Transcript Climate change and infectious disease

Climate change and its impact on
health in the Pacific Basin
Alistair Woodward
School of Population Health
University of Auckland
Main points
• Climate change represents a new category of
environmental problem
• Increased frequency of extreme weather will have
most dramatic consequences for human health
• Changes in surface temperature, water availability
and sea level will also affect the Pacific Basin
• In response, mitigation and adaptation are both
required
Climate change
“change of climate which is attributed directly or
indirectly to human activity that alters the composition
of the global atmosphere and which is in addition to
natural climate variability observed over comparable
time periods”
UN Convention on Climate Change
Classic environmental health
New category of problem global overload
C arbon dioxi de i n th e atm osph e re at its h i gh e st le ve l for
400,000 ye ars, an d wil l dou ble in th e n e xt ce n tu ry
PREDICTED CLIMATE CHANGE UNDER
THREE SCENARIOS (UKMO)
Business as Usual
4
S 750
Temp 3
increase
(o C)
2
S 550
1
1900
2000
2100
Time
2200
Changes in river runoff
from the present day to the 2080s
Unmitigated emissions
University of
Southampton
Change in annual runoff (%)
–75
–50
–25
–5 to 5
25
50
75
In the 2050s, the Pacific will be
•
•
•
•
•
warmer
drier
subject to more intense rainfall
experiencing more intense storms
facing sea level rise of about 20 cm
How climate change can cause disease and
injury
Direct
• Thermal extremes
• Floods and storms
Indirect
• Vector-borne disease
• Other infections
• Food shortages
• Worsening pollution
• Social disruption
HEAT WAVE - EUROPE
An Estimated
14,800 Deaths
occurred in
France
Heat Index, Summer 2003
Causes of European heatwave?
“well outside the range of expected
variability”
“human-induced component of climate
change has more than doubled the risk of
heatwaves as extreme as the 2003 event”
Stott et al, Nature 2004;432:610-4
Small island regions and coastal flooding, HadCM2: thousands of people
flooded per year
region
1990
2080 - business as
usual
2080 - adaptation
Caribbean
10
1350
560
Indian Ocean
9
920
460
Pacific Ocean
4
290
160
from Nicholls et al, 1999
Increased sea surface temperatures associated
with coral bleaching and increased rates of
ciguatera (fish poisoning) in SW Pacific
Dengue
• Dengue fever is the world’s most important viral
vector-borne disease.
• Affects hundreds of millions of people each year
• Transmitted predominantly by a single species of
mosquito, Aedes aegypti.
• This species is adapted to living near to human
habitation, feeds during the day and prefers
humans to other species.
Model of baseline transmission
(1961-1990 climate)
Model of future transmission
(2080s climate)
Climate change - what to do about it?
• Mitigation
– Reduce the use of oil and coal
– Increase uptake of CO2 by carbon sinks
– Capture, store and re-use emissions
• Adaptation
– Manage ecosystems to reduce impact of climate change (eg forests,
marine reserves)
– Design built environment for an altered climate
– Health system change to reduce vulnerability (eg early warning
systems for heatwaves)
– Social and economic policy (eg development assistance, trade,
migration)
Main points
• Climate change represents a new category of
environmental problem
• Increased frequency of extreme weather will have
most dramatic consequences for human health
• Changes in surface temperature, water availability
and sea level will also affect the Pacific Basin
• In response, mitigation and adaptation are both
required