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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]

Abstract: Uplift of the Tibetan Plateau is ultimately driven by the Cenozoic collision between the Indian and Eurasian plates and their continued convergence. One approach for studying the Tibetan Plateau uplift is to verify the paleoelevation changes from collision to present day. This is important for understanding both the tectonics and the climatic effects. The new high resolution palynological record of the uppermost Oligocene to the lowest Miocene strata from the Lunpola Basin indicates that the vegetation types during the latest Oligocene–earliest Miocene were dominated by mixed coniferous–broadleaved forests being different from the modern steppe vegetation. By using the Coexistence Approach to the fossil pollen records, after calibration the effects of temperature difference and the lapse rate, a maximum paleoelevation of 3190±100m asl was estimated in the Lunpola Basin in the latest Oligocene–earliest Miocene, being 1500 to 2000m lower compared with the previous oxygen isotope paleoelevation in the same region. [Copyright &y& Elsevier]