Decrease In Glacier Area Research Articles

Acceleration of Abramov Glacier (Pamir‐Alay) retreat since the Little Ice Age

The Koksu River valley is located in the Pamir‐Alay mountain range and contains 25 glaciers larger than 1 km2 and numerous smaller glaciers. The largest glacier in the catchment is Abramov Glacier with a current surface area of 22.55 km2 (in 2022), which was extensively monitored between 1965 and 1999, and resumed in 2011. The long and detailed mass balance time series provide, among other information, benchmark climate variables for the Pamir‐Alay range. We report 10 new cosmogenic 10Be exposure dates of glacial moraines directly deposited by Abramov Glacier to extend the glacial history of the valley. Six boulders indicate that the Local Last Glacial Maximum occurred at 17.1±1.0 ka. Four boulders suggest a Little Ice Age (LIA) glacial advance around AD 1750. Secular glacier mass balance reconstructions suggest a progressively negative mass balance since the LIA advance. The decrease in mass balance accelerated in the last quarter of the 20th century. Results from repeated ground penetrating radar (GPR) measurements suggest that Abramov Glacier lost about 403 million m3 of ice volume between 1986 and 2018. Based on the reconstruction of the glacier surface, the corresponding equilibrium line altitude, which is closely correlated with the mass balance, increased by about 70 to 80 m during this period. Our results also suggest that Abramov Glacier has become increasingly out of equilibrium with the climate over the last two decades. This is supported by repeated GPR measurements of the tongue area, which indicate a dramatic decrease in glacier area and ice volume over the period 1986–2018.

Two-Decadal Glacier Changes in the Astak, a Tributary Catchment of the Upper Indus River in Northern Pakistan

Snow and ice melting in the Upper Indus Basin (UIB) is crucial for regional water availability for mountainous communities. We analyzed glacier changes in the Astak catchment, UIB, from 2000 to 2020 using remote sensing techniques based on optical satellite images from Landsat and ASTER digital elevation models. We used a surface feature-tracking technique to estimate glacier velocity. To assess the impact of climate variations, we examined temperature and precipitation anomalies using ERA5 Land climate data. Over the past two decades, the Astak catchment experienced a slight decrease in glacier area (−1.8 km2) and the overall specific mass balance was −0.02 ± 0.1 m w.e. a−1. The most negative mass balance of −0.09 ± 0.06 m w.e. a−1 occurred at elevations between 2810 to 3220 m a.s.l., with a lesser rate of −0.015 ± 0.12 m w.e. a−1 above 5500 m a.s.l. This variation in glacier mass balance can be attributed to temperature and precipitation gradients, as well as debris cover. Recent glacier mass loss can be linked to seasonal temperature anomalies at higher elevations during winter and autumn. Given the reliance of mountain populations on glacier melt, seasonal temperature trends can disturb water security and the well-being of dependent communities.

Spatiotemporal quantification of key environmental changes in Stok and Kang Yatze regions of Ladakh Himalaya, India

Tourism fuelled economic transformation of Ladakh region is bringing a change in demography and livelihood preferences leading to increased exploitation of scarce natural resources. In addition to the nerve centre of tourism-related activities (Leh city), rural hinterlands of Ladakh are also witnessing a stark transformation in land and resource use patterns. In this study, we quantified and assessed the changes in key environmental parameters of rural Ladakh between 1969 and 2020. We observed a decrease in glacier area, glacier volume and vegetation cover by approximately 19%, 13% and 14%, whereas built-up and lake area increased by approximately 238% and 122%, respectively. Simultaneously, local population of the region doubled while tourism footprint increased by approximately 620-folds. The study highlights the environmental changes happening at a higher rate in rural regions around Leh city. Therefore, need of the hour is to recognize the disruptive changes being brought in the traditional way of life and to devise strategies to reorient the development paradigm towards sustainable resource use and management.

Glacier recession since the Little Ice Age: Implications for water storage in a Rocky Mountain landscape

ABSTRACTGlaciers have significant influence on hydrology, vegetation, and wildlife in mountainous regions, and are receding globally. To quantify the impacts of sustained glacier loss, we mapped a complete set of glacier areas from the Little Ice Age (LIA) using very high-resolution satellite imagery (30 cm) within Glacier National Park (GNP), Montana, a region that encompasses 4098.81 km2 in the northwestern United States. We measured glacier change across the park using LIA glacier area as a baseline and then estimated change in glacier area and volume over time. An estimated 146 glaciers existed within the current boundaries of GNP during the LIA. By 2005, only fifty-one (35 percent) persisted. Nearly 90 percent of LIA glaciers had lost more than 50 percent of their area by 2005. This decrease in glacier area equates to an estimated ice volume loss of 1.52 km3, or 1.37 km3 of water storage, roughly equivalent to 90 percent of Lake McDonald, the largest lake in the park. Understanding rates of deglaciation and implications for water storage and use can assist local resource managers and downstream communities in planning for change.

RS analysis of glaciers change in the Heihe River Basin, Northwest China, during the recent decades

The Heihe River Basin is the second largest inland river basin in Northwest China and it is also a hotspot in arid hydrology, water resources and other aspects of researches in cold regions. In addition, the Heihe River Basin has complete landscape, moderate watershed size, and typical social ecological environmental problems. So far, there has been no detailed assessment of glaciers change information of the whole river basin. 1:50,000 topographic map data, Landsat TM/ETM+ remote sensing images and digital elevation model data were used in this research. Through integrated computer automatic interpretation and visual interpretation methods, the object-oriented image feature extraction method was applied to extract glacier outline information. Glaciers change data were derived from analysis, and the glacier variation and its response to climate change in the period 1956/1963–2007/2011 were also analyzed. The results show that: (1) In the period 1956/1963–2007/2011, the Heihe River Basin’s glaciers had an evident retreat trend, the total area of glaciers decreased from 361.69 km2 to 231.17 km2; shrinking at a rate of 36.08%, with average single glacier area decrease 0.14 km2; the total number of the glaciers decreased from 967 to 800. (2) Glaciers in this basin are mainly distributed at elevations of 4300–4400 m, 4400–4500 m and 4500–4600 m; and there are significant regional differences in glaciers distribution and glaciers change. (3) Compared with other western mountain glaciers, glaciers retreat in the Heihe River Basin has a higher rate. (4) Analysis of the six meteorological stations’ annual average temperature and precipitation data from 1960 to 2010 suggests that the mean annual temperature increased significantly and the annual precipitation also showed an increasing trend. It is concluded that glacier shrinkage is closely related with temperature rising, besides, glacier melting caused by rising temperatures greater than glacier mass supply by increased precipitation to some extent.

Contrasting Signals of Glacier Changes in Zanskar Valley, Jammu & Kashmir, India Using Remote Sensing and GIS

The study of advancement and recession of the glaciers in the Himalayas is essential due to their contrasting response towards climatic change. In the present study, Survey of India (SOI) topographical maps of 1962, IRS: LISS-III image of 2001 and LANDSAT-5: TM (Thematic Mapper) image of 2009 were used to analyze the glacier fluctuations in a part of Zanskar valley. The analysis carried out on 212 glaciers indicated decrease of 57 km2 (8 %) of glacier area over many glacier which was partly compensated with area increase by 42 km2 (6 %) in other glaciers, resulting an overall glacier area decrease by only 15 km2 (2 %) from 1962–2001. Due to glacier fragmentation the number of glaciers increased from 212 in 1962 to 238 by 2001. Although majority of glaciers (88 %) exhibited retreat (up to 13 my−1), minor advancement ( 5 km2) located over wider altitudinal range (700 m–1,000 m) whereas smaller glaciers ( 5 km2). During 2001–2009 majority of the glaciers were apparently stable in terms of their area and snout position indicating less impact of climate forcing in parts of Zanskar valley as compared to other parts of the Himalaya.

Glacier shrinkage in the Ebinur lake basin, Tien Shan, China, during the past 40 years

AbstractThe Ebinur lake basin, Tien Shan, China, was described in the early 20th century as the ‘Green Labyrinth’. This relatively productive area supports agriculture and stands in contrast to the regional aridity. Glacier melt runoff is an important source of water for this arid region and has played a significant role in its economic development. However, over the past 40 years the ecology and environment of the region have seriously degenerated due to human activity and climate change. To investigate changes in glacier water supply, measurements from two reference glaciers were performed and used to validate satellite data and historical data for glaciers in the water catchment. Variability in regional glacier total area and volume over the past 40 years was reconstructed from historical documents, aerial photographs and remote-sensing data. Our investigations of 446 glaciers showed that from 1964 to 2004 the total glacier area decreased by 14.7% (0.4% a–1), corresponding to an estimated volume change of 20.5%. During this period, the most dramatic decrease in glacier area corresponded to a rapid rise in temperature. This reduction in glacier area is accelerating and impacting the future sustainability of the region’s water resources.

Glacier and runoff changes in the Rukhk catchment, upper Amu-Darya basin until 2050

A conceptual hydrological model was set up in the upper Panj catchment, the main tributary of Amu-Darya river. After a manual calibration procedure involving model runs with different restrictions, the model reproduced both daily hydrographs of Tanimas river at the Rukhk gauging station (NSE=0.86) and the snow water equivalent of the Irkht station (R2=0.85) in a very satisfactory way. Based on two glacier inventories from the mid-20th century (WGI, World Glacier Inventory) and from 2003 (GLIMS, Global Land Ice Measurements from Space), a simple parameterization scheme based on steady state conditions was applied to infer the ice volumes and glacier areas for these different time periods. Assuming temperature rises of 2.2°C and 3.1°C, which mark the extreme values of regional climate scenarios, the same method was used to extrapolate glacierization to the year 2050. The results show that these temperature rises will reduce the current glacier extent of 431km2 by 36% and 45%, respectively.To assess future changes in water availability, the hydrological model input was modified according to the regional climate scenarios and the resulting glacier changes. The use of an elevation distributed deglacierization pattern is a clear improvement over methods used previously, where the impact on runoff was tested by excluding either the lower half or the total glacier area. The runoff scenarios reveal only a slight reduction in annual runoff, because the glacier area decrease is almost balanced out by enhanced melt rates. However, there is an important seasonal shift of water resources from summer to spring, unfavorably affecting agriculture and irrigation in the lowlands.

Rangeland Management in Sagarmatha (Mount Everest) National Park and Buffer Zone, Nepal: An Ecological Perspective

Abstract Sustainable management of rangeland ecosystems has direct implications for conservation of biological diversity and for the livelihoods of local communities in the Himalayan region in general and the Sagarmatha National Park and Buffer Zone (SNPBZ) in particular. This study aims to analyze the status of rangeland management in the SNPBZ from an ecological perspective. We used multivariate and bivariate analysis and geographic information system techniques to analyze ecological data and land use trends. A significant annual change with a 3.38% decrease in glacier area was observed between 1978 and 1996. We observed 168 plant species in the SNPBZ with a range of 3–17 species per sample plot, where about 67% of plants were found to be palatable for livestock. Our study shows that total available fodder biomass on rangeland in the SNPBZ has not been fully utilized yet, because the total available supply exceeds the present demand under some assumptions: reduction of biomass through grazing causes hig...

Glacier surface-area changes in Sagarmatha national park, Nepal, in the second half of the 20th century, by comparison of historical maps

AbstractWe investigate variations in the surface area of glaciers in Sagarmatha national park, Nepal, during the second half of the 20th century through comparison of a map applicable to the late 1950s with the official map of Nepal in the early 1990s. The comparison reveals a slight overall decrease in glacier area (by 4.9%, from 403.9 to 384.6 km2), a result which, though potentially subject to errors arising from cartographic interpretation, is in line with the area reductions found by other studies of Asian glaciers. We find that the areas of some individual glaciers, the largest situated at higher altitudes, increased during the study period. This was most apparent for the glaciers oriented to the south, with the increase occurring mainly in the glacier accumulation zones while the fronts tended to recede. Meanwhile, the smaller glaciers, situated lower and on steep basins, experienced a reduction. For the smaller glaciers, the sections most affected by change were the accumulation zones, and these glaciers showed a tendency for the front to advance. In this region there is a lack of climate data for high altitudes. Nevertheless, observations from stations situated around the park suggest that, alongside temperature variations which are often considered the primary factor eliciting glacier response, changes in precipitation play a significant role.

Late-20th-century changes in glacier extent in the Caucasus Mountains, Russia/Georgia

AbstractGlaciers occupy an area of ~1600km2 in the Caucasus Mountains. There is widespread evidence of retreat since the Little Ice Age, but an up-to-date regional assessment of glacier change is lacking. In this paper, satellite imagery (Landsat Thematic Mapper and Enhanced Thematic Mapper Plus) is used to obtain the terminus position of 113 glaciers in the central Caucasus in 1985 and 2000, using a manual delineation process based on a false-colour composite (bands 5, 4, 3). Measurements reveal that 94% of the glaciers have retreated, 4% exhibited no overall change and 2% advanced. The mean retreat rate equates to ~8ma–1, and maximum retreat rates approach ~38 m a–1. The largest (>10 km2) glaciers retreated twice as much (~12ma–1) as the smallest (<1 km2) glaciers (~6ma–1), and glaciers at lower elevations generally retreated greater distances. Supraglacial debris cover has increased in association with glacier retreat, and the surface area of bare ice has reduced by ~10% between 1985 and 2000. Results are compared to declassified Corona imagery from the 1960s and 1970s and detailed field measurements and mass-balance data for Djankuat glacier, central Caucasus. It is concluded that the decrease in glacier area appears to be primarily driven by increasing temperatures since the 1970s and especially since the mid-1990s. Continued retreat could lead to considerable changes in glacier runoff, with implications for regional water resources.