Climate change

The last 35 years have seen significant warming of the earth’s atmosphere. This is closely linked to human activity, in particular an increase in the industrial emission of greenhouse gases such as carbon dioxide and methane. Climate change has already resulted in an increased intensity and duration of floods and droughts, as well as rising sea levels in Lower Mekong countries.  Many aspects of life have been affected including food production, infrastructure security and the livelihoods of coastal communities.

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This graph shows that atmospheric CO2 concentrations have increased since the Industrial Revolution.  Source: Courtesy NASA/JPL-Caltech. Usage terms: JPL Image Use Policy

Climate change in the Lower Mekong Basin

Lower Mekong countries  benefit both directly and indirectly from major rivers, such as the Mekong and Ayeyarwady. The diversity and abundance of natural resources in these catchments provides sustenance, livelihood support, habitat for many species. The natural wetlands within the catchment provide a wide range of ecological services, including flood mitigation, water storage, and wastewater treatment.

The Mekong basin and associated river network. Distribution coverage by country: China (21 percent), Myanmar (3 percent), Lao People’s Democratic Republic (25 percent), Thailand (23 percent), Cambodia (20 percent) and Vietnam (8 percent). Map created by ODM, view more water related datasets on Map Explorer


The deltas of these rivers are especially important for food production. For example, almost 60 percent of Myanmar’s rice is grown in the Ayeyarwady delta and adjacent coastlines.1 In Vietnam, the Mekong Delta makes up just 12% of the area of the country, but produces more than 50% of its rice, 60% of its fruits and 50% of its marine fishery. Nearly a quarter of the population earn their livelihood from these resources.2

Any changes to the hydrology of these rivers directly impacts the people and ecosystems depending on them. A growing body of data shows that climate change has already impacted food security related to agriculture and fisheries, as well as water security as a consequence of droughts and floods.

The Asian Development Bank has estimated that in 2015 alone, extreme weather events attributed to climate change resulted in losses in Cambodia of US$1.5 billion, of approximately 10 percent of the national GDP.3 Across the Lower Mekong as a whole, the costs of climate change have been estimated at a minimum of US$16 billion per year.4 

Changes to the flooding and flow regimes of river basins can have irreversibles impact on ecosystems, which in turn has an affect on a wide range of sectors, from tourism to public health, as well as individual livelihoods

Despite having vastly lower per capita greenhouse gas emissions than China, the United States or European Union5, Lower Mekong countries are amongst the most vulnerable in the world to the impacts of climate change. Myanmar, Vietnam and Thailand were among the 10 most affected countries between 1996–2015 on the Global Climate Risk Index, while Cambodia was ranked 13th.6

Vulnerability to climate change depends on many factors, including geography, resilience to extreme weather events, and the ability to adapt to the impacts of climate change. With a high population density and economic activity centred around coastal and riverine ecosystems, a significant portion of the population in the Lower Mekong region is at risk for these impacts. The poor, who are more highly dependent on natural resources and lack the capacity to adapt or respond to climate change are disproportionately affected

Total greenhouse gas emissions (kiloton) of Carbon Dixoide over a 40 year period within the Mekong. View metadata

Adaptation and mitigation

Climate change adaptation are changes to the existing practices of communities to cope with actual or predicted impacts of climate change on ecosystems. Examples of adaptation include the more efficient use of water resources, or changing the types of crops planted of forestry practices to reduce vulnerability to events such as storms or fires. Climate change mitigation is actions aimed at reducing the damage caused by human-induced climate change, such as reducing greenhouse gas emissions and enhancing the use of carbon sinks.

All of the Lower Mekong countries have developed plans and strategies for both mitigating and adapting to climate change. These include:

On a global scale there have been a number of climate change initiatives focused on climate change mitigation, or reducing greenhouse gas emissions. All five Lower Mekong states have signed and ratified the Paris Agreement on Climate Change, which entered into force on 4 November 2016. As part of this agreement each country has also released an Intended Nationally Determined Contribution (INDC) to identify their voluntary targets for mitigation and adaptation activities  to reduce the growth in greenhouse gas emissions.

The overall aim is to limit global temperature rise to below 2 degrees celsius. This aim is being facilitated United Nations’ Sustainable Development Goal 13 – Take urgent action to combat climate change and its impacts.

Forest governance, forest degradation, and deforestation

As part of these INDC’s, reducing deforestation and forest degradation is a major focus for action for the Lower Mekong countries. Forestry, agriculture and other land use activities account for almost a quarter of global greenhouse gas emissions 7, which is more than the global transportation and industry sectors combined. Most deforestation occurs in developing nations.


Forest cover change maps sourced from Hansen. Map created by ODM, view more environmental datasets on Map Explorer.


Improving forest governance is a major element in many climate change mitigation schemes. Initiatives that specifically target forests, including the EU Forest Law Enforcement, Governance, and Trade (FLEGT) Action Plan , and the United Nations Programme on Reducing Emissions from Deforestation and Forest Degradation in Developing Countries (REDD+). All Lower Mekong countries are members of ASEAN, which submitted a common position paper on REDD on behalf of its member states in 2008. 

Infrastructure development and climate change

Major infrastructure projects such as large hydropower dams can compound problems caused by climate change. For example , in the Mekong Delta of Vietnam, saltwater intrusion is already reducing the production of rice and farmed shrimp.8 Vietnam’s Ministry of Natural Resources and Environment has estimated that saltwater intrusion may affect up to 45% of the Mekong Delta as a result of climate change.9 A reduction of freshwater flows due to dams being developed in China and Laos is expected to make the problem much worse.  

Related to Climate Change


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