The world’s biggest iceberg — the “Megaberg” known as A23a — has started disintegrating in the waters of the Southern Ocean, after drifting for nearly 40 years since breaking off from Antarctica. Such events are signals of the accelerating cryosphere crisis.
The year 2025 has been declared the International Year of Glaciers’ Preservation. The impact of climate change is most visibly felt through glacier retreat and water flows. Discussions at COP27 (November 2022) reported that many countries are experiencing accelerated glacier melting. For example, more than 1,000 of Tajikistan’s 14,000 glaciers have completely disappeared. The total volume of Tajikistan’s glaciers–accounting for more than 60% of the water resources in the Central Asian Region–has decreased by almost one-third.
Glaciers in the Himalayas (India) have been exhibiting continuous retreat: East Ranthong Glacier (15.1 meter/year), Gangotri Glacier (19.9±0.3 meter/year), Samudratapu Glacier (15.1 meter/year), and Dokriani Glacier (16.6 meter/year).
The retreat of Hindu Kush Himalayan (HKH) glaciers is estimated at 14.9±15.1 meter/year on average, varying across river basins: 12.7±13.2 meter/year in the Indus, 15.5±14.4 meter/year in the Ganga, and 20.2 ± 19.7 meter/year in the Brahmaputra. Both the number of retreating glaciers and the extent of retreat are reported to be the highest in the western Himalayas, while the eastern Himalayan basin is relatively less affected. Continuous glacier retreat could lead to the formation and expansion of glacial lakes, posing serious risks to downstream communities and infrastructure through glacial lake outburst floods (GLOFs).
Glacier melting is influenced by climatic factors (temperature, rainfall, snowfall) as well as non-climatic factors such as geography and topography. Nearly 800 million people living in the Indus, Ganga, and Brahmaputra river basins are dependent on Himalayan glaciers, which provide water supplies during the lean summer season when precipitation is scarce and demand is high. Together, the Indus, Ganga, and Brahmaputra contribute close to 50% of India’s utilizable surface water resources. Contributions from snow and ice melt to the total annual river discharge are about 60%, 9%, and 21% for the Indus, Ganga, and Brahmaputra basins, respectively.
In the Brahmaputra and Ganga river basins, rainfall makes a significant contribution, but it is largely limited to 30–40 days of the monsoon season. Consequently, snow and glacier melt play a disproportionately high role in sustaining these rivers. While glacier melting is a natural process, its current accelerated rate is mainly caused by global warming and climate change. This trend cannot be slowed unless the drivers of global warming and climate change are effectively addressed or controlled. There is also a strong link between the Himalayan glaciers and India’s energy security: 33% of our country’s thermal capacity and 52% of its hydropower depend on rivers originating in the Himalayas.
The Hindu Kush Himalaya (HKH) region–commonly referred to as the ‘Third Pole’–has the largest concentration of snow and glaciers outside the polar regions. Stretching from Afghanistan in the west to Myanmar in the east, it is the source of 10 major rivers including the Indus, Ganga, and Brahmaputra. The Indian Himalayan Region, part of this larger HKH system, spans across 13 Indian states and Union Territories (UTs), and supports approximately 50 million people. There are about 9,575 glaciers in the Indian Himalayas across the Indus, Ganga, and Brahmaputra basins. However, about 90% of glaciers are small–less than 5 sq km in area and many even below 1 sq km. Recent flash floods in Parichu River and other rivers in Uttarakhand provide conclusive evidence of the growing vulnerability of dam projects in the Himalayas.
Agenda for Action
There is a need to:
Establish an integrated national cryosphere information system as a long-term mechanism, linked with global cryosphere monitoring systems to develop standardized approaches for tracking changes. Advancing research in cryosphere monitoring is critical.
Institutionalize regular reporting on glacier and snow changes at scales relevant to local, national, regional, and global needs. Assessments of short-, medium-, and long-term water availability under current and future deglaciated conditions should be prioritized.
Integrate glacier preservation into climate strategies, water management policies, and disaster risk-reduction plans. Partnerships with international organizations, the private sector, academia, and NGOs are essential to leverage expertise, resources, and funding.
Raise awareness at all levels about the impacts of glacier change on downstream communities, and ecosystems. Urgent adoption of adaptation strategies is needed.
Ensure hydropower projects conduct comprehensive climate vulnerability assessments. Integrated river basin management must be implemented to rejuvenate and sustain water resources.
Although India’s water storage capacity has substantially improved since independence, it remains rather low compared to international standards. For example, India’s per capita storage capacity is about 209 cubic meters (CM), compared to USA (2,193 CM), Brazil (2,632 CM), and China (416 CM). To address increasing variability in water resources due to climate change, substantial additional storage capacity must be developed.
Bibliography
Tayal, Shresth. (2019). Climate Change Impacts on Himalayan Glaciers and Implications on Energy Security of India, TERI Discussion Paper. New Delhi: The Energy and Resources Institute; link: https://www.teriin.org/sites/default/files/2019-11/cc-impact-himalayan-glacier.pdf
Government of India, Ministry of Earth Sciences. (2023, July 20). Steps to preserve the Himalayan glaciers: Rajya Sabha Unstarred Question No. 32. Retrieved from https://moes.gov.in/sites/default/files/RS-in-32-27-07-2023.pdf