Regional Vulnerability to Changing Water Resources and Extreme Hydrological Events
Study site in Songkhone district, Lao PDR where risk and vulnerability assessment was undertaken
This research studied the impact of climate change on hydrological condition and rain-fed agriculture in Southeast Asia with focus on the lower Mekong River basin as well as assessed vulnerability and adaptation of rain-fed farmers to climate change impact. In this study, future climate scenarios were developed using a climate model with the given condition of increasing atmospheric CO2 concentration from the baseline of 360ppm to 540ppm and 720ppm (in other words, 1.5 and 2 times the baseline). The results of the simulation suggest that average temperature in the region tends to be slightly cooler under climatic condition at CO2 concentration of 540ppm but will be slightly warmer than the baseline condition under climate condition at CO2 concentration of 720ppm. The range of temperature change is 1-2oC. The hot period of the year will extend longer and the cool period will be significantly shorter while the length of rainy season would remain the same, but with higher rainfall intensity. These changes in climate pattern will result in higher discharge of most of the Mekong River tributaries, which is higher in proportion to the increase in precipitation. Agriculture sector, especially rain-fed systems will also be affected by the change in climate pattern. The result from simulation using crop modeling technique shows that yield of rice productivity in the study site in Thailand will increase by 3-6%; but on the contrary, may reduce by almost 10% in the study site in Lao PDR. Rice production in the Mekong River delta in Viet Nam tends to be severely impacted by climate change, especially summer-autumn crop production, of which the yield may reduce by over 40%. Change in rice productivity was used as proxy for climate change impact to assess risk and vulnerability of rain-fed farmer. The assessment shows that vulnerability to climate change impact of farmers in the lower Mekong River region varies from place to place, according to the degree of climate impact as well as socio-economical and physical conditions in each location. Results from farmer surveys in selected communities in Lao PDR, Thailand and Vietnam show adaptation strategies shaped by the socio-economic condition of their surrounding community. Farmers in communities with less developed socio-economic conditions, such as Lao PDR, tend to pursue simple strategies targeted at increasing coping capacity and sustaining basic needs that can be implemented at the household or community level with limited financial and other resources. Farmers in communities with more developed socio-economic conditions, as the case study in Thailand, tend to pursue strategies targeted at reducing the variability of income and at improving the productivity and resilience of their farms. The measures that they adopt tend to depend more on market and other institutions, improved technologies and financial resources than is the case for farmers in less developed communities.
What are impacts of climate change on the hydrological regime and fresh water resources in Mekong River Basin?
What are impacts of climate change on rain-fed rice productivity in Mekong River Basin?
How would rain-fed farmers in the region be vulnerable to the impact of climate change?
How would rain-fed farmers in the region adapt to impact of climate change?
To develop high resolution climate scenario – in geographical and temporal terms.
To understand the impact of climate change on the regional hydrological regime and rain-fed agriculture in the Mekong River basin.
To develop and test the framework and method to measure vulnerability of households in the community to climate impact.
To understand coping capacity and adaptation to climate impact of the rain-fed farmer in the lower Mekong River region.
This study can be divided into 2 parts, which used different approaches in the study.
The study on climate change and its impact on biophysical systems is based on the modeling approach. This area of study was focused on changes in climate pattern and its first order impact on hydrological condition and agriculture, particularly the rain-fed system, in the region. Climate model was used to simulate high resolution future climate scenario. Climate change impact was analyzed by using future climate data from the simulation as input to hydrological model and crop model for further simulation on hydrological regime of the Mekong River sub-basins and potential crop productivity yield in the study sites.
Assessment of vulnerability and adaptation to climate impact were based on field survey by individual household interviews and focus group meeting. The analysis of field interview data was based on quantitative analysis and multi-criteria method, which used multiple criteria and indicators developed for this case study.
Thailand, Lao PDR, Vietnam, 2003-2006