This document discusses why the health sector should engage with issues of global warming and climate change. It notes that (1) health risks from climate change are increasing and extreme weather events may overwhelm health systems, and (2) climate change jeopardizes other health gains, especially for low-income populations. The health sector has been slow to recognize and respond to these risks. Climate change is occurring faster than expected in the 1990s, with rising greenhouse gas emissions, temperature increases, and sea level rise. Impacts include water shortages, reduced crop yields, and species extinction risks. The document reviews health effects directly from climate impacts like injuries and diseases, as well as indirect effects through changes to food, wealth, and environment.

1. AJ McMichael
National Centre for
Epidemiology and Population Health
The Australian National University
Canberra
Global Warming and Climate Change:
Why the Health Sector Should be Engaged
SEARO Office, New Delhi, March 2008

2. Should the Health Sector Engage?
1. Health risks are real … and are increasing.
2. Extreme weather events likely to increase: Could
overwhelm health sector’s capacity.
3. CC jeopardises other ongoing health gains – esp.
in low-income/vulnerable populations
(e.g. Millennium Devt Goals; HIV/AIDS pandemic; etc.)
4. Health sector has, generally, been slow to
recognise and respond to risk. Consequently:
 Inadequate capacity-building (research, prevention, policy)
 Deficient contact/engagement with other sectors
5. Society has been slow to understand that threat to
health is the most serious, fundamental, risk.
 Population health is ultimate marker of ‘sustainability’

3. Climate Change: Health Impacts
and Policy Responses
Global Environmental
Changes, affecting:
• Climate
• Water
• Food yields
• Other materials
• Physical envtl. safety
• Microbial patterns
• Cultural assets
Natural
processes and
forcings
Impacts on human
society:
• livelihoods
• economic productivity
• social stability
• health
Human society:
• culture, institutions
• economic activity
• demography
Feedback
Adaptation:
Reduce impacts
Human pressure
on environment
Mitigation: Reduce
pressure on environment

4. Overview of Recent CC Science
Together, the reported GCM model runs for the 6 IPCC
emissions scenarios forecast, for 2100, increases in
temperature (central estimate per scenario) of 1.4-5.8 o
C.
Most of the uncertainty reflects unknowable human futures
(the scenarios); the rest is due to model uncertainties.
A further ~0.7 o
C is ‘committed’ (on top of the 0.6o
C already
realised)
IPCC Fourth Assessment Report (2007) already looks
conservative. Recent studies indicate accelerating change.
Political discourse in high-income countries is now starting
to acknowledge need for 80+% reduction in emissions
relative 2000.

5. Climate Change: Faster
than expected in 1990s
IPCC 4 (2007) was limited to
science published by early
2006
Subsequent research shows
increasing rates of:
 Global GHG emissions
3.3% p.a. in 2000s, vs 1.3% p.a.
in 1990s
 Temperature rise
especially in polar regions
 Ice melt (Arctic: 40% loss since
1980, accelerating 2006-07)
 Sea-level rise
CO2 Concentration
Av Surface Temp
Sea Level Rise (cm)
Dashed lines =
1990s projections
Rahmstorf, Church, et
al., Science 2007
Solid lines =
observed
1975 1985 1995 2005

6. Water: 75-250m Africans may face water-shortage by 2020.
Crops:
Rain-fed agriculture could decline by 50% in
some African countries by 2020.
Crop yields could:
increase by 20% in some parts of Southeast Asia … but
decrease by up to 30% in Central/South Asia.
Glaciers and snow cover: Expected to decline, reducing
supply of melt water to major regions, cities.
Species: 20-30% of all plant and animal species face
increased risk of extinction if 1.5-2.5 o
C rise.*
Scientific literature review of >29,000 studies of physical and biological changes in
natural world: 89% consistent with accompanying warming.
Intergovernmental Panel on Climate Change,
WkGp2 Report (2007): Some Key Findings

7. Excerpt from UNDP
Press Release, Nov 27

8. Climate Change & Health
Climate
Change
Impacts
Physical
systems
(ice, rivers, etc.)
Biological
& seasonal
cycles
Economy:
infrastructure,
output, growth
e.g. prime focus of Stern
Report (UK, 2006)
Human Health:
• Injuries/deaths
• Thermal stress
• Infectious diseases
• Malnutrition
• Mental stresses
• Conflict, drugs, etc.
Indirect
impacts Wealth (and distribution);
local environment; etc.
Direct health
impacts (heat,
extreme events,
etc.)
Food yields

9. Cartogram: Emissions of greenhouse gases
Density-equalling cartogram. Countries scaled according to cumulative emissions
in billion tonnes carbon equivalent in 2002. Patz, Gibbs, et al, 2007