Climate change is disrupting Himalayan rivers, policies must keep up

In South Asia, climate change will make water-allocation decisions more complex, and potentially more contentious, across three areas: urban growth, low-carbon electricity, and agriculture.

The latest IPCC report on climate impacts, adaptation and vulnerability brings alarming news to the Himalaya and, by extension, South Asia. It provides further evidence that global warming has melted Himalayan glaciers and changed the hydrological regime in the region (6.1, p. 106)[1], which will have downstream consequences across South Asia. It also focuses on the looming spectre of water scarcity in mountain communities, created by a noxious brew of haphazard development, disruptions to mountain water sources and an increasingly unpredictable water cycle.

It also notes that some Himalayan river basins and communities will have to absorb more heat than the global average. It notes that a global temperature increase of 1.5°C would imply a 2.1°C increase for the Indus, Ganga and Brahmaputra basins; a 2°C global increase would increase temperatures by 2.7°C in these basins (, 41). Thinly resourced governments and already fragile ecological systems will, therefore, have to adapt quicker than the rest of the world.

Against this background of ecological emergency, the report notes the ‘conspicuous’ absence of transboundary scale adaptation policies (, 78). This is the latest reminder, after ICIMOD’s Hindu-Kush Himalayan Assessment Report and the IPCC’s report on oceans and the cryosphere, both in 2019, that the Himalaya’s present an unignorable policy challenge. If mismanaged, it could have consequences for many hundreds of millions of people across Asia. Scientific evidence convincingly points to a clear, common threat to South Asia.

The three main atmospheric circulations over the Hindu Kush Himalaya

Source: ICIMOD (Modified by Bandyopadhyay and Modak (2022) with assistance from Sanjoli Johana Shah.)

A striking feature of the evidence presented in the new IPCC report about South Asia is that, read together, it indicates that water-allocation decisions will – in the long run – become more complex, and potentially more contentious, across three areas: urban growth, low-carbon electricity, and agriculture.

First, it is becoming clearer that rapid mountain urbanisation is an important macro-trend for water demand, with many small mountain towns currently under 100,000 people predicted to become major urban centres in the next decade and consume more water (6.1, 106). The water systems that feed these towns are being disrupted by encroaching urban sprawl while increased rainfall variability leads to scarcity, flooding, and landslides.

Yet simultaneously, it is predicted that lowland populations will grow more reliant on mountain resources by mid-century (CCP 5.3.1., 26). This could set up a tension between large and growing cities in the plains (like Delhi) and water for emerging mountain cities, though these trade-offs will be highly context specific.

Photographic evidence of ice loss in Mt Everest, taken in 1921 and 2007 by George Mallory and David Breashers respectively. Credit: Nepali Times

Second, the report predicts that hydropower capacity will grow, driven partially by growing carbon mitigation efforts (4.5.2, 81). This sets up the second tension between water for energy and other uses, including urban consumption, agriculture, and ecosystem sustenance (or e-flows). Water allocations for energy – usually transported to distant urban centres – have long been politically contentious in the Himalayas, especially where local towns, farms, land and ecology are disturbed.

In recent months, national governments in the region have been paying far more attention to cross-border electricity trade, with India making clear its intentions of being the lynchpin for a global energy grid, a new understanding between India and Nepal on power trade, and the growing likelihood of Nepal becoming a large exporter of hydroelectricity to India and Bangladesh in coming years. Hydropower will play an ever-more important role in South Asian diplomacy, which means local water trade-offs and their consequences will become more visible.

Finally, the report points to agriculture entering a state of flux. It shows that farmers in Bangladesh, India and Nepal have, on the margins, been changing what they choose to grow and dealing with boundary changes in cultivable areas for some crops (, 50). The future of the Himalayan water system thus grows more uncertain: we cannot clearly say which crops will be grown, where and when a few decades from now, which makes strategic long-term water allocations even more complex.

How should policymakers respond to these trends? There are clearly no quick, easy fixes. The best solutions are structural ones that build our ability to respond to a complex problem that will unfold over many decades. As I have argued elsewhere, governments in South Asia should spend more time and effort in funding scientific institutions to understand a new era in Himalayan river management. At its most basic level, this involves funding organisations to decode where the hydrological system is the most vulnerable and presents the most risks, such as which glaciers are melting fastest. But it also involves understanding social trends (in areas like urbanization and migration) and long-term flashpoints in water use between urban and rural populations, between energy, agriculture and food, and between provinces and countries.

Old arguments about integrated river basin management, in which water managers from different political jurisdictions get together to arrive at a science-based plan for how the basin will be developed over many decades, become even more relevant now. Basin-wide coordination never took off in South Asia, but the complexities and consequences of climate change make it an urgency.

Finally, South Asian governments should consider creating a joint pool of money for climate-salient projects in Himalayan rivers (more details here). This would force joint decision-making because the money would have to be held and disbursed by a regional organisation (though what that might be after SAARC is an open question). Funds could be used for anything from flood defences to new transmission lines for electricity trade. The core logic of such a move is that jointly mobilised resources might prompt a wider, systemic view of the basin rather than a narrow focus on sections of these rivers that flow through national boundaries.


Jayanta Bandyopadhyay and Sayanangshu Modak, Governing the ‘Water Tower of Asia’: The Case for a System of Integrated Knowledge for the Hindu Kush Himalaya, March 2022, Observer Research Foundation.

Acknowledgement: I thank Mandakini Chandra and Sharon Mathew, colleagues at CPR, for helping look through the voluminous IPCC WG2 report for South Asian implications.

[1] The numbers within brackets refer to chapter section in the linked IPCC WG2 report and page number.

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