UNDERSTANDING CLIMATE CHANGE
IN THE LOWER MEKONG BASIN
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The global discussion on climate change was until recently, focused mainly on its causes - namely; the increasing levels of greenhouse gases in the atmosphere; as well as negotiations on mitigation measures and emission ceilings. Emissions of greenhouse gasses per capita and emission intensity are low in the Lower Mekong Basin compared with other parts of the world. The impacts of climate change are, however, predicted to be significant, as are the subsequent predicted consequences for human development and poverty alleviation in the region. See the map on the right to see how climate change will impact the Mekong region.
Changes in weather patterns as a result of climate change are expected to cause a decrease in rainfall during the dry season and more rain in the wet season, with increasing variability across the region. This may lead to increasing seasonal water shortages, as well as higher frequency and increased severity of floods.
The mega-deltas of the big river basins in Asia are considered particularly vulnerable because of the combination of flooding, sea level rise and large human populations. Seasonal water shortages will increase the likelihood and severity of saltwater intrusion into the Mekong Delta. This will have serious implications for natural ecosystems, agriculture and food production, as well as exacerbate the challenges of satisfying increasing food demands from growing populations.
Studies undertaken to date suggest a range of potentially significant impacts are possible by 2030 that may exacerbate or increase levels of poverty and slow development, including:
- An increase in the mean temperature of approximately 0.8°C;
- Increases in annual precipitation of more than 13.5% (equivalent to 0.2m) in some areas leading to an increase in the severeity of flooding;
- Decreases in dry season precipitation in other areas making some parts of the basin more drought prone;
- In the upper reaches of the Mekong Basin, melting glaciers will increase the contribution of snow melt to water in the river system;
- More extreme weather events;
- Impacts on productivity of agricultural activities;
- Salinity intrusion into the Mekong Delta, which will have a significant impact on agriculture, aquaculture and capture fisheries, which may mean the displacement of millions of people.
Increasing competition between land-use interests may lead to a number of conflicts and a decrease in the availability of arable land may lead to the displacement of large numbers of people - especially in Viet Nam, which has a large proportion of its population living in the delta.
At the present time, the detailed understanding of how climate change may threaten each individual country's environmental and social systems varies significantly. The Governments of Thailand and Viet Nam have developed climate change scenarios and projections and have accomplished some studies on impact assessment and potentials for adaptation. Climate change information for Cambodia and Lao PDR is less developed but expected to increase in the coming years.
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