Substantial increase in future land exposure to compound droughts and heatwaves in China dominated by climate change

Abstract

Increased frequency and magnitude of compound droughts and heatwaves (CDH) under climate warming pose a severe threat to food production on cropland, biodiversity in forests and grasslands, as well as the health of urban populations. However, there is a lack of comprehensive assessments on the different land use types exposed to CDH events. In this study, we explored the changes in cropland, forest, grassland, urban, and bare land exposure to CDH frequency and magnitude (CDHMI) in China under different emission scenarios in the far-future (2070–2099) based on 12 model simulations from the Coupled Model Intercomparison Project Phase 6 (CMIP6) and Land Use Harmonization Version 2 (LUH2) data. The results indicate that with global warming, China is expected to face more frequent and severe CDH events in the future, particularly under high-emission scenarios. Correspondingly, Cropland, forest, grassland, and bare land exposure to CDH frequency and CDHMI show significant upward trends during 2015–2099, increasing at greater rates in high emission scenarios. Although the urban exposure to CDH frequency and CDHMI is projected to decelerate or even decline after 2050, urban exposure to CDH frequency and CDHMI under high-emission scenario will still increase by 605.20% and 207.32% during the far-future period (2070–2099) compared to 1981–2010, respectively. Regionally, the substantial increase in cropland, forest, grassland, urban, and bare land exposure to CDH frequency and CDHMI is concentrated in Northwestern China and Southern China due to the significant rise in frequency and magnitude of CDH events in these areas. The conclusions underline the importance and urgency of taking effective measures to limit emissions and respond to climate change.