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The collapse of glacial, permafrost, and ice-rich moraine slopes in high-altitude mountainous areas not only threatens downstream residents and infrastructure but also displaces ice mass to lower and warmer elevations, accelerating glacial ablation to some extent. Despite being considered rare, ice-rich slopes collapse more frequently than commonly thought due to climate change. For example, two adjacent mountain glaciers in the Aru Range of the Tibetan Plateau, characterized by large volumes (68 × 106 m3 and 83 × 106 m3, respectively) and low surface slope angles (12.3° and 12.9°, respectively), collapsed surprisingly in 2016. While the mechanisms behind these collapses have garnered broad attention, the ability to quantitatively assess the instability of ice-rich slopes remains limited due to the complex interplay of multi-physical processes. Taking the Aru glacier collapses as reference cases, this paper presents a conceptual model, implemented through coupled thermo-hydro-mechanical simulation, to evaluate the stability of high-altitude ice-rich slopes due to climate change, rainfall and ice ablation. Results indicate that the methodology captures the effects of temperature change, rainfall and meltwater on the instability events well, demonstrating promising potential in evaluating potential collapse zones of ice-rich slopes similar to the Aru glaciers. Furthermore, the role of climate change in the well-known Aru events is demonstrated using a state-of-the-art global climate reanalysis dataset. Findings reveal that the increase in liquid water infiltrating the Aru glaciers since 2010 was a critical factor leading to the instability events. • A conceptual model is proposed to analyse the stability and collapse zones of ice-rich slopes. • The modelling elucidates the causes of twin collapses of the Aru glaciers. • Results contribute to ice-rich slope instability prediction and associated disaster risk management. [ABSTRACT FROM AUTHOR]

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]

The paper concerns ice dams and glacial lake outburst floods (GLOFs) in the Karakoram. Some 146 events are identified, including 30 major disasters. Large downstream populations and major infrastructure are threatened. Risk factors differ from recent reports of other Himalayan GLOFs associated with glacier recession and global warming. Ice dams are largely or entirely active ice, put in place by advancing glaciers. Climate change is a factor, but the ice cover in the Karakoram has been sustained, and even some increase in mass. Surge-type glaciers comprise or affect~70% of our inventory. The most frequent, large GLOFs come from local clusters of glaciers in five sub-basins, given special attention here. In four there were new ice dams formed since 2008 and two generated dangerous GLOFs. An urgent need arises to track short-term ice and lake behavior and how surge dynamics may be involved. Satellite images and DEMs are employed in cross-correlation feature tracking and elevation change respectively. The glaciers of interest all exhibit irregular movement, including recent advances, but with great variability and no clear relation to climatic fluctuations. • Study updates inventory of ice dams and related GLOFs in the Karakoram. • Study reports recent evidence of surface displacement and elevation changes of glaciers involved in ice dam generation. • Surge-type glaciers comprise or affect ~70% of inventory of ice dams and related GLOFs. • Four glaciers formed new ice dams since 2008, two (Kyagar, Khurdopin) generating dangerous GLOFs. • The studied glaciers exhibit irregular movement, but with great variability and no clear relation to climatic fluctuations. [ABSTRACT FROM AUTHOR]

Studies on long-term fluctuations in glacier volume and mass are crucial for understanding past climate change. In this paper, we utilized Picea schrenkiana to develop a 525-year chronology of latewood blue intensity (LWBI) in the Tianshan Mountains. Relying on temperature as the main controlling factor for tree growth and glacier mass balance (GMB) variations, the LWBI chronology was used to reconstruct the summer temperature (JJA, R 2 adj = 47%) and the annual glacier mass balance (annual GMB, R 2 adj = 39%) in the Tianshan Mountains over the past 400 years. The reconstruction results show that the rapid warming since 1974 has caused the Tianshan No.1 glacier (TS No.1) to experience an unprecedented melting trend within the last four centuries. It is disturbing that the glacier still remain in an ablation state for the next 80 years under both representative concentration paths (RCP) 4.5 and 8.5 scenarios, which will exacerbate the adverse environmental impacts of glacial hazards. Our study provides a continuous record for glacier research in high mountains Asian and contributes to a more detailed assessment of glacier and climate change in this region. The spatial correlation analysis of the PC1 and the ERA5 grid temperature dataset after the original (a), detrended (b) and first-order difference (c) calculations in the verification period (1950–2005), all insignificant correlations (P > 0.05) were masked out, where A represent the Tianshan Mountains (this study), B represent Central Europe Alps (Büntgen et al., 2006), C represent East Asia (Davi et al., 2002), D represent Dunde ice core (Thompson et al., 2006), and E represent Guliya ice core (Thompson et al., 1997). Comparison of Tianshan temperature reconstruction (PC1) with other MXD-based temperature reconstructions, where (d) is the comparison between PC1 and Central European Alps summer (June to September) temperature reconstruction, (e) is the comparison between PC1 and East Asian Japanese warm season (May to September) temperature reconstruction, and (f) is the comparison between PC1 and Northern Hemisphere summer (June to August) temperature reconstruction (Schneider et al., 2015). (g) is the comparative between the PC1 and Atlantic multidecadal variability (AMV, Wang et al., 2017). Comparison of TS No.1 GMB reconstruction with ice core accumulation data, where (h) is the comparison between TS No.1 GMB reconstruction and Dunde ice core water equivalent net balance (accumulation, 5-year average), (i) is the comparison between TS No.1 GMB reconstruction and Guliya ice core water equivalent net balance (accumulation, 10-year average). All comparison series are Z-score normalized and low-pass filtered with a step size of 10 years (ice core accumulation data are 5 year) to achieve low-frequency fluctuations. [Display omitted] • A 525-year latewood blue intensity (LWBI) chronology was developed to study glacial dynamics for the Tianshan Mountains. • The results showed that the last 20 years to be outside the range of natural variability of the last 400 years. • The Tianshan No. 1 glacier will continue to melt rapidly in the next 80 years under the RCP 4.5 and 8.5 scenarios. [ABSTRACT FROM AUTHOR]

Abstract High elevation or high latitude hydropower production (HP) strongly relies on water resources that are influenced by glacier melt and are thus highly sensitive to climate warming. Despite of the wide-spread glacier retreat since the development of HP infrastructure in the 20th century, little quantitative information is available about the role of glacier mass loss for HP. In this paper, we provide the first regional quantification for the share of Alpine hydropower production that directly relies on the waters released by glacier mass loss, i.e. on the depletion of long-term ice storage that cannot be replenished by precipitation in the coming decades. Based on the case of Switzerland (which produces over 50% of its electricity from hydropower), we show that since 1980, 3.0%–4.0% (1.0–1.4 TWh yr−1) of the country-scale hydropower production was directly provided by the net glacier mass loss and that this share is likely to reduce substantially by 2040–2060. For the period 2070–2090, a production reduction of about 1.0 TWh yr−1 is anticipated. The highlighted strong regional differences, both in terms of HP share from glacier mass loss and in terms of timing of production decline, emphasize the need for similar analyses in other Alpine or high latitude regions. Graphical abstract Image 1 Highlights • First quantification of Alpine hydropower production share from glacier mass loss. • Since 1980, 1.0 to 1.4 TWh yr-1 of Swiss hydropower comes from glacier mass loss. • Expected country-scale production reduction by 2070–2090 of 1.0 TWh yr-1. • Notable regional differences despite of continuous retreat of all Swiss glaciers. [ABSTRACT FROM AUTHOR]

Glacier melt water is an important water resource in arid regions of central Asia during the dry seasons, and it is very susceptible to climate disturbances. In this paper, based on the glacier datasets of the first and second Chinese Glacier Inventories, the glacier change in the Chinese Tien Shan from 1960s to 2010 was quantify by assessing the Annual Percentages of Area Changes ( APAC ), Annual Percentages of Volume Changes ( APVC ), and Equilibrium Line Altitude ( ELA ). The results indicated that the mean glacier area and mean glacier volume decreased by 0.7% ± 0.6% per year and 0.83% ± 0.73% per year in the Chinese Tien Shan during the period of 1960–2010, respectively. The mean ELA increased by 24.87 ± 126.84 m during the study period. In addition, we also found that the glacier retreat in the Bogda Mountains was the fastest, mainly due to the sensitivity of small glaciers to climate change, with an APAC of −0.86% ± 0.49% per year and APVC of −1.04% ± 0.55% per year, and the mean ELA increased by 44.35 ± 55.07 m. Moreover, increases in both air temperature (in terms of Thawing Degree-Day (TDD) and Freezing Degree-Day (FDD)) and precipitation were found over the study area during the past five decades. However, such increases in precipitation did not result in any significant changes in the ratio of annual snowfall to total precipitation (S/P) across the Chinese Tien Shan Mountains. Hence, the glacier shrinkage mainly resulted from the significant increase in TDD and FDD in the study region. [ABSTRACT FROM AUTHOR]

This paper briefly reviews the physical and human geography of the Kamchatka region and summarises previous research on Holocene climate dynamics. We provide context for the rest of the Special Issue of the Journal Global and Planetary Change entitled ‘Holocene climate change in Kamchatka’, the primary focus of which is the use of lake sediment records for palaeoclimatic inferences. In this paper an additional perspective from ongoing tree ring, ice core and borehole temperature reconstructions illustrates that the Kamchatka region is rich in paleoclimatic proxies. The period of the last 200 years is sufficiently covered by the proxy information, including reconstructions with annual resolution. In this period the tree-rings, ice cores, boreholes, and glacier fluctuations recorded a 1 °C warming and a general glacier retreat, i.e. the transition from the Little Ice Age climate to the modern one. Although the proxies have different resolution, accuracy and seasonality in general they demonstrate a coherent picture of environmental changes in the last two centuries. The tree ring and ice core records are up to four-six hundred years long and they provide information on annual to decadal variability of summer temperature, accumulation processes, volcanic eruptions and lahar activity. [ABSTRACT FROM AUTHOR]

Climate models and ongoing monitoring studies predict the remaining glaciers in Africa are predicted to disappear by the middle of the 21st Century. These will likely be the only glaciers present on the continent for some tens of thousands of years, until the next global ice age. This paper considers the implications of the shrinking cryosphere in Africa for the surrounding environment and local communities. Glacier retreat will give rise to significant and irreversible downstream effects on East African mountain landscapes in future decades, including impacts on water resources; slope stability and geohazards; ecosystems and ecosystem services; and human socioeconomic and cultural activities and heritage. This foresight study is the first to discuss future environmental impacts of deglacierization in East Africa, and this is framed around understanding the interconnections that exist between physical and human landscape elements in mountainous regions. A key outcome is the identification of elements of mountain systems that are most sensitive to environmental disturbance as a result of global warming, such as long-term water availability and processes that give rise to geohazards, and highlighting the need for management and mitigation of these varied impacts. • Glaciers in East African mountains are rapidly melting. • These will be the only glaciers present in Africa until the next global ice age. • Glacier retreat will result in significant and irreversible downstream environmental effects. • Most affected will be regional water resources, geohazards, and ecosystem services. • Change in mountain landscapes will impact on socioeconomic and cultural activities. [ABSTRACT FROM AUTHOR]

Patagonia features the most extensive glaciers of the Southern Hemisphere, excluding Antarctica, and a vast inventory of glacial landforms, so it is thought to have played a key role in (paleo)glacier studies since the late 19th century. However, no systematic attempts to characterize the specific research trends and the scientific community focused on Patagonian cryosphere have been conducted so far. To fill this gap, we analyzed the metadata associated to 305 articles compiled from the Web of Science database following a bibliometric approach covering the period between 1976 and 2020. Our results point to an irregular but net increase on the number of contributions on Patagonian (paleo)glaciers. Mass balance analyses based on satellite data of present-day glaciers and the reconstruction of past glacier activity by dating glacial landforms formed during the Last Glacial Termination, were the most addressed topics during the analyzed period. Patagonian (paleo)glacier studies are mostly published in generic Earth Sciences publications, followed by Quaternary and glaciological journals. Most of the studies were led by scientists from the United Kingdom, followed by Chile, Argentina and United States. In terms of collaborations, these studies can be divided into two main clusters, one composed by researchers from United States, Chile and Argentina institutions, and another mostly composed by British researchers. So far, the most prolific authors are nearly equally distributed in nationality, yet gender inclusion and international collaborations are still caveats that must be solved. Even though our query on the Web of Science missed highly influential (so-called) grey literature, such as local scientific journals and technical reports, the reviewed scientific literature unambiguously indicates that Patagonia is a privileged location for (paleo)glaciers studies worldwide and that it will continue offering vast opportunities to tackle critical questions related to global cryosphere and past-to-present climate changes. • Patagonia is a privilege site for studying present and past glacier dynamics and the evolution of climate changes at hemispheric and global scale. • Glacier dynamics during the 20th century and and the Last Glacial Termination are the most common topics addressed in past decades in the WOS. • Patagonian (paleo)glacier studies has contributed to the development or improvement of diverse analytical techniques. • United Kingdom, United States, Chile and Argentina produced the largest number of WOS-listed papers on (paleo)glaciers in past decades. • The related scientific community is fairly heterogeneous. Although, inclusion and international collaboration issues still need to improve. [ABSTRACT FROM AUTHOR]

Much research, especially within the framework of the Fluvial Archives Group, has focused on river response to climate change in mid-latitude non-glaciated areas, but research into the relationships between Quaternary glacial and fluvial dynamics remains sparse. Understanding glacial–fluvial interactions is important because glaciers are able to influence river behaviour significantly, especially during glacial and deglacial periods: (1) when they are located downstream of a pre-existing fluvial system and disrupt its activity, leading to hydrographical, hydrosedimentary and isostatic adjustments, and (2) when they are located upstream, which is a common scenario in mid-latitude mountains that were glaciated during Pleistocene cold periods. In these instances, glaciers are major water and sediment sources. Their role is particularly significant during deglaciation, when meltwater transfer towards the fluvial system is greatly increased while downstream sediment evacuation is influenced by changes to glacial–fluvial connectivity and basin-wide sediment storage. This means that discharge and sediment flux do not always respond simultaneously, which can lead to complex fluvial behaviour involving proglacial erosion and sedimentation and longer-term paraglacial reworking. These processes may vary spatially and temporally according to the position relative to the ice margin (ice-proximal versus ice-distal). With a focus on the catchments of Europe, this paper aims to review our understanding of glacial impacts on riversystem behaviour. We examine the methods used to unravel fluvial response to 'glacial forcing', and propose a synthesis of the behaviour of glacially-fed rivers, opening perspectives for further research. [ABSTRACT FROM AUTHOR]

Rapid shrinkage and dramatic volume loss of the glaciers on Mt. Bogda in the eastern Tianshan Mountains have resulted in water shortages in the surrounding arid regions of China. Understanding ice thickness and its variation is important to the analysis of changes in glacial volume, which are directly related to regional hydrology and water resources. Fan-shaped Diffluence Glacier and Heigou Glacier No. 8 are located on the northern and southern slopes of Mt. Bogda, respectively. In this paper, the spatial distribution of the ice thickness of these two glaciers and the changes in their area and volume are discussed based on a 2009 survey result and comparison to previous investigations. The mean ice thickness of the tongue of Fan-shaped Diffluence Glacier was about 82.3 m and the calculated ice volume was 385.2 × 10 6 m 3 in 2009. It had thinned by 14 ± 8 m (0.30 ± 0.17 m a − 1 ) from 1962 to 2009, equivalent to an ice volume loss of 65.5 ± 37.4 × 10 6 m 3 . The mean ice thickness of the tongue of Heigou Glacier No. 8 was 58.7 m and the calculated ice volume was 115.1 × 10 6 m 3 in 2009. The tongue of Heigou Glacier No. 8 thinned by 13 ± 6 m (0.57 ± 0.26 m a − 1 ) from 1986 to 2009, which corresponds to an ice volume loss of 25.5 ± 11.8 × 10 6 m 3 . The greater thinning and retreat of Heigou Glacier No. 8 than those of Fan-shaped Diffluence Glacier is partially due to topographic characteristics. The difference can be attributed mainly to the greater increase in temperature on the southern slope than on the northern slope. [ABSTRACT FROM AUTHOR]

This paper comprises a detailed description of glaciers of the Kaffiøyra region, an area of Svalbard, located in north-western Spitsbergen. The primary objective of this work is to present the essential conditions and characteristics of changes in the dynamics and spatial extent of the glaciers in that region. Most of the research consisted in direct field measurements carried out in 1996–2015, and the investigated changes were mainly related to the mass balance on the Waldemarbreen, the Irenebreen and the Elisebreen. In order to identify the changes of the glaciated area of the studied region, a detailed analysis of the degree of changes in the glaciers' surface area and recession was carried out, starting with the period of their maximum extent in the late 19th and early 20th centuries, i.e. by the end of the Little Ice Age. Statistical analysis of measurement data from 1970 to 2015 enabled the development of a simple empirical formula used to work out the mass balance with a similar accuracy to that achieved using direct methods. The mean annual mass balance of the three analysed glaciers was: ˗0.72 m w.e. in the case of the Waldemarbreen in 1996–2015, − 0.84 m w.e. in the case of the Irenebreen in 2002–2015, and − 0.65 m w.e. in the case of the Elisebreen in 2006–2013. For the Waldemarbreen the change of mass balance with time was estimated to be − 0.040 (± 0.003) m w.e. a − 1 . In the same period for the Irenebreen it was − 0.052 (± 0.024) m w.e. a − 1 . From the time of their maximum reach in the late 19th and early 20th centuries to 2015, the total area of the Kaffiøyra region valley glaciers decreased by about 43.0% on average. Glaciers in the region retreated at an average rate of 12 ma − 1 . The changes of the glaciers' front positions, which make the north-western coast of Spitsbergen, are similar to the changes observed for other Svalbard glaciers of this type. The investigations of the glacier mass balance in the Kaffiøyra region are especially important, being some of only a few long-term mass balance records available regarding Svalbard. [ABSTRACT FROM AUTHOR]

Glaciers, as the core part of the cryosphere, are very sensitive to climate change. As an indicator of glacier changes, the characteristics of glacier-originated rivers have profound significance to global climate change and local water resources. In this paper, the Mingyong River, a glacier-originated river replenished by groundwater, was selected to study the river hydrological cycle characteristics by integrating natural tracer radium isotopes with hydrochemical parameters. The results showed that there were significant differences in radium isotope activities and hydrochemical parameters between groundwater and river water, and the radium activities increased along the river, which reflected the fact that the river was supplied by groundwater seepage. We also found that the activity ratios of 224Ra/228Ra in river and groundwater were less than one unit, which indicated that the groundwater and river water circulated rapidly and that the radioactive equilibrium of short-time radium isotopes had not yet been reached. According to the geochemical behavior of radium in river water body, the mass balance equation of radium was established. 228Ra and 224Ra were used to estimate the groundwater seepage of different segments of the Mingyong River. The results demonstrated that the groundwater seepage fluxes calculated by 224Ra and 228Ra were similar and increased along the river from 123.12 to 657.68 m3 m−1 d−1. Our results have certain significance in revealing the characteristics of the local hydrological cycle and demonstrate that radium isotopes can be used as a tool to estimate the groundwater discharge of rivers in glacial environments. [Display omitted] • Estimated the groundwater seepage along a glacier originated river. • Ra isotopes mass balance model of the river is established. • Verified Ra isotopes is an effective tool in glacial area. [ABSTRACT FROM AUTHOR]

In the Northern Caucasus, glacier and climatic variations over the past centuries remain insufficiently documented. In this review, we summarized the high-resolution information on glacier and climate fluctuations in the region for the past millennium and provided a synthesis of these two lines of evidence with respect to regional climate change. The key areas considered in the paper are the Elbrus area, the Teberda and Arkhyz valleys in the Western Caucasus and the Cherek Bezengiisky and Tsey valleys in the Eastern Caucasus, where the most paleoclimatic evidence has been retrieved. We focused on the fluctuation records of the ten glaciers that are best documented. To reconstruct changes in glacier length in the past, we used aerial photos, optical space images, repeated photographs and old maps. The ages of moraines were defined with the help of instrumental records, historical images, old maps, and tree-ring dating. Lichenometry was used as a supplementary tool to determine the relative ages of glacial landforms. We reviewed the collection of control points used for the lichenometric curves and determined the time limit of potential use of this method in the Caucasus to be up to one millennium. High-resolution tree-ring-based hydroclimatic reconstructions in the Northern Caucasus are presented based on the reconstruction of June–September temperature (1595–2012 CE), the mass balance reconstruction of the Garabashi Glacier (1800–2008 CE) and the runoff of the Teberda River (low-frequency variations) for May, July and August for 1850–2005 CE. The synthesis of all the available paleoclimatic records revealed several distinct climatic periods. Evidence of a warm interval (traditionally referred to as the “Arkhyz break in glaciation”) preceding the Little Ice Age (LIA) in the Caucasus is based on archeological, palynological, geochemical and pedological data. However, the conclusions concerning the duration and magnitude of this warming are still vague due to the low resolution of the data available and ambiguous interpretation of the evidence. The first LIA maximum glacier extent in the past millennium is poorly constrained. According to our data, it occurred prior to the year 1598 CE (tree-ring-based minimum age). Two other major phases of advances occurred in the second half of the 17th century CE and the first half of 19th century CE. General glacier retreat in the Northern Caucasus started in the late 1840s CE, with four to five minor readvances in the 1860s–1880s CE and three readvances or steady states in the 20th century CE (1910s, 1920s and 1970s–1980s). Since the last LIA maximum in the middle of the 19th century CE, most glaciers have decreased in length by more than 1000 m, and the rise in the elevation of the glacier fronts has exceeded 200 m. The glacier advances correspond to summer temperature minima and are generally coherent with the reconstructed mass balance of the Garabashi Glacier. A comparison of a tree-ring-based summer temperature reconstruction in the Northern Caucasus with detailed reconstructions of summer temperature and glacier fluctuations in the Alps shows a pronounced agreement between the records and supports the similarity between the patterns of climatic and glacier variations in the two regions. [ABSTRACT FROM AUTHOR]

Although glacial landsystems produced under warm/wet based conditions are very common on Earth, even here, observations of subglacial landforms such as eskers emerging from extant glaciers are rare. This paper describes a system of sinuous ridges emerging from the in situ but now degraded piedmont terminus of a Late Amazonian-aged (∼150 Ma) glacier-like form in the southern Phlegra Montes region of Mars. We believe this to be the first identification of martian eskers that can be directly linked to their parent glacier. Together with their contextual landform assemblage, the eskers are indicative of significant glacial meltwater production and subglacial routing. However, although the eskers are evidence of a wet-based regime, the confinement of the glacial system to a well-defined, regionally significant graben, and the absence of eskers elsewhere in the region, is interpreted as evidence of sub-glacial melting as a response to locally enhanced geothermal heat flux rather than climate-induced warming. These observations offer important new insights to the forcing of glacial dynamic and melting behaviour on Mars by factors other than climate. [ABSTRACT FROM AUTHOR]

The Gravity Recovery and Climate Experiment (GRACE) satellites can estimate the high-precision time-varying gravity field and the changes of Earth's surface mass, which have been widely used in water cycle and glacier mass balance. However, one of larger errors in GRACE measurements, land–ocean leakage effects, restricts high precision retrieval of ocean mass and terrestrial water storage variations along the coasts, particularly estimation of mass loss in Greenland. The land–ocean leakage effect along the coasts in Greenland will contaminate the mass loss signals with significant signal attenuation. In this paper, the precise glacier mass loss in Greenland from GRACE is re-estimated with correction of land–ocean leakage effects using the forward gravity modeling. The loss of Greenland ice-sheets is − 102.8 ± 9.01 Gt/a without removing leakage effect, but − 183.0 ± 19.91 Gt/a after removing the leakage effect from September 2003 to March 2008, which has a good agreement with ICESat results of − 184.8 ± 28.2 Gt/a. From January 2003 to December 2013, the total Greenland ice-sheet loss is at − 261.54 ± 6.12 Gt/a from GRACE measurements with removing the leakage effect by 42.4%, while two-thirds of total glacier melting in Greenland occurred in southern Greenland in the past 11 years. The secular leakage effects on glacier melting estimate is mainly located in the coastal areas, where larger glacier signals are significantly attenuated due to leaking out into the ocean. Furthermore, the leakage signals also have remarkable effects on seasonal and acceleration variations of glacier mass loss in Greenland. More significantly accelerated loss of glacier mass in Greenland is found at − 26.19 Gt/a 2 after correcting for leakage effects. [ABSTRACT FROM AUTHOR]

Summary Glacier and snow cover changes with related impacts on melt runoff can seriously affect human societies which are depending on fresh water from cryospheric sources. Observed trends and projected future evolutions of climatic and cryospheric variables clearly show the need to adapt to these changes. Accordingly, the topics addressed herein have been put on the agendas of many larger funding agencies. This article provides a brief overview on major ongoing activities on glacier, snow and related runoff research in order to then analyze data gaps and research needs from a climate change adaptation perspective. Major data needs are identified with respect to the spatial and temporal coverage of local-scale data and related needs for (data) services that distribute and maintain these data sets. Moreover, clear research needs are also recognized at the local scale where process knowledge needs to be improved (e.g., the influence of albedo on snow and ice or debris cover on glaciers) in order to derive plausible climate change impacts assessments. The paper then discusses directions on how to move forward to better serve the practical needs for climate change adaptation planning. In the future, substantial support by large funding agencies might be key for capacity building in target regions of climate change adaptation programs, for longer-term and more sustainable commitments, and for the development of approaches, which aim at assessing the transferability of data, techniques, and tools. [ABSTRACT FROM AUTHOR]

Summary Glacier shrinkage caused by climate change is likely to trigger diminished and less consistent stream flow in glacier-fed watersheds worldwide. To understand, model, and adapt to these climate-glacier-water changes, it is vital to integrate the analysis of both water availability (the domain of hydrologists) and water use (the focus for social scientists). Drawn from a case study of the Santa River watershed below Peru’s glaciated Cordillera Blanca mountain range, this paper provides a holistic hydro-social framework that identifies five major human variables critical to hydrological modeling because these forces have profoundly influenced water use over the last 60 years: (1) political agendas and economic development; (2) governance: laws and institutions; (3) technology and engineering; (4) land and resource use; and (5) societal responses. Notable shifts in Santa River water use—including major expansions in hydroelectricity generation, large-scale irrigation projects, and other land and resource-use practices—did not necessarily stem from changing glacier runoff or hydrologic shifts, but rather from these human variables. Ultimately, then, water usage is not predictable based on water availability alone. Glacier runoff conforms to certain expected trends predicted by models of progressively reduced glacier storage. However, societal forces establish the legal, economic, political, cultural, and social drivers that actually shape water usage patterns via human modification of watershed dynamics. This hydro-social framework has widespread implications for hydrological modeling in glaciated watersheds from the Andes and Alps to the Himalaya and Tien Shan, as well as for the development of climate change adaptation plans. [ABSTRACT FROM AUTHOR]

The total glacial area of the Cordillera Blanca, Peru, has shrunk by more than 30% in the period of 1930 to the present with a marked glacier retreat also in the recent decades. The aim of this paper is to assess local air temperature and precipitation changes in the Cordillera Blanca and to discuss how these variables could have affected the observed glacier retreat between the 1980s and present. A unique data set from a large number of stations in the region of the Cordillera Blanca shows that after a strong air temperature rise of about 0.31°C per decade between 1969 and 1998, a slowdown in the warming to about 0.13°C per decade occurred for the 30years from 1983 to 2012. Additionally, based on data from a long-term meteorological station, it was found that the freezing line altitude during precipitation days has probably not increased significantly in the last 30years. We documented a cooling trend for maximum daily air temperatures and an increase in precipitation of about 60mm/decade since the early 1980s. The strong increase in precipitation in the last 30years probably did not balance the increase of temperature before the 1980s. It is suggested that recent changes in temperature and precipitation alone may not explain the glacial recession within the thirty years from the early 1980s to 2012. Glaciers in the Cordillera Blanca may be still reacting to the positive air temperature rise before 1980. Especially small and low-lying glaciers are characterised by a serious imbalance and may disappear in the near future. [ABSTRACT FROM AUTHOR]

Mt. Everest (Qomolangma or Sagarmatha), the highest mount on Earth and located in the central Himalayas between China and Nepal, is characterized by highly concentrated glaciers and diverse landscapes, and is considered to be one of the most sensitive area to climate change. In this paper, we comprehensively synthesized the climate and environmental changes in the Mt. Everest region, including changes in air temperature, precipitation, glaciers and glacial lakes, atmospheric environment, river and lake water quality, and vegetation phenology. Historical temperature reconstruction from ice cores and tree rings revealed the distinct features of 20th century warming in the Mt. Everest region. Meteorological observations further proved that the Mt. Everest region has been experiencing significant warming (approximately 0.33 °C/decade) but relatively stable precipitation during 1961−2018 AD. Projected results (during 2006−2099 AD) under different representative concentration pathway scenarios showed a general warming trend in the region, with larger warming occurring in winter than in summer. Meanwhile, the precipitation projections varied spatially with no significant trends over the region. Intensive glacier shrinkage was characterized by decreasing glacier areas, while glacier-fed river runoff increased. Glacial lakes expanded with increasing glacial lake areas and numbers. These findings indicated a clear regional hydrological response to climate warming. Owing to the remote location of Mt. Everest, the present atmospheric environment remained relatively clean; however, long-range transport of atmospheric pollutants from South Asia and West Asia may have substantially influenced the Mt. Everest region, resulting in increasing concentrations of pollutants since the Industrial Revolution. Anthropogenic activities have been shown to influence river and lake water quality in this remote region, especially in the downstream. The end of the vegetation growing season advanced in the northern slope and did not change in southern slope region of the Mt. Everest, and there was no significant change in start date of the growing season in the region. This review will enhance our understanding of climate and environmental changes in the Mt. Everest region under global warming. • Climate and environmental changes were synthesized in the Mt. Everest region. • Glaciers have retreated significantly, posing impacts to river runoff and glacial lakes. • Transboundary transport of atmospheric pollutants influenced the region. • TThere was no significant change in start date of the growing season. [ABSTRACT FROM AUTHOR]

This paper presents a review of Late Quaternary climatic changes and glacier variability in the Himalaya and East Africa, focusing on the role of Indian Summer Monsoon (ISM), East African monsoon, and Westerlies monsoons. Multi-proxy studies which are based on five different archives (lakes, peat bogs, speleothems, marine sediments, and ice cores) including sixty-six records from India and nearby regions, particularly in the Himalaya and in addition to six archives from the equatorial Eastern part of Africa encompasses with high-resolution published and unpublished records for the last 50 ka BP. The proxy data is discussed towards REMO-ESM model Coupled Model Intercomprasion Project phase 5 (CMIP5 Project) results. Our results indicate that both Western Himalaya and East Africa had undergone mega-droughts from ~17.0–15.0 ka BP, and precipitation had increased during the Early Holocene (10.0–7.0 Ka BP) during the time span when the Westerlies dominated regions. The model results suggest that the Westerlies monsoon has significantly contributed to the Northwestern Himalaya and somewhat to a lesser degree to the Western Himalaya and lower solar insolation in the winters did support the glacier advance during the LGM. The time series from the proxy data are compared with glacier fluctuations in different valleys to understand the response of the aforementioned monsoon system including other forcing factors which drive these variabilities. The review results indicate that the Westerlies was the main driver of the climate and glacier fluctuations in Northwestern Himalaya during the Late Quaternary. The Early and Late Holocene glacier fluctuation was mainly controlled by Westerlies precipitation in Northwestern Himalaya and the ISM controlled the glacier fluctuations in the Western Himalaya during Late Quaternary. [ABSTRACT FROM AUTHOR]

Glacier caves are unique and spectacular wonders of nature that can be found in very few places in the world. They have different shapes, capacity or wall structures that most often form anew every winter season. The article explores an interesting aspect of glacier cave acoustics as these spaces have never been investigated in that respect. The paper shows the methods and results of spatial impulse measurements in four different glacier caves of the Svalbard archipelago located near the city of Longyearbyen. The basic room acoustic parameters together with Sound Pressure Levels have been measured or calculated together with parametric statistical analysis. The results show the diversity of acoustical climates inside the glacier caves that strongly depends on the morphology and dimensions of the caves. The analysis of measurement locations (within particular caves) shows the strong influence on sound absorption by the snow located at the entrance of the caves. The conducted research shows the potential of acoustical measurements in the process of monitoring the cave morphology and therefore climate changes as well. [ABSTRACT FROM AUTHOR]