Sea level rise is a complex phenomenon related to the global climate change. Although the mean increases in sea level rise associated with the Intergovernmental Panel on Climate’s Change (IPCC) non mitigation scenarios are modest-ranging from 0.2 to 0.5 meters during this century, future sea level rise is not expected to be globally uniform. Some regions, including South-East Asia, show a sea level rise substantially more than the global average.
This paper focuses on the potential impacts of sea level rise on Vietnam coastal cities and explores the concept of a desirable urban adaptation policy required to cope with this profound and durable disaster.
Vietnam cities facing sea level rise
By 2007, 27.4 per cent (23.4 million)of the Vietnam’s population lived in urban areas, and of this urban population almost 75% lived in coastal and delta zones. Vietnam has long coast ( 3260km) and a dense river network, including the Red River and the Mekong River that originate in catchements in other countries and create large river deltas (17,000km2 and 59,000km2, respectively), characterized by an accerelated urbanization.
Climate change concerns Vietnam deeply. The recent study of Dasgupta and others ranks Vietnam among the top five countries most affected by one meter rise in sea level with 10.79% of population, 10.21% of GDP,10.74% of urban areas and 28.67% of wetlands affected.Many of the largest cities of Vietnam such as Hochiminh City, Haiphong, Hue, Danang, Nhatrang, Vungtau are directly subjected to the impacts of sea level rise.
Vietnam ratified the Kyoto Protocol since 1999. A Climate Change Office has been set up within the Ministry of Natural Resource and Environment (MONRE).
Recently, the Science, Technology and Environment Committee of the Parliament examines at first time the impacts of climate change on the national development sustainability. MONRE actually is preparing a national targeted program to cope with climate change and sea level rise for the period 2009-2015.
Impacts of sea level rise on Vietnam urban areas
Costal and near - coastal low-lying urban areas are particularly vulnerable to sea level rise related hazards, including:
- Total submersion
- Salinization of ground and surface water
Total submersion will be likely the destiny of the Camau peninsula, that will cause a land loss of 8000km2 and the resettlement of a population exceeding 1.5 million inhabitants.
By virtue of being located at riversides and low lying plains, especially at the Mekong Delta, many cities have been subjected to periodic flooding since its early days. At coastal areas flooding can occur for a range of sometimes interacting reasons,including storm surges induced by typhoons, land subsidence due to excessive ground water withdrawal (Hanoi), high tide (Haiphong, Hochiminh City), intense local precipitation in areas with poor drainage, sedimentation of river estuaries. Associated with the rising sea level, flooding will become catastrophic and cause dramatic damage to urban areas.
Variations in river and coastal flow, storm surges and sea level can cause significant erosion of river banks and sea beaches leading to land loss, relocation of urban quarters and degradation of beach resources that are used for tourism.
The sea level rise also causes salt water penetration far upstream in dry season, especially during droughts, and salinization of coastal ground water. This event will endanger water supply of all coastal cities, including Hochiminh City and Hanoi.
All abovementioned major impacts of sea level rise once occurred will engender huge negative effects to the development of Vietnam in the future. In difference from others short-term natural disasters, sea level rise is a very slow-onset and irreversible event that demands long-term response such as coastal cities relocation to higher land, protection of coastal and near coastal low-lying urban areas by increasing the robustness of infrastructural designs and systematic investments in seawalls and dykes, improving water supply, drainage and sanitation. The impacts of sea level rise on rural areas will generate an additional migration of people to cities, therefore an efficient demographic management will be needed. Briefly, given that the forthcoming sea level rise could massively impact the society and be truly national in scope, there is a need to formulate an overall proactive adaptation policy as suggested by the United Nations Framework Convention on Climate Change (UNFCCC).
Preliminary considerations for Vietnam adaptation policy
The effects of sea level rise vary greatly among countries, even for countries in a same region, therefore adaptation efforts must be tailored to specific needs of Vietnam. However, adaptation policy has to focus on general principles rather than specific details. Given the strong decentralization in Vietnam, each coastal provincial government has the capacity to develop and to adopt its appropriate region-specific coping programs.
As the sea level rise is a long-lasting process, and there are some uncertainties regarding IPCC results, the adaptation policy must be thought of as an ongoing learning by doing participatory process, including planning, implementation, monitoring and adjustment.
Nobel laureate Tom Schelling has argued that the best way for developing countries to adapt to climate change is to develop. Thus, Vietnam disaster adaptation planning should be part of national development planning and should be discussed at local and national levels, and urban hazard mitigation needs to be seen as one goal within integrated coastal zone management.
For Vietnam, sea level rise risk is a serious risk. Therefore, this source of risk should be sufficiently accounted for in cost-benefit analysis (CBA) in development planning and in appraisals of infrastructure investment and risk management projects. Then, properly developed specific CBA associated with political, economical, social and technological (PEST) analysis should be integral elements of decisionmaking and may contribute to improve the allocation of scarce resources to the most profitable and least risky undertakings.
Raising societal perception and preparedness to sea level rise is needed but should be undertaken carefully step by step in view to avoid scattering panic among the public.
As sea level rise is global, there is a need for regional and international cooperation in forecasting, information gathering and exchange. In this regard, are involved not only United Nations, World Bank and others intergovernmental organizations. For the same purpose many institutions of civil society such as NGOs and CBOs can provide a bridge between researchers and stakeholders of different countries.
Sea level rise poses a great threat to Vietnam coastal cities and will affect the country macroeconomy. The disaster adaptation policy should be considered as a continuing learning in doing process. The best way for Vietnam to cope with sea level rise is to develop with the support of international response organizations into a developed country in the near future.
The World Bank.2003. Building Safer Cities. The Future of Disaster Risk.
The World Bank.2008. Global Monitoring Report. MDGs and the Environment. Agenda for Inclusive and Sustainable Development.