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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]

Abstract: Long-term high-resolution climate proxies are essential for understanding climate variability on the Tibetan Plateau (TP), where few long-term climate records are available. In this paper, we describe a summer (August) temperature reconstruction over the period 1385–2002 based on a tree-ring width chronology of Balfour spruce (Picea likiangensis var. balfouriana) on the southeastern TP created using the Regional Curve Standardization method. The reconstruction explains 44.7% of the variance in the instrumental temperature records during the calibration period (1962–2002), and captures temperature variability over a broad region of the TP. Warmer than average Augusts were found during the periods 1446–1494, 1509–1522, 1553–1567, 1797–1812, 1845–1905 and 1918–2002. Cooler than average Augusts occurred from 1385–1416, 1426–1445, 1495–1508, 1523–1552, 1568–1686, 1695–1718, 1725–1796, 1813–1844 and 1906–1917. A warming trend in the 20th century was unprecedented during the past six centuries. The reconstruction closely matched other tree-ring summer temperature reconstructions from neighboring regions, as well as patterns from ice-core δ18O data, and fluctuated in synchrony with Northern Hemisphere temperature reconstructions. [Copyright &y& Elsevier]

In this paper, we review evidence for a major biotic turnover across the Oligocene/Miocene in the Tibetan Plateau region. Based on the recent study of six well-preserved fossil sites from the Cenozoic Lunpola and Nima basins in the central Tibetan Plateau, we report a regional changeover from tropical/subtropical ecosystems in the Late Oligocene ecosystem (26–24 Ma) to a cooler, alpine biota of the Early Miocene (23–18 Ma). The Late Oligocene fossil biota, comprising of fish (climbing perch), insects and plants (palms), shows that the hinterland of the Tibetan Plateau was a warm lowland influenced by tropical humidity from the Indian Ocean. In the Early Miocene, the regional biota became transformed, with the evolution and diversification of the endemic primitive snow carp. Early Miocene vegetation was dominated by temperate broad-leaved forest with abundant conifers and herbs under a cool climate, and mammals included the hornless rhinoceros, Plesiaceratherium , a warm temperate taxon. This dramatic ecosystem change is due to a cooling linked to the uplift of Tibetan region, from a Late Oligocene paleo-elevation of no greater than 2300 m a.s.l. in the sedimentary basin to a paleo-elevation of about 3000 m a.s.l. Another factor was the Cenozoic global climatic deterioration toward to an ice-house world. • The Tibetan uplift had a profound impact on the evolution of terrestrial ecosystems. • The Oligocene subtropical ecosystem was replaced by a Miocene cooler biota in Tibet. • The Late Oligocene biota showed that the Tibetan hinterland was a warm lowland. • The Early Miocene biota eventually culminated in the present ecosystem of Tibet. • This dramatic ecosystem change is due to the cooling effect of the Tibetan Plateau. [ABSTRACT FROM AUTHOR]