18-Jul-2022: Scientists solve the curious case of Himalayan glaciers resisting global warming

Researchers have taken a significant leap toward solving the mystery of why few pockets of glaciers in the Karakoram Range are resisting glacial melt due to global warming, defying the trend of glaciers losing mass across the globe, with the Himalayas being no exception. They have attributed this phenomenon called ‘Karakoram Anomaly’ to recent revival of western disturbances (WDs). 

Himalayan glaciers are of paramount importance in the Indian context, especially for the millions of dwellers living downstream who rely on these perennial rivers for their day-to-day water needs. They are fast receding under the impacts of global warming, and stifling stress on the water resources is inevitable in the coming decades. In contrast, the glaciers of central Karakoram have surprisingly remained unchanged or slightly increased in the last few decades. This phenomenon has been puzzling glaciologists and providing climate deniers with a very rare straw to clutch at.

Dr. Pankaj Kumar, Associate Professor at the Indian Institute of Science Education and Research (IISER) Bhopal, found this peculiar because the behaviour seems to be confined to a very small region, with only Kunlun ranges being another example of showing similar trends in the whole of Himalaya.

A recent study conducted under his supervision has postulated a new theory to explain this defiance of the impacts of global warming in certain pockets as opposed to other glaciers of the region.

In a paper published in the American Meteorological Society’s Journal of Climate, his group claimed that the recent revival of western disturbance has been instrumental in triggering and sustaining the Karakoram Anomaly since the advent of the 21st century. The study was supported by the Climate Change Programme of the Department of Science and Technology.

It is for the first time that a study brought forth the importance that enhanced WD-precipitation input during the accumulation period plays in modulating regional climatic anomaly. 

Aaquib Javed, a Ph.D. student of Dr. Kumar and lead author of the study, said, “WDs are the primary feeder of snowfall for the region during winters. Our study suggests they constitute about around 65% of the total seasonal snowfall volume and about 53% of the total seasonal precipitation, easily making them the most important source of moisture. The precipitation intensity of WDs impacting Karakoram has increased by around 10% in last two decades, which only enhances their role in sustaining the regional anomaly.”

The group applied a tracking algorithm (developed at the University of Reading) to three separate global reanalysis datasets to track and compile a comprehensive catalog of WDs impinging the Karakoram-Himalayan region in the last four decades. The analysis for the tracks passing through the Karakoram reveals the role of snowfall as a crucial factor in mass balance estimations.

While previous studies have highlighted the role of temperature in establishing and sustaining the anomaly over the years, it is for the first time that the impact of precipitation in feeding the anomaly has been highlighted. The researchers have also quantified the impact of precipitation in feeding the anomaly.

Calculations by the scientists reveal that contribution of WDs in terms of snowfall volume over the core glacier regions of Karakoram have increased by about 27% in recent decades, while precipitation received from non-WD sources have significantly decreased by around 17%, further strengthening their claims.

“The anomaly provides a very bleak but nonetheless a ray of hope towards delaying the inevitable. After recognising the importance of WDs in controlling the anomaly, their future behaviour might very well decide the fate of Himalayan glaciers as well,” Dr. Kumar pointed out.

6-Apr-2022: Melting of Himalayan Glaciers

The government has carried out studies and maintains data regarding melting of glaciers in the Indian Himalayan region.

Several 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 conditions.

Ministry of Earth Sciences (MoES) through its center National Centre for Polar and Ocean Research (NCPOR) has been monitoring six glaciers in the Chandra basin (2437km2 area) in western Himalaya since 2013. A state-of-the-art field research station ‘Himansh’ established in Chandra basin and operational since 2016 for conducting field experiment and expeditions to glaciers. 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±0.22mw.e.y-1 during 2013-2020 is observed. 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 conducted studies on melting of the glaciers by assessment of mass balance on nine glaciers and also carried out monitoring the recession/ advancement of 76 glaciers in Himalayan region. Majority of Himalayan glaciers are observed melting/ retreating at varying rates in different regions.

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.

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.

Divecha Centre for Climate Change, IISc Bangalore under the aegis of DST has investigated Sutlej River basin and reported that there will be an increase in glacier melt contribution until the middle of the century and then there will be a decline. Numerous small glaciers located in the low altitude region of the Sutlej basin indicate significant loss in the area till the middle of the century, creating a scarcity of water during the dry summer season.

The melting of glaciers is a natural process and cannot be controlled. However, melting of glaciers does increase the risks related to glacier hazards.  Various Indian institutes, organizations and universities are monitoring the Himalayan glaciers using remote sensing data at large scale to assess the calamities associated with the melting. Recently, the National Disaster Management Authority (NDMA) in collaboration with the Swiss Development Corporation (SDC), prepared the Guidelines, Compendium and Summary for Policy Makers on the management of the Glacial Lake Outburst Floods (GLOFs).

31-Mar-2022: Lesser snowfall and greater rainfall in the Himalayas in the last few years

Union Minister of State (Independent Charge) Science & Technology; Minister of State (Independent Charge) Earth Sciences; MoS PMO, Personnel, Public Grievances, Pensions, Atomic Energy and Space, Dr Jitendra Singh said that recent study has shown that there have been lesser snowfall and greater rainfall in the Himalayas in the last few years.

In a written reply to a question in the Rajya Sabha today, Dr Jitendra Singh said, Studies from the National Centre for Polar and Ocean Research (NCPOR), under the Ministry of Earth Sciences (MoES) show that over four glacierized basins (Chandra, Bhaga, Miyar and Parvati) of western Himalaya show an overall decreasing trend of precipitation during 1979-2018. However, this trend is not monotonic, with higher (23.9%) reduction in precipitation during accumulation (winter) season than ablation (summer) season (15.4%). Further, studies indicated that while the snowfall is decreasing, the liquid precipitation (rainfall) has been increasing over these glacierized basins particularly during the accumulation months.

The Minister said that increased rainfall in place of snowfall during spring would lead to early exposure of glaciers, enhanced glacier melt rate as well as could accelerate the frequency and magnitude of avalanches and flash floods. He said, avalanches, landslides are natural phenomenon that cannot be prevented. However, early warning and forecasts for rainfall and snowfall are being issued by various institutions under MoES and Ministry of Defence.

23-Nov-2021: Change in course of Himalayan glacier can help to understand the glacial-tectonic interaction

Indian researchers studying an unnamed glacier in one of the less explored region in the upper Kali Ganga valley, Pithoragarh district, Uttarakhand, India, have reported that the glacier had abruptly changed its main course. It is for the first time that such change in course has been reported from a Himalayan glacier, and the researchers have attributed this to the accumulated influence of both climate and tectonics.

The abnormal behaviour of this unnamed glacier clearly suggests that not only is climate a controlling factor, but tectonics also plays an important role in glacial catchments. The recent disaster in Rishiganga is a latest example which suggests that the rock mass on which the glacier was sitting gradually became fragile (due to weathering, percolation of meltwater in joints, crevasses, freezing and thawing, snowfall, overloading, and gradually operating tectonic forces forcing rocks to mechanical disintegration) with due course of time and detached from the source rock. It clearly suggests that the Himalaya is an active mountain range and highly fragile where tectonics and climate play a critical role.

A team of scientists from Wadia Institute of Himalayan Geology (WIHG), Dehradun, Uttarakhand, an autonomous institute under the Department of Science & Technology, Government of India, found that the unnamed NE moving glacier had been abruptly truncated and forced to move towards SE.

Based on remote sensing and an old survey map, the study assessed that the glacier had been affected by active fault and climate change. Tectonic activity and change in climatic conditions had changed the course and morphology of this glacier. An active fault produced a fault scarp that measures about 250 m in height with a northerly dip. The fault trace is 6.2 km in length and trends towards NW-SE. This study based on the tectonically sculptured unique glacier landform was published in the ‘Geoscience Journal’.

The WIHG team observed that the 5 km long unnamed glacier, which covered around 4 km2 area in Kuthi Yankti valley (Tributary of Kali River), has abruptly changed its main course. It moved, truncated, and ultimately merged with the adjacent glacier named Sumzurkchanki as a result of tectonic forcing during the time between Last Glacial Maxima (19-24 ka) and Holocene. It is one of the unique behaviours of the glacier, and no such observation has so far been reported on this type of glacier kinematics.

The study indicates that climate is not the only factor that triggers disasters in the Himalaya, which is an active mountain range, but tectonics also plays an important role in glacial catchments.

The study opens the doors for a new approach in glacier studies, particularly focused on the course change and evolution of new landforms formed by glacial-tectonic interplay.