第九届青年地学论坛

The current Earth’s surface warming rate may increase with elevation, known as Elevation-Dependent Warming (EDW), which has profound environment impacts on the fragile environments in high-elevation mountains regions. However, EDW has not been well constrained due to the short duration and sparse distribution of available instrumental data. Also, the Holocene temperature discrepancy between paleoclimate reconstructions and climate model simulations—known as the Holocene temperature conundrum—calls for new high-quality Holocene temperature records at high elevations. Here, we present two new quantitative paleotemperature reconstructions for two alpine lakes with the elevation at 4214 m and 4667 m above sea level in the Hengduan Mountains, southeastern Tibetan Plateau, respectively. The two records both reveal an abrupt warming occurred during ~6 ka BP, which generally coincide with the temperature history revealed at Tiancai Lake with the lower elevation at 3898 m in the same region during the Holocene (Feng et al., 2022) . By comparing three quantitative Holocene temperature records based on the same branched glycerol dialkyl glycerol tetraethers calibration, we find that the warming rate was higher at higher elevations, which coincides with the vegetation and glacier-snow cover. We conclude that the observed Elevation-Dependent Warming was probably driven by the surface albedo feedbacks caused by the sparse vegetation cover and prolonged seasonal snow cover, which had a stronger influence at higher elevations.
 

brGDGTs,Elevation-Dependent Warming,lake sediments,southeastern Tibetan Plateau,Holocene