Adaptation to Climate Change: Experiences and Trends in the Mekong Delta

Transcription

1 Adaptation to Climate Change: Experiences and Trends in the Mekong Delta Dr. Duong Van Ni, Cantho University, Vietnam Ni 2005 Location of Vietnam in the Southeast Asia & the Mekong delta Land of ~18M (21% of VN) Food Production: 50% of VN Fish Production: 65% of VN Fruit Production: 70% of VN 1

2 Land uses often depends on: Topography, Soil characters, Hydrology, Infrastructures, Economy and Policies. A cross section of Land uses Melaleuca forest Depression area Irrigated paddy rice Fruit trees Old settlement Canals Rivers Rainfed paddy rice New settlement Coastal mangrove forest Sea Aquaculture 2m (modified from Tuan, 2009) Diagram showing different land uses in a cross section from inland (left) to coastal land (right). The average elevation is about 1.5m above the sea level! 2

3 0 20 Kil ometers Kilometers K ilometers 40 Land uses vs Topography Shrimp farming Rice-fish crop Irrigated rice crop High tide Low tide Land uses (shrimp) vs Policy changes The Government Decision 09 in June 2000, officially allowing diversification of land with low rice productivity into aquaculture or other uses LAND USE CHANGE MAP I N THE MEKONG DELTA - VI ETNAM IN YEAR 2000 IN YEAR 2002 CAMBODIA IN YEAR 1990 CAMBODIA CAMBODIA CAO LANH HO CHI MINH CITY TAN AN MY THO HA TIEN LONG XUYEN CAO LANH HO CHI MINH CITY TAN AN M Y THO HA TIEN LONG XUYEN CAO LANH HO CHI MINH CITY TAN AN M Y THO LONG XUYEN VINH LONG BEN TRE VINH LONG BEN TRE GULF OF THAILAND CAN THO VINH LONG TRA VINH BEN TRE GULF OF THAILAND RACH GIA CAN THO TRA VINH GULF OF THAILAND RACH GIA CAN THO TRA VINH SOC TRANG SOC TRANG BAC LIEU SOC TRANG CA MAU BAC LIEU S O U T H C H I N A S E A CA M AU BAC LIEU S O U T H C H I N A S E A CA MAU S LEGEND "SS": Spring Summer "SW" : Summer Winter "WS" : Winter Spring "RS" : Rainy Season 3 irrigated rice crops ( WS-SS-SA ) 2 irrigated rice crops ( WS - SA ) 2 irrigated rice crops ( WS - RS ) 2 rainfed rice crops ( SA - RS ) 2 rice crops + 1upland crop 2 rice crops + fish 1 rainy season rice 1 irrigated rice + 1upland crop 1 rainy season rice - Shrimp Vegetables, upland crop Sugarcane Pineapple Shifting land Coconut - Settlement areas Shrimp field Melaleuca forest Eucalyptus forest Mangrove forest Mangrove forest + Shrimp Nipapalm, brush on riverside Salt field No policy Policy 10 yrs 2 yrs National park, Natural reservation Agro - Porestry land & unused land Unused land Forestry land without trees Rocky hills Land for minerals/ construction materials Tidal mudflat Orchards - Settlement areas Integrated Resources Mapping Centre (IRMC) River, canal Oct.2002 In 1990 In 2000 In

4 Saline water shrimp (Penaeus monodon) Fresh water shrimp (Macrobrachium rosenbergii) The Mekong delta was leading exporter of: 1st of catfish (1 M ton/yr); 2nd of rice (6 M ton/yr) and 8th of shrimp (2.5 M ton/yr) Basa cat fish Rice (Pangasius sp.) (Oriza sativa) Environmental threats: by habitat alteration by over- exploitation by pollution by invasive species by global climate change 4

5 IPCC classified large, heavily populated deltas hot spots of societal vulnerability to climate change. Relative vulnerability of coastal deltas as indicated by the indicative population potentially displaced by current sea-level trends to 2050 (Extreme > 1 million; high 1 million to 50,000; medium 50,000 to 5,000) (IPCC 2007) 75 per cent of the population affected by a 1 meter rise in sea level on the Asian megadeltas and deltas Land cover of lower Mekong basin In 1970 = 50% In 2007 = 27% Threats 1. Habitat alteration Cutting forest for rubber plantation in the upland area Cutting mangrove forest for shrimp production in the coastal area 5

6 Threats 2. Over-exploitation Dams existing or planned on the Mekong river (exploit energy) Hydro-power dams in the Mekong river: Existing Under construction Planning Over- exploitation of fish (exploit resource) 3. Pollution Threats Waste water of cities Dead fish by pollution 6

7 4. Invasive species Threats Apple snails Mimosa pigra Threats 5. Climate change Salt water intrusion to the Mekong delta of Viet Nam at 1m of sea level rise scenario! Source: MONRE 2009 Flooding from September to November Source: Triet

8 Development threats: Social differentiation Migration Urbanization Diseases (HIV) Cultural degradation Threats Urbanization Social differentiation DVNi Source: Thanhnien

9 Conceptual Adaptation to the threats Summary Relation between Rural area, Urban area, Delta s resources and strategy for Adaptation: Legislation, Direct assistance, Technology and Education Urban area Lands Houses Jobs (incomes) Rural area C Technology Education changes B Direct assistance (land, credit) Landless Homeless Jobless Migration Exploitation A (Legislation) Delta s resources Fruitless The first approach (A) is to use legislation to control over- exploitation or to prevent migration to towns and cities. The second (B) is the provision of direct assistance (land, credit) in order to prevent poverty increasing. The third approach (C) is to attempt to adaptation by providing technologies for alternatives and education. Ni,

10 Adaptation and trend 1. At the coasts: Reduce shrimp farming and Mangrove forest replanting The current land uses and it s products Technology support for the alternatives Direct incomes to the locals Adaptation and trend 2. At the extreme salty area: Restore biodiversity Scirpus littoralis Intensive aquacultures Restore Sea grass (Scirpus littoralis) for making handy craft; Integrated Shrimp (Penaeus monodon) and Mud crab (Scylla olivacea) during the dry season and followed by Tilapia (Oreochromis niloticus) or Elongated goby (Pseudapocryptes elongatus) during the rainy season (salt resistant species) 10

11 Adaptation and trend 3. At the salt & fresh water interface: Shrimp_Rice farming model Mono shrimp farming crop! Nipa palm Tuan 2009 Technology support to maintain Shrimp_Rice farming model: Paddy rice crop planted during the wet season (increase fresh water storage period); shrimp crop (Penaeus monodon) during the dry season (allow sediment feeding the farms) and keeping Nipa palm to wind resistant and biodiversity restoration Adaptation and trend 4. At the drought prone areas: Rice + Fish farming model New rice varieties with salt and drought tolerant genes Avoid intensive mono paddy rice cropping system Fish + Shrimp Fish pond functioned as a reservoir for rice crop if drought happen and served as storage to reduce submergence; Fishes and shrimp (Macrobrachium rosenbergii) can controlled insects population and reduce pesticide uses to maintain biodiversity in the farm 11

12 Adaptation and trend 5. At the acid sulphate soil areas: Rice - Melaleuca model Melaleuca cajuputi Intensive rice farming created acidities and drain-off acid water to the river! Rice crop Melaleuca trees functioned as a filter and sink to acidities. The Melaleuca land also functioned as a reservoir to keep flood water during the wet season for irrigation paddy rice crop during the dry season and functioned as sediment trap and waves resistant in flooding period. Adaptation and trend 6. At the flood areas: Netting aquaculture model Closed dike forced farmer applied 7 rice crops per two year (3.5 crop/year!) Cat fish (Pangasius sp.) Allow water flow through, sediment load to the farms Policy support: The sluices were managed to open for two months (September to October) for flood water re-enter the land. Macrobrachium rosenbergii 12

13 7. Diversify infrastructures Adaptation and trend Adapted houses: iron roofs (wind); build on sticks (flood) Traditional houses Water Water Sky way (flood water flow through on the ground) Floating houses can moved to the saved area Climate Change Adaptation Strategies : 8 Examples for Deltaic Coasts 1. Reduce stressors that cause subsidence, land loss, and erosion halt activities that alter deltaic processes and destroy habitats; 2. Restore natural coastal defenses; 3. Restore natural flow regimes that create and maintain deltas; 4. Accommodate sea level rise and natural processes in human development and restoration planning; 5. Remove impediments to inland migration of deltaic ecosystems (restored and natural); 6. Enhance organic sedimentation rates and mineral sediment availability; 7. Acquire coastal lowlands for storm protection, flood water retention; 8. Factor understanding of natural processes and trends into management, inform by monitoring. Virginia

14 Lesson learnt to implementation The objectives of management of land, water and living resources are a matter of societal and timeconsuming choices! Technology supports to the successful land uses at different ecosystems are drives for understanding of adaptation; Translate theses understanding to education are keys to build capacity of the local, regional and international communities to adapt the changes, including climate change! Thanks 14