Can India and Pakistan overcome decades of mistrust to save the Indus Waters Treaty?

Sixty years ago, David Lilienthal published an article in Collier's Weekly that would prove uncannily prescient. Lilienthal, former chairman of the Tennessee Valley Authority and the U.S. Atomic Energy Commission, had just returned from a visit to India and Pakistan and described two fledgling nations on the verge of another war over Kashmir. He made an unlikely suggestion to defuse tensions: The rivals should agree to manage jointly the Indus River and its main tributaries, some of which flowed through the contested region. Water, he claimed, was a hidden driver of South Asia's most dangerous territorial dispute and might also be the key to resolving it.

While Lilienthal's vision was never fully realized, his article helped sow the seeds of the Indus Waters Treaty, now widely hailed as one of the most successful international water-sharing agreements.

A resolution of the Kashmir conflict seems as elusive today as it did in 1951. Since 1989, armed Kashmiri separatists, some with Pakistani support, have waged a low-grade, off-and-on insurgency against Indian security forces. (Protests last summer against India's heavy-handed rule in the Kashmir Valley roiled the region for several weeks, leading to the deaths of at least 110 Kashmiris, many of them teenage boys.) * Still, without the IWT, Kashmir might have been the source of even wider conflict.

Lilienthal recognized a truth that remains little discussed but as relevant as ever: The struggle for Kashmir was motivated in large part by Pakistan's desperation to control the rivers that flowed through the region. "The starting point should be … to set to rest Pakistan's fears of deprivation and a return to desert," he wrote. The treaty would defuse these tensions at a critical point in the young nations' relations, by clearly spelling out how much water each was entitled to use from the rivers that crossed the western border.

India and Pakistan signed the IWT in 1960, after protracted negotiations facilitated by the World Bank. Before the partition of British India in 1947, each province had jurisdiction to build dams and other infrastructure for electricity and irrigation on the portions of the rivers that flowed through their land; after partition, a series of patchwork agreements left several key issues, such as whether and how much Pakistan should pay India for water and canal maintenance costs, unresolved. The IWT gave "unrestricted use" of the basin's three western rivers (the Indus, the Jhelum, and the Chenab) to Pakistan and the three eastern rivers (the Ravi, the Beas, and the Sutlej) to India. Today, the treaty governs the use of roughly 55 trillion gallons of water per year, which sustains more than 210 million people in the basin.

The IWT has since solidly weathered three Indo-Pakistani wars (including two over Kashmir) and countless flare-ups between the now nuclear-armed neighbors. The Indian and Pakistani members of the treaty-stipulated Indus Waters Commission have met at least once every year, conducting amicable discussions and sharing important hydrological data even when their nations' diplomatic relations have been severed.

Yet the treaty shows signs of strain. In 2005, Pakistan invoked the arbitration provisions of the treaty—for the first time in its history—in response to India's construction of a large hydropower project on the Chenab River. Pakistan has since raised objections to several other power projects on IWT-governed rivers, spurred by its ancient fears that India's storage of water in those dams could threaten its agricultural production. While the treaty's existing provisions have largely been able to contain these disputes, two emerging trends—climate change and Kashmiris' desire for greater control over their water resources—threaten to undermine the very foundations of the treaty as a tool for averting conflict.

The Indus receives at least 30 percent of its flow from the region's shrinking glaciers—more than any other Asian river. As global warming plods on, experts expect increased flows and possibly flooding in the near term as the glacial "water towers" melt. But this spike will be followed by a long, painful tail of perennial scarcity as the glaciers' role in providing water during the dry season becomes greatly diminished.

The Indus basin's overwhelming dependence on snow and ice melt has led Shakil Romshoo, a professor of geophysics and geology at the University of Kashmir in Srinagar, to conclude that global warming will destabilize the IWT within the next few decades. In Kashmir, "the surface runoff … is decreasing," he says. "And on this surface water depends the entire economy of Pakistan."

About 80 percent of Pakistan's cultivated lands are irrigated by water from the Indus system, the lion's share being governed by the IWT. Of the IWT water, more than 70 percent of flows from the Indian state of Jammu and Kashmir. The math gets worse for Pakistan: The country's population is projected to increase by 82 percent, from 184 million in 2010 to 335 million in 2050; per capita water availability was nearly 80 percent lower in 2005 than 1947, plunging from 5,600 cubic meters to 1,200 cubic meters, dangerously close to the 1,000-cubic-meter-per-person-per-year "water scarcity" threshold defined by the widely used Falkenmark index. A growing alarm in Pakistan over this hydrological straitjacket has in recent years spurred jihadi leaders based there to frame their attacks against India as a struggle to secure the rivers that form Pakistan's "lifeline."