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With global warming, changes in glaciers and glacial lakes on the Tibetan Plateau call for a serious inspection. The Southeastern Tibetan Plateau (SETP) is a typical monsoonal marine glacier area that is extremely vulnerable to climate change. It is affected by both humid and warm Indian Ocean currents. Outlines of glaciers and glacial lakes in SETP have been extracted from Landsat satellite images with an automatic extraction method based on image compositing with Google Earth Engine and Random Forest algorithm. Alongside the outlines, meteorological data have been collected from 1990 to 2021. The results show that since 1990 the glacier area of SETP has retreated by about 2165.33 km2 (~25.28%), the glacial lake area has increased by about 36.41 km2 (~21.45%), and their number has increased by 477 (~27.32%). The reliability and scientific validity of this study is proven by comparison with existing glacier inventories. By analyzing the meteorological data, the inverse correlation between the glacier area and temperature has been found. Despite decreases in cumulative precipitation, the glacial lake level rise and consequent area expansion have been observed. A fitting equation for the response pattern of glacier changes to temperature and precipitation change is presented and will provide a basis for future studies. [ABSTRACT FROM AUTHOR]

Worldwide, there are great challenges for meteorological monitoring and glacier ablation monitoring in high-altitude mountain areas. It is often difficult to capture fine-scale climate and glacial changes in high-altitude mountainous areas due to the harsh natural environment and the extreme lack of observational sites. Based on high-altitude meteorological stations erected on the eastern shore of Aqikkule Lake (AQK) and at the terminus of Shenshechuan Glacier (SSG), as well as on mass balance data from SSG, the characteristics and correlation of temperature, solar radiation, relative humidity, precipitation, wind speed and direction of the two regions, and the mass balance in the ablation area of SSG from 30 May 2022 to 18 May 2023 were analyzed, and the average melting depth of SSG was simulated. The results indicate the following: (1) The average annual temperature of AQK and the terminus of SSG is −3.7 °C and −7.7 °C, respectively, and the vertical lapse rate of temperature in the summer half of the year is greater than that in the winter half of the year. Precipitation timing has a great influence on daily temperature differences. (2) Precipitation in both places is concentrated in summer; the glaciers in this area are of the summer recharge type, and precipitation has a significant reducing effect on the solar incident radiation and increases the relative humidity in this region. (3) AQK and SSG both have local circulation development, in the area of AQK all year round due to the lake effect, while the terminus of SSG only has the development of valley winds in the summer, being controlled in the winter by the westerly wind belt. (4) The average mass balance value of the ablation area of SSG was −1786 mm as measured by the range poles method. The average annual ablation depth of SSG simulated by using the empirical formula was 587–597 mm, which is not large compared with other glacier areas in the Tibetan Plateau, and it has the characteristics of typical continental-type glaciers. [ABSTRACT FROM AUTHOR]

Holocene environmental and climate change on the Tibetan Plateau is intensively studied and discussed with the aim to better understand the factors controlling the hydrology of individual river catchments and especially the availability of water which is of utmost significance for the communities downstream in times of rapid climate change. Thus, a late glacial and Holocene sediment record from Lake Heihai in the Kunlun-Pass region was investigated using ostracod and geochemical analyses. Cold and dry conditions were inferred between ca. 12.9 and 12.3 cal ka BP and higher temperatures before and afterwards. The cold spell probably corresponds to the Younger Dryas (YD) event in the North Atlantic region. Warmer and wetter conditions with highest lake levels and decreased lake-water salinity were recorded from ca. 10.8 to 7.0 cal ka BP when the summer monsoon was strengthened. The cold 8.2 cal ka BP event is not significantly recorded in the region probably due to the predominance of the summer monsoon over the westerlies. A declined lake level and increased lake-water salinity as the result of cold and dry conditions are inferred from ca. 7.0 to 4.5 cal ka BP when the strengthening of the mid-latitude westerly circulation probably triggered glacier advances in the catchment. An even lower lake level existed during cold conditions with glacier advances from ca. 4.5 to 1.2 cal ka BP. The level of Lake Heihai rose again after ca. 1.2 cal ka BP due to warmer conditions, causing the retreat of glaciers and higher runoff. Our record from the Kunlun Pass region provides further evidence for the catchment-specific response of hydrographical systems which are partly controlled by glaciers as major water sources. [ABSTRACT FROM AUTHOR]

Ice cores from the northwestern Tibetan Plateau (NWTP) contain long records of regional climate variability, but refrozen meltwater and dust in these cores has hampered development of robust timescales. Here, we introduce an approach to dating the ice via the isotopic composition of atmospheric O2 in air bubbles (δ18Oatm), along with annual layer counting and radiocarbon dating. We provide a robust chronology for water isotope records (δ18Oice and d-excess) from three ice cores from the Guliya ice cap in the NWTP. The measurement of δ18Oatm, although common in polar ice core timescales, has rarely been used on ice cores from low-latitude, high-altitude glaciers due to (1) low air pressure, (2) the common presence of refrozen melt that adds dissolved gases and reduces the amount of air available for analysis, and (3) the respiratory consumption of molecular oxygen (O2) by micro-organisms in the ice, which fractionates the δ18O of O2 from the atmospheric value. Here, we make corrections for melt and respiration to address these complications. The resulting records of water isotopes from the Guliya ice cores reveal climatic variations over the last 15,000 y, the timings of which correspond to those observed in independently dated lake and speleothem records and confirm that the Guliya ice cap existed before the Holocene. The millennial-scale drivers of δ18Oice are complex and temporally variable; however, Guliya δ18Oice values since the mid-20th century are the highest since the beginning of the Holocene and have increased with regional air temperature. [ABSTRACT FROM AUTHOR]

The Indian summer monsoon (ISM) is a significant component of global climate and plays a key role in transporting heat and moisture from tropical oceans to the Indian subcontinent. The ISM has a critical role in ecosystem functioning as well as the development of regional agriculture and societies. However, it is difficult to ascertain the extent to which these two drivers interact and impact regional biogeochemistry from contemporary process studies because of the widespread human footprint, and millennial-scale ISM dynamics remain poorly understood over the last 20,000 years. Here we used high-resolution diatoms from alpine lakes at different elevations in the southwest monsoon region to reconstruct summer temperature and environmental variability since the Last Glacial Maximum (LGM). By comparing with other proxy-based temperature reconstructions of the Tibetan Plateau and the monsoon proxy records from South Asia, we found a 3–6 °C warming trend and ISM strengthening since the LGM. Our results indicate that summer temperature began to increase since 17.5 cal. kyr BP, marking the onset of deglacial warming. During the early to middle Holocene, the climate clearly warmed and then decreased afterward. The maximum warm interval occurred during the mid-Holocene, which followed changes in Northern Hemisphere summer insolation. Additionally, examinations of fossil diatom assemblages revealed that changes in compositions were closely linked with global and Indian monsoon climate changes on glacial and interglacial time scales. The abrupt temperature increases from extreme cold to warm transition during the Late-glacial/Holocene boundary (∼3 °C) are strongly associated with regional replacement of major biotic species compositions. The presence of biotic transition and the increased rate of temperature increase during the Late-glacial/Holocene transition confirm the importance of climate change in restructuring biological communities. This suggests that biotic structures necessary to survive such rapid climate regime were susceptible to impacts of the speed and magnitude of temperature change in monsoon region. • Composite mean July temperature inferred by diatoms from multiple lakes and comparison with palaeoclimatic bio-proxies. • Quantitative estimates show a regionally coherent Holocene maximum warmth over the southeastern Tibetan Plateau. • Temperature increases by ca. 1.5–3.4 °C since the Holocene represent a first threshold in ecosystem responses to climate warming [ABSTRACT FROM AUTHOR]

The timing and extent of late Quaternary glaciation in the Hailuogou valley of eastern Tibetan Plateau have been extensively studied over past decades. Debate however exists in the timing of the Gongga II moraine that represents the maximum glaciation in the Hailuogou valley. Furthermore, the Gongga II glaciation is not quantitatively reconstructed; and what climate conditions could support this maximum glaciation is unknown. This study used a glacier-climate model driven by data from local weather stations to simulate the Gongga II glacier extent by fitting modeled glaciers to field geological evidence. Running multiple simulations with different temperature-precipitation combinations, we inferred the climate scenarios sufficient to generate the Gongga II glacier extent. The modeled Gongga II glaciers have an area of ∼119 km 2 and an average volume of 1.35 × 10 10 m 3 , with an average equilibrium-line altitude of 4050 m asl. Combined with other independent climate reconstructions, the glacier-climate model simulations suggested that the Gongga II glacial stage most likely occurred in the LGM. [ABSTRACT FROM AUTHOR]

We investigated 4.84-m-long sediment record spanning over the Late Glacial and Holocene from Lake Donggi Cona to be able to reconstruct circulation pattern on the Tibetan Plateau (TP). Presently, Lake Donggi Cona is located at the boundaries of Westerlies and Asian monsoon circulations in the northeastern TP. However, the exact timing and stimulating mechanisms for climatic changes and monsoon shifts in this region are still debated. We used a 19-ka-long stable isotope record of sedimentary n -alkanes to address this discrepancy by providing insights into paleohydrological conditions. The δD of n C 23 is influenced by lake water evaporation; the δD values of sedimentary n C 29 are mainly controlled by moisture source and temperature changes. Long-chain n -alkanes dominate over the core whereas three mean clusters (i.e. microbial, aquatic and terrestrial) can be inferred. Multi-proxies suggest five major episodes in the history of Lake Donggi Cona. The Lake Donggi Cona record indicates that the Late Glacial (18.4–14.8 cal ka BP) was dominated by low productivity of mainly microbial and aquatic organisms. Relatively low δD values suggest low temperatures and moist conditions eventually caused by stronger Westerlies, winter monsoon and melt-water influence. Likely, the shift (∼17.9 cal ka BP) from microbial to enhanced aquatic input suggests either a change from deep to shallow water lake or a break in local stratification. Between 14.8 and 13.0 cal ka BP, variable climatic conditions prevailed. Although the Westerlies weekend, the increase in temperature enhanced the permafrost and snow melting (displayed by a high sedimentary accumulation rate). Higher δD values indicate increasingly arid conditions with higher temperatures which eventually lead to high evaporative conditions and lowest lake levels. Low vegetation cover and high erosion rates led to high sediment accumulation resulting in stratification followed by anoxia in the terminal lake. From 13.0 to 9.2 cal ka BP, lowered values of δD along with high contents of terrestrial organic matter marked the early-Holocene warming indicating a further strengthening of summer precipitation and higher lake levels. A cooling trend was observed in the mid-Holocene between 9.2 and 3.0 cal ka BP accompanied by higher moisture availability (displayed by lowered δD values) caused by reduced evaporative conditions due to a drop in temperature and recovering Westerlies. After 3.0 cal ka BP, a decrease in lake productivity and cold and semi-arid conditions prevailed suggesting lower lake levels and reduced moisture from recycled air masses and Westerlies. We propose that the summer monsoon was the predominant moisture source during the Bølling-Allerød warm complex and early-Holocene followed by Westerlies in mid-to-late Holocene period. Stable carbon isotope values ∼ - 32‰ indicate the absence of C 4 -type vegetation in the region contradicting with their presence in the Lake Qinghai record. The δD record from lake Donggi Cona highlights the importance of the interplay between Westerlies and summer monsoon circulation at this location, which is highly dynamic in northeastern plateau compared to the North Atlantic circulation and insolation changes. Consequently lake Donggi Cona might be an important anchor point for environmental reconstructions on the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

The southeastern Tibetan Plateau is an important area of monsoonal maritime glaciation, and it serves as a watershed for several major Asian rivers, including the Brahmaputra River and the Lantsang River. Glacial activity is sensitive to climate change in this area. However, due to high annual ablation and accumulation in this region, ice cores over long time scales are difficult to retrieve. In addition, reconstructed glacial activity from moraine dates is usually discontinuous. Here, we use a sediment core retrieved from Laigu Lake, which is a proglacial lake located in the headwaters of the Parlung Zangbo River, the largest tributary of the Brahmaputra River, to reflect glacial activities over the last ~ 8000 years in this area. Samples of the sediment core were analyzed for magnetic susceptibility, XRF (X-ray florescence) scanned elemental concentration and grain size. The results indicated that the magnetic susceptibility and CPS (peak area counts per second) of strontium (Sr) could be used as proxies for glacial activity. The CPS of Sr and the magnetic susceptibility were lower and the glacial activity was weak before 4.3 cal ka BP. Expansion of the glaciers in this area began from 4.3 cal ka BP and continued to develop after ~ 3.3 cal ka BP. From 2.2 cal ka BP to 1.6 cal ka BP, the glaciers retreated substantially, followed by another development period until the onset of modern global warming. Based on our findings and other climate records, we concluded that glacial activity in the southeastern Tibetan Plateau areas was mainly influenced by Northern Hemisphere temperatures and summer insolation over a sub-orbital time scale, but did not respond to the Indian monsoon. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau holds an ample record of past glaciations, and there is an extensive set of glacial deposits dated by exposure dating. Here a compilation is presented of 10Be exposure ages from 485 glacial deposits with 1855 individual samples on the Tibetan Plateau, and ELA depression estimates for the glacial deposits based on a simple toe to headwall ratio approach. To recalculate the Tibetan Plateau exposure ages, 10Be production rates from 24 calibration sites across the world are compiled and recalibrated yielding an updated global reference 10Be production rate. The recalculated exposure ages from the Tibetan Plateau glacial deposits are then divided into three groups based on exposure age clustering, to discriminate good (well-clustered) from poor (scattered) deglaciation ages. A major part of the glacial deposits have exposure ages affected by prior or incomplete exposure, complicating exposure age interpretations. The well-clustered deglaciation ages are primarily from mountain ranges along the margins of the Tibetan Plateau with a main peak between 10 and 30 ka, indicating glacial advances during the global LGM. A large number of deglaciation ages older than 30 ka indicates maximum glaciation predating the LGM, but the exposure age scatter generally prohibits accurate definition of the glacial chronology. The ELA depression estimates scatter significantly, but the main part is remarkably low. Average ELA depressions of 337 ± 197 m for the LGM and 494 ± 280 m for the pre-LGM indicate restricted glacier expansion. [ABSTRACT FROM AUTHOR]

Field investigation has shown that the middle reaches of the Yarlung Zangbo River, in Tibet (known as the Bhramaputra River in reaches downstream) has 11 terraces. The ages of these terraces were determined as follows: T11>2000 ka, T10 = 1783 ka, T9 = 1238 ka, T8 = 683 ka, T7 = 382 ka, T6 = 150 ka, T5 = 82 ka, T4 = 67 ka, T3 = 43 ka, T2 = 28 ka and T1 = 10 ka. These terraces formed during several stages of the Quaternary when the Tibetan Plateau was uplifting, recording tectonic-climatic cycles or subcycles of 1.2, 0.4, 0.1, 0.04 and 0.02 million years duration. The tectonic-climatic cycles identified by this study are correlated with red soil and palaeosol records. The preservation of the Oligocene to Early Miocene conglomeratic Dazhuka Formation, close to the present altitude of the main planation surface of the Tibetan Plateau and occurring only in the Yarlung Zangbo valley, suggests that this river has existed since at least 7 Ma. Discoveries of old and thick fluvial gravel layers extending to within 630 m of the valley floor show that the Yarlung Zangbo River was already incised by 2000 m or more below the surface of the Tibetan Plateau, that much of the incision from plateau to valley floor had been accomplished and that the plateau was already substantially uplifted prior to the Quaternary. In addition to its importance for understanding the evolution of the Tibetan Plateau, this study documents the impact of varying rates of tectonic uplift on river development. [ABSTRACT FROM AUTHOR]

Abstract: Fully understanding the timing and climate of Last Glacial Maximum (LGM) is still lack in the head of the Tashkurgan Valley, northwest Tibetan Plateau (TP). The recent improvements in cosmogenic 10Be exposure dating and glacier modeling present an opportunity to estimate the LGM climatic conditions. In the paper, we investigated the moraines and used the 10Be exposure dating on the moraine boulders to constrain the timing of the LGM, the Kuzigun glacial stage in the head of the Tashkurgan Valley. Then, we used a coupled mass-balance and ice-flow model to quantify the paleoclimate from past glacier extents constrained by mapped and dated Kuzigun glacial moraines in the area. We showed that the glaciers terminated at an elevation of 4100–4200 m asl during the Kuzigun glacial stage and the glacial stage occurred during or slightly before 15–23 ka, corresponding to the timing of the global LGM. The modeled mass balances indicated that present-day equilibrium line altitude (ELA) ranges from 5150 to 5250 m asl, and LGM ELA is between 4550 and 4600 m asl in the area, suggesting an ELA lowering of ∼600 m during the LGM. Model results suggested that the temperature during the LGM in the head of the Tashkurgan Valley is 5–8 °C colder than today, considering a 30–70% reduction in precipitation compared to today. The paleoclimate estimates are generally consistence with previous studies that showed the LGM climate was colder and drier than today on the TP. [Copyright &y& Elsevier]

Abstract: Dust over the Himalayas and southern Tibetan Plateau may influence high-elevation temperature and hydrology across Asia, but little is known about long-term dust variability and its relationship with regional climate over the last millennium. Here we have reconstructed a proxy record of past dust and temperature impacts on glacial streamflow and sediment deposition in Kiang Co, a small lake on the southwestern Tibetan Plateau. Terrigenous elemental variability in the Kiang Co sediment record, a proxy for glaciofluvial sediment deposition in the lake, covaries with the Dasuopu ice core dust record from the central Himalayas on centennial timescales. The relationship between the Kiang Co sediment record and Dasuopu indicates coherent dust forcing across the central Himalayas over much of the last millennium, and suggests that regional dustiness influences glacial streamflow and sediment transport on centennial timescales. In addition, the Kiang Co terrigenous elemental abundance record is positively correlated with May–September temperatures from the Tibetan Plateau to central India from 1870 to 2007AD, highlighting the important influence of temperature on melting and streamflow in this region, as well as a relationship between dust and temperature on centennial timescales. These findings strengthen the likelihood of future dustiness with continued warming, along with further increases in melting and high-elevation streamflow in coming decades. [Copyright &y& Elsevier]

We present a glacial geomorphological map covering 1.04 × 105 km2 of the Shaluli Shan (Shan = Mountain), southeastern Tibetan Plateau. Using a 90 m digital elevation model from the Shuttle Radar Topography Mission and 15/30 m Landsat Enhanced Thematic Mapper Plus satellite imagery, we have mapped glacial valleys, marginal moraines, hummocky terrain, glacial lineations and ice-scoured terrain. Lineations and scoured areas largely overlap on the low relief granite plateau of the Shaluli Shan and relate to former ice cap glaciation. These landscape features indicate that past ice cap glaciation included basal sliding conditions, and thus warm-based ice. Glacial valleys and marginal moraines are dominant landforms in the high mountain ranges of Shaluli Shan and occur on and fringing the plateau. This glacial geomorphological map forms the basis for paleoglaciological reconstructions of this southeastern Tibetan Plateau region and indicates the former presence of multiple glaciations involving valley glaciers and ice caps. The map is presented at a scale of 1:630,000. [ABSTRACT FROM AUTHOR]

Abstract: A sediment core from a closed basin lake (Lake Kuhai) from the semi-arid northeastern Tibetan Plateau was analysed for its pollen record to infer Lateglacial and post glacial vegetation and climatic change. At Lake Kuhai five major vegetation and climate shifts could be identified: (1) a change from cold and dry to relatively warmer and more moist conditions at 14.8 cal ka BP; (2) a shift to conditions of higher effective moisture and a stepwise warmer climate at 13.6 cal ka BP; (3) a further shift with increased moisture but colder conditions at 7.0 cal ka BP; (4) a return to a significantly colder and drier phase at 6.3 cal ka BP; (5) and a change back to relatively moist conditions at 2.2 cal ka BP. To investigate the response of lake ecosystems to climatic changes, statistical comparisons were made between the Lake Kuhai pollen record and a formerly published ostracod and sedimentary record from the same sediment core. Furthermore, the pollen and lacustrine proxies from Lake Kuhai were compared to a previously published pollen and lacustrine record from the nearby Lake Koucha. Statistical comparisons were done using non-metric multidimensional scaling and Procrustes rotation. Differences between lacustrine and pollen responses within one site could be identified, suggesting that lacustrine proxies are partly influenced by in-lake or local catchment processes, whereas the terrestrial (pollen) proxy shows a regional climate signal. Furthermore, we found regional differences in proxy response between Lake Kuhai and Lake Koucha. Both pollen records reacted in similar ways to major environmental changes, with minor differences in the timing and magnitude of these changes. The lacustrine records were very similar in their timing and magnitude of response to environmental changes; however, the nature of change was at times very distinct. To place the current study in the context of Holocene moisture evolution across the Tibetan Plateau, we applied a five-scale moisture index and average link clustering to all available continuous palaeo-climate records from the Tibetan Plateau to possibly find general patterns of moisture evolution on the Plateau. However, no common regional pattern of moisture evolution during the Holocene could be detected. We assign this to complex responses of different proxies to environmental and atmospheric changes in an already very heterogeneous mountain landscape where minor differences in elevation can cause strong variation in microenvironments. [Copyright &y& Elsevier]

17.81 m sediment core from Lake Naleng, a freshwater lake in the south-eastern part of the Tibetan Plateau was examined for its non-pollen palynomorph (NPP) composition. The frequencies of 15 NPPs and three aquatic pollen types were determined in 160 samples. Since the origin of several NPP types is still unknown, multivariate analysis, supported by findings from the corresponding fossil pollen flora, was carried out to extract information about their ecological environments. The analysis allowed a classification of all microfossils in four groups of environmental response, which provided an approach to tracing lake history and palaeoclimatic changes in the area since the Late Glacial (since 17,700 cal years b.p.). Unstable lake conditions and a low organic productivity were reconstructed for the Late Glacial before 14,600 cal years b.p. with high inputs of terrestrial material. Climate conditions became wetter during the Bølling/Allerød interval indicated by high productivity in the lake. After a short climate deterioration (12,500-11,500 cal years b.p.), stable lake conditions were inferred from the record. During the late Holocene (since 2,700 cal years b.p.) changes in the NPP composition might be related to human impact, the latter being inferred from the pollen data through the presence of grazing indicators. [ABSTRACT FROM AUTHOR]

The Qinghai-Tibetan Plateau is one of the most extensive habitats for alpine plants in the world. Therefore, the patterns of genetic variation in populations on the Plateau can reveal the detailed demographic history of alpine plants. We analysed the geographical structure of chloroplast matK sequence variation in Potentilla fruticosa L. (Rosaceae), a shrub currently found across the entire Plateau. We obtained sequence data from 508 individuals from 23 populations at sites ranging from the high-altitude interior to the relatively low-altitude northeastern Plateau. In the interior region, genetic diversity was high and included ancestral haplotypes. In contrast, northeastern populations were characterized by relatively low genetic diversity and recently derived haplotypes. The estimated expansion time in the interior population was 17 times that in the northeastern population. These data suggest that P. fruticosa expanded its range on the Plateau during periods of climatic cooling and contracted to the interior region during warmer periods. Thus, the interior region acted as a refugium and greatly contributed to the diversification of P. fruticosa. [ABSTRACT FROM AUTHOR]

Abstract: We present a late glacial pollen record (17,700 to 8500 cal yr BP) from a Lake Naleng sediment core. Lake Naleng is located on the southeastern Tibetan Plateau (31.10°N 99.75°E, 4200 m) along the upper tree-line. Variations in the summer monsoon are evident from shifts in vegetation that correspond to late glacial climate trends from other monsoon-sensitive regions. Alpine steppe was recorded between 17,700 and 14,800 cal yr BP, indicating low effective moisture at the study site. Expansion of alpine meadows followed by advances in the position of tree-line around Lake Naleng suggest that climate became warmer and wetter between ∼14,800 and 12,500 cal yr BP, probably representing an enhancement of the Asian monsoon. Climatic cooling and reduced effective moisture are inferred from multivariate analysis and the upward retreat of tree-line between ∼12,500 and 11,700 cal yr BP. The timing and nature of these shifts to warm, wet and then cold, dry climatic conditions suggest that they correspond to the Bølling/Allerød and Younger Dryas intervals. Abies-Betula forests, representing warm and moist conditions, spread during the early Holocene. [Copyright &y& Elsevier]

Abstract: Our 12.81m long record from Lake Ximencuo provides insight into the Lateglacial and Holocene evolution of the lake and the Nianbaoyeze glacier in its catchment, and the regional climate history since ∼19kyr. Lake Ximencuo was a permanent deep lake throughout its history. In contrast to numerous lakes on the Tibetan Plateau which experienced shallow lake levels or even desiccation during the Lateglacial, Lake Ximencuo was fed by large quantities of meltwater in the Lateglacial. The existence of glaciated upper catchment areas is apparently a prerequisite for lakes on the Tibetan Plateau which maintained relatively high water levels during the generally cold and dry periods following the global LGM (∼21kyr). A minor re-advance of the Nianbaoyeze glacier was recorded coeval with the Greenland Stadial 2a (∼16.4 and 14.5kyr), followed by rapid warming apparently synchronous with the Greenland Interstadial 1. Warmest conditions were recorded at Lake Ximencuo during the early Holocene which was punctured by a remarkable pulse of climate deterioration around 8.3kyr. This spell represents probably the 8.2kyr event of the North Atlantic region, suggesting that it had a significant impact on the Tibetan Plateau. Colder conditions of longer duration occurred from 4.7 to 3.7kyr, apparently in phase with numerous records signalling colder and drier conditions on the Tibetan Plateau. Two minor spells of colder conditions and probably catchment erosion were recorded in the late Holocene between 2.0 and 1.4kyr and between 0.5 and 0.1kyr with the latter representing the Little Ice Age. It is unclear, whether human activities may have accelerated or even solely triggered the late Holocene erosion events. [Copyright &y& Elsevier]

The δ18O record in deep-sea sediments show a significant reduced amplitude of the ice volume variations before Marine Isotope Stage 11, about 400 ka ago, with less warm interglacials and less cold glacials. The deuterium temperature and the greenhouse gases records in the Antarctic ice cores show the same feature. As the reduction in the amplitude of climate and greenhouse gases concentration variations before 400 ka BP is present in both deep-sea and ice cores, it is tempting to conclude that this is a worldwide phenomenon. This is not necessarily true, at least as far as some of the records, in particular of China and Europe, are concerned. The loess in northern China, the sedimentary core in the eastern Tibetan Plateau and the palaeosols in southern China all record an unusually warm and wet climate during Marine Isotope Stage 13, indicating an extremely strong East Asian summer monsoon. The pollen record from Europe shows that the climatic conditions during the interglacials previous to Marine Isotope Stage 11 are at least as warm as the younger interglacials. During Marine Isotope Stage 13, unusually strong African and Indian monsoon are recorded in the sediments of the equatorial Indian Ocean and of the Mediterranean Sea. Other extreme climate events are also recorded in sediment cores of the equatorial Atlantic, the Pacific, the subtropical South Atlantic Ocean and in the Lake Baikal of Siberia. [ABSTRACT FROM AUTHOR]

Guxiang and Baiyu Glaciations are two previously recognized local glaciations of the Tibetan Plateau. They have been widely used as the reference standard for classifying Late Quaternary glaciations on the Tibetan Plateau and its surrounding mountains. However, the numerical chronologies of both glaciations have been lacking. In this study, cosmogenic 10Be dating was undertaken to define the timing of these two glaciations. The surface boulders deposited by the glaciers of the Guxiang and Baiyu Glaciations have exposure ages of 112.9±16.7-136.5±1 5.8 ka BP and 11.1±1.9-18.5±2.2 ka BP, respectively. It is likely that the Guxiang and Baiyu Glaciations correspond to marine isotope stages 6 and 2,' respectively. [ABSTRACT FROM AUTHOR]

A modelling experiment with changes in vegetation types at the Last Glacial Maximum (21 ka BP) is performed by using an AGCM coupled with a simplified simple biosphere model (AGCM+SSiB). The results show that the decrease in temperature is large in Tibet and Eastern Asia at 21 ka. The amplitudes of the decrease vary with seasons and locations. Annual mean temperature decreases between 13 °C and 2 °C. Summer and annual precipitation in eastern China at 21 ka is only about 50% of that at present; while little more or unchanged precipitation appears in northwest, west and southwest of China. The effective precipitation (P–E) shows much drier conditions in eastern and southeastern China than today. A comparison with geological evidences of lake-status and pollen-based vegetation shows that this simulation is in broad scale agreement with the geological records. The changes by using palaeo-vegetation data to prescribe land surface show improved signals in the 21 ka climate simulations in East Asia. This result encourages us to study the potential causes, feedbacks and mechanisms of palaeoclimate changes using the AGCM+SSiB modelling approach continuously. [ABSTRACT FROM AUTHOR]

Focuses on climate variation over the last interglacial period recorded in the lake carbonate deposit of eastern Qinghai-Xizang Plateau, with reference to a study conducted. Methodology used to conduct the study; Results of the study.

Discusses the ice record provided by the Guliya ice cap on the Qinghai-Tibetan Plateu. The information about the regional climatic conditions over the last glacial cycle; The development of a time scale for the interpretation of the paleoclimatic information; The evidence for old ice; Abrupt climate changes.

The Tibetan Plateau (TP) is primarily influenced by the northern hemispheric middle latitude Westerlies and the Indian summer monsoon (ISM). The extent, long-distance effects and potential long-term changes of these two atmospheric circulations are not yet fully understood. Here, we analyse modern airborne pollen in a transition zone of seasonally alternating dominance of the Westerlies and the ISM to develop a pollen discrimination index (PDI) that allows us to distinguish between the intensities of the two circulation systems. This index is applied to interpret a continuous lacustrine sedimentary record from Lake Nam Co covering the past 24 cal kyr BP to investigate long-term variations in the atmospheric circulation systems. Climatic variations on the central TP widely correspond to those of the North Atlantic (NA) realm, but are controlled through different mechanisms resulting from the changing climatic conditions since the Last Glacial Maximum (LGM). During the LGM, until 16.5 cal kyr BP, the TP was dominated by the Westerlies. After 16.5 cal kyr BP, the climatic conditions were mainly controlled by the ISM. From 11.6 to 9 cal kyr BP, the TP was exposed to enhanced solar radiation at the low latitudes, resulting in greater water availability. [ABSTRACT FROM AUTHOR]