Global Climate Change case study: Where are rising sea levels threatening human and natural environments?
AAG Center for Global Geography Education
By completing this case study, you will be able to:
Sea level rise is one of many consequences related to global climate change. Sea level rise poses a particularly serious threat to countries where high population densities and significant economic activities are located near coastal areas (World Bank 2007). The Intergovernmental Panel on Climate Change (IPCC) has projected that globally sea levels would rise on average between 0.5 meters and 1 meter by the end of 2100. Increases in sea levels would vary globally, with some models suggesting that regions of South-East Asia would experience the higher end of this projection (Liem 2008).
This case study focuses on the impacts of sea level rise on the Xuan Thuy National Park region in northern Vietnam. This unique coastal wetland ecosystem provides a starting point for understanding the socio-economic and biophysical vulnerabilities associated with sea level rise. The case study begins with a discussion of the three dominant factors that cause sea level rise and then focuses on Xuan Thuy National Park.
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Suggested citation: Narins, T., Pavri, F., Quỳnh, N., and Zappa, M. 2010. Global Climate Change case study: Where are rising sea levels threatening human and natural environments? In Solem, M., Klein, P., Muñiz-Solari, O., and Ray, W., eds., AAG Center for Global Geography Education. Available from http://globalgeography.aag.org.
There are three dominant factors that impact sea level rise:
1. Ocean thermal expansion
As the ocean warms it also expands. This process has taken place throughout the Earth's history, and because of the variability in ocean temperatures, will likely continue even if greenhouse gasses stabilize. Thermal expansion of the oceans is predicted to be the biggest contributor to future sea level rise over the next 100 years (IPCC 2007).
2. Glacial melt from Greenland and Antarctica
Melting of mountain glaciers and ice caps is also expected to contribute to rising sea levels because these colder regions are more sensitive to a warming climate. Greenland and the Antarctic have enough water to raise the sea level by 70 m, therefore even small changes would could result in significant impacts (World Bank 2007).
3. Change in terrestrial storage
The actual amount of water stored terrestrially changes depending on ground water extraction, reservoir construction, and other variations in the hydrologic system. While these activities have a small impact on global sea level changes, in certain cases, they may even offset some accelerated, local sea level rise (IPCC 2007).Sea level rise is quite difficult to measure at specific coastal locations because of regional variability. Similar to global climate change, global sea level rise is expected to impact some regions more than others. Relative sea level rise in Vietnam is measured from tidal gauge data collected at four stations by the Marine Hydrometeorological Center (Hanh and Furukawa 2007).
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With more than 3200 km of shoreline, Vietnam's coastal zone provides a diverse range of natural resources and favorable conditions for social and economic development (fisheries, aquaculture, agriculture, tourism, transportation, urbanization, etc.). However, these ecosystems are also highly vulnerable, due to several coastal hazards such as typhoons, storm surges, erosion, earthquakes, environmental pollution, sea level rise related to global climate change, and human activities such as mangrove extraction to meet shrimp farming and fuel wood demands.
Consequently, Vietnam has been identified as one of the countries most threatened by rapid sea level rise. As a result of Vietnam's long coastline, 74% of the population lives in low-lying areas such as coastal plains or river deltas that are threatened by sea level rise. Most of the projected 1 meter sea level rise is expected to impact areas of the Mekong and Red River Deltas, where roughly half of Vietnam's population lives. At the high end of SLR predictions, a rise of 5 meters would impact 35% of the country's population (Figure 1) (World Bank 2007). The coastal cities in Vietnam will likely face issues of submersion, flooding, erosion, and salinization of ground and surface water in the coming century. Sea level rise in rural areas will likely force more people to urban areas and create greater demographic pressures in cities (Liem 2009). Vietnam's long coastline also exposes the country to environmental hazards such as floods, tropical cyclones and storm surges, which could also be potentially exacerbated by the impact of climate change. Even a small increase in sea level can result in increased risk of storm surges or prolonged flooding of low lying areas.
Figure 1. Estimates of the areas of inundation caused by a 1-5 meter sea level rise in Vietnam.
The red areas indicate portions of Vietnam's land regions which would be severely affected by a 1-5 meter rise in sea level.
(Source: World Bank 2007)
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Vietnam has already begun experiencing the effects of sea level rise. In the past 40 years, sea level has increased almost 9 centimeters. According to Vietnam's Initial National Communication to the UNFCCC (United Nations Framework Convention on Climate Change), coastal sea level is expected to be up 33 centimeters by 2050, 45 centimeters by 2070 and 1 meter by 2100. Vietnam's geographic features and coastal orientation makes it highly vulnerable to the impacts of climate change, specifically sea level rise. The coastline, which is 3,260 kilometers in length, contains the Mekong and Red River deltas, two of the world's largest river deltas. As a result of the location of the deltas and their proximity to high population areas, a one-meter rise in the sea level along the coast of Southeast Asia would potentially result in a 5% land loss and an 11% population displacement in Vietnam (World Bank 2007).
Scientists have studied the vulnerability of populations and ecosystems to natural and anthropogenic hazards. In recent years, researchers have focused on assessing biophysical and socio-economic vulnerabilities within an ecosystem to assess the impacts of potentially hazardous conditions such as sea level rise. In this case study, we consider the Xuan Thuy wetlands along the northern coast of Vietnam to assess its vulnerability to sea level rise.
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The Ramsar Convention on Wetlands (Ramsar Convention) was signed on February 2, 1971 in Ramsar, Iran. The Ramsar Convention aims to stem progressive encroachment and halt the loss of wetlands now and in the future, in order to ensure the biodiversity of waterfowl of national and international importance. Vietnam became a contracting party of the Ramsar Convention in 1989 and has considered its international responsibilities for the conservation and wise use of wetlands in full compliance with international regulations. Vietnam has also designated some wetlands within its territory for inclusion in the List of Wetlands of International Importance according to Ramsar criteria (Ramsar sites). The wetland region which today contains Xuan Thuy National Park was accepted as a Ramsar site in 1989. The main activities of Ramsar Vietnam include implementing conservation and wise use policies, devising legal strategies for protection, conducting wetland inventories, promoting wetlands research and educational outreach activities, and enhancing international cooperation and mobilizing financial support from international organizations and individuals for wetland conservation activities.
Click on the icon below to view photographs of Xuan Thuy National Park
The Xuan Thuy National Park is more than 15 hectares in total area, with 7.1 hectares comprising the core zone and 8.0 hectares comprising the buffer zone (Nhuan et al. 2009). In 2003, the Vietnamese government officially designated Xuan Thuy as a national park in recognition of its high biodiversity and productivity resulting from the density of flora and fauna species located in this region. All of the land in Xuan Thuy National Park is very low lying, ranging in altitude between 0.5 and 0.9 meters above sea level. The park's low elevation means that the park is particularly at risk to sea level rise. Moreover, this coastal wetland ecosystem is already facing destruction from hazards which include erosion, channel siltation, storm and flooding, salt contamination, and environmental pollution. Along with over-fishing and mangrove deforestation, pollution is destroying the mangrove forests and reducing marine stocks. Moreover, sea level rise poses significant inundation risks, and as predicted over the next 100 years in the case of Xuan Thuy, could completely inundate the park which lies between 0 - 1 meter above sea level.
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Wetlands, such as the Xuan Thuy, are complex ecosystems that flourish between the terrestrial and aquatic worlds. Wetlands the world over are characterized by unique soil conditions brought on by the presence of water for at least part of the year and flora and fauna that are uniquely adapted to these conditions. Locally specific climatic and soil conditions result in unique wetland types. These diverse wetlands range from salt tolerant mangrove forests in tropical and sub-tropical latitudes, such as those found in Xuan Thuy National Park, to fens typified by neutral soils and grasses in temperate regions (Mitsch and Gooselink 2000).
Until more recently, countries have actively pursued wetland drainage and conversion strategies, but these policies were driven by the lack of scientific knowledge about the role of wetlands within the larger biosphere and their often erroneous representation as "wastelands" (Mitsch and Gooselink 2000). Beginning in the second half of the 20th century, however, researchers began documenting the valuable biological and ecological functions provided by wetland habitats at local, regional and global scales (Dugan 1994; Williams 1990). Scientists examined the complexity of wetland ecosystems and graphed feedback loops and decreased ecological productivity from converting wetlands in to other land uses (Mitsch and Gooselink 2000). These studies also illustrated wetlands' significant hydrological and biogeochemical contributions.
It is now commonly accepted that wetlands improve water quality through toxin removal and they allow for the cycling of organic and inorganic nutrients through the ecosystem. They perform important roles in the nitrogen, sulfur, methane and carbon cycles, and accelerate groundwater recharge. Wetlands also protect against erosion from coastal storms and flood events. Moreover, research indicates that when wetlands are found along coastlines, these ecosystems form the foundation of complex marine food chains (Whigam et al. 1993). The Xuan Thuy and similar mangrove ecosystems not only provide all these important biophysical functions, but also help filter out impurities and serve as important protective barriers to storm surges. The removal of coastal wetlands for aquaculture or agricultural production, in turn, give rise to a host of biophysical vulnerabilities in the form of large scale soil loss due to wave action and coastal erosion susceptibility during storms and annual flood events, predicted to increase in severity due to climate change.
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In coastal Xuan Thuy District, (see Figure 2), the connections between the region's economic & political forces and those of climate change are striking. These two broad markers of human society - economics and politics - sometimes grouped together under the term 'development' are an essential part of our existence. Without them, concerns about the potentially disastrous effects of climate change would not exist - "without people, there is no disaster" (O'Keefe et al., 1976).
Figure 2. The Red River Dela and the Xuan Thuy District
(Source: Kelly and Adger 2000, 339)
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In spite of climate change's threat to agriculture in the region, the amount of agricultural output here has doubled in since the mid-1980s with the introduction of new agricultural technology (Adger, 1999, p. 258). While Xuan Thuy is a fairly prosperous region in northern Vietnam, the diversity of the agriculture based industries here can all be characterized as being "climate dependent" (Adger, 1999, p. 260). An examination of the connections between the type of agriculture a resident of the Xuan Thuy district engages in and his or her vulnerability to climate change will be helpful in understanding the struggles the Xuan Thuy region confronts in the face of continued and more intense climactic events and disasters.
Farmers in the region will be more or less impacted by extreme or seasonal climate events, depending on the type of agricultural activity in which they participate. While typhoons have the greatest negative impact on rice farming, because they disrupt rice seedlings, other major agricultural industries such as the growing of fruits and vegetables are not as adversely affected by landfall typhoons. Another agricultural activity, salt-making, depends on periods without rain and high temperatures (Adger, 1999, p. 260). For these reasons, farmers in the Xuan Thuy district, regardless of the type of agricultural production they engage in, are all susceptible to economic loss during future changes and extremes in regional climate.
Despite being protected by a combination of artificial dikes and mangrove forests, the Xuan Thuy region and the populations living around Xuan Thuy National Park could witness damage to the area's aquaculture industry – should environmental conditions such as storm surges, sea level rise and high waves reach this district (Kelly & Adger, 2000, p. 337). A rise in sea level may also require that crab and shrimp farms be relocated while coastal fisheries may disappear (Anh, 2009, p. 8). In addition, studies have found that populations of lower commercial value tropical fish would increase in the coasts of Vietnam, while populations of the higher commercial value subtropical fish would migrate to other regions or decrease (Raksakulthai, 2002, p. 18). The activity of converting wetlands to fish farms has been the so-called "blue" revolution (Alongi 2002; Seto 2007). Studies suggest that output from aquaculture is now responsible for almost one-third of the seafood consumed globally (FAO 2002). The Xuan Thuy National Park region has observed its fair share of aquaculture production. While aquaculture can be a monetarily rewarding activity for local populations, the negative impacts of this industry including the discharge of large quantities of waste, the intensive use of antibiotics, and the leaking of pathogens into wild fisheries can increase the vulnerability of an ecosystem (Naylor 2001; Paes-Osuna 2001). Additionally, the clearance of mangrove to make way for aquaculture, as seen in the case of Xuan Thuy National Park, and the crowding out of native species can threaten the collapse of estuarine and marine food webs.
Pause and Reflect 1: Click here and read the short article about how satellite images of Xuan Thuy National Park and the Red River Delta help scientists monitor the human modification of the coastal wetland ecosystem.
In what ways could the analysis of satellite images from the past 30 years help in the understanding of sea level rise?
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Because its large population centers and major economic hubs are located near the coast, Vietnam would be the country most negatively affected (among the eighty-four countries in a major study) should there be a one meter sea level rise in the near future. Such a rise could negatively affect 10% of Vietnam's national GDP and could potential displace almost 11% of the entire country's population (Dasgupta et al., 2009). The disastrous effects of sea level rise in areas such as Xuan Thuy can be summarized as follows:
Inundation and the resulting loss of land and saline water intrusion, in the Mekong Delta and parts of the Red River Delta, the country's most important agricultural areas, will pose serious threats to farmers as well as to agricultural exports such as rice (of which Vietnam is the second largest exporter in the world), and possibly to national food security (Raksakulthai, 2002, p. 18).
In January and April 2006, the Center for Marine Conservation and Community Development coordinated with local groups near Xuan Thuy National Park to assess the potential for an eco-tourism industry in the region. The results of this survey indicated that the park "has significant attractions, from the wetland itself, to migratory birds and the local people's culture and traditions" (Vietnamnet website). In terms of ecotourism, the Vietnamese Centre for Marine Conservation and Community Development (MCD) has posted videos of Ecotourism opportunities in Xuan Thuy National Park (MCD website).
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According to a report commissioned by the United Nations Viet Nam Programme Coordination Group on Gender, there are three main factors to consider when examining the linkages between climate change and gender (specifically women) in Vietnam. These factors are: 1) access to resources, 2) diversity of income sources and 3) the social status of men and women in the community (Anh, 2009, p. iv). Social vulnerability to climate change, defined here as "the exposure of groups or individuals to stress as a result of the impacts of climates change and related climate extremes" (Adger, 1999, p. 252) is more severe in women than men. In the face of long-term gradual climate change which will affect ecological and agricultural systems, women are more vulnerable to resource scarcity than are men. Women are more dependent on land and natural resources for their well-being and livelihoods (Anh, 2009, p. iv).
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According to worldwide climate projections, sea level rise related to global climate change and human activities, will disproportionately affect Vietnam. Because of its long coastline, and the proximity of its major population centers and industrial hubs being geographically located close to the coast, Vietnam could face the most devastating consequences of global sea level rise.
Xuan Thuy National Park, an internationally designated wetland conservation site, faces particular vulnerability due to both its low average altitude above sea-level and immediate proximity to the South China Sea. Agriculture, aquaculture and tourism initiatives in and surrounding the park will have to adapt to the prospects of life in an era of increased global climate extremes. Because wetlands play a key role in maintaining the biophysical stability of regions and countries by minimizing erosion from coastal storms and flood events, successful protection of key areas such as Xuan Thuy National Park will serve as way of gauging a country's ability to deal with future global climate change.
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