Elevated atmospheric CO2 drove spatial variability in terrestrial organic carbon burial during the Toarcian hyperthermal

Enhanced organic carbon burial associated with widespread black shale deposition functioned as a critical feedback mechanism for removing excess carbon from the atmosphere-ocean system during the Early Toarcian hyperthermal (~183 Ma). Although records from Chinese basins (Tarim, Ordos, Sichuan) suggest substantial terrestrial burial in lakes, spatial patterns and drivers remain unclear. To address this, we employ the fully coupled global climate model (Community Earth System Model, CESM 1.2.2) and the BIOME4 vegetation model to investigate the response of terrestrial organic carbon burial to Toarcian warming. Our simulations suggest that elevated atmospheric CO₂ during the Toarcian hyperthermal triggered a substantial poleward shift in global mid-latitude monsoon domains, resulting in spatial variations in moisture flux. Despite increased global productivity, moisture availability primarily controlled terrestrial carbon burial. Our results suggest that lakes with stable water supply were key carbon sinks during warming. Apoleward shift in mid-latitude moisture domain caused by elevated CO2 levels drove spatial variability in terrestrial carbon burial during the Toarcian hyperthermal, based on simulations from a global climate model and vegetation model.