Interhemispheric synchrony of Mid-Late Holocene SST in the Indo-Pacific warm pool linked to upper water column dynamics

The sea surface temperature (SST) of the Indo-Pacific warm pool (IPWP) plays a crucial role in global climate system. Despite its importance, knowledge of its SST changes over century to millennial timescales remains limited and controversial, hindering our comprehensive understanding of climate change mechanisms. Our study bridges this gap with a novel SST reconstruction spanning approximately 7000 years, derived by aggregating 75 coral Sr/Ca-SST records from the South China Sea. These records reveal a notable synchronization in SST variations with foraminiferal reconstructions across the IPWP, reflecting a prevalent pattern of interhemispheric cooling and multi-century variability in the IPWP during the Mid-Late Holocene. Further analysis reveals that these (sub)millennial SST variations are closely linked to subsurface water temperature and ocean heat content (OHC) changes, supporting the theory that the release of deeper OHC acted as a heat source for low-latitude processes during the Holocene.