Retreat of Glaciers

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7-Mar-2023: Climate change, glacier topography & morphology control glacial retreat

Change in debris cover plays a critical role in the glacier surface lowering, shrinkage, retreat, and mass balance, according to a recent study. Therefore, these factors need to be accounted for in future studies for a complete understanding of the observed glacier changes and responses.

Despite the importance of the Himalayan glaciation, the knowledge of the glacial dynamics and the factors that influence these dynamics is scanty. Recent studies of Himalayan glaciers indicate wide variability in retreat rate and mass balance in different sectors of the mountain range, primarily linked to the topography and climate of the region. However, variable retreat rates of glaciers and inadequate supporting field data (e.g., mass balance, ice thickness, velocity, etc.) of the Himalayan glaciers make it challenging to develop a coherent picture of climate change impact.

One of the significant characteristics of the Himalayan glaciers is that the glaciers are mainly debris-covered and have been receding since the end of the Little Ice Age. The supraglacial debris on the surface of glaciers is commonly found to have significant control over the rate of loss of mass of ice due to sun, wind, or rain (ablation). It has been observed that the thickness of supraglacial debris significantly alters the glacier response to climate forcing.

A team of scientists from Wadia Institute of Himalayan Geology (WIHG), Dehradun, Uttarakhand, India (An autonomous institute under DST, India), quantitatively evaluated the influence of the debris cover on the loss of ice mass in summer (summer ablation) and on terminus recession of glaciers.

Dr. Manish Mehta and his team studied two glaciers with different characteristics --- the Pensilungpa Glacier (PG) in Suru River and the Durung-Drung Glacier (DDG) in Doda River basins of Zanskar in the Leh district of Ladakh for a comparative study of glacier fluctuations between 1971 and 2019. While a thick debris cover characterizes the PG, the DDG has a thin debris cover, and their comparative analysis helped them trace the influence of various factors on the mass balance process.

They found that the glacier retreat rate is controlled by climate change and the topographic setting and morphology of the glacier. Their comparative study published in the journal Sustainability also confirms the possible influence of factors such as snout geometry, glacier size, elevation range, slope, aspect, debris cover, as well as the presence of supra and proglacial lakes other than the climate in the heterogeneous glacial dynamics and underlined the need to include these in glacial studies.

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7-Mar-2023: Climate change, glacier topography & morphology control glacial retreat

Change in debris cover plays a critical role in the glacier surface lowering, shrinkage, retreat, and mass balance, according to a recent study. Therefore, these factors need to be accounted for in future studies for a complete understanding of the observed glacier changes and responses.

Despite the importance of the Himalayan glaciation, the knowledge of the glacial dynamics and the factors that influence these dynamics is scanty. Recent studies of Himalayan glaciers indicate wide variability in retreat rate and mass balance in different sectors of the mountain range, primarily linked to the topography and climate of the region. However, variable retreat rates of glaciers and inadequate supporting field data (e.g., mass balance, ice thickness, velocity, etc.) of the Himalayan glaciers make it challenging to develop a coherent picture of climate change impact.

One of the significant characteristics of the Himalayan glaciers is that the glaciers are mainly debris-covered and have been receding since the end of the Little Ice Age. The supraglacial debris on the surface of glaciers is commonly found to have significant control over the rate of loss of mass of ice due to sun, wind, or rain (ablation). It has been observed that the thickness of supraglacial debris significantly alters the glacier response to climate forcing.

A team of scientists from Wadia Institute of Himalayan Geology (WIHG), Dehradun, Uttarakhand, India (An autonomous institute under DST, India), quantitatively evaluated the influence of the debris cover on the loss of ice mass in summer (summer ablation) and on terminus recession of glaciers.

Dr. Manish Mehta and his team studied two glaciers with different characteristics --- the Pensilungpa Glacier (PG) in Suru River and the Durung-Drung Glacier (DDG) in Doda River basins of Zanskar in the Leh district of Ladakh for a comparative study of glacier fluctuations between 1971 and 2019. While a thick debris cover characterizes the PG, the DDG has a thin debris cover, and their comparative analysis helped them trace the influence of various factors on the mass balance process.

They found that the glacier retreat rate is controlled by climate change and the topographic setting and morphology of the glacier. Their comparative study published in the journal Sustainability also confirms the possible influence of factors such as snout geometry, glacier size, elevation range, slope, aspect, debris cover, as well as the presence of supra and proglacial lakes other than the climate in the heterogeneous glacial dynamics and underlined the need to include these in glacial studies.

2022

9-Feb-2022: Rapid melting of Himalayan Glaciers

The government is aware of and maintains data regarding melting of Himalayan glaciers. Various Indian institutes/universities/organizations (Geological Survey of India (GSI), Wadia Institute of Himalayan Geology (WIHG), National Centre for Polar and Ocean Research (NCPOR), National Institute of Hydrology (NIH), Space Application Centre (SAC), Indian Institute of Science (IISc) etc.) monitor Himalayan glaciers for various scientific studies including glacier melting and have reported accelerated heterogeneous mass loss in Himalayan glaciers. The mean retreat rate of Hindu Kush Himalayan glaciers is 14.9 ± 15.1 meter/annum (m/a); which varies from 12.7 ± 13.2 m/a in Indus, 15.5 ± 14.4 m/a in Ganga and 20.2 ± 19.7 m/a in Brahmaputra river basins. However, glaciers in the Karakoram region have shown comparatively minor length change (-1.37 ± 22.8 m/a), indicating the stable condition.

The government is aware of the study conducted by the University of Leeds, regarding the rapid melting of Himalayan glaciers, published in Journal Nature Scientific Reports in 2021.

The University of Leeds reconstructed the size and ice surfaces of 14,798 Himalayan glaciers during the Little Ice Age, which was 400-700 years ago. The study concludes that the Himalayan glaciers have lost ice ten times more quickly over the last few decades than on average since the last major glacier expansion. In the last 400 to 700 years, the glaciers have lost around 40 per cent area – shrinking from 28,000 square kilometer (km2) to around 19,600 km2.

The Ministry of Earth Sciences (MoES) through its autonomous institute NCPOR is monitoring six glaciers in the Chandra basin (2437km2 area) in western Himalaya since 2013.The rate of annual mass balance (melting) ranging from -0.3±0.06 meter water equivalent per year (m w.e.y-1)to -1.13±0.22m w.e.y-1 during 2013-2020. Similarly, a mean thinning of ~50±11 m with a mean annual mass loss of –1.09±​ 0.32 mw.e. a–1 was observed for the Baspa basin during 2000-2011.

GSI has taken up project on melting of glaciers in Beas Basin, South Chenab basin and Chandra Basin in Himachal Pradesh, Shyok and Nubra basin in Ladakh during Field Season 2021-22.

Department of Science and Technology (DST) has supported various R&D projects for studying Himalayan Glaciers under the National Mission for Sustaining Himalayan Ecosystem (NMSHE) and National Mission on Strategic Knowledge for Climate Change (NMSKCC). The mass balance studies conducted for some Himalayan glaciers by University of Kashmir, Sikkim University, IISc and WIHG, revealed that majority of Himalayan glaciers are melting or retreating at varying rates.

WIHG is monitoring a few glaciers in Uttarakhand, which reveal that the Dokriani Glacier in the Bhagirathi basin is retreating at 15-20 m/a since 1995, whereas Chorabari Glacier in the Mandakini basin is retreating at 9-11 m/a during 2003-2017. WIHG is also monitoring Durung-Drung and Pensilungpa glaciers in Suru basin, Ladakh, which are retreating at 12 m/a and ~ 5.6 m/a, respectively.

NIH has been conducting several studies for the assessment of runoff from melting of glaciers at catchment and basin scales across Himalaya.

Recent publication suggests that at regional scale, mass loss rate varies between − 0.41 ± 0.11 m.w.e.y− 1 in the eastern, − 0.58 ± 0.01 m.w.e.y− 1 in the central, − 0.55 ± 0.37 m.w.e.y−1 in the western Himalaya and − 0.10 ± 0.07 m.w.e.y− 1 in Karakoram region in the last decade.

Melting glaciers have significant impact on water resources of Himalayan rivers due to change in glacier basin hydrology, downstream water budget, impact on hydropower plants due to variation in discharge, flash flood and sedimentation. They also increase in risk related to glacier hazards due to enhanced number and volume of glacier lakes, accelerated flash flood and Glacial Lake Outburst Floods (GLOFs), impact on agro practices in high Himalayan region etc.

NCPOR has utilized Rs. 11.88 crore during last five years for Himalayan Glacier research. Rs. 15.44 crore has been utilized by DST and Rs. 1.1 crore by GSI during the last five years.

2021

6-Aug-2021: Increasing Temperature and Low Winter Precipitation are Causing Retreat of Glaciers in Zanskar Valley, Ladakh

The Pensilungpa Glacier (PG), located in Zanskar, Ladakh, is retreating, and a recent study has attributed the retreat to an increase in the temperature and decrease in precipitation during winters. Since 2015, the Wadia Institute of Himalayan Geology (WIHG), Dehradun, an autonomous institute under the Department of Science & Technology, GoI, has been working on various aspects on glaciology, i.e., glacier health (mass balance) monitoring, dynamics; discharge, past climatic conditions, speculation for future climate change and its impact on glaciers in this region. A team of scientists from the institute ventured to study the less explored region of the Himalayas, i.e., Zanskar, Ladakh.

Based on field observations for glaciers mass balance collected via stake networking  (stake made of bamboo, is installed (insert) on the glacier surface using the steam drill for mass balance measurement) over the glacier surface since 2016-2019, they assessed the impact of climate change through the lens of past and present response of the Pensilungpa Glacier (PG), Zanskar Himalaya, Ladakh. Field observations for the last 4 years (2015–2019) showed that the glacier is now retreating by at an average rate of 6.7 ± 3 m a−1. In the study published in the journal Regional Environmental Change, the team attributes the observed recessional trends of the Pensilungpa Glacier to an increase in the temperature and decrease in precipitation during winters.

The study also points at the significant influence of debris cover on the mass balance and retreat of the glacier's endpoint, especially in summer. Furthermore, the mass balance data for the last 3 years (2016–2019) showed a negative trend with a small accumulation area ratio.

The study also suggests that due to continuous rise in the air temperature in line with the global trend, the melting would increase, and it is possible that the precipitation of summer periods at higher altitudes will change from snow to rain, and that may influence the summer and winter pattern.