Overview
•
Direct and indirect impacts
•
Projected health impacts
3
Direct / indirect impacts
•
Climate change can impact directly on
health – e.g. through UV radiation, heat
stress, accidents caused by storms.
•
It can also impact indirectly – e.g. by
altering conditions for disease vectors,
reducing agricultural productivity, and
triggering conflict over scarce
Direct / indirect impacts
"The intimate connection between food
security, water security, energy security
and climate change - to deal with one in
isolation is to present enormous problems”
Professor John Beddington, Chief Scientific Advisor to the Government, speaking at The Climate Connection national
5
Climate Change is Happening Now
6
7
1°C 2°C 3°C 4°C 5°C
Sea level rise
threatens major cities Falling crop yields in many areas, particularly
developing regions
Food
Water
Ecosystems
Risk of Abrupt and Major Irreversible Changes
0°C
Falling yields in many developed regions
Rising number of species face extinction
Increasing risk of dangerous feedbacks and abrupt, large-scale shifts in the climate system Significant decreases in water
availability in many areas, including Mediterranean and Southern Africa Small mountain glaciers
disappear – water supplies threatened in several areas Extensive Damage to Coral Reefs Extreme Weather Events
Rising intensity of storms, forest fires, droughts, flooding and heat waves Possible rising yields in
some high latitude regions450 ppm CO2 eq
650 ppm CO2 eq
Projected Impacts of Global
Temperature Change
9
Extreme Weather Events & Disease Clusters
Human Changes to Global Activated
Nitrogen Cycle, 1900-2050
• Human health risks include:
– Decreased crop yields
– Nitrogen oxides (air pollution)
11
National Carbon Dioxide
Emissions
Total CO
2
Emissions
13
Health Burden of Climate Change
Impacts
Deaths from malaria and dengue fever, diarrhoea, malnutrition, flooding, and (in OECD countries) heatwaves
Painful spots
•
Core knowledge: the effects of climate change
on current responsibilities of Environmental
Health
– air, water, food, pest control, home health
•
Areas for development: Environmental Health
Practitioners as agents for carbon reduction and
adaptation.
15
•
Air quality
•
Water safety
•
Food safety
•
Pest control
•
Housing
Climate change affects the current
Air quality
Climate change impacts
•
Increasing temperatures combine with air
pollution to increase ground level ozone,
causing morbidity from respiratory disease.
•
Tighter controls on pollution to air may be
needed just to maintain current air quality.
•
Surveillance and early warning systems for
17
China Haze 10 January 2003
Health impacts of
climate change
19
Projected impacts
•
Heatwave-related health problems
•
Cold-related illness & deaths
•
Air pollution
•
Flooding
•
Infectious diseases - food borne, waterborne and
vector-borne diseases
•
Exposure to UV radiation
•
Extreme weather-related events
•
New threats appropriate responses
Pathways for Weather to Affect
Health: Example = Diarrheal Disease
Temperature Humidity Precipitation
Distal Causes Proximal Causes Infection Hazards Health Outcome
Living conditions (water supply and sanitation)
Food sources and hygiene practices Survival/ replication of pathogens in the environment Contamination of water sources Rate of person to person contact Consumption of contaminated water Consumption of contaminated food Contact with infected persons Incidence of mortality and morbidity attributable to diarrhea Vulnerability (e.g. age and nutrition) Contamination of
food sources
21
Daily
Temperature Daily Diarrhea Admissions
Diarrhea increases by 8% for each 1ºC increase in temperature
Effect of Temperature Variation on
Diarrheal Incidence in Lima, Peru
Corvalan et al., 2003
Pathways from Driving Forces to
Potential Health Impacts
23
Climate Change
may entail
changes in
variance, as well
as changes in
mean
Methods for:
•
Estimating the current distribution
and burden of climate-sensitive
diseases
•
Estimating future health impacts
attributable to climate change
•
Identifying current and future
adaptation options to reduce the
burden of disease
25
Estimate Potential Future
Health Impacts
•
Requires using climate scenarios
•
Can use top-down or bottom-up
approaches
– Models can be complex spatial models or be based on a simple exposure-response
relationship
•
Should include projections of how other
relevant factors may change
•
Uncertainty must be addressed explicitly
Sources of Uncertainty
•
Data
– Missing data or errors in data
•
Models
– Uncertainty regarding predictability of the system
– Uncertainty introduced by simplifying relationships
•
Other
– Inappropriate spatial or temporal data
– Inappropriate assumptions
– Uncertainty about predictive ability of scenarios
27
Estimating the Global Health
Impacts of Climate Change
•
What will be the total potential health
impact caused by climate change
(2000 to 2030)?
•
How much of this could be avoided
by reducing the risk factor (i.e.
stabilizing greenhouse gas (GHG)
emissions)?
Comparative Risk Assessment
2020s 2050s 2080s Greenhouse gas emissions scenariosGlobal climate modelling:
Generates series of maps of predicted future climate
Health impact model:
Estimates the change in relative risk of specific diseases
Campbell-Lendrum et al., 2003
Time
2080s 2050s
29
Criteria for Selection of
Health Outcomes
•
Sensitive to climate variation
•
Important global health burden
•
Quantitative model available at the global
scale
– Malnutrition (prevalence)
– Diarrhoeal disease (incidence)
– Vector-borne diseases – dengue and falciparum malaria
– Inland and coastal floods (mortality)
– Heat and cold related CVD mortality
Due to both direct & indirect effects:
• Increased physical activity due to extended warm weather. But, outcomes could be worse due to extreme heat
• Reduced obesity and road traffic injuries through active transport
• Possibly healthy eating through adoption of
sustainable farming & food policy and diets containing less animal products
• Reduced respiratory illness by improvements in air quality
• Increased home energy efficiency reducing temperature-related illness
31
Global health impacts of
climate change
Climate change affects the most fundamental
determinants of health: air, food, water, shelter,
freedom from disease.
The impacts on human health are not evenly
distributed. Developing country populations,
particularly in small island states, arid and high
mountain zones, and in densely populated coastal
areas, are first and hardest hit.
33
WHO: five major health
impacts of climate change
1. Malnutrition
2. Deaths and injuries caused by storms and floods. (Flooding can also be followed by outbreaks of diseases, such as cholera)
3. Water scarcity / contamination (droughts and sudden floods) – increased burden of diarrhoeal disease.
4. Heatwaves – direct increases in morbidity and
mortality; indirect effects via increases in ground-level ozone, contributing to asthma attacks.
Major global killers are
affected by climate
Each year:
•
Weather– related disasters kill over
60,000
•
Undernutrition kills 3.5 million
•
Diarrhoea kills 2.2 million
•
Malaria kills 900,000
35
•
Can take the long view
•
Understands the science
•
Other health initiatives will be overtaken by the
effects of climate change
•
Action on climate change has health effects itself
– Positive (“health co-benefits”)
– Negative
Why the health sector?
1) Raising awareness: of the health implications of climate
change
2) Strengthening partnerships: to place health at the
centre of climate change policy
3) Generating evidence: on the health effects of adaptation
and mitigation policies
4) Strengthening public health systems to cope with
additional threats posed by climate change
Main objectives for international
public health
37
With impoverished populations in the developing world
the first and hardest hit, climate change is very likely to
increase the number of preventable deaths. The gaps
in health outcomes we are trying so hard to address
right now may grow even greater.
This is unacceptable.
Climate change and health: preparing for unprecedented challenges.
WHO Director General Margaret Chan. December, 2007
Why health should be central:
• Main reasons for concern (e.g. disasters, food shortage, displacement, disease) are health and wellbeing issues
• Most energy and environment decisions (e.g. choice, use of fuel sources) have major direct health implications
2. Partnerships to raise the profile of health in
climate change policy
39
3. Providing Evidence -
Health Adaptation• Describing risks from national to global level
• Measuring the effectiveness of interventions
• Evaluating health effects from decisions in other sectors
• Improving decision-support tools
• Assessing the financial costs
Protection of handwashing against diarrhoea, highlighting studies in water-stressed situations.
Adapted from Curtis V, Cairncross S. 2003; Lancet Inf Dis 3:275-281
"Health benefits from reduced air pollution as a result of actions to reduce greenhouse gas
emissions… may offset a substantial fraction of mitigation costs" – IPCC, 2007
We have an opportunity to reduce:
- The 800,000 annual deaths from urban air pollution, and the 1.6 million from indoor air pollution
- The loss of 1.9 million lives, and 19 million years of healthy life, from physical inactivity
- The 1.2 million deaths and over 50 million injuries from road traffic accidents
3. Providing Evidence:
Improving health while reducing greenhouse gas emissions
41
4. Strengthening public health systems
Strengthened action on diseases of poverty:
Including wider coverage with vector control and vaccination programmes.
Much of "adaptation" is basic, preventive public health:
Improved surveillance and response: E.g. heatwave warnings,
compliance with International Health Regulations to prevent international spread of disease.
Better management of environmental health determinants:
43
DISCLAIMER
The views expressed in this presentation are those of the authors within the Climate TRAP
project and do not necessarily reflect the views or policies of any participating organisation.
