We present a quantitative mean annual air temperature (MAAT) record spanning the past 4700 years based on the analysis of branched glycerol dialkyl glycerol tetraethers (brGDGTs) from a sediment core from Xiada Co, an alpine lake on the western Tibetan Plateau (TP). The record indicates a relatively stable and warm MAAT until 2200 cal yr BP; subsequently, the MAAT decreased by ∼4.4°C at ∼2100 cal yr BP and maintained a cooling trend until the present day, with centennial-scale oscillations centered at ∼800 cal yr BP, ∼600 cal yr BP, and ∼190–170 cal yr BP. MAAT decreased abruptly at ∼500–300 cal yr BP and reached its minimum for the past 4700 years. We assessed the representativeness of our record by comparing it with 15 published paleotemperature records from the TP spanning the past ∼5000 years. The results show divergent temperature variations, including a gradual cooling trend, a warming trend, and no clear trend. We suggest that these discrepancies could be caused by factors such as the seasonality of the temperature proxies, the length of the freezing season of the lakes, the choice of proxy-temperature calibrations, and chronological errors. Our results highlight the need for more high-quality paleotemperature reconstructions with unambiguous climatic significance, clear seasonality, site-specific calibration, and robust dating, to better understand the processes, trends, and mechanisms of Holocene temperature changes on the TP.

我们基于对来自青藏高原西部高山湖泊夏达错沉积岩芯的支链甘油二烷基甘油四醚 (brGDGT) 的分析，提出了过去 4700 年的定量平均年气温 (MAAT) 记录。记录表明，直到 2200 年 BP 之前，MAAT 都相对稳定且温暖；随后，MAAT在~2100cal yr BP时下降了~4.4°C，并一直保持降温趋势，直到今天，百年尺度的振荡集中在~800 cal yr BP、~600 cal yr BP和~190-170校准年血压。MAAT 在约 500-300 cal BP 时突然下降，并达到过去 4700 年来的最低值。我们通过与过去 5000 年来青藏高原 15 个已发表的古温度记录进行比较，评估了我们的记录的代表性。结果显示温度变化存在差异，包括逐渐变冷的趋势、变暖的趋势以及无明显趋势的情况。我们认为这些差异可能是由温度代理的季节性、湖泊冰冻季节的长度、代理温度校准的选择以及时间误差等因素引起的。我们的结果强调需要更多高质量的古气温重建，具有明确的气候意义、明确的季节性、特定地点的校准和可靠的年代测定，以更好地了解青藏高原全新世温度变化的过程、趋势和机制。