Undermined co-benefits of hydropower and irrigation in the Mekong River basin under under 1.5°C and 2°C global warming

Dam construction, although often controversial due to its environmental impacts, is mostly aimed for multiple functions, such as irrigation water supply, hydropower generation, and some other purposes in the meantime. These functions bring substantive benefits to the society. However, global warming impacts on the interaction of the positive outcomes of damming remain little known, particularly in terms of the sustainability of their complementary relations. This study used an integrative analysis based on hydrological, techno-economic and agricultural model framework to assess the effects of global warming of 1.5°C and 2°C on the co-benefits between hydropower and irrigation in the Mekong River basin. The results show that the hydropower generation and irrigation water supply in the Mekong River basin will both decrease under 1.5°C and 2°C global warming compared to the historical period. The co-benefits between the hydropower production and the irrigation water supply in the Mekong River basin is more undermined by the global warming of 2° relative to 1.5°. Moreover, the changes of co-benefits are sensitive to the consideration of the protected areas in the basin. Therefore, it is important for decision makers to consider the tradeoff between the environment and dam construction for ensuring energy and food security under climate changes.