climate Change and Ocean Acidity Report by (UK) Royal Society, 30 June 2005

Increase in atmospheric carbon dioxide has significantly increased ocean acidity.

Report chairman: "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 – zooplankton, crustaceans, shellfish – is very sensitive to pH. These species are base of marine food web. )

that is in combination
That is, in combination:
  • Over-fishing
  • Ocean warming
  • Ocean acidification

… are all impairing the food web and the future productivity of ocean fisheries

Illustrates problem of emerging global non-sustainability

slide25
Climate Change and Health: Pathways

1

Direct impact

e.g. heatwaves, floods, fires

Changes to physical systems/processes

3

Climate change

Social, economic, demographic disruptions

e.g. urban air pollution

Health impacts

Biological changes: processes, timing

2

e.g.mosquito numbers,range; photosynthesis  crop yields

Mediating processes

(indirect)

Changes to ecosystem structure and function

e.g. fisheries; constraints on microbes; nutrient cycles; forest productivity

slide26
Empirical studies

Estimation, modelling

Learn

Detect

Past

Present

Future

Natural climate variation:

- identify ‘effect’

- quantify risks

Current climate change:

- detect effects

- quantify effects

- attribute burden

Future climate change:

- estimate risks

- est. attrib burden

Three Types of Study

slide27
Perth

Brisbane

Adelaide

Melbourne

Sydney

Monthly cases of Salmonella food-poisoning in relation to monthly temperatureAustralian cities, 1991-2001(modelled best-fit graphs)

100

90

Salmonella cases / month

80

70

60

50

40

30

20

10

0

10

15

20

25

28

Temperature oC

D’Souza, Hall, et al., NCEPH/ANU, 2003

12 day heatwave 3 14 aug 2003 maximum temperature aug 10
12-day Heatwave, 3-14 Aug, 2003Maximum Temperature, Aug 10

Excess Mortality:

France:

14,800

Italy:

10,000

Spain &

Portugal:

5,000

Etc.

Total =

30,000+

slide29
Paris, Heatwave (Aug 2003): Daily Mean Temps and Deaths

35oC

350

300

30

Mean daily temp, 2003

+12oC

~12oC above season norm

250

25

+8oC

200

20

150

Mean daily temp 1999-2002

15oC

Daily deaths

100

50

0

~900 extra deaths during heatwave

Based on: Vandentorren S, et al. AJPH 2004;94:1518-20.

slide30
Daily temperature and deaths:

what happens at temperature extremes?

Impact of Europe 2003 heat-wave suggests graph c, not b, applies at unusually hot temperatures

c

b

We already have sufficient observations within this ‘normal’ temperature range

?

Daily death rate

a

Old adults

Young adults

Average

Warm

Hot

Extremely hot

Daily temperature

slide31
Tick-borne (viral) Encephalitis, Sweden: 1990s v 1980s (winter warming)

Changing Distribution of the Tick Vector

Early 1980s

Mid-1990s

White dots indicate locations where ticks were reported. Black line indicates study region.

Lindgren et al., 2000, 2001

slide32
Schistosomiasis: Potential transmission of S japonicum in Jiangsu province due to raised avg January temperature.[Red lines = part of planned Sth-Nth water canal.]

Temperature change in China from 1960s to1990s

0.6-1.2 oC

1.2-1.8 oC

Freezing zone 1970-2000

Freezing zone 1960-1990

Baima lake

Hongze lake

Yangtze River

Recent studies in China indicate that the increase in recorded incidence of schistosomiasis over the past decade may in part reflect recent warming. The “freeze line” limits survival of the intermediate host (Oncomelania water snails) and hence limits transmission of Schistosomiasis japonica. This parasite has moved northwards, putting 20.7 million extra people at risk (Yang, Vounatsou, et al. 2005).

Shanghai

slide33
Hurricane Katrina crossing Gulf of Mexico

Yellow/orange/red areas at or above 82°F (27.8°C) – the temperature needed for hurricanes to strengthen.

(NASA, 2005)

drought
Drought

CSIRO Mk2 model: 2030 (high)

% change in drought frequency

CSIRO estimates:

  • By 2030, drought frequency increases by up to 20% over most of Australia
  • By 2070, drought frequency increases by 20-80% in south, 20-40% in Qld, 0-20% elsewhere (except central WA)

+80

+60

+40

+20

0

-20

-40

+80

+60

+40

+20

0

-20

-40

Mpelasoka et al. (in preparation)

evidence of el ni o 1997 2006
Evidence of El Niño: 1997, 2006

Sept 15 2006

Sept 20 1997

Sept 20 1997

Note: Warm surface equatorial waters are flowing east across the Pacific, brining rain to Central and South America coasts, and leaving drought in Australia (and beyond)

slide37
P.vivax

P.falciparum

Malaria Transmissibility: Temperature and Biology

Survival probability

Plasmodium Incubation period

Biting frequency

1

50

0.3

0.8

40

0.6

(per day)

30

0.2

(days)

(per day)

0.4

20

0.1

0.2

10

0

0

0

15

20

25

30

35

40

10

15

20

25

30

35

40

10

15

20

25

30

35

40

Temp (°C)

Temp (°C)

Temp (°C)

TRANSMISSION POTENTIAL

1

0.8

0.6

Also: Pascual et al 2006

0.4

0.2

0

14

17

20

23

26

29

32

35

38

41

Temperature (°C)

slide41
Dengue Fever: Modelling of receptive geographic region for Ae. Aegyptiimosquito, under alternative climate-change scenarios for 2050

.

.

Darwin

.

Katherine

.

.

Cairns

.

.

.

Darwin

Broome

Townsville

.

.

Katherine

Port Hedland

.

.

.

Mackay

Cairns

.

Risk region for medium

emissions scenario, 2050

.

Broome

Rockhampton

Townsville

.

Carnarvon

Port Hedland

.

Mackay

Rockhampton

Current risk region for dengue transmission

.

.

.

Darwin

Brisbane

.

Katherine

.

Cairns

.

.

Broome

Townsville

.

Port Hedland

.

Mackay

.

Risk region for high

emissions scenario, 2050

Rockhampton

Carnarvon

NCEPH/CSIRO/BoM, 2003

environmental refugees un projection 2006
Environmental Refugees UN 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 – physical, nutritional, infectious, mental, and conflict situations
co 2 stabilisation global warming
CO2 Stabilisation & Global Warming

5.8

2.9

2.3

1.5

1.4

1.2

Stabilising CO2 at:

550 ppm by 2150 could limit warming to 1.5-2.9°C by 2100.

450 ppm by 2090 could limit warming to 1.2-2.3°C by 2100.

Note: Current level = 380 ppm (vs 275 pre-industrial)

major domains of adaptation
Major Domains of Adaptation
  • Strengthening natural and infrastructural defences against physical disasters
    • Institutional disaster preparedness
  • Advance warning of epidemic outbreaks (Colombia, Indonesia, etc.)
  • Managing water resources
    • Safety/quality and access
    • Mosquito breeding
  • Reducing urban vulnerability
    • Protecting energy systems (decentralisation?)
    • Minimising heat islands
  • Protecting food-producing systems and food access
  • Data systems: Monitoring, surveillance, analysis, dissemination
  • Health-care system: structure, staffing, connectedness
tasks for formal health sector
Tasks for formal health sector

1. Disease prevention

2. Public education

3. Disaster Preparedness

4. Early warning systems

5. Surveillance of disease occurrence and risk factors

6. Forecasting of likely future health risks

7. Engage in inter-sectoral discussions & policy devt

8. Minimise greenhouse gas emissions by health system infrastructure

-Resource-intensive hospitals: ~60% of public consumption

- Vic DHS: “HERO”; green hospitals

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