Late marine isotope stage 3 palaeoclimate for East Asia: A data–model comparison

Climate prediction under impact of anthropological greenhouse-gas emission is impossible to validate, but it can be inferred from past climate and modeling. In East Asia, a general warm–wet period at late Marine Isotope Stage 3, ca. 30–40 ky BP has been identified based upon extensive geological records; this provides an arid/humid reference for possible future warming caused by human activities. Based upon syntheses of geological evidence and the AGCM + SSiB modeling, this paper presents climate simulations focused on 35 ky BP, using forcing of insolation, glaciation and land surface conditions for East Asia. Results of the simulation can be compared with geological records and show that (1) the climate patterns of 35 ky BP were warm–wet conditions in northern China, but with warm–dry conditions in southern China compared to today; (2) mean annual temperatures were higher in most mid-low latitude areas, mainly contributed to by increased winter temperatures, suggesting that insolation has generated significant climate effects through the coupling in atmospheric circulation with land surface patterns; (3) Quaternary ice sheets in the Northern Hemisphere played an important role in temperature decrease at the mid-high-latitudes, and also enhanced the south–north temperature gradients, which in turn, increased moisture transport from low to high latitudes and increased monsoonal precipitation over the Tibetan Plateau; and (4) Vegetation changes in East Asia resulted from an increased temperature in the low latitudes, extended rain-belt northwards into China, and an enlarged area of increased precipitation inland.