Analysis of extreme droughts and floods during 1001–2000 CE in Guangxi, South China, based on historical documents

The escalating frequency of extreme droughts and floods amidst global warming poses a significant threat to public health and socio-economic development, making it a critical issue of research in natural disasters. Reconstructing past extreme droughts and floods through historical documents is an essential approach. However, Guangxi, a region in South China, encounters a scarcity of such documents and limited specialized studies on extreme droughts and floods. This study addresses this gap by reconstructing annual drought and flood indices in Guangxi, China, spanning the period from 1001 to 2000 CE, utilizing drought and flood records from historical documents dating back to the Song Dynasty. We determined the yearly sequences of extreme droughts/floods at 88 sites using percentile threshold values and conducted statistical analyses to explore variations in their frequencies and intensities across different periods and regions. Our findings indicate a robust correlation between extreme droughts and stalagmite δ¹⁸O-reconstructed precipitation records in South China. Notably, the increase in extreme flood frequency around 1300 CE may be associated with the climatic transition from the Medieval Warm Period to the Little Ice Age, along with weakened Asian summer monsoon intensity. Since 1900 CE, the Central Pacific El Niño has emerged as the dominant driver of El Niño patterns, and concurrent rises in temperatures and greenhouse gas emissions may have significantly contributed to the surge in extreme droughts and floods. These insights enhance our comprehension of historical climate change and provide a scientific basis for anticipating future extreme climate events and guiding disaster preparedness and mitigation strategies.