Dry or humid? Mid-Holocene humidity changes in arid and semi-arid China

Spatial changes of effective moisture during the mid-Holocene have been reconstructed based on the compilation of recently published paleoclimate records, including ice core, lake level, pollen assemblage, and loess-paleosol records. Both geological data and the spatial pattern indicate that it was dry in deserts during the mid-Holocene, but the timing of the beginning and end of dry intervals differs from place to place. Deserts having higher aridity index values remain dry longer. Dry intervals during the mid-Holocene are more possibly asynchronous than synchronous in arid and semi-arid China. In the Xinjiang region, except in sites located in deserts, the climate is generally wet during 7000–5000 a BP. In the northern Qinghai-Tibetan Plateau, effective moisture in most sites began to decrease after 5000 a BP. The climate became dry after 4000 a BP except in the deserts in the Loess Plateau and the Inner Mongolia Plateau.