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The highly glacierized eastern part of the Tibetan Plateau is the key source region for seven major rivers: Yangtze, Yellow, Lancang-Mekong, Nu-Salween, Irrawaddy, Ganges, and Brahmaputra rivers. These rivers are vital freshwater resources for more than one billion people downstream for their daily life, irrigation, industrial use, and hydropower. However, the glaciers have been receding during the last decades and are projected to further decline which will profoundly impact the water availability of these larger river systems. Although few studies have investigated glacier mass changes in these river basins since the 1970s, they are site and temporal specific and limited by data availability. Hence, knowledge of glacier mass changes is especially lacking for years prior to 2000. We therefore applied digital elevation models (DEMs) derived from large scale topographic maps based on aerial photogrammetry from the 1970s and 1980s and compared them to the Shuttle Radar Topography Mission (SRTM) DEM to provide a complete picture of mass change of glaciers in the region. The mass changes are presented on individual glacier bases with a resolution of 30 m and are also aggregated into gridded formats at resolutions of 0.1° and 0.5°. Our database consists of 13117 glaciers with a total area of ~21695 km2. The annual mean mass loss of glaciers is -0.30 ± 0.12 m w.e. in the whole region. This is larger than the previous site-specific findings, the surface thinning increases on average from west to east along the Himalayas-Hengduan mountains with the largest thinning in the Irrawaddy basin. Comparisons between the topographic map-based DEMs and DEMs generated based on Hexagon KH-9 metric camera data for parts in the Himalayas demonstrate that our dataset provides a robust estimation of glacier mass changes. However, the uncertainty is high in high altitudes due to the saturation of aerial photos over low contrast areas like snow surface on a steep terrain. The dataset is well suited for supporting more detailed climatical and hydrological analyses and is available at https://doi.org/10.11888/Cryos.tpdc.301236 (Liu et al., 2024). [ABSTRACT FROM AUTHOR]

Glaciers play a vital role in the Asian mountain water towers and have significant downstream impacts on domestic, agricultural, and industrial water usage. The rate of glacier mass loss in the Southeastern Tibetan Plateau (SETP) is among the highest in Asia and has intensified in recent decades. However, a comprehensive quantification that considers both spatial and temporal aspects of glacier mass loss across the entire SETP is still insufficient. This study aimed to address this gap by utilizing geodetic datasets specific to each glacier by calibrating the Open Global Glacier Model (OGGM) driven by HAR v2 and reconstructing the glacier mass balance of 7756 glaciers in the SETP from 1980 to 2019 while examining their spatial variability. The findings reveal that the average mass balance during this period was −0.50 ± 0.28 m w.e. a−1, with an accelerated loss observed in the 2000s (average: 0.62 ± 0.24 m w.e. a−1). Notably, central glaciers in the SETP exhibited relatively smaller mass loss, indicating a gradient effect of increased loss from the central region toward the eastern and western sides. By the end of this century, the area, length, and volume of glaciers in the entire SETP region are projected to decrease by 83.57 ± 4.91%, 90.25 ± 4.23%, and 88.04 ± 4.52%, respectively. Moreover, the SETP glacier melt runoff is estimated to decrease by 62.63 ± 6.16% toward the end of the century, with the "peak water" point of glacier melt runoff predicted to occur in 2023 under the SSP585 scenario. Sensitivity experiments demonstrated that the SETP glaciers are more than three times more sensitive to temperature changes than to precipitation variations, and the observed decrease in monsoon precipitation indicates the weakening magnitude of the Indian summer monsoon in recent years. The spatially refined and high-temporal-resolution characteristics of glacier mass loss presented in this study contribute to a better understanding of specific glacier changes in the SETP. Additionally, the prediction results provide valuable references for future water resources management and policy formulation in the SETP region. [ABSTRACT FROM AUTHOR]

Olivine crystals in alkaline basalts preserve important information about the Oxygen fugacity and thermal condition of the mantle‐derived magma. This paper presents new olivine mineral chemistry and whole‐rock geochemistry for Early‐Cretaceous alkali basalts in the Ganjia area, northeastern margin of the Tibetan Plateau. The olivine phenocrysts of Ganjia basalts have low Ni (74–2261 ppm) and high Ca contents (1217–4443 ppm), similar to the olivines in MORB, suggesting that they were crystallized from peridotite‐derived basaltic magma. Al‐in‐olivine/spinel thermometer results indicate crystallization temperatures of olivine around 1202 ± 46°C, corresponding to a mantle potential temperature of 1279 ± 47°C, with low oxygen fugacity of FMQ −1 to FMQ 0, suggesting a reduced mantle source. Whole‐rock geochemical compositions of the Ganjia basalts were characterized by low SiO2 contents (45.39%–48.70 wt%), high alkali contents (3.88–5.11 wt%), positive Nb and Ta anomalies, and enrichment in LREEs, HFSEs and LILEs, similar to those of OIB rocks, with high ratios of (Dy/Yb)N (1.38–1.54) and (La/Yb)N (5.37–7.42) ratios, indicating garnet residue. The above results suggest that the Early Cretaceous intraplate alkaline basalts in West Qinling were formed by a low degree of partial melting of peridotite and that no high‐temperature mantle plume existed. The Qinling Orogenic Belt may have been affected by the subduction of the Palaeo‐Pacific. We propose that the Ganjia basalts originated from the interaction between the upwelling asthenosphere and a lithospheric source. [ABSTRACT FROM AUTHOR]

Influenced by the Indian monsoon, the Kangri Karpo Mountains (KKM) of the southeastern Tibetan Plateau is the most humid part of the plateau, and one of the most important regions with numerous monsoon temperate glaciers. Glacier mass balance estimates have been strongly negative in the KKM over recent decades, but the spatiotemporal characteristics of surface velocity are poorly understood. Using phase-correlation feature tracking on Landsat images, this study estimates spatiotemporal variabilities of monsoon temperate glaciers for the period of 1988–2019. Results show that a significant slowdown was observed below an elevation of 4900 m, while an accelerated ice flow was found at an elevation of 4900–5800 m over the past 30 years. The trend of slowdown was −0.1 m a−1 dec−1 during 1988–2000, and then it increased to −0.5 m a−1 dec−1 during 2001–2019. [ABSTRACT FROM AUTHOR]

Previous studies have identified vegetation shifts on the Tibetan Plateau in response to climate change. However, the speed and direction of these changes in alpine vegetation are not well understood. To quantify the responses of the distribution of alpine vegetation to global warming of 1.5 °C or 2 °C, BIOME4 was modified using the Penman–Monteith equation to estimate the reference evapotranspiration, and was run with projected climate data under the RCP4.5 and RCP8.5 scenarios. Gradients of temperature (1–5 °C) and precipitation (−30%–30%) were used to examine the sensitivity of changes in the vegetation pattern to climate. This study suggests that forests on the Tibetan Plateau will expand northwestward with climate warming. Among all forest types, the distribution area of broad-leaved forests will show the greatest increase, whereas mixed needle-broad-leaved forests will show the greatest percentage decrease (~45.5%) relative to the baseline period. Climate warming will result in alpine shrub expansion towards the interior of the Tibetan Plateau, with an average center shift of 309 km under the RCP4.5 scenario with a warming of 1.5 °C. A proportion of alpine meadow will be replaced by alpine shrub, causing it to shrink by ~6.8% under RCP4.5 with a warming of 1.5 °C and by ~15.5% under RCP8.5 with a warming of 2 °C. We conclude that all vegetation types on the Tibetan Plateau are susceptible to a warming climate. Increasing temperatures will move the vegetation boundaries northwestward and this trend will be enhanced by increases in precipitation. Understanding the response of vegetation patterns to warming will facilitate better strategies for carbon storage management. [Display omitted] • Response of vegetation distribution under global warming on the Tibetan Plateau • A BIOME4 model was modified by using Penman-Monteith model • Alpine vegetation distribution may be altered under global warming of 1.5 and 2 °C • Temperature increase may move vegetation boundary northwestwardly • Lead to better strategies on vegetation conservation and carbon management [ABSTRACT FROM AUTHOR]

• Mass balance was negative in the southeastern ITP, neutral in the northwestern ITP. • Mass loss accelerated in the southeastern ITP, decelerated in the northwestern ITP. • No significant differences in height changes on the surge and non-surge glaciers. • Glacier mass loss was equivalent to 15.3% of the total lake water storage increase. The Tibetan Plateau interior basin (ITP) can be regarded as the intermediate zone between balanced or slight positive mass balance and pronounced mass loss. As an endorheic basin, glacier meltwater plays an important role in adjusting lake levels and river runoff. The spatiotemporal pattern of glacier mass balance in the ITP has been estimated from TOPO DEM, SRTM, and TerraSAR-X/TanDEM-X imageries from ∼1970 – ∼2013. Glacier mass balance was negative in the southeastern ITP, moderately negative in the central ITP, and neutral in the northwestern ITP. In addition, glacier mass loss accelerated in the southeastern ITP, and decelerated, even shifted from negative to positive, in the northwestern ITP between the periods of ∼1970 – 2000 and 2000 – ∼2013. Assuming that all the glacier meltwater was drained to the lakes, the glacier mass loss was equivalent to approximately 15.3 ± 8.1 % of the total lake water storage increase in the early 21st century. Although climate changes are consistent with the spatial pattern of glacier mass loss, the relationship between the heterogeneous spatiotemporal pattern of mass balance and climate change needs more detailed investigations. [ABSTRACT FROM AUTHOR]