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Mountain glaciers are one of the most sensitive indicators of climate change. Reconstructing past glacier extents provides valuable insights into the climate change for specific regions where instrumental records are not enough and even absent. In the paper we mapped the outlines for 691 Little Ice Age (LIA) glaciers in terms of prominent moraines beyond contemporary glaciers in the Tanggula Mountains, central Tibetan Plateau (TP). Based on these glacier outlines, we reconstructed the ice thicknesses and surfaces for the LIA glaciers in the region. Accordingly, we calculated the equilibrium-line altitudes (ELAs) for contemporary and LIA glaciers. By comparing the ELAs between the contemporary and LIA glaciers, we estimated the LIA summer temperature decreases in different subregions of the Tanggula Mountains. Since the LIA, the ELA have risen by 35.6 ± 18.8 m, 26.1 ± 17.6 m, and 63.1 ± 38.6 m in the respective western, central, and eastern subregions of the Tanggula Mountains. Assuming no change in precipitation, the LIA summer temperature would decrease by 0.22 ± 0.12 °C, 0.14 ± 0.09 °C, and 0.34 ± 0.21 °C in the three subregions, respectively. Moreover, glaciers in the western, central, and eastern subregions have lost 13.3%, 23.9%, and 42.8% of their area, 15.4%, 25.3%, and 39.6% of their length, and 20.8%, 39.0%, and 61.0% of their volume, respectively. By compiling the LIA ELA data from previous studies, we also estimated the LIA summer temperature changes for other regions of the TP. The LIA ELA and summer temperature changes relative to the present showed a decreasing trend from the edges towards the interior on the TP. • LIA glaciers and summer climate were reconstructed at the Tanggula Mountains. • LIA summers were 0.22 ± 0.12 °C, 0.14 ± 0.09 °C, and 0.34 ± 0.21 °C cooler than present in three subregions. • Summer temperature change had a decreasing trend from the edges towards the interior on the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

The vegetation history of the central Tibetan Plateau over the last two millennia provides an important baseline for exploring future vegetation evolution. In this paper, we analyze high-resolution records of pollen, grain-size, total organic carbon (TOC) and total nitrogen (TN) for a 66.5 cm deep sediment core collected from Beilei Co on the central Tibetan Plateau. Between ca. 210 CE and 1988 CE, pollen spectra together with other proxies show that the Beilei Co region was covered by alpine steppe and experienced a relatively stable environment, with only slight changes in vegetation composition and minor climatic variations. However, since 1988 CE, abundances of Artemisia and Cyperaceae have begun to increase, while those of Chenopodiaceae (current accepted Latin name is Amaranthaceae) and Asteraceae have decreased sharply. Both the pollen assemblages and other proxies show that the study area is currently undergoing a major change and that the period of vegetation stability that has characterized the past two millenia has now ended. We argue that the recent changes in the vegetation may be caused by increasing precipitation and/or thawing permafrost due to global warming. In the future, the alpine steppe around Beilei Co may be replaced by alpine meadow. • High-resolution pollen spectra covering last two millennia completed for the central Tibetan Plateau. • Vegetation of the central Tibetan Plateau is stable for most of the time until the last few decades. • The central Tibetan Plateau is experiencing an unprecedented phase of wetting. [ABSTRACT FROM AUTHOR]