Basin‐wide impacts of climate change on ecosystem services in the Lower Mekong Basin

Abstract

Water resources support more than 60 million people in the Lower Mekong Basin (LMB) and are important for food security-especially rice production-and economic security. This study aims to quantify water yield under near- and long-term climate scenarios and assess the potential impacts on rice cultivation. The InVEST model (Integrated Valuation of Ecosystem Services and Tradeoffs) forecasted water yield, and land evaluation was used to delineate suitability classes. Pattern-downscaled climate data were specially generated for the LMB. Predicted annual water yields for 2030 and 2060, derived from a drier overall scenario in combination with medium and high greenhouse gas emissions, indicated a reduction of 9-24% from baseline (average 1986-2005) runoff. In contrast, increased seasonality and wetter rainfall scenarios increased annual runoff by 6-26%. Extreme drought decreased suitability of transplanted rice cultivation by 3%, and rice production would be reduced by 4.2 and 4%, with and without irrigation projects, relative to baseline. Greatest rice reduction was predicted for Thailand, followed by Lao PDR and Cambodia, and was stable for Vietnam. Rice production in the LMB appears sufficient to feed the LMB population in 2030, while rice production in Lao PDR and Cambodia are not expected to be sufficient for domestic consumption, largely due to steep topography and sandy soils as well as drought. Four adaptation measures to minimize climate impacts (i.e., irrigation, changing the planting calendar, new rice varieties, and alternative crops) are discussed.

Ranking of CMIP5 GCM Skills in Simulating Observed Precipitation over the Lower Mekong Basin, Using an Improved Score-Based Method

“…In our study, we highlighted similarly good performances from HadGEM2-ES, CCSM4, and IPSL-CM5A-MR over the LMB, which is part of the Asian monsoon region, and part of the Mekong River Basin, which are both affected by the southwest monsoon. However, our results showed differences from the above studies, which indicated that it is significant to assess GCM performance not only at a large scale, but also at a regional scale: A river basin such as the LMB should especially be taken into important consideration due to its special geographical position and climatic characteristics, as well as its significant effects [30,31].…”

“…Moreover, further increases in population and accelerated urbanization have exacerbated the demand for water resources [29]. Additionally, changes in precipitation are likely to have great impacts on the water cycle system, water resources, and agricultural production of the Lower Mekong Basin (LMB) [5,30,31]. Therefore, assessing GCM performances in simulating precipitation is essential for future precipitation change and policy-making over the LMB.…”

Assessing the Performance of CMIP5 GCMs for Projection of Future Temperature Change over the Lower Mekong Basin

“…Future climate change will affect water yield and rice cultivation in the tributary countries over the Lower Mekong Basin (LMB) [30]. Due to the population growth in the Lower Mekong Basin (LMB), the demands for agricultural products from the LMB is expected to increase by 20-50% in the next 30 years [31].…”

Biodiversity and ecosystems in Asia: studies and activities of International Long‐Term Ecological Research Network in East Asia and Pacific

“…A further four original articles include studies of the status of biodiversity, ecosystem structure, and ecosystem services in terrestrial, riverine, and marine environments in different parts of Asia. In their study, Trisurat et al (2018) present a forecast of future changes in ecosystem services in the Lower Mekong Basin by quantifying changes in water yield, while Nguyen et al (2018) review plans to conserve the wetlands in the Vietnamese Mekong Delta by changing the present hydrological management. Galindon et al (2018) compare the status of biodiversity in forests in limestone quarries in different sub-regions of the Philippines with different management histories (reforestation).…”