Climate Challenges in the Mekong Delta

Social-Ecological Transformation, Vietnam | 01.05.2021

Climate Challenges in the Mekong Delta

The Mekong Delta region in southwestern Vietnam is home to over 20 million people, and is crucial to the country’s agricultural and aquaculture production. It is also a unique natural habitat, teeming with thousands of plant and animal species that cannot be found anywhere else. Yet it is also one of the parts of Southeast Asia most threatened by accelerating climate change.

As sea levels continue to rise, coastal erosion is becoming a bigger and bigger problem for the region. Since 2005, the Delta’s total land mass has in fact been decreasing annually. The region also faces more severe floods, not to mention a growing risk of drought due to decreasing rainfall and abnormal weather patterns. By 2050, the entire Mekong Delta could find itself below sea level.

One of the institutions in Vietnam working on solutions to these challenges is the Research Institute for Climate Change, established in 2008 under a joint agreement between the US and Vietnam to cooperate on training and research to produce healthy ecosystems and sustainable major river deltas in a changing climate. The Institute is a leading unit in the region in scientific research as well as science and technology transfer related to natural disasters, climate change, and its impacts, along with sea level rise. The Institute focuses on researching strategic solutions and action plans to adapt and mitigate the impacts of climate change for localities through many appropriate models in the Mekong Delta and other deltas in the world.

Philip Degenhardt of the Rosa-Luxemburg-Stiftung’s Southeast Asia Office in Hanoi spoke with the Institute’s director, Nguyen Hieu Trung, to learn more about the challenges that climate change is imposing in the Mekong Delta, and how people are responding.


PD: What are the main problems and challenges facing the Mekong Delta at the moment, both internally and externally?

NHT: Currently, the Mekong Delta is facing many problems and challenges arising from factors outside of the region such as weather fluctuations due to climate change. Moreover, agricultural production in the region is affected by changes in the Mekong River flow due to the reservoirs of the upstream hydroelectric dam. On top of that, a changing ecosystem along with pollution is affecting the livelihoods of the Mekong Delta population, especially in the coastal areas. These factors are international and global, however, and thus unmanageable by the population and authorities in the Mekong Delta alone.

In addition, problems due to internal factors within the Mekong Delta such as an intensification of crops in agricultural and fishery production and excessive groundwater extraction are leading to rapid land subsidence. The region is also experiencing rapid urbanization, with which local infrastructures cannot keep up.

Consequently, these factors affect natural ecosystems and intensify pollution related to land and water, resulting in various socio-economic problems such as lower incomes and job losses, thereby amplifying poverty.

Are there different impacts within the different regions of the Delta?

The Mekong Delta region can be divided into three sub-regions, each of which is affected differently by the factors mentioned above.

The first sub-region is characterized by flood ecology, intensified by the annual flooding season. The flood control strategy for this ecoregion has been associated with closing dykes in deeply flooded areas to increase three-crop rice production. In the long run, however, agricultural output can drop due to land degradation and land subsidence, leading to increased flooding when storms and floods hit harder than usual.

The second sub-region, the middle fresh water alluvial, concentrates a dynamic interaction between two flooded ecological sub-regions and the coast. Therefore, the problems often faced by this sub-region are many unusual changes, essentially due to a large shift between low inundation to deep- and long-term inundation during the wet season, as well as from non-saline to saline water during the dry season. Therefore, many areas in the middle area of the riverside have to continuously change their production structure in order to adapt to abnormal fluctuations of water sources.

The main problems faced by the third sub-region, the coastal area, are the reduction of coastal forest area due to changes in terms of natural ecology characteristics (besides human factors), salinity intrusion, and over-exploitation of groundwater. This accelerates the process of subsidence of the topsoil.

The cause of subsidence may mainly be due to groundwater extraction, and the extent of subsidence also causes more negative effects than sea-level rise. In the future, if land subsidence persists, we will have to pay for flood prevention, migration, and loss of agricultural productivity.

How does climate change impact these recent challenges?

Climate change impacts rainfall distribution during the wet season, which increases the occurrence of large storms and inundation in the upstream provinces of the Mekong Delta. Climate change can also prolong the dry season, which reduces the water volume flowing from the main stream of the Mekong River to the Delta, leading to a lack of fresh water. Moreover, salt water from the sea entering into the main rivers and canals can affect freshwater agriculture and fisheries as well as domestic water supply in coastal provinces. In addition, changes in temperature increase the likelihood of diseases and environmental pollution, which directly affects the health of people and aquaculture.

Moreover, the impacts of climate change can also be observed within the upstream countries as the climate becomes more extreme. These countries will have to internalize measures to regulate the amount of water pouring into the Mekong Delta, but they usually cause negative impacts to the life and production activities in the Mekong Delta at the same time.

For example, when heavy storms occur at the source, hydropower dams have to rapidly discharge large amounts of water downstream, causing more flooding in these areas. On the other hand, when the amount of rain upstream is less than usual, the upstream dams store a larger of amount of water while at the same time reducing the amount of water flowing into the Mekong Delta. Furthermore, the high tide will make salt intrude deeper into the Mekong Delta.

The Mekong Delta is facing a multidimensional crisis: declining water levels in the Mekong River itself, saltwater intrusion into the Delta, and subsidence of the ground. What impact does this have on Vietnam’s so-called “rice bowl” and agricultural production more generally?

The impact of drought on the Mekong Delta is becoming more and more serious. Compared to the drought and saline intrusion in 2015–2016, 2019–2020 was much more severe in the Mekong Delta. According to the Ministry of Agriculture and Rural Development, the total damage caused by saline drought in the Mekong Delta region rose to about 39,000 hectares during 2019–2020. Coastal provinces had thousands of hectares of late winter-spring rice which had been sowed by farmers but severely lacked water, thus risking huge losses.

The issue of subsidence and riverbank erosion in the Mekong Delta also needs to be addressed. The research findings from the Rise and Fall project, a collaboration between Can Tho University and Utrecht University in the Netherlands, show that the average ground elevation in the Mekong Delta is descending by about two centimetres per year, mostly in Cà Mau Peninsula. This reduces the total area in which rice cultivation is possible and increases production costs by necessitating upgrades to the dyke system and sluice gates to ensure flood and salinity control.

What kinds of challenges do small-scale farmers face?

According to our findings and reports from the Agriculture and Rural Development Departments of the Mekong Delta provinces, the challenges which farmers are facing today include a growing intensity of extreme and irregular weather due to the impacts of climate change, which also affect people’s living conditions.

Not only are the impacts of climate change severe, but farmers also lack deep awareness relating to these impacts due to the inaccessibility of information. On the other hand, merely acquiring this information does not mean they will be fully prepared, as they do not have enough capital, time, manpower, or material resources to anticipate or mitigate the impacts of climate change. In other cases, even when they are able to adapt well to climate change, product prices can be volatile due to their lack of access to stable markets. Finally, poor transport infrastructure and housing construction unable to withstand the impacts of floods, droughts, and environmental pollution are challenges which should not be overlooked.

What new models of agricultural production could these farmers apply?

According to the report on the situation of agricultural production by the Department of Agriculture and Rural Development of the Mekong Delta provinces, there are various measures to adapt to the problem.

Firstly, we can save water by installing automatic watering systems for the cultivation of vegetables and fruit trees—misting, dripping, etc. Secondly, freshwater from the wet season can be stored in ponds, lakes, and garden ditches for use in the dry season. Thirdly, by growing vegetables in net houses and greenhouse and conducting intensive shrimp farming with canvas lining, we can reduce the exposure to risks of natural disasters. Fourthly, by using models with a closed nutrient cycle such as the combined fish-rice model, the rice-fish-lotus-tourism model, or the shrimp-seafood-forest model, emissions can be reduced towards environmentally friendly levels.

Rice production in the Mekong Delta has a regional impact on the food security of many countries. How will these changes affect food security in Vietnam and the region?

The Mekong River Delta is the largest rice-exporting region in Vietnam, accounting for 90 percent of the country’s rice export volume and 70 percent of seafood output. Agriculture and food security are the sectors most vulnerable to the impacts of climate change.

Climate change has impacted growth, crop yield, and the planting season, increasing the risk of diseases. The consequences arising from these include reduced yields and productivity, thereby affecting farmers’ incomes and Vietnam’s food security in particular—but also the rest of the world.

What is the Vietnamese government’s plan to tackle these issues?

The national plan to adapt to climate change includes three groups of tasks and solutions:

  • First, improving the effectiveness of climate change adaptation through strengthening the state’s management capacity on climate change and promoting the integration of climate change adaptation into strategic and regulatory system plans.
  • Second, enhancing resilience and adaptive capacity for communities, economic sectors, and ecosystems through investment in adaptation actions, science, and technology to be prepared to adapt to climate change.
  • Third, boosting disaster risk reduction and damage reduction, along with preparedness to respond to natural disasters and increased climate extremes due to climate change, such as via the establishment of regional coordination institutions and mechanisms for sustainable development in the Mekong Delta. Alongside this, promoting the training and development of human resources, scientific research, and technological development, as well as strengthening international cooperation and strategic communication to raise public awareness of the impacts of climate change.

Climate Challenges in the Mekong Delta

Publisher: Rosa-Luxemburg-Stiftung

Author: Nguyen Trung Hieu

Editors: Philip Degenhardt (interview) and Phung Quynh Nga (translation)

Date: May 2021

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