Vulnerability assessment of major wetlands in the Asia-Pacific region to climate change and sea level rise
Supervising Scientist Report 149
van Dam RA, Finlayson CM & Watkins D (eds)
Supervising Scientist, 1999
ISBN 0 642 24352 2
- SSR149 - Vulnerability assessment of major wetlands in the Asia-Pacific region to climate change and sea level rise (PDF - 5830 KB)
- Preliminary pages and project description (PDF - 438 KB)
- Part 1 - Vulnerability assessment of the Yellow River Delta to predicted climate change and sea level rise (PDF - 1310 KB)
- Part 2 - Vulnerability assessment of Olango Island to predicted climate change and sea level rise (PDF - 3630 KB)
- Appendices (PDF - 165 KB)
About the report
Vulnerability assessment of the Yellow River Delta to predicted climate change and sea level rise
Li Peiying, Yuan Jun, Liu Lejun & Fu Mingzuo
The Asia-Pacific Network for Global Change Research (APN) funded a study assessing the vulnerability of the Yellow River Delta (YRD), in China, to predicted climate change and sea level rise. The study was coordinated by the Environmental Research Institute of the Supervising Scientist (eriss), in Australia, and Wetlands International-China Program, with the major local collaborator being the State Oceanic Administration of China.
The study's major objectives were to raise awareness of the issue of climate change and sea level rise in the Asia-Pacific region, to provide advice and training to national and local agencies on procedures for Vulnerability Assessment, and specifically, to obtain a preliminary understanding of the potential impacts of climate change and sea level rise on the biological, physical and socio-economic attributes of the YRD.
The YRD was chosen as a study site primarily because it has been nominated for the East Asian-Australasian Shorebird Reserve Network. Due to its importance as a habitat for migratory and resident shorebirds, a 1500 km² Nature Reserve has been established along the eastern coast of the delta.
The assessment included the following steps:
- Description of the YRD, including its physical, biological and socio-economic attributes;
- Identification of natural and anthropogenic 'forcing factors', including predicted climate change and sea level rise, and their impacts;
- Assessment of the vulnerability to existing forcing factors;
- Assessment of the vulnerability to climate change and sea level rise;
- Documentation of current responses to coastal hazards;
- Recommendations for future monitoring and management strategies;
- Identification of information gaps and research priorities.
Information was obtained from existing literature, including a number of quantitative estimates of impacts of climate change on specific attributes of the YRD.
The YRD represents the meeting point of the Yellow River with the Bohai Sea, in eastern China. The delta covers approximately 6000 km2, although historically it has been in a dynamic state due to the high sediment load and frequently changing course of the Yellow River. More recently, the river course has been stabilised, allowing substantial development to occur. The YRD is now a highly urbanised and industrialised region, with a population of 1.64 million and major industries including oil extraction and crop and cattle farming. Subsequent demands on water resources, both from within and upstream of the YRD have greatly reduced the flow of the Yellow River in the last decade. The Nature Reserve was established in recognition of the YRD's importance as a site for migratory and non-migratory shorebirds, however, it is under great pressure from urbanisation, farming, and oil and natural gas extraction.
The major physical attributes of the YRD include the river and underground water, the low topographical relief of the delta, the geomorphic units of the terrestrial delta, the subaqueous delta and the tidal flats, the sediment load of the Yellow River and subsequent sedimentation, and the natural resources of oil, gas and water. The major biological attributes include terrestrial and aquatic plants and animals, particularly the birdlife, which includes 152 species of protected birds. Over 500 000 shorebirds are estimated to utilise the wetlands of the YRD during their northward migration. The major socio-economic attributes include the population of over 1.64 million, and the primary industries of oil and natural gas extraction and crop and cattle farming.
The predicted climate change scenario for the YRD was based on regional climate change scenarios for temperate Asia or China specifically, by the IPCC and other investigators. The scenario used for this study included the following estimates:
- A rise in relative sea level of 48 cm by 2050 (specific for the recent YRD);
- A rise in mean air temperature of 1.4°C by 2050 and 3°C by 2100 (for China/East Asia);
- A rise in annual precipitation of 2-4.5% by 2050 (for East China).
The major natural forcing factors acting on the YRD (excluding climate change) are sedimentation, the Asian monsoon, El Niño, and flooding and storm surge. Major impacts associated with these include erosion and expansion of the coastal wetlands, damage to infrastructure, crops and livestock, and loss of human life. Major anthropogenic forcing factors include the large population and associated types of land use, oil and natural gas development, and water and air pollution. The major impacts include a reduction in freshwater supply, a reduction in surface and ground water quality, degradation of the Nature Reserve and the subsequent loss of wetland habitat and biodiversity.
The YRD is already extremely vulnerable to existing forcing factors. Although river flows have decreased in the last decade, the YRD is still highly vulnerable to flooding from both upstream sources and from storm surges. The high utilisation of water resources, while aiding in the development of industry and agriculture and enhancing the standard of living, will eventually result in major ecological consequences, such as salinisation, loss of wetland habitat and desertification. Without proper management, urban, industrial and agricultural activities will further pollute the already poor quality waters within the YRD.
The YRD is also vulnerable to predicted climate change and sea level rise. Increased moisture stress, insect pests and plant diseases resulting from climate warming are expected to have unfavourable effects on agricultural production. Salt marshes and other coastal wetlands are thought to be particularly vulnerable to permanent inundation and erosion as a result of sea level rise and increased storm surge. This would have flow-on effects to tourism, freshwater supplies, fisheries and biodiversity. Sea level rise will result in a number of other impacts including a reduction in the protective capacity of the dyke systems. Assuming a 1 m sea level rise and 2-3 m storm surge, approximately 40% of the YRD could be inundated. Saltwater intrusion will also be a major issue, further reducing already limited freshwater resources. The above impacts will have major consequences for both the socio-economic and biological attributes of the YRD.
A series of dyke systems have been in place in the YRD for many years to protect against floods both from upstream and from storm surges. Some of these have been upgraded whilst others require attention. Many of these flood control dykes will serve as protective barriers to sea level rise and increased storm surge, although the extent to which they can protect the adjacent land is uncertain. Other control measures are in place to prevent or minimise floods resulting from ice jam in the river. Freshwater shortages are being addressed by increasing the capacity of existing reservoirs or proposing the construction of new reservoirs.
The study identified a number of management strategies or countermeasures for protecting the YRD from both existing forcing factors and predicted climate change and sea level rise including:
- Integration of information from programs monitoring sea level rise, coastal zone ecology and sensitivity, and socio-economic and cultural indicators;
- Stabilisation of the course and mouth of the Yellow River;
- Consideration of flood risk in urban and industrial planning;
- Protection and management of coastal wetlands and the Nature Reserve;
- Control of urban and industrial pollution;
- Establishment of reservoirs for water storage and conservation;
- Increasing community awareness about environmental protection.
In addition, recommendations regarding the management of the Nature Reserve include:
- Development of an appropriate administrative and management system;
- Drafting and implementation of appropriate environmental protection laws;
- Increasing scientific research to provide a basis for management;
- Enhancing community awareness of ecology and environmental protection.
The YRD currently faces a range of serious ecological and socio-economic problems, most of which are related to water supply, be it in shortage, excess (flooding) or of poor quality. These issues highlight the need to consider both economic development and environmental protection when planning the future sustainable development of the YRD. In addition, it is now imperative that the issue of climate change and sea level rise are incorporated in any such plans. This study highlights the vulnerability of the YRD to predicted climate change and sea level rise, particularly in terms of exacerbating the region's current water supply and quality problems. The proposed management strategies provide the first step in effectively addressing the issue of climate change and sea level rise.
Vulnerability assessment of Olango Island to predicted climate change and sea level rise
The Asia-Pacific Network for Global Change Research (APN) funded a study assessing the vulnerability of Olango Island, in the Central Philippines, to predicted climate change and sea level rise. The study was coordinated by the Environmental Research Institute of the Supervising Scientist (eriss), in Australia, and Wetlands International-Oceania, with the major local collaborator being the Philippines Department of Environment and Natural Resources (DENR).
The study's major objectives were to raise awareness of the issue of climate change and sea level rise in the Asia-Pacific region, to provide advice and training to national and local agencies on procedures for Vulnerability Assessment, and specifically, to obtain a preliminary understanding of the potential impacts of climate change and sea level rise on the biological, physical and socio-economic attributes of Olango Island.
Olango Island was chosen as a study site for several reasons: It is a small, coral reef island (~6 × 3 km) with low topographical relief and a maximum elevation above sea level of only 9 m; it sustains a population of over 20 000 and is already under pressure from anthropogenic activities including fishing, groundwater extraction and mangrove harvesting; it is a major wetland site for shorebirds, being nominated for the East Asian-Australasian Shorebird Reserve Network and listed as a wetland of international importance by the Ramsar Wetland Convention. Due to its importance as a flyway stopover site, a 920 ha wildlife sanctuary was established in the south of the island.
The vulnerability assessment included the following steps:
- describing the physical, biological and socio-economic attributes of Olango Island;
- establishing a predicted climate change scenario based on existing literature;
- identifying existing natural and anthropogenic 'forcing factors' and their impacts;
- assessing vulnerability to existing forcing factors;
- assessing vulnerability to climate change and sea level rise;
- documenting current responses to coastal hazards;
- recommending future monitoring requirements and management strategies;
- identifying information gaps and research priorities.
Information was obtained from existing literature. In addition, the outcomes of a workshop with participants from local, regional, national and international government and non-government agencies were used in the assessment.
The major physical attributes of Olango Island include the low topographical relief, sandy shorelines and limestone outcroppings, the groundwater lens and the monsoonal climate. The major biological attributes include mangrove forests, seagrass beds, coral reefs, birdlife and other wetland fauna. The major socio-economic attributes include the large population in general, livelihood activities such as fishing and shell and seaweed collection, infrastructure and freshwater supply.
The predicted climate change scenario for Olango Island was based on predicted regional scenarios by the Intergovernmental Panel on Climate Change (IPCC) and the Philippine Atmospherical, Geophysical and Astronomical Services Administration (PAGASA) where possible. Where such information did not exist, estimates from IPCC global scenarios were used.
The predicted scenario for Olango Island is:
- A rise in mean sea level of 30 cm by 2030, and 95 cm by 2100;
- An increase in mean global sea surface temperature of 0.5°C by 2010 and 3°C by 2030;
- A 20% increase in typhoon intensity;
- A tendency for increased rainfall, intensity and frequency.
The major existing natural forcing factors on Olango Island are the south-west and north-east monsoons, typhoons, storm surge and El Niño. Some of these have positive impacts on the island, by way of recharging the underground water supply, while the major negative impacts include flooding, erosion and infrastructure damage. The major anthropogenic forcing factors involve the exploitation of natural resources, such as over-fishing and illegal fishing, over-extraction of groundwater, mangrove harvesting and coral extraction. These factors could result in erosion, saltwater intrusion, shortages of freshwater, habitat destruction and the loss of biodiversity.
Assessment of the vulnerability of Olango Island to existing forcing factors indicated that the island is already under enormous pressure, mostly from natural resource exploitation, although typhoons and associated storm surges also exert negative impacts. Many of the natural resources are already severely degraded, particularly the fisheries and the under ground supply of freshwater. The sustainability of these resources is in doubt, although recent management recommendations have provided the first step towards long-term sustainability.
Climate change and sea level rise will undoubtedly place additional stress on Olango Island and its attributes. Given its low elevation and topographical relief, more than 10% of the current land mass would be lost in the event of a 95 cm rise in sea level. In addition, more severe typhoons and storms surges would result in an even greater portion of the island being subjected to inundation and flooding. Given that the majority of human settlement on the island occurs in close proximity to the shoreline, this represents a major problem. An increase in sea level would also facilitate saltwater intrusion into the underground freshwater lens, although this could be offset by an increase in rainfall. Potential effects on the biological attributes include loss of mangrove stands due to an inability to recolonise inland, bleaching and death of corals due to increased sea surface temperature, and loss of feeding grounds and roosting habitat for resident and migratory shorebirds. Potential effects on socio-economic attributes include the displacement of people, loss of infrastructure and loss of livelihood options.
While the current issues facing Olango Island are immediate and serious, the vulnerability of the island to climate change and sea level rise is sufficiently great to require consideration in future management plans.
Current responses to the current and future hazards facing Olango Island include a number of resolutions and ordinances at the local (Barangay) level, such as the declaration of local fish sanctuaries and marine reserves, and prohibition of sand extraction and illegal fishing. Regional responses, such as the Mactan Integrated Master Plan address land use issues for Olango Island, while DENR has drafted management recommendations for the wildlife sanctuary, in which the issue of climate change and sea level rise is recognised. DENR also conducts a bird monitoring program in the wildlife sanctuary. The USAID-funded Coastal Resource Management Project (CRMP) has completed a Coastal Environmental Profile of Olango Island, which will assist in developing a coastal zone management plan. On a national scale there also exist a number of plans and policies relating to coastal zone management and mitigation/protection plans against coastal hazards.
Major parameters recommended for future monitoring are outlined. They include: geophysical parameters such as storm surge, shoreline erosion, mean sea level, groundwater salinity and water and air temperature; biological parameters such as bird populations, mangrove growth and distribution, seagrass cover, coral cover and reef fish biomass; socio-economic parameters such as tourism growth, population structure and infrastructure development. A number of future management strategies are also proposed, including the creation and maintenance of buffer zones, the provision of livelihood opportunities for the local people and developing awareness of techniques for natural resource management. Management measures to address potential impacts of climate change and sea level rise include reviewing the feasibility of physical barriers to protect against storm surge, prohibition of shoreline vegetation harvesting, regulation of groundwater extraction, protection of the groundwater catchment area, establishing fish sanctuaries, seeking alternative livelihoods, developing a formal education program and reassessing future coastal development plans.
A number of information and research gaps were also identified. There were major deficiencies in storm surge data, the quantification of coral and sand extraction, natural disaster damage estimates for lives, property, and natural resources, groundwater salinity and transmissibility data, the biology and ecology of endangered species, and the impacts of mangrove forestation on the seagrass beds. In addition, the lack of a detailed topographic map made it difficult to make precise estimates of the potential impacts of sea level rise on the island.
The vulnerability assessment highlighted the magnitude of the immediate threats facing the local communities and natural resources of Olango Island. First and foremost among these threats are the increasing population and the associated depletion of the fisheries and underground freshwater supply. Even in the absence of climate change and sea level rise, sustainability of these resources will not be achievable if management plans do not address the problems. Olango Island possesses many characteristics that make it highly vulnerable to climate change and sea level rise; it is a small, low-lying coral reef island with a large, technologically poor population. Thus, climate change and sea level rise will only serve to place further stress on those natural resources that are already under threat. Subsequently, recently drafted local, regional and national management plans need to recognise and address the possible consequences of climate change and sea level rise.