Climate change in the Greater Mekong

Climate change exacerbates the impacts of current environmental threats such as habitat loss, poorly planned infrastructure, and unsustainable natural resource extraction. These threats reduce ecosystem resilience (i.e., the capacity of ecosystems to ‘bounce back’ or recover from disturbances and damage). Climate change further stresses and therefore degrades the ecosystems upon which the region’s social and economic future depends.

Ecosystem deterioration will have cascading effects, which will eventually affect people. For example, water scarcity may reduce agricultural productivity, which will lead to food scarcity, unemployment and poverty.

Among lower Mekong Basin countries, Laos and Cambodia have been identified as the most vulnerable in part because of their limited capacity to cope with climate related risks (Yusuf and Francisco 2009). In all countries, climate change complicates existing problems. For example, rising seas will compound the effects of floods caused by land subsidence and coastal erosion.


"The city of Bangkok is sinking by 5-10 mm each year. Land subsidence and groundwater extraction combined with sea level rise could leave Bangkok under 50-100 cm of water by 2025." United Nations Environment Programme (2009)

How will climate change impact the Greater Mekong?

Warmer and wetter

Across the region, temperatures have risen by 0.5 to 1.5ºC in the past 50 years and continue to rise. While rainy seasons may contract over parts of the region, overall rainfall is expected to rise. This means more intense rain events when they occur. More frequent and damaging droughts and floods will cause, and have already caused, extensive damage to property and loss of life.

The life-supporting glaciers of the Himalayas are melting and receding rapidly. Although their contribution to the Mekong River is small, the high altitude wetlands they feed might disappear in less than 30 years. Their rapid water discharge will cause severe floods and a dry aftermath. This will be catastrophic not only for the fragile alpine ecosystems but also for people living in the upper basin of the Mekong. It is imperative that governments keep these places and people in mind when setting mitigation targets, because they are already facing imminent severe impacts.

Sea level rise

Sea level rise is threatening the region’s coastal communities and ecosystems are becoming more stressed. By the end of the century, higher sea levels in the Mekong Delta, where nearly half of Vietnam’s rice is grown, may inundate about half (~1.4 million ha) of the delta’s agricultural lands and displace millions of people.

"A 1-m sea level rise would cause disruptions to over 10% of Vietnam’s population, or 8.5 million people." World Bank.

Human impacts

The human impacts of climate change can be devastating, and the region’s poorest people will be disproportionately affected. Beyond the acute impact of strong and frequent natural disasters, people will also suffer "chronically" from an accelerated degradation of the ecosystems.

The rivers, the forests, the floodplains are sources of food, clean water, timber and fuel for many people and are also fundamental to their culture. Degradation of ecosystems from climate change will decrease their productivity and capacity to provide livelihoods for people.

Agricultural impacts

Agriculture is a very important sector in this region for both the economies and livelihoods, and rural farmers are already experiencing climate change. Warmer temperatures have contributed to declining crop yields. Storms are destroying entire harvests, and with this, a whole year's income for a farmer. As the climate changes, stronger rains and more severe droughts will cause further impacts on crops. Resisting these changes may only be a short-term solution. Instead, farming practices, choice of crops, crop distributions and growing seasons can be adjusted to provide alternatives that are adapted to the new climate.

Assessing climate change

Regional Scale Vulnerability Assessment

In a project funded by the MacArthur foundation, WWF is assessing the climate change vulnerability of the Mekong River’s freshwater and riparian habitats as well as the priority landscapes of the Greater Annamites and the lower Mekong Dry Forests ecoregions.

The assessment is being done through a combination of mapping, modeling, literature review, and consultation with regional experts. In all ecoregions, the emphasis is on understanding how resilient the Mekong region’s landscapes and freshwater ecosystems may be to climate change impacts.

At the end of this two-year project, we aim to produce a set recommendations to facilitate adaptation to potential impacts from climate change on the critical species, habitats and protected area networks in the region.

Importantly, this assessment is engaging stakeholders from multiple sectors, including government, researchers and other technical experts, and other conservation organizations. We are also incorporating other ongoing studies on climate impacts on the region. Building and strengthening these relationships is crucial for our success in the mission for the Greater Mekong Region to adapt to climate change.

See the "MacArthur Project Synthesis Report" document (right, under "Reports" section) for an extensive summary of the workshops undertaken during this two-year project.

Provincial Scale Vulnerability Assessment

Coastal areas in the Greater Mekong are highly vulnerable to the impacts of climate change, yet there has been little discussion of how to integrate climate-related concerns into the plans and policies that will shape future economic development. The WWF Greater Mekong Programme recently collaborated with WWF's Macroeconomics Programme and local climate researchers on innovative pilot studies that assessed climate change vulnerability and its implications for development in two coastal provinces that are priorities for WWF: Krabi in Thailand and Ca Mau in Vietnam.

Down-scaled climate models were used to predict key impacts and identify the most vulnerable places and people. The team organized outreach workshops to engage local stakeholders, including government agencies, the private sector, and community representatives, to explore potential impacts on key economic sectors, such as agriculture, aquaculture, and tourism, and to discuss strategies that would improve resilience to expected impacts and shift future development planning onto a more sustainable path.