Geopolitical analysts warned a generation ago that “the world’s future wars will be fought over water, not oil.”Former World Bank Vice President Ismail Serageldin warned in the mid-1990s that “the wars of the new millennium will be fought over water.”

Thirty years later, that admonition seems ever more relevant.

In April 2025, India said it was putting the Indus Waters Treaty (IWT) in abeyance — after the Pahalgam incident — sparking fresh fears about the viability of one of the world’s longest-standing transboundary water-sharing agreements.

The deal, mediated by the World Bank and signed in September 1960, has withstood three wars and decades of political antagonism between the two nuclear-armed neighbours, making it one of the most enduring international agreements controlling shared water resources.

Indus Water Treaty

The Indus Waters Treaty governs the use of rivers flowing through the Indus basin between India and Pakistan.

The three western rivers, the Indus, Jhelum and Chenab, are given mainly to Pakistan, and the three eastern rivers, the Ravi, Beas and Sutlej, to India, with stated rights and obligations for each country over the shared river system.

The treaty means far more to Pakistan than a diplomatic agreement.

The Indus river system is the country’s main source of irrigation, supplying water for agriculture, food security, the textile industry and a large share of energy generation.

Any extended disruption of these water supplies would have enormous economic, environmental and humanitarian effects.

Issue of national security

The problem has always been framed in terms of national security for Pakistan.

After a meeting of the National Security Committee on April 24, 2025, the Foreign Office said the Indus Waters Treaty was “a binding international agreement brokered by the World Bank and contains no provision for unilateral suspension” .

The statement further added:
““Water is a vital national interest of Pakistan and the lifeline of its 240 million people and its availability will be safeguarded at all costs.”

It also cautioned:
“Any effort to interrupt or divert the flow of water of Pakistan under the Indus Waters Treaty and the invasion of the rights of lower riparian will be viewed as an Act of War and countered with full force across the entire spectrum of National Power.”

The remarks illustrate how disagreements over shared water might spark larger military escalation between the two nuclear-armed states, with implications far beyond South Asia.

The danger of nuclear

Scientific studies demonstrate that the effects of a big nuclear war between India and Pakistan will be felt beyond the region.

In a study published in ‘Science Advances’, researchers imagined a scenario where India fires 100 strategic nuclear weapons on urban centres and Pakistan answers with 150.

The report anticipates immediate fatalities of between 50 million and 125 million.

Nuclear explosions would have caused firestorms that would have sent 16 to 36 teragrams of black carbon into the sky . This would have reduced global sunlight by 20-35% , lowered average world temperatures by 2-5°C , reduced precipitation by 15-30% , and disrupted agricultural production for over a decade .

Such climate impacts could lead to widespread crop failures, catastrophic famine and millions of fatalities globally, the researchers find.