Global Climate Change Health Risks – and Preventive Strategies by dffhrtcv3

VIEWS: 5 PAGES: 47

									  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
• 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)
                         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.

1987                     World Overshoot Day =
                         [World biocapacity / World
                         Ecological Footprint ] x 365
2000

2006                     This year, in just 282 days, we
                         consume the biosphere’s entire
                         capacity for 2006.

                         www.footprintnetwork.org/gfn_sub
                             php?content=overshoot
       October 9, 2006
 Estimated deaths and DALYs attributable to climate change
       Selected health outcomes in developing countries

    Floods

               Total =
               150,000
    Malaria    deaths/yr

                                                      Now (2000)
 Diarrhoea
                                                       Future (2030)

Malnutrition


           120 100 80      60   40   20   0       2      4     6       8    10
                Deaths (thousands)              DALYs (millions)
                                               WHO,
                                              2000 2004: Global Burden of
                                                             2030
                                                          Disease
 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
    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
Summary of Direction, Magnitude, and Certainty
 of Projected Health Impacts [IPCC: draft only]
                                              Negative Impact Positive Impact
Very High Confidence
Effects on geographic range & incidence of
malaria


High Confidence
 Undernutrition & consequent disorders
 Extreme events
   (heatwaves, storms, floods, droughts)
 Illness/death due to (amplified) poor air quality
 Cold-related deaths


Medium Confidence
 Diarrhoeal diseases
       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
    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


Temperature variation
from 1961-90 average oC




                               Climate Research Unit, UEA, 2005
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 ocean heating
Australia: Recent climate change                            [CSIRO]

• Warming of 0.9oC since 1910,
  mostly since 1950
• Minimum temperatures have
  risen twice as fast as
  maximum temperatures            Trend in mean temp,
                                  1950-2005 (oC/10 yrs)

• 2005 was Australia’s warmest
  year on record
• More heatwaves, fewer frosts
• More rain in north-west since
  1950; less in south and east
                                   Annual total rainfall,
                                  1950-2005 (mm/10 yrs)
 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)
   20
Earth’s Average
   19
                          IPCC (2001)
Surface Temp (OC)         estimate:
   18                     + 1.4-5.8 oC by 2100

   17
                                    Central
                                   estimate:
   16      Most of warming since     2.5 oC
           1950 is due to human    increase
           actions (IPCC, 2001)
   15

   14                                    Band of 1200-yr historical
                                         climatic variability
   13
    1860     1900          1950    2000           2050       2100
                              Year
      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
     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
Greenland Ice Sheet: Increase in Area Melted in Summer,
from 1992 to 2002 (Arctic Climate Impact Assessment, 2004)




             1992                          2002




                 Orange area = melt-zone
          Great Barrier Reef
Annual bleaching by 2030-50 (CSIRO, 2006)
  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
  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)




       Grand Banks cod fishery                              Global marine
                                                            fish harvest




                                                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…”
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:
• 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
  Climate Change and Health: Pathways
                                1
                                    Direct
                                    impact
                                 e.g. heatwaves,
                                 floods, fires

                        Changes to physical
                        systems/processes                     3
Climate                e.g. urban air pollution         Social,       Health
change                                                  economic,
                        Biological changes:             demographic   impacts
             2          processes, timing               disruptions
          Mediating    e.g. mosquito numbers,range;
          processes    photosynthesis  crop yields
          (indirect)
                        Changes to
                        ecosystem structure
                        and function
                       e.g. fisheries; constraints on
                       microbes; nutrient cycles;
                       forest productivity
         Three Types of Study
       Empirical studies
                                           Estimation,
   Learn                  Detect           modelling

   Past                  Present              Future
Natural climate       Current climate      Future climate
variation:            change:              change:
- identify ‘effect’   - detect effects     - estimate risks
- quantify risks      - quantify effects   - est. attrib burden
                      - attribute burden
    Monthly cases of Salmonella food-poisoning in
           relation to monthly temperature
   Australian cities, 1991-2001 (modelled best-fit graphs)

   100                                                   Sydney
    90                                                   Melbourne
Salmonella                                               Brisbane
    80
cases / month                                            Perth
    70
                                                         Adelaide
    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

Excess
Mortality:
France:
14,800
Italy:
10,000
Spain &
Portugal:
5,000
Etc.

Total =
 30,000+
Paris, Heatwave (Aug 2003): Daily Mean Temps and Deaths
 350                                                              35 oC

 300                                                              30
          Mean daily
          temp, 2003                           +12 oC                     ~12oC above
 250                                                              25      season norm
 200                   +8 oC
                                                                  20

 150
                Mean daily                                        15 oC
Daily deaths    temp 1999-2002
 100


  50


   0




                                            ~900 extra deaths
                                            during heatwave
                                 Based on: Vandentorren S, et al. AJPH 2004;94:1518-20.
        Daily temperature and deaths:
   what happens at temperature extremes?
               Impact of Europe 2003 heat-
               wave suggests graph c, not         c
                b, applies at unusually hot
                       temperatures
                                                      b

         We already have sufficient
         observations within this
Daily    ‘normal’ temperature range
death                                         ?
rate                                                  a
               Old adults


               Young adults


         Average         Warm          Hot    Extremely hot
                      Daily temperature
Tick-borne (viral) Encephalitis, Sweden: 1990s v 1980s (winter warming)
                 Changing Distribution of the Tick Vector



        Early                                       Mid-
        1980s                                       1990s




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

                                                     Lindgren et al., 2000, 2001
 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
                                         Freezing zone 1970-2000
                                                                            0.6-1.2 oC
                                          Freezing zone 1960-1990
                                                                            1.2-1.8 oC
                                                 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                    Shanghai
Schistosomiasis japonica. This parasite has moved northwards, putting
20.7 million extra people at risk (Yang, Vounatsou, et al. 2005).
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)
  Estimating Future
Influences of Climate
Change on Health and
     Health Risks
                    Drought
                                      CSIRO Mk2 model: 2030 (high)
CSIRO estimates:                      % change in drought frequency

• By 2030, drought frequency                                   +80
  increases by up to 20% over                                  +60
                                                               +40
  most of Australia                                            +20

• By 2070, drought frequency                                   0
                                                               -20

  increases by 20-80% in                                       -40


  south, 20-40% in Qld, 0-20%                                  +80
  elsewhere (except central                                    +60
                                                               +40
  WA)                                                          +20
                                                               0

  Mpelasoka et al. (in preparation)                            -20
                                                               -40
     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)
Malaria Transmissibility: Temperature and Biology
                                                                      Biting frequency                                Survival probability
Plasmodium Incubation period
  50                                                                                                                  1
                                                               0.3
         40                                                                                                          0.8




                                                                                                         (per day)
                             P.vivax




                                                   (per day)
(days)




         30                  P.falciparum                      0.2                                                   0.6

         20                                                                                                          0.4
                                                               0.1
         10                                                                                                          0.2

         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:                               0.4


          Pascual et al                       0.2

                                               0
          2006                                  14 17 20 23 26 29 32 35 38 41
                                                                Temperature (°C)
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




                                         Ebi et al., 2005
Dengue Fever: Modelling of receptive geographic
region for Ae. Aegyptii mosquito, under alternative
        climate-change scenarios for 2050
                                                                                               .
                                                                                          Darwin

                                                                                               .   Katherine


                      .                                                .                                         .
                                                                                                                 Cairns


                                                                                                                  .
                  Darwin                                            Broome

                      .                                              .                                            Townsville




          .
                           Katherine

                                       .                              Port Hedland
                                                                                                                      .   Mackay

 Broome

 .                                     .
                                       Cairns
                                       Townsville
                                                           .             Risk region for medium Rockhampton               .
   Port Hedland
                                           .    Mackay
                                                               Carnarvon
                                                                         emissions scenario, 2050
      Current risk region for                   . Rockhampton



      dengue transmission                           .
                                                    Brisbane                                Darwin .
                                                                                                   . Katherine



                                                                               .                                  .Cairns
                                                                      Broome


                                                                       .                                           .  Townsville

                                                                           Port Hedland
                                                                                                                          . Mackay



                                                                .       Risk region for high
                                                                Carnarvon
                                                                                                Rockhampton
                                                                                                                           .
                                                                        emissions scenario, 2050

                                                                                   NCEPH/CSIRO/BoM, 2003
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
CO2 Stabilisation & Global Warming
                             6
                                                                               5.8
                                    SRES high
   Temperature change ( C)


                             5      SRES low
  o




                                    IPCC 450 ppm low
                             4      IPCC 450 ppm high
                                    IPCC 550 ppm low
                             3      IPCC 550 ppm high
                                                                               2.9

                                                                               2.3
                             2
                                                                               1.5
                                                                               1.4
                             1                                                 1.2




                             0
                             1980    2000       2020    2040   2060   2080   2100

Stabilising CO2 at:         Year

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
• 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
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
That’s
 all

								
To top