The lack of a precisely-dated, unequivocal climate proxy from northern China, where precipitation variability is traditionally considered as an East Asian summer monsoon (EASM) indicator, impedes our understanding of the behaviour and dynamics of the EASM. Here we present a well-dated, pollen-based, ~20-yr-resolution quantitative precipitation reconstruction (derived using a transfer function) from an alpine lake in North China, which provides for the first time a direct record of EASM evolution since 14.7 ka (ka = thousands of years before present, where the “present” is defined as the year AD 1950). Our record reveals a gradually intensifying monsoon from 14.7–7.0 ka, a maximum monsoon (30% higher precipitation than present) from ~7.8–5.3 ka, and a rapid decline since ~3.3 ka. These insolation-driven EASM trends were punctuated by two millennial-scale weakening events which occurred synchronously to the cold Younger Dryas and at ~9.5–8.5 ka, and by two centennial-scale intervals of enhanced (weakened) monsoon during the Medieval Warm Period (Little Ice Age). Our precipitation reconstruction, consistent with temperature changes but quite different from the prevailing view of EASM evolution, points to strong internal feedback processes driving the EASM, and may aid our understanding of future monsoon behaviour under ongoing anthropogenic climate change.

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We present a pollen‐based precipitation reconstruction and multi‐proxy records from a 485‐cm‐long sequence from a sediment core from Xingyun Lake, Yunnan Plateau, south‐west China, which depicts the evolution of the Indian Summer Monsoon (ISM) during the last 8500 years. Pollen and other palaeoenvironmental records document several stages of vegetation history and climate change. The warmest and wettest climate in the Xingyun Lake catchment occurred before 5500 cal a BP, and subsequently the climate became gradually drier. After 2000 cal a BP the regional environmental conditions became unstable, and a wet Medieval Warm Period is probably recorded. Our reconstruction of the ISM is similar to that portrayed by Holocene speleothem δ18O records from southern China, but is distinctly different from the East Asian Summer Monsoon (EASM) evolution, which features a mid‐Holocene maximum. Our results support the hypothesis that the ISM and EASM evolved asynchronously during the Holocene, and imply that the Chinese speleothem δ18O records from southern China may principally reflect changes in moisture source from the Indian monsoon domain, and thus record the history of the ISM rather than the EASM.

Arid northwestern China is considered to be a major source of atmospheric dust supply to the Northern Hemisphere. However, dust storm evolution and dust emission processes in the past remain unclear due to the scarcity of geologic archives in this region. Hydrologically closed lakes in dust source areas act as a trap, providing the opportunity to trace the history of dust emission or eolian activity. Here we present the results of dust storm proxies and a dust storm history from Lake Sugan in the Qaidam Basin, a dust source area, on the northern Qinghai‐Tibetan Plateau. Grain size analyses of the materials deposited during modern dust storms and of the lake surface sediments demonstrate that the coarse component of the lake sediments was transported primarily by ambient winds when dust storms occurred. In combination with a sediment chronology generated by counting annual laminations, a 2000‐year dust storm history was reconstructed on the basis of changes in the coarse component and magnetic susceptibility of the lake sediments. Frequent and/or intensive dust storms occurred during the intervals AD 300–500, AD 1180–1240, and AD 1500–1700. The occurrence of dust storms largely coincided with the strengthening of the Siberian High with colder air masses from high latitudes, such as during the Little Ice Age, frequently encroaching into the dust source areas in northwestern China. Our results suggest that wind strength plays an important role in dust emissions in arid source areas. However, dust storms in the late 20th century are most likely associated with disturbance of the ground surface caused by petroleum exploitation in the Qaidam Basin.

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