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The mountains systems of Central Asia are primary targets to study late Pleistocene climate evolution given their location at the crossroads of several atmospheric circulation systems. The timing of glacier extent during this period remains understudied, especially in the Altai Mountains. Here, we have reconstructed glacier extent during three main Late Pleistocene stadials in the upper Kalguty basin (south‐eastern Russian Altai) based on field‐based geomorphic analysis. Additionally, surface exposure dating with 10Be and 26Al at a key site was used to infer a minimum‐limiting age for the outermost well‐preserved Pleistocene frontal moraine system and to date the inception of glacier withdrawal. According to our data, around 20.6 ± 1.8 ka Kalguty Glacier was still 200 m thick at the key site, 10 km upstream of the outermost moraine, and the site was totally deglaciated shortly after 20.4 ± 0.4 ka. These results point to a rapid retreat of this low‐gradient valley glacier after its probably MIS 2 maximum which was prior to 21 ka and probably prior to 22.5 ka. Two other glacier stages have been identified upvalley, characterized by a depression of the equilibrium‐line altitude of 420 and 314 m with respect to the Little Ice Age, thus corresponding to Lateglacial advances. Our glacier reconstruction further provides a geomorphological and geochronological background to put into context archaeological findings in this area. [ABSTRACT FROM AUTHOR]

The evolution of a glacial lake is a true reflection of glacial and climatic change. Currently, the study of glacial lakes in the Altai Mountains is mainly concerned with the application of high-resolution remote sensing images to monitor and evaluate the potential hazards of glacial lakes. At present, there is no rapid and large-scale method to monitor the dynamical variation in glacial lakes in the Altai Mountains, and there is little research on predicting its future tendency. Based on the supervised classification results obtained by Google Earth Engine (GEE), combined with an analysis of meteorological data, we analyzed the spatial and temporal variations in glacial lakes in the Altai Mountains between 2000 and 2020, and used the MCE-CA-Markov model to predict their changes in the future. According to the results, as of 2020, there are 3824 glacial lakes in the Altai Mountains, with an area of 682.38 km2. Over the entire period, the glacial lake quantity growth rates and area were 47.82% and 17.07%, respectively. The distribution of glacial lakes in this region showed a larger concentration in the north than in the south. Most glacial lakes had areas smaller than 0.1 km2, and there was minimal change observed in glacial lakes larger than 0.2 km2. Analyzing the regional elevation in 100 m intervals, the study found that glacial lakes were predominantly distributed at elevations from 2000 m to 3000 m. Interannual rainfall and temperature fluctuations in the Altai Mountains have slowed since 2014, and the trends for the area and number of glacial lakes have stabilized. The growth of glacial lakes in both number and surface area is expected to continue through 2025 and 2030, although the pace of change will slow. In the context of small increases in precipitation and large increases in temperature, in the future, glacial lakes with faster surface area growth rates will be located primarily in the southern Altai Mountains. [ABSTRACT FROM AUTHOR]

Mt. Munkhkhairkhan is the most crucial region for understanding climate and glaciation changes in Mongolia. This study investigated the relationship between glacial area changes and the climate elements of Mt. Munkhkhairkhan in the Mongolian-Altai Mountains using a remote sensing approach, in-situ observations, the Mann–Kendall (MK) test, Innovative Trend Analysis Method (ITAM), Sen's slope estimator test, and statistical analysis. The study results showed that for the last 30 years, the annual average air temperature of Mt. Munkhkhairkhan has been slightly increasing. Total annual precipitation (mainly snow) in the mountain area decreased from 1990 to 2000, but since 2000, a significant increase in precipitation levels has appeared. For the last 30 years, the glacial area has decreased by 32% to 11.7 km2. Multiple regression results showed a strong correlation between Temperature, Precipitation, and Glaciers (Multiple R = 0.69, R2 = 0.48). Ruther indicated that Temperature (t = −2.332, p = 0.036) and Precipitation (t = −3.212, p = 0.007) were significant predictors in the model. Air temperature and precipitation explained 48 percent of the change in the glacier area, and R = 0.69 is a strong correlation. The glaciers and snow area in the study area have changed due to climate warming and precipitation changes and are located in arid and semi-arid regions of Central Asia. This study of Mt. Munkhairkhan shows that climate change significantly impacts glaciers and snow. [ABSTRACT FROM AUTHOR]

Catastrophic drainage of ice-dammed lakes in the Altai Mountains has been inferred from geomorphological evidence in the Katun Valley (Russia), and is presumed to have occurred during the Pleistocene. The sedimentary features have been difficult to date directly, due to the absence of organic carbon, and the improbability that luminescence signals in sand grains would be reset during transport. However, the development of rock-surface luminescence dating provides a new opportunity to date the features: clasts have a different transport history to sand grains, and their luminescence depth profiles can be inspected for evidence of bleaching before burial. Here we investigate two sites in the Altai Mountains, and use rock-surface luminescence burial dating to constrain the age of the megaflood deposits. In the Katun Valley, we sampled granite cobbles from a frozen sediment clast emplaced as a dropstone within a massive megaflood gravel terrace. Burial ages for the clasts range from 16.7 to 21.4 ka, with a mean age of 19.8 ± 1.5 ka. This represents the depositional age of the fluvial sediments that preceded the lake outburst flood, (and hence places a maximum age on the catastrophic flood). Clasts sampled from mega-ripples in the Kurai Basin are shown to have a mid-to-late Holocene burial age, which is not consistent with the possible origin of these features during a catastrophic drainage of a glacier-dammed lake. Instead, the burial age of the Kurai Basin sediments may reflect local-scale periglacial or seismic processes along the Kurai Fault Zone. [ABSTRACT FROM AUTHOR]

Optimizing the functions and services provided by the mountain cryosphere will maximize its benefits and minimize the negative impacts experienced by the populations that live and work in the cryosphere-fed regions. The high sensitivity of the mountain cryosphere to climate change highlights the importance of evaluating cryospheric changes and any cascading effects if we are to achieve regional sustainable development goals (SDGs). The southern Altai Mountains (SAM), which are located in the arid to semi-arid region of central Asia, are vulnerable to ecological and environmental changes as well as to developing economic activities in northern Xinjiang, China. Furthermore, cryospheric melting in the SAM serves as a major water resource for northeastern Kazakhstan. Here, we systematically investigate historical cryospheric changes and possible trends in the SAM and also discover the opportunities and challenges on regional water resources management arising from these changes. The warming climate and increased solid precipitation have led to inconsistent trends in the mountain cryosphere. For example, mountain glaciers, seasonally frozen ground (SFG), and river ice have followed significant shrinkage trends as evidenced by the accelerated glacier melt, shallowed freezing depth of SFG, and thinned river ice with shorter durations, respectively. In contrast, snow accumulation has increased during the cold season, but the duration of snow cover has remained stable because of the earlier onset of spring melting. The consequently earlier melt has changed the timing of surface runoff and water availability. Greater interannual fluctuations in snow cover have led to more frequent transitions between snow cover hazards (snowstorm and snowmelt flooding) and snow droughts, which pose challenges to hydropower, agriculture, aquatic life, the tail-end lake environment, fisheries, and transboundary water resource management. Increasing the reservoir capacity to regulate interannual water availability and decrease the risk associated with hydrological hazards related to extreme snowmelt may be an important supplement to the regulation and supply of cryospheric functions in a warmer climate. [ABSTRACT FROM AUTHOR]