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

Estimated Typhoon Parameters Maximum Wind Vel. [m/s] Lowest Cent. Press. [hPa] Lowest Center PressureMaximum Wind Velocity

Severity of Typhoon Effect (Hot Spots) Severity Rank １ Rank ２ Rank ３ Rank ４ Rank ５ Rank ６ Rank ７ Rank ８ Rank ９

Inundation by Local HWL(Tide)

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

Inundation by Local HWL + SLR 59cm + 100yr Strom Surge Inundation by Local HWL + SLR 59cm + 100yr Strom Surge Asia 362 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

DateMax Wind (m/s) Max Wind Radius (km) Storm surge (m) Casualties （ people ） 30 Oct ,179 9 May , May , May , May , Oct Nov , Nov Nov ,069? 25 May ,069? 29 Nov Apr , Nov May May May 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 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 Death Rate (Dead/Population)

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!