Climatic change in arid areas of China and monsoon fluctuations during the past 10 kyears

Based on the analysis of proxy climatic data of saline lake sediments, loess deposits and glacial advances in arid areas of northwestern China, climatic changes during the Holocene can generally be divided into three periods: (1) 11–9 (or 8•5) ky B.P., a warming period, with glaciers in western mountains in retreat, reduced rates of loess deposition and rising lake levels. (2) 9(8•5)–3•5(3) ky B.P., the Climatic Optimum warm period when most arid regions became wetter, forests and steppe vegetation spread, deserts contracted and no glacial advances were recorded. (3) 3•5(3) ky B.P.–present, glaciers advanced, deserts expanded and loess deposition rate increased and it became colder approaching the present climatic conditions. Two climatic patterns dominated the arid areas of China in the Holocene, viz. the monsoonal and westerlies. In the monsoon climatic regime, warm–wet and cold–dry patterns appeared alternatively, but in the inland areas of westerlies regime a cold–wet and warm–dry climate dominated.