A comprehensive understanding of the regional vegetation responses to long‐term climate change will help to forecast Earth system dynamics. Based on a new well‐dated pollen data set from Kanas Lake and a review on the published pollen records in and around the Altai Mountains, the regional vegetation dynamics and forcing mechanisms are discussed. In the Altai Mountains, the forest optimum occurred during 10–7 ka for the upper forest zone and the tree line decline and/or ecological shifts were caused by climatic cooling from around 7 ka. In the lower forest zone, the forest reached an optimum in the middle Holocene, and then increased openness of the forest, possibly caused by both climate cooling and human activities, took place in the late Holocene. In the lower basins or plains around the Altai Mountains, the development of protograssland or forest benefited from increasing humidity in the middle to late Holocene.

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The sparsity of long-term reliable climatic records hampers our understanding of human–environment interactions in the semi-arid Hexi Corridor, NW China. Here, we present a late-Holocene pollen record from a small alpine lake, Tian’E, in the western Qilian Mountains. The chronology is provided by nine accelerator mass spectrometry (AMS) 14C dates from terrestrial plant remains. The ratios of Artemisia and Amaranthaceae (A/C) are used to reconstruct the history of regional humidity: An unstable climate occurred during 1530–1270 BC; there were three relatively wet periods, at 1270 BC–AD 400, AD 1200–1350, and AD 1600–present; and there were two dry periods, from AD 400 to 1200 and from AD 1350 to 1600. Comparison with tree-ring data indicates that continuous droughts were responsible for the abandonment of several archaeological sites and ancient cities in the region, including the major city of Dunhuang, which was abandoned in AD 1372 and AD 1524 for nearly 200 years.

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