Late mid-Holocene cooling indicated by the Chibuzhang Co record in the central Tibetan Plateau

Accurate temperature reconstructions for the Tibetan Plateau (TP), a key area in global paleoclimatic research, can provide insights into the disputed Holocene temperature changes inferred from proxy records and model simulations. Here, we quantitatively reconstructed the mean annual air temperature (MAAT) since 12.7 cal ka BP in Chibuzhang Co using a novel terrestrial paleothermometer (the ring indices of OH-GDGTs, RI-OH). The reconstruction closely matched the record of submerged plant biomass as indicated by fatty acids, which, in Chibuzhang Co, is controlled by lake water temperature. We found that the Holocene MAAT in Chibuzhang Co was dominated by the local mean annual insolation, and influenced, to varying degrees and across different timescales, by the Laurentide Ice Sheet, westerly jet (WJ), and radiative forcing by greenhouse gases. Importantly, a cold and volatile period was observed at 5-3 cal ka BP. This period has also been widely recorded across mid-latitude regions of East Asia, suggesting that the cooling pattern was regional. This regional cooling may have been due to the combined effect of reduced local insolation and a southward shift of the WJ. Our findings thus support a region-specific interpretation of the "Holocene temperature conundrum". Since regional atmospheric circulations patterns such as WJ can have an important impact on temperature evolution, regional specificity should be taken into account in global temperature integration.