1

Nobuo Mimura

Institute for Global Change Adaptation Science Ibaraki University/IR3S

International Symposium “Cities at Risk”

Sea-Level Rise and Coastal Vulnerability

Contents of Presentation

1. Global and Regional Picture - Climate Change and Sea-Level Rise

2. Local and Individual Pictures - Mangrove erosion in Thailand - Cyclones in Bangladesh - Tsunami in Maldives - Coastal Protection in Tokyo

3. Challenges

1. Global and Regional Picture –Climate Change and Sea-Level

(IPCC AR4, 2007)

(IPCC WGI AR4, 2007)

Global Mean Sea-Level

- 17cm rise for the past 100 yrs- Present speed of SLR is 3.2 mm/yr.- In a long tem, collapse of Greenland ice sheet may induce 2-7m SLR.

5

Temperature Rise(2071~2100)

Tropical Cyclones 1949-2007

Estimated Typhoon Parameters

Maximum Wind Vel. [m/s]------

2030405060

172030405060

Lowest Cent. Press. [hPa]---------

860880900920940960980

1000

860880900920940960980

10001013

Lowest Center Pressure Maximum Wind Velocity

Severity of Typhoon Effect (Hot Spots)

Severity

Rank

１Rank

２Rank

３Rank

４Rank

５Rank

６Rank

７Rank

８Rank

９

Inundation by Local HWL(Tide)Inundation by Local HWL(Tide)

Inundation by Local HWL + SLR 59cmInundation by Local HWL + SLR 59cm

Inundation by Local HWL + SLR 59cm + 100yr Strom Surge

Inundation by Local HWL + SLR 59cm + 100yr Strom Surge

Asia362 million people (10.2% of 2000 pop.)

Population Growth in Asia

Vulnerability of Maga-deltas

・ Several millions more people will be flooded annually.・ Proactive and planned adaptation is necessary.

Extreme: >A million （ by 2050 ） High: 　　　 50 K to one million Medium ： 5K to 50 K

（ IPCC WGII AR4, 2007 ）

Case-1

Erosion of Mangrove

in Thailand

2. Individual Pictures

Landsat image around river mouth of Chaophraya

Erosion at the front

Land Subsidence in Bangkok Source:Somkid(2002)

Case-2

Tropical Cyclones in Bangladesh

Date Max Wind (m/s)

Max Wind Radius (km)

Storm surge (m)

Casualties（ peopl

e ）

30 Oct 1960 57.5 74 4.57-69.10 5,179

9 May 1961 40.8 64 2.44-3.05 11,468

28 May 1963 55.6 74 4.27-5.18 11,520

11 May 1965 58.1 74 3.66 19,279

31 May 1965 44.7 64 6.10-7.62 12,000

23 Oct 1966 40.3 64 6-6.67 850

12 Nov 1970 61.7 74 6.10-9.14 500,000

24 Nov 1974 44.7 64 2.8-5.2 200

9 Nov 1983 33.3 64 3.05-4.57 11,069?

25 May 1985 42.5 64 3.05-4.57 11,069?

29 Nov 1988 44.4 64 1.52-3.05 5708

29 Apr 1991 62.5 74 6.10-7.62 138,000

25 Nov 1995 58.3 74 - 650

19 May 1997 55.6 74 4.6 126

26 May 1997 41.7 74 3.0 70

16 May 1998 45.8 74 1.83-2.44 -

History of Cyclone Damages

Combining Early Warning System and Hard Measures

Cyclone Shelter (Chittagong Port City )

Evacuation Road to a Cyclone Shelter

Coastal Dike

(News Week Japanese 1/12) 　

Case-3 2004 Indian Ocean Tsunami- Coastal vulnerability and countermeasures

Male Island

(Preliminary Report of Survey Team, JSCE, April 2005)

埋め立て地と浸水地域の分布　　 (Preliminary Report of Survey Team, JSCE, April 2005)

Male Island

Case-4 Coastal Protection in Tokyo

Affected Pop (million)

HWL 2.3

HWL+SLR 3.2

HWL+SLR+SS 4.2

Increased Population at Risk in Tokyo

History of Flood Damage in Japan

Dead/Missing

Changes in Death Rate Due to Natural Disaster (1945 ～ 1990)

Year

De

ath

Ra

te (

De

ad/

Po

pula

tion

)

3. Challenges

1. Asian cities in low-lying deltas will be increasingly at risk. - Impacts of climate change and SLR - Large population growth and development

2. Development policies and city management aim mainly at short-term goals. - Today’s problems - Large portion of today’s investments will be affected by CC/SLR i.e. 10 to 50% of investment to infrastructure such as coastal dikes, loads, bridges, irrigation facilities.

3. How to incorporate the future risk of CC/SLR into today’s management. - Role of adaptation: increase the preparedness with solving today’s problems - Win-Win approach both to present and future problems - Mainstreaming adaptation

4. Major target of adaptation for coastal cities is management of growth. - Impact and vulnerability assessment is the first step. - Regulate migration of population - Incorporate adaptation to CC in to infrastructure construction and city planning

Thank you very much!