Temperature-induced dry climate in basins in the northeastern Tibetan Plateau during the early to middle Holocene

Abstract Ongoing global warming will have a significant impact on terrestrial water resources, especially in arid and semi-arid regions. Assessing changes in the hydrology and water resources in inland basins under a warm climate in the recent geological past can provide a valuable context for assessing their current and possible future status. Here we present a record from a rapidly-accumulating sediment core from Lake Dalianhai in the Gonghe Basin in the northeastern Tibetan Plateau. The chronology of the uppermost 51.63 m of the core is based on AMS 14C dates from 11 samples of terrestrial plant microfossils and 14 bulk samples. Hydroclimatic variations within the basin during the last 23,000 yr were reconstructed from sedimentological and geochemical parameters and paleoshoreline records. The results indicate that the Gonghe Basin experienced relatively arid conditions during 23,000-14,700 cal yr BP. Lake Dalianhai was refilled at 14,700 cal yr BP and a high lake level was sustained until the beginning of the Holocene, as indicated by changes in the concentration of OH-GDGTs. However, the lake level was low during the early to middle Holocene (11,700-4700 cal yr BP) and increased during the late Holocene. Based on a comparison with lake level records and aeolian sand deposits from the region, we conclude that the climate was extremely dry in basins in the northeastern Tibetan Plateau during the early to middle Holocene. We propose that strong evaporation combined with high summer temperatures during the early to middle Holocene were responsible for the dry climate at that time, rather than changes in mid-latitude precipitation. Given the situation occurred during the early to middle Holocene, ongoing global warming may seriously threaten water resources in inland China, even if precipitation increases substantially.