气候变化领域集成服务门户

Changes in paleoenvironments from 3500 to 1300 cal. yr BP have been documented by a high-resolution grain-size and organic carbon isotope record in core Z8 from the Shandong mud wedge in the southern Yellow Sea (YS). The sensitive grain-size component, sorting coefficients and delta C-13(org) values were used to identify the paleohydrologic variations and the intensity of the East Asian winter monsoon (EAWM). The coarse fraction of sediment, together with organic isotope and sea surface temperature (SST) data, shows a weak EAWM during 3500-2300 cal. yr BP, a gradual increase in the EAWM from 2300 to 1700 cal. yr BP and an enhanced EAWM since 1700 cal. yr BP. Superimposed on this general trend, several prominent short-lived strong EAWM episodes peaked at approximately 3300, 3100, 2900, 2750, 2620, 2220, 1900, 1700 and 1400 cal. yr BP. The paleoenvironmental record matches ancient Chinese historical climate records as well as socioeconomic changes, with lower economic levels occurring during stronger EAWM episodes. The results show that prosperous stages of ancient Chinese dynasties mainly occurred in weak EAWM periods, while collapses and/or changes in ancient Chinese dynasties generally occurred during cold periods with a strong EAWM. We suggest that the persistent short-lived strengthening of the EAWM could have exerted a remarkable influence on ancient agricultural societies through decreases in both winter temperature and monsoonal precipitation.