Projected changes in average and extreme precipitation under global warming in Vietnam

Vietnam, with its long coastline and low-lying river deltas, is highly vulnerable to flooding and extreme precipitation events. Climate change is likely to exacerbate these risks by intensifying precipitation in a warmer, moister atmosphere. While the Clausius-Clapeyron relation suggests a 6%–7% increase in atmospheric moisture per degree of warming, actual changes in average and extreme precipitation can deviate from this rate due to regional variations in moisture availability, atmospheric convection, and other climatic factors. However, the scarcity of high-quality future climate data for Vietnam has limited our ability to assess the response of extreme precipitation to different levels of global warming. In this study, we bias-corrected daily precipitation data from Phase 6 of the Coupled Model Intercomparison Project (CMIP6) to evaluate future changes in annual average and extreme daily precipitation under four global warming scenarios across two future time periods. Results indicate that while average precipitation shows relatively small changes, extreme precipitation is projected to increase, with the magnitude rising by 12.1% between 2030 and 2059 and by 19.3% between 2070 and 2099 compared to current levels. For each degree of global warming, extreme precipitation in Vietnam is expected to rise by 5.4%, with a more significant increase in the northern regions. These findings underscore the substantial impact of global warming on flood risks in Vietnam, highlighting the urgent need for effective mitigation and adaptation strategies.