Quantitative reconstruction of the temperature since the late Glacial using phytoliths from Hongyuan Peatland in the eastern Tibetan Plateau

Abstract

The “Holocene temperature conundrum” remains unresolved, particularly in climate-sensitive regions like the Tibetan Plateau. Reconstructing Holocene temperatures, especially in such regions, provides unique insights into this unresolved issue and helps explore the mechanisms of temperature variability, which is essential for future climate predictions. To address these uncertainties, additional paleotemperature records are crucial. In this study, we quantitatively reconstruct the mean annual temperature (MAT) from the Hongyuan Peatland in the eastern Tibetan Plateau spanning 13,300 years, using phytoliths as a proxy—a method not previously applied in this area. Our reconstruction reveals a gradual warming trend throughout the Holocene, supported by model simulations and compiled results. Comparisons of temperatures with previous reconstructions from Hongyuan Peatland reveal that proxy seasonality influences temperature trends. Moreover, the calibration sets, the topsoil datasets, the characteristics of the proxies, and the model components can influence the amplitudes of temperature changes. Comparisons of phytolith-based temperature records across China show that Holocene temperature trends vary with latitude, which is related to annual insolation. In the eastern Tibetan Plateau, variations in MAT during the Holocene can be attributed to increasing mean annual solar radiation, rising CO₂ concentrations, and the melting of ice sheets. Our study assesses the potential of phytoliths as a reliable proxy for paleotemperature reconstruction in high-elevation areas and confirms the warming trend of MAT in the eastern Tibetan Plateau.