Greater Noida (World Desk): The United Nations will celebrate first ever World Day for Glaciers on March 21, 2025. On this occasion, the UNESCO will also release a report on the role of glaciers in water security.
According to UN’s World Water Development Report 2025, In High Mountain Asia, glaciers shrunk between 5 and 21% from 2000-2023 due to human-induced climate change, with some of the biggest declines seen in the Himalayas. 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. Glacier meltwater contributes up to 65% of the Brahmaputra and 70% of the flow of the Ganges during drought, and 41% of the total annual runoff of the Upper Indus.
The United Nations said in a press release that 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 by about 51% in the Upper Indus Basin, 80% in the Upper Brahmaputra Basin and 108% for the Upper Ganges Basin by the end of the century if emissions are high.
The UN further says, “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. 52% of hydroelectric power in India is generated on rivers which start in the Himalayas.”
The UN report also mentions, “The Himalayan region is one of the most vulnerable in the world to glacier-related disasters. Globally, 15 million people are vulnerable to potential glacial lake outburst floods, with more than 3 million of these in India alone. The number and size of glacial lakes is growing as the climate has warmed and glaciers have started to melt, and the situation will worsen without cuts to fossil fuel use. In High Mountain Asia, hazards from glacial lake outburst floods are set to triple by 2100.”
“In 2013, unusually rapid snow melt, the Chorabari glacier melting, and intense rain combined to cause a glacial lake outburst flood in Kedarnath (Indian Himalayas). 6,000 people were killed, 30 hydropower plants were destroyed or severely damaged, and roads and bridges were destroyed. In 2023, a catastrophic glacial lake outburst flood in Sikkim, India, caused the Teesta III hydroelectric dam to collapse. More than 100 people were missing or confirmed dead, and thousands were affected. The South Lhonak glacier that triggered this flood has been shrinking rapidly in recent decades as a result of climate change, and scientists said that the glacial flood was “significantly exacerbated by the effects of climate warming”. Glacier retreat also increases the risks of landslides, rockfalls and debris falls in high mountain areas,” the UN report added.
