Evaluating the impacts of climate change and land-use change on future droughts in northeast Thailand.

The impacts of climate change (CC) on droughts are well documented, but the effects of land-use change (LUC) are poorly understood. This study compares the projected individual and combined impacts of these stressors on future droughts (2021-2050), with respect to baseline (1981-2010) in one of the major tributaries of the Mekong River. LUC impacts on hydrological droughts are minimal compared to CC, with the latter expected to shorten the recurrence interval of a 20-year return period event to every 14 years. Both CC and LUC have significant impacts on agricultural droughts with heightened sensitivity. 'Once in a Decade' agricultural droughts will be 40% (35%) longer and 88% (87%) more severe under the CC (LUC) scenario. Under both stressors, the events occurring every 20 years will be twice as frequent. Results highlight the intensification of future droughts and the urgency for actions to mitigate/adapt to climate change and manage land use. Future policy shall holistically address agricultural water management, sustainable land use management, and crop management to cope with future droughts. We recommend developing resilient agricultural practices, enhanced water resource management strategies, and incorporating drought risk into land-use planning to mitigate the compounded impacts of CC and LUC.

Using multi criteria decision analysis in a geographical information system framework to assess drought risk.

In this study we use the Mun river basin to demonstrate how a Multi Criteria Decision Analysis - Geographical Information Systems (MCDA-GIS) methodology can be used to assess drought risk. This paper not only provides a step forward in considering other elements such as land use change, climate within drought risk but also splits annual risk across three seasons (wet, cool and hot), previously not done. We also investigate how land use change, in the form of a/reforestation and changing crop varieties could potentially mitigate future risk. MCDA rankings from experts found that climatic factors such as rainfall, evapotranspiration and maximum temperature were the most significant. By splitting up the seasons we have been able to observe the temporal and spatial changes in drought risk at an increased detail, an important step in mitigating water security issue in the future. Results for cool months found an increased risk in the north and east (Surin, Si Sa Ket and Rio Et). With hot months finding increased risk in the east (Surin and Si Sa Ket especially) and west in Nakon Ratchasima. Whereas the wet season risk was greatest in the West (Nakon Ratchima, Khon Kean and Mara Sarakham). Differences in future land use scenarios compared to 2017 found that if current trends continued (BAU), the areas at risk from drought will increase. However, by changing land use in the form of a/reforestation (COB) or changing crop types (PRO), drought risk will decrease. Thus, the MCDA-GIS methodology serves as a great starting point, providing a high flexibility in data, meaning the methodology can readily applied to other case studies across the world.