Climate change is not just a threat in the Mekong River Basin. Its impact is present and affecting the livelihoods of the millions who rely on the river’s natural resources. The Lower Mekong River Basin (LMB), comprising Cambodia, Lao PDR, Thailand, and Viet Nam, is recognised as one of the regions most vulnerable to climate change. The economies of the LMB countries, their ecosystems, sustainability, and social harmony are all at risk.
Across the LMB, the effects of climate change are obvious. Rising temperatures and changes in the intensity of rainfall, river flow, floods, and droughts are destroying homes, infrastructure, crops and fisheries. As a result, vulnerable communities are faced with food shortages and diminished livelihoods. Additionally, predicted rises in sea levels are set to increase salinity and floods in the Mekong Delta, causing damage to crops in the most productive area of the basin.
According to the MRC research, a wide range of potential changes are projected to occur over the next 20 to 50 years. Temperatures are projected to increase across the basin and across seasons. By 2060 the average annual basin-wide increase could be between 0.4˚C and 3.3˚C depending on the trajectory of global greenhouse gas emissions. Average change in rainfall by 2060 under a dry climate scenario is projected to fall by 16%, and under a wet climate scenario, to increase by 17%.
Agricultural yields are likely to be affected. Changes in agricultural practices, and irrigation and technological improvements will be required to offset these impacts. Hydropower production will be at risk due to increased droughts. Navigation may be affected by lower dry season flows making some parts of the upper Mekong impassable at certain times of the year. Roads and water supply infrastructure are at risk from more intense rainfall, increased flooding and landslides, while significant expenditure may be required to protect coastal infrastructure from rising sea levels and storm surges.
Many plant and animal species are highly vulnerable to climate change with large numbers of fish particularly at risk due to their sensitivity to hydrological cues. Under a moderate scenario to 2060, soil erosion losses are projected to increase by 16.9%.
The impacts of such changes are likely to be particularly severe given local communities’ reliance on natural resources. However, the impacts will not be felt evenly as some people and communities are more exposed than others or will experience changes sooner or to a greater extent. Impacts are not limited by national boundaries. Upstream impacts can have implications downstream, and vice versa, and adaptation options implemented by one country may pose direct or significant cross-border implications for other countries.
Decision-makers and strategists in the lower Mekong countries are increasingly aware of the effects of climate change and are integrating the issue into national plans. However, many activities have been focused on natural disaster response rather than climate change adaptation and have been aimed at national levels. Building on these efforts, the MRC actively supports its Member Countries with technical advice, research, and dialogue-based forums to encourage knowledge sharing and foster an understanding of climate change within a transboundary context. The MRC supports the countries through:
- Basin-wide strategies such as the Mekong Climate Change Adaptation Strategy and Action Plan (MASAP) which sets out the strategic priorities and actions at basin level to address climate change risks and strengthen basin-wide resilience.
- Technical guidelines seek to help the Member Countries ensure that climate change adaptation is harmonised with effective strategies and plans at various levels, and that the monitoring and reporting system on climate change is operationalised.
- Studies and assessments that determine impacts of climate change on water and related resources to support planning and decision-making.
- Capacity development that enhances the capacity of the Member Countries in implementing their climate change related national strategies.
Responding to the Member Countries’ call for a collaborative regional adaptation initiative to cope with climate change, in 2009 the MRC established the Climate Change Adaptation Initiative (CCAI), aimed at understanding and reducing the impacts of climate change in the LMB.
A central theme of the CCAI was to assess climate change impacts and vulnerabilities, and review existing monitoring systems and indicators to improve understanding on the status and impacts of climate change. In addition, the CCAI explored ways to protect communities and biodiversity in the Mekong region from a changing climate. It also supported implementation of pilot adaptation projects and actions in communities in each of the lower Mekong countries.
The CCAI provided comprehensive capacity building through training and exchanges, strengthening understanding of how vulnerabilities can be identified and tackled. Additionally, the CCAI assisted the Member Countries to use the findings of studies and pilots to design policy frameworks to guide adaptation in practice, integrating climate change into development planning.
To ensure the sustainability of adaptation actions and strategies, the CCAI facilitated partnerships that offer constant support to the Member Countries. A wide network of partners was envisaged, enabling knowledge exchange and regional cooperation in the decades to come.
To further support the Member Countries to increase climate resilience, the CCAI facilitated the development of the Mekong Adaptation Strategy and Action Plan (MASAP). Approved by the MRC Council in December 2017, the MASAP identifies critical dimensions of development that need transboundary cooperation for the purpose of adaptation to climate change and enhances the capacity of the Member Countries to implement their national strategies. It also supports the mainstreaming of regional climate change adaption at national level and informs the development of the Basin Development Strategy (BDS) 2021-2030, Flood Management and Mitigation Strategy, and Fisheries Management Strategy.
Under the BDS 2021-2030, implemented through the Strategic Plan 2021-2025, the MRC further supports the Member Countries to mainstream climate change adaptation to enhance climate resilience, and flood and drought mitigation into national strategies, plans and projects. It promotes joint transboundary projects on climate change adaptation and enhances access to international climate finance.
The MRC has conducted a number of basin-wide studies to assess the impacts of climate change in the LMB. These include:
- Basin-wide assessment of climate change impacts on hydropower production: Published in 2018, the assessment analyses the impacts of climate change on hydropower potential in the LMB. The study provides relevant indicators of change in potential hydropower generation and informed preparation of the MASAP.
- Analysis of historical trends, variability and changes in hydro-climatic conditions in the LMB: Published in 2017, the report analyses whether historical trends, variability and changes identified in LMB hydro-climatic conditions are due to natural variability. It investigates relationships between trends, variability and changes in selected indicators of historical hydro-climatic conditions in the LMB and large-scale ocean-atmospheric processes known to influence the Southeast Asian region.
- Climate change impacts for Council Study sectors: Completed in 2017, the study examines impacts under three scenarios of change between 2020 and 2040. These include (i) changes for people including food security and employment; (ii) changes in environment; and (iii) changes in economics.
- Basin-wide assessment of climate change impacts on water resources and related resources in the LMB: Published in 2017, the study provides information on the impacts of potential future climate change on hydrology, flood, drought, hydropower, ecosystems and biodiversity, fisheries, and agricultural production to support decision-making on climate change adaptation measures at regional and country levels.
To convey adequate information on climate change impacts and adaptation needs, the MRC has recently developed the following guidelines:
- Technical guidance on MASAP mainstreaming at national level: The guidance aims at mainstreaming climate change adaptation into national programs and activities.
- Technical guidance on operationalisation of the monitoring and reporting system on climate change and adaptation: The guidelines support operationalisation of the monitoring and reporting system on the status of climate change impacts and adaptation based on an agreed set of indicators.
- SIMCLIM tool for climate change scenarios: SimCLIM is a software tool designed to facilitate the assessment of risks from climate change.
The MRC has produced a series of knowledge products, including technical papers and assessments, to facilitate decision-making and mainstreaming of climate change adaptation at national and regional levels.