A new report released on the occasion of the first-ever World Day for Glaciers has indicated that glaciers in the Himalayas shrunk between 5 and 21 per cent from 2000-2023 due to human-induced climate change.
March 21 is the World Day for Glaciers as part of 2025 being the International Year of Glacier’s Preservation declared so by the United Nations.
The report says that many of the rivers that flow from the Himalayas will be disrupted as glaciers continue to melt, and the changes will likely be largest in the dry season.
High Mountain Asia has the biggest area of ice outside the polar regions, leading to it being named the ‘Third Pole’. Of the nearly 100,000 glaciers containing approximately 7,000 cubic kilometres of ice in this region, about half are found in the Himalayan and Karakoram mountains. Ten of Asia’s largest rivers—including the Indus, the Brahmaputra, and the Ganga—start in the Hindu-Kush Himalayas. Together, these rivers provide water for a quarter of the world’s population.
Seasonal glacial meltwater alone from this region provides enough water to meet the basic needs of around 220 million people, or most of the annual municipal and industrial needs of Pakistan, Afghanistan, Tajikistan, Turkmenistan, Uzbekistan, and Kyrgyzstan combined.
Glacier meltwater contributes up to 65 per cent of the Brahmaputra and 70 per cent of the flow of the Ganga during drought, and 41 per cent of the total annual runoff of the Upper Indus.
As glaciers melt, flooding has increased in recent decades, especially in the Upper Indus and Ganges basins. Flooding is predicted to worsen more with higher emissions scenarios.
The combination of more extreme rainfall and glacier melt could increase the peak flow of a 50-year return flood (average time interval between occurrences of a flood event of a certain magnitude or higher) by about 51 per cent in the Upper Indus Basin, 80 per cent in the Upper Brahmaputra Basin and 108 per cent for the Upper Ganges Basin by the end of the century if emissions are high.
Glacial meltwater from the Himalayas will peak in the next few decades. It will then decline, leaving some of the world’s most populous places, and largest systems of irrigated agriculture, far more vulnerable to floods and droughts. In northern India, there will be lower river flows, especially in the dry season. After mid-century; this will impact energy, water, and food security.
This will also impact power supply as 52 per cent of hydroelectric power in India is generated on rivers which start in the Himalayas.
The report also highlights that five of the past six years have seen the most rapid glacier retreat on record. Glaciers in many regions will not survive the 21st century, while meltwater from them is currently the second largest contributor to sea-level rise.
