Climate change and its impact on health in the Pacific Basin Alistair Woodward School of Population...

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

“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

Climate change

Classic environmental health

New category of problem - global overload

Carbon dioxide in the atmosphere at its highest level for400,000 years, and will double in the next century

Time

Business as Usual

S 750

S 550

PREDICTED CLIMATE CHANGE UNDER THREE SCENARIOS (UKMO)

4

3

2

1

Tempincrease(o C)

1900 2000 2100 2200

Changes in river runoff from the present day to the 2080s

Unmitigated emissions

University of Southampton

–75 –50 –25 –5 to 5 25 50 75Change in annual runoff (%)

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 - EUROPEHEAT WAVE - EUROPE

Heat Index, Summer 2003

An Estimated 14,800 Deaths occurred in France

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 19902080 - business as

usual2080 - 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