Holocene warm-humidification trends recorded in lacustrine sediments in Arid Central Asia: Synthesis insights from climate reconstruction, carbonate carbon-oxygen isotopes and n-alkanes

Study region: Arid Central Asia (ACA). Study focus: The contradictory understanding of Holocene climate change trends in ACA remains unresolved. This study compiled Holocene temperature and moisture changes from 23 lacustrine sediment sites in the ACA region based on quantitative proxies (reconstructed temperature and precipitation), physico-chemical proxies (carbon and oxygen isotopes of carbonates), and biological proxies (n-alkanes). New hydrologic insights: Holocene climate patterns characterized by early Holocene cold-dry, mid-Holocene cool-humid, and late Holocene warm-humid conditions in the ACA region. Multiple tipping points have been identified by different proxies during 108 and 6.53 cal ka BP, indicating inconsistencies among compilations of different proxy records. The long-term fluctuating warm-wetting trend in ACA is generally consistent with records from the westerly region, where Holocene climate changes are complex, in contrast to the relatively synchronized patterns in monsoonal Asia. Phase shifts of the North Atlantic Oscillation (NAO), driven by summer and winter insolation variations, caused latitudinal oscillations of westerly moisture transport. During mid-to-late Holocene, NAO negative phases shifted westerly moisture southward, dominating the warming-humidification trend in ACA region. However, the water resources in this region will exhibit complex spatiotemporal differentiation in the future, with wet regions becoming wetter and arid regions drier. This study demonstrates that multi-proxy compilation enhances understanding of regional climate change, but requires discerning environmental signals from different proxies.