Neither nation can pull out of the treaty unilaterally as there is no exit clause, according to Sheikh, who said the countries “must agree over practical solutions”.

With Pakistan due to hold a general election this year, still recovering from devastating floods, and battling a financial crisis and an insurgency by Tehreek-e-Taliban Pakistan militants, “there is limited bandwidth to get involved in water treaty talks”, said Delhi-based Omair Ahmad, an international relations analyst who has studied the treaty.

Ahmad Rafay Alam, a Pakistani environmental lawyer and activist, said reopening the treaty is unlikely given Pakistan’s multiplying concerns and the two nations’ mutual suspicions.

“But I understand (Pakistan’s) Ministry of Foreign Affairs is preparing a reply,” he said, adding that it was unlikely to be public as the government did not publish such documents.

CLIMATE IMPACTS LACKING

Pakistan’s Institute of Policy Studies said in 2017 that the Indus Waters Treaty now needs to be considered in light of other international agreements such as the 2015 Paris Agreement to limit global warming, which Pakistan and India have both signed.

“There is very little in the treaty for the best possible use of the water resources of the river system, especially when we are in an era of climate change,” said Ashok Swain, a professor at Sweden’s Uppsala University and UN cultural agency UNESCO’s chair of international water cooperation.

Besides above-ground water flows, the Indus Basin’s underground water storage is the world’s second most “overstressed”, with almost no new water flowing into storage to offset extraction, a 2015 study in the journal Water Resources Research found.

The Kathmandu-based International Centre for Integrated Mountain Development warned in 2019 that even if global warming can be limited to 1.5 degrees Celsius, glaciers that feed the Indus Basin are projected to lose a third of their total volume by the end of the century.

It is not just academics and analysts who have raised concerns about the water treaty’s challenges in dealing with climate change impacts.

In 2021, an Indian parliamentary standing committee on water resources urged the government to initiate a process for renegotiating the treaty with Pakistan as “present-day pressing issues such as climate change, global warming and environmental impacts … were not taken into account”.

Yet India has yet to cite the climate or environment in any discussions around the treaty and that is unlikely to change, said Himanshu Thakkar, coordinator of the New Delhi-based South Asia Network of Dams, Rivers and People, a research group.

“The way it has panned out … with all the hostilities and lack of trust from both sides, there is little chance of an agreement on dispute resolution bilaterally,” he added.