Climate crisis exposes flaws in Indus pact as some rivers may dry up quicker

Hindustan Times

03-05-2025

The Indus river basin, among the most vulnerable regions globally to climate change, is experiencing dramatically different impacts across its eastern and western tributaries, recent scientific research has shown, potentially making previous agreements on sharing of waters between India and Pakistan irrelevant.
Approximately 50-60% of the Indus basin's annual water discharge comes from snow and glacial melt, with recent research revealing stark differences in how climate change affects various parts of the basin.
Recent papers have now found that western tributaries like the Indus, Kabul, Jhelum and Chenab are fed by glaciers with more stored water, while eastern tributaries including the Beas, Ravi, and Sutlej draw from significantly lower glacier stored water reserves. Crucially, the pace of glacial melt is higher in the Western Himalayas that feed eastern rivers compared to the Upper Indus basin. This east-west disparity challenges the fundamental assumptions of the 1960 Indus Waters Treaty, which allocated rivers based on historically stable flow patterns.
'From an entirely scientific perspective, the water sharing practices need to be revisited in view of climate change that can alter flow and increase disasters downstream,' said Anil Kulkarni, distinguished visiting scientist and glaciologist from Indian Institute of Science (IISc).
The issue has gained renewed significance after India put the Indus Waters Treaty in abeyance following a terrorist attack in Kashmir on April 22. Under the treaty, India exclusively uses water from the eastern rivers (Ravi, Beas and Sutlej), while Pakistan has rights to the western rivers (Indus, Jhelum and Chenab), which hold 80% of the basin's water.
A 2023 study titled 'Differential loss of glacier stored water in the Indus River basin', published in Current Science by researchers from the Birla Institute of Technology and Science, Indian Institute of Science, and Indian Space Research Organisation, used a combination of models to assess glacier stored water and mass loss. Their research found significant spatial variability in stored water and mass loss across the basin.
'Except for the upper Indus basin, all other sub-basins show a substantial rate of glacier mass loss, which can affect future water availability,' the paper concluded, suggesting the need to reconsider water-sharing practices.
The upper Indus basin, allocated to Pakistan under the treaty, lies mainly in the Karakoram region, which exhibits the 'Karakoram anomaly' -- a surprising stability of glaciers despite the global trend of retreat.
'Latest projections indicate that glacial melt may begin in the upper Indus basin only in the 2050s. But other rivers and catchments will see far greater and faster glacial loss before then,' explained Kulkarni.
'The understanding is that water flow and hence availability will increase for the rest of the rivers (except Indus) now and then fall drastically around mid-century following extensive loss of glaciers.'
A 2019 science policy brief by IISc's Divecha Centre for Climate Change predicted that due to high negative glacier mass balance and area loss, discharge for the eastern rivers (India's allocation) is expected to peak early in 2030, compared to 2070 for the western basin.
According to research by the Kathmandu-based International Centre for Integrated Mountain Development (ICIMOD), glacial mass balance rates vary significantly: Western Himalayan glaciers at -0.36 meter water equivalent per year since 2010, Karakoram at -0.09, and Eastern Himalayas at -0.51.
These changes carry serious implications for the basin's more than 300 million residents, who already face increased uncertainty due to rising temperatures, extended dry periods, floods, unseasonal rain, and glacial lake outburst floods (GLOFs). Water demand is also expected to rise as climate impacts become more pronounced, further straining resources.
'So far, there have been about 150 GLOF events recorded in Pakistan and 60 in India - mostly after the 1950s,' said Sher Muhammad, remote sensing Specialist at ICIMOD. 'The recorded fatalities in India due to these GLOFs are over6,000, compared to 11in Pakistan.'
Pakistan experienced devastating floods in 2022 following extreme summer heat, resulting in 1,100 deaths and affecting 33 million people.
The Indus basin spans 1.1 million square kilometres across four countries: 52% in Pakistan, 33% in India, 8% in China, and 6% in Afghanistan. From 1991 to 2015, the mean temperature across the Western Himalaya and Karakoram regions rose by 0.65°C, according to monitoring by the Indian Institute of Science.
Future projections suggest that even if global warming is limited to 1.5°C, warming in the Hindu Kush Himalaya will be higher, with a 4–25% increase in monsoon rainfall expected long-term.
Himanshu Thakkar of South Asia Network on Dams, Rivers and People emphasised that 'contribution from glaciers and snow to western rivers is higher compared to eastern rivers. Monsoonal flow also contributes to eastern rivers. Apart from conflict and geopolitics, these rivers are a source of life to people.'