1Climate Change and Disaster Risk

Science and impacts

Session 1World Bank Institute

Maarten van Aalst

2Climate Change and Disaster Risk

Climate change and its implications for disaster risk

1. Rising use of fossil fuels (oil, coal, gas)

2. Rising concentrations of greenhouse gases in the atmosphere

3. Rising temperatures (global warming)

4. Changes in local average climate (warmer, changing rainfall, higher sea levels, etc.)

5. Changes in local risk of extremes (heat wave, flood, drought, storm, etc.)

CHANGING VULNERABILITY CHANGING DISASTER RISK

6. Socio-economic circumstances, natural resources, political stability, etc.

(A)

(B)

(C)

3Climate Change and Disaster Risk

Disaster trends

100

200

300

0

geophysical

Number of disasters

hydro-meteorological

400

‘90

Source: CRED

‘91 ‘92 ‘93 ‘94 ‘95 ‘96 ‘97 ‘98 ‘99 ‘00 ‘01 ‘02 ‘03 ‘04 ‘05 ‘06

epidemics,insect infestations

4Climate Change and Disaster Risk

The greenhouse effect

5Climate Change and Disaster Risk

The earth is warming

Warmest 12 years:1998,2005,2003,2002,2004,2006, 2001,1997,1995,1999,1990,2000

6Climate Change and Disaster Risk

1928

2004

Upsala glacier, Argentina

Source: Greenpeace

7Climate Change and Disaster Risk

Rain and snowfall patterns

Smoothed annual anomalies for precipitation (%) over land from 1900 to 2005; other regions are dominated by variability.

Increases

Decreases

8Climate Change and Disaster Risk

2020

Black: observations

Red curve: Climate model simulation with all changes, including human influence

Blue curve: Climate model simulation with only natural changes (sun, volcanoes)

Black: observations

“Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations”

9Climate Change and Disaster Risk

Temperature projections for 2100

Low scenario (B1): 1.8°C (likely range 1.1°C to 2.9°C)

High scenario (A1FI): 4.0°C (likely range 2.4°C to 6.4°C)

10Climate Change and Disaster Risk

2020

Regional temperature projections

11Climate Change and Disaster Risk

Increases in rainfall very likely in high latitudesDecreases in rainfall likely in most subtropical land regions

Changes in rainfalls patterns

12Climate Change and Disaster Risk

Severe implications

13Climate Change and Disaster Risk

Implication of extremes (a) more warm days and heat waves

Heat WaveSummer 2003 Europe

Warmer and more frequent hot days and nights over most land areas (virtually certain)More heat waves over most land areas (very likely) Increased incidence of death and serious illness in older

age groups and urban poor Increased electric cooling demand and reduced energy supply reliability Increased risk of damage to a number of crops Increased heat stress in livestock and wildlife Shift in tourist destinations

14Climate Change and Disaster Risk

Increase in mean temperature…….

15Climate Change and Disaster Risk

Implication of extremes (b) less and warmer cold days

Warmer and fewer cold days, and nights over nearly all land areas (already observed: very likely, projected for coming decades: virtually certain)

Decreased cold-related human morbidity and mortality Decreased risk of damage to a number of crops, and increased risk to others Extended range and activity of some pest and disease vectors (e.g., malaria, dengue) Reduced heating energy demand

16Climate Change and Disaster Risk

Implication of extremes (c) more heavy rainfall and snowFrequency of heavy precipitation events increases over most areas (already observed: likely, projected for coming decades: very likely) Increased flood, landslide, avalanche, and mudslide

damage Increased soil erosion Increased flood runoff could increase recharge of some floodplain aquifers Increased pressure on public and private flood insurance systems and disaster relief

17Climate Change and Disaster Risk

Implication of extremes (d) more droughts

Area affected by droughts increases (already observed: likely, in many regions projected for coming decades)

Decreased crop yields Increased damage to building foundations caused by ground shrinkage Decreased water resource quantity and quality Increased risk of forest fire

18Climate Change and Disaster Risk

The most important spatial pattern (top) of the monthly Palmer Drought Severity Index (PDSI) for 1900 to 2002.

The time series (below) accounts for most of the trend in PDSI.

Drought is increasing most places

19Climate Change and Disaster Risk

Implication of extremes (e) heavier tropical cyclones

Increase in tropical cyclone peak wind intensities, meanand peak precipitation intensities (already observed: likely, in some areas projected for coming decades: likely) Increased risks to human life, risk of infectious disease epidemics, and many other risks Increased coastal erosion and damage to coastal buildings and structures Increased damage to coastal

ecosystems such as coral reefs and mangroves

20Climate Change and Disaster Risk

Implication of extremes (f) extreme high sea levels

Increased incidence of extreme high sea levels (already observed: likely, projected for coming decades: likely)

Increased coastal erosion and damage to coastal buildings and structures

Saltwater intrusion, impacts on agriculture and drinking water

21Climate Change and Disaster Risk

Implication of extremes (g) circulation changes

Climate change is affecting storm tracks, winds and temperature patterns

22Climate Change and Disaster Risk

Some aspects of climate have not been observed to change

Tornadoes

Dust-storms

Hail

Lightning

23Climate Change and Disaster Risk

Operational relevance of climate information

Most of the information is not at the scale we might want for field applications, although some important broad trends are getting clearer (e.g., “more variability in rainfall”)

Disaster managers and development planners should note the significant rise in risks. However, they should not expect (and do not need!) perfect climate information to manage that rise in risks.