Impacts of Future Changes in Heavy Precipitation and Extreme Drought on the Economy over South China and Indochina

Heavy precipitation and extreme drought have caused severe economic losses over South China and Indochina (INCSC) in recent decades. Given the areas with large gross domestic product (GDP) in the INCSC region are distributed along the coastline and greatly affected by global warming, understanding the possible economic impacts induced by future changes in the maximum consecutive 5-day precipitation (RX5day) and the maximum consecutive dry days (CDD) is critical for adaptation planning in this region. Based on the latest data released by phase 6 of the Coupled Model Intercomparison Project (CMIP6), future projections of precipitation extremes with bias correction and their impacts on GDP over the INCSC region under the fossil-fueled development Shared Socioeconomic Pathway (SSP5-8.5) are investigated. Results indicate that RX5day will intensify robustly throughout the INCSC region, while CDD will lengthen in most regions under global warming. The changes in climate consistently dominate the effect on GDP over the INCSC region, rather than the change of GDP. If only considering the effect of climate change on GDP, the changes in precipitation extremes bring a larger impact on the economy in the future to the provinces of Hunan, Jiangxi, Fujian, Guangdong, and Hainan in South China, as well as the Malay Peninsula and southern Cambodia in Indochina. Thus, timely regional adaptation strategies are urgent for these regions. Moreover, from the sub-regional average viewpoint, over two thirds of CMIP6 models agree that maintaining a lower global warming level will reduce the economic impacts from heavy precipitation over the INCSC region.