From near Mount Kangrinboqe in Tibet rise four major rivers, which stretch east and west across the Himalaya and down to the sea like the limbs of a venerable water goddess. Where these rivers flow, they define civilizations and nations: Tibet, Pakistan, northern India, Nepal, Bangladesh. How their water is spent has long depended on the people living downstream. How the rivers are replenished depends on two things: monsoon rains and glacial ice melt. Both phenomena, for millennia the preserve of the gods, are now in the hands of humans too. (See why these 10 rivers are vital to Asia’s survival.)
Rivers emerging from the eastern Himalaya, like the Brahmaputra, are mostly fed by the summer monsoon; their flow may well increase as a warming climate puts more moisture in the atmosphere. But most water in the Indus, which flows west from Mount Kangrinboqe, comes from the snows and glaciers of the Himalaya, the Karakoram, and the Hindu Kush. Glaciers especially are “water towers”: They store winter snowfall as ice, high in the mountains, and they surrender it as meltwater in spring and summer. In this way, they provide a steady flow that nourishes humans and ecosystems. Downstream, in the plains of Pakistan and northern India, the world’s most extensive system of irrigated agriculture depends on the Indus. The glaciers that feed it are a lifeline for some 270 million people. (The Indus River is a lifeline for millions. This map shows the threats it faces.)
Most of those glaciers are now shrinking. At first, that will increase the flow in the Indus. But if temperatures rise as predicted, and the glaciers continue to melt back, the Indus will reach “peak water” by 2050. After that, the flow will decline.
Humans already use 95 percent of the Indus, and the population of the basin is growing fast. Writing recently in the journal Nature, an international group of scientists (supported by the National Geographic Society) analyzed glacial water towers worldwide. The Indus is the most critical, they said: Given the region’s “high baseline water stress and limited government effectiveness,” it is “unlikely that the Indus … can sustain this pressure.” Pakistan will suffer most.
From 2003 to 2006, I traveled the 2,000-mile river, from the Arabian Sea to its source in Tibet, researching my book Empires of the Indus. Already it was clear that it was under strain. The Indus had changed out of all recognition from the mighty river described by British colonial officials. It had been diminished by the demands of irrigation, industry, and daily life. Because of dams and barrages, it no longer reached the sea, and its mangrove-forested delta was dying. Its lakes were polluted with effluents and sewage.
I was struck by how the Indus, celebrated from ancient times in sacred Sanskrit hymns, was treated as a resource but no longer as an object of reverence. Everyone I met, from peasants to politicians, thought the river was being mismanaged. They spoke of corrupt or inefficient engineering projects, inequitable water sharing, and ecosystems destroyed in the name of profit.
At the time, not many people were talking about the effect of global warming on the Indus. It wasn’t until 2010 that the scale of the problem became clear—through dramatic floods rather than a shortage. The future of total rainfall in the Himalayan region is uncertain, but there has been a clear increase in extreme rains. In August 2010, when the Indus was already full of summer meltwater, it was hit by a freak monsoon. The torrential rain—in some places, a year’s worth in a few hours—caused the river to breach its banks throughout its southern course. More than 1,600 people died; damages reached $10 billion.
“Flooding on that scale was unheard of,” said Usman Qazi, an Islamabad-based disaster-relief expert with the United Nations Development Programme. “But it will become more common,” he added. “Climate change–related floods are one of the biggest hazards in this country.”
This is the starkest difference since I wrote my book: The specter of climate change now haunts all discussions of the future of the Indus. The challenge is made infinitely more complex because the Indus and five of its tributaries are shared by India and Pakistan, neighbors and enemies since 1947, while China controls the headwaters. When I reached Tibet in 2006, on my journey to the source, I was shocked to find that there was no water in the Indus: China had recently dammed the river’s upper reaches.
India, Pakistan, and China have huge populations and abundant reasons to protect their resources. All three have nuclear weapons. We think of climate change as happening in increments, almost imperceptibly. But along the Indus, it could trigger a conflict that changes the world overnight.
There was a time when humans were so grateful for rivers, they made them into divinities.
In the Rig Veda, India’s most ancient Sanskrit text, the Indus is the only river worshipped as both god and goddess, father and mother—probably because it was here, in the Indus Valley, that Hinduism took its first form, experts believe.
North of Kangrinboqe, the great river bubbles modestly out of the ground, as if that four-armed goddess were breathing out. It runs west through the mountains, along the top of India, and across the disputed border into Pakistan. Where the Himalaya meets the Karakoram and the Hindu Kush, in a knot of stone and ice, the river makes a sharp left and is funneled south, a thousand miles through the plains of Punjab and Sindh to the Arabian Sea.
About 40 miles north of that turning point, in the valley of the Hunza, an Indus tributary, I walked onto Ghulkin, a glacier with orchards and villages on either side. It was black with dirt and rubble from the mountains. I stepped over creaking crevasses; with my fingers I touched the ice body itself. From the summit, the view was exhilarating. The torrential brown river cut its way through the valley. Leading down to it were exquisite strips of psychedelic green, fields and orchards in which every leaf is watered by irrigation channels connected directly to the glacier.
In northern Pakistan, Islamic monotheism manages to coexist with a shamanistic appreciation of glaciers’ power. I was told many times that Ghulkin was a male glacier, “advancing down the valley in search of a female mate”—that is, a retreating glacier—in a mystical courtship dance. Glaciers advance, local people said, because they’re accumulating mass. That’s true—but as I learned later from glacial geologist Bethan Davies at Royal Holloway in London, a glacier also can slide downhill like a child’s sled because it has started to melt and come unstuck.
That may be what happened in 2018 to Shishper, another glacier nearby: It suddenly began sliding toward the town of Hassanabad, advancing as much as 120 feet a day. “It looked like a train,” local geologist Deedar Karim told me. Shishper rolled over irrigation channels and crashed into a bridge. By the time I saw it last October, it had slowed to a foot a day—which is still fast for a glacier.
In the upper Indus Basin, glaciers no longer advance or retreat glacially. The Hoper and Barpu Glaciers have melted back so far that settlements and their laboriously constructed irrigation networks have been drained. You see them abandoned on the mountainside: houses the same soft brown as the dry hills. “They were cultivating fields and trees there in my childhood,” said Niat Ali, a 60-year-old ex-army man. He reeled off a list of defunct settlements: Shishkin, Hapa Kun, Hamdar, Barpu Giram.
Melting glaciers also present a more urgent threat. Sometimes the meltwater pools behind a dam of rock rubble or ice—which can explode, unleashing a “glacial lake outburst flood,” or GLOF. In 2018, in the Ishkuman Valley, a flood submerged the villages of Bad Swat and Bilhanz. Nayab Khan, 48, felt the land shaking as “the water brought huge boulders. The boulders were colliding. It continued for 12 days.” The debris dammed the Immit River, forming a new lake, 20 feet deep, that destroyed his home and 41 others.
Climate change has helped put seven million people in northern Pakistan at risk of such floods. The three glaciers near the village of Pasu “are the three dragons,” said Ashraf Khan, an apple farmer and teacher. “We are living in their mouths.” In 2008 one dragon unleashed a GLOF in winter, when “normally everything is frozen solid.” Last August, summer meltwater “washed away a hotel, an office of the Pakistan Army’s intelligence bureau, and an orchard.”
The villagers of Pasu, like everybody else in the north, can see the weather is changing. The summers are now so hot that for the first time in their lives, people are ordering fans from downcountry. The winters are milder, for which most seem grateful. The gold panners who migrate to Hunza seasonally, living in tents along the river, celebrate the warmer weather—even the floods. “The floods bring more minerals out from the rocks,” Mahboob Khan explained. He was sieving sand from freezing river water, then rolling it with toxic mercury in his palm to extract specks of gold. He didn’t care about climate change.
I was astonished by how few people I met in northern Pakistan knew what was melting their glaciers or blamed the rest of the world. Farther south, in the big cities, a sense of injustice is crystallizing. Pakistan, a developing country of about 230 million, ranks only 144th out of 192 countries in per capita greenhouse gas emissions. As Pakistan’s climate change minister, Malik Amin Aslam, put it to me: “It’s not because of us, yet we are bearing the brunt.”
When independence was declared in 1947, and the Partition of the old British colony created India and Pakistan, each country got less of the Indus than it wanted. The long, westward-flowing stretch in the north lies in the former princely state of Jammu and Kashmir, and both new countries wanted all of that. The border dividing Kashmir remains tensely disputed.
Downstream in the fertile plains of Punjab, the British had built dams and barrages on the Indus and its tributaries and diverted water from those headworks into a vast web of irrigation canals. In Punjab the new border cut through five tributaries, giving Pakistan most of the farming settlements around the canals but leaving India with the headworks at Firozpur, on the Sutlej River.
Officials on the Indian side asserted their power immediately in spring 1948, shutting the gates of the headworks. That sharply reduced the flow into Pakistan. The gates reopened after a few weeks. But as Majed Akhter, a geographer at King’s College London, told me, that experience of Indian willfulness is the “founding violence” for Pakistani officials. Last October, Indian prime minister Narendra Modi threatened to cut the flow again.
Pakistan got some reassurance in 1960, when the World Bank persuaded both countries to sign the Indus Waters Treaty. The treaty divided the river basin, awarding water in the Indus and two western tributaries to Pakistan, with the three eastern tributaries going to India. The international community pushed the countries to build more dams and canals. Pakistan completed the Tarbela Reservoir in 1976. India finished the 400-mile Indira Gandhi Canal in 1987 to carry water and the green revolution from the Punjab south as far as Rajasthan’s Thar Desert.
Analysts in both countries agree that the canals, by providing copious water at artificially low cost, encourage waste. “We grow paddy in the desert!” exclaimed Ali Tauqeer Sheikh, a member of Pakistan’s National Climate Change Council. But “100 years on, we can’t keep blaming the British.” Large farmers, he said, are “the political elite and simply refuse water pricing.”
Water shortages on both sides of the border are at crisis levels. In India’s Punjab, debt drives about a thousand farmers to suicide every year. Pumping groundwater is expensive; every year they have to bore deeper wells as the water table falls—to 400 feet in some places. The groundwater depletion is caused by the growing of rice, a thirsty crop. Meanwhile, river water is shipped away as far as Rajasthan.
Across the border from Rajasthan, in the Pakistani province of Sindh, I traveled to a canal-irrigated part of the Thar Desert. The irrigation water was coming from nearly 200 miles away—from the barrage at Sukkur on the Indus, built in 1932 by the British. Here, at the end of the canal system, women and children were out in the fields, harvesting the famous Dundicut chili. In the open-air chili market of Kunri, the biggest in Pakistan, my eyes watered as I watched mountains of vivid red fruits being auctioned.
But the 2019 harvest was a dud, explained Mian Saleem, president of Sindh’s Red Chillies Growers Association: Extreme weather had cut the yield by two-thirds. In May the temperature reached 117 degrees, withering the crop. “In 40 years, I never felt such heat,” Saleem said. Then came “rain in October for the first time in my life.” Picking was delayed, and the fruit rotted.
In the village of Rano Khan Rahimoon, I spoke with landless sharecroppers, Hindus and Muslims living side by side in painted mud-walled houses. They grow chilies and other cash crops, and they were eloquent about their biggest problem: water. “Sometimes the canal water comes, sometimes it doesn’t,” said Attam Kumar, 28.
“The problem is threefold,” he went on. “Scarcity of canal water, unusually heavy monsoons, and this poisoned groundwater we are forced to drink.” Wells, he said, have been contaminated by runoff from fertilized fields. Kumar pulled up the shirt of Salaam, an 11-year-old boy, to show me the scar from his kidney surgery. Four of the 150 villagers have had kidneys removed. “This poison is shortening our lives,” Kumar said.
The next morning I took tea with a landowner and former federal minister, then spoke with the manager of a 6,000-acre mango farm, where servants were watering a rose garden in the desert. Both men lamented the newly erratic weather as they cracked open bottles of Evian. But they weren’t worried about running short of canal water; they were powerful enough to be given what they needed.
After a delicious lunch at the mango farm, I stopped by the village hospital. The doctor, Moomal Waqar, was in despair about the number of patients with kidney and gallstone ailments. Like the sharecroppers, she blamed unfiltered drinking water polluted by fertilizer. “Who here,” she asked, “can afford mineral water bottles?”
Poisoned water is widespread in Pakistan. A team led by Joel Podgorski of the Swiss Federal Institute of Aquatic Science and Technology reported in 2017 that up to 60 million people in the Indus Basin may drink groundwater contaminated by arsenic. The arsenic is naturally present in soils; it may also come from fertilizers. It gets leached into the aquifer by heavy irrigation.
“Arsenic poisoning exactly matches the irrigated areas,” said Hassan Abbas, a hydrogeologist in Punjab. “We have poisoned one of the largest groundwater reserves in the world.”
Pakistan also has one of the world’s highest rates of childhood malnutrition—at least a third of all children suffer from it. The country’s highest rates of all, said Daanish Mustafa, a Pakistani geographer at King’s College London, are “in the irrigated districts,” where agricultural practice prioritizes export crops over food security.
All these problems come back to the way water is used in the Indus plains. Dams, barrages, and canals made water abundant and cheap while trapping much of the river’s fertile silt in the reservoirs. The green revolution in the 1960s and 1970s brought even thirstier hybrid crops, along with chemical fertilizers and pesticides. Flood irrigation requires lots of both, because standing water is a vector of insect pests and because the water washes the chemicals away—into groundwater. The result, according to Abbas, is that “we now take 10 times more water from the river than we need to.” Water is scarce and contaminated in a land where it was once plentiful and clean.
Like many water experts I spoke with, Abbas advocates a radical overhaul of the system. Both Pakistan and India have ancient water-harvesting traditions, adapted to the rhythms of the river and the rains, that have been neglected since British times. Instead the two countries have focused on huge engineering projects—on dams and canals. Both have plans for new dams in the Indus Basin.
Climate change, Abbas argues, could be a blessing for Pakistan—an incentive to rethink the system. It could transition from expensive hydroelectric dams to cheaper solar power. It could replace flood irrigation with drip irrigation from pipes tapping into an unpolluted aquifer under the Indus. Finally, it could restore wetlands and forests in a corridor along the Indus and its tributaries. They would absorb floodwaters, thus avoiding a repeat of the 2010 disaster, and at the same time recharge the aquifers. Dams and reservoirs provide Pakistan with only 30 days’ supply in a drought; the Indus aquifer alone has enough water for three years, Abbas calculates.
He thinks rainfall- and river-water capture might even recharge the aquifer under Karachi, Pakistan’s commercial capital. On the edge of the Indus Delta, it’s one of the world’s largest water-stressed cities: Fifteen million people have sucked its aquifer dry. Kinjhar Lake, an Indus-fed reservoir 60 miles away, is their nearest source.
By the time the river nears the sea, it has almost ceased existing. In an alley in Goth Ibrahim Haidri, a fishing village near Karachi, I passed a line of women waiting with their waterpots for a tank truck. They said they’d been waiting for three days. Such scenes are common in low-income neighborhoods here. The rich take the lion’s share of freshwater from the Indus and its lakes, often buying it illegally. The poor wait in line or buy cheaper, brackish water.
Many residents of Goth Ibrahim Haidri are migrants from the delta. Their ancestral home was ruined from two directions. Since the Ghulam Muhammad Barrage was constructed in 1955, the Indus has flowed down to the sea only weakly, fitfully; instead, boosted by climate change, the sea has risen to meet the river, rendering it salty far upstream.
At sunset I stood by the sea watching the pretty wooden fishing boats come into harbor. Like Pakistan’s trucks, they were painted in a riot of colors, adorned with flowers and fish. Mohammad Ali Shah, head of the Pakistan Fisherfolk Forum (PFF), grew up here and swam in this sea as a child. He would never let his grandchildren do so, he said—it’s far too polluted.
PFF is campaigning for a law that would grant personhood—and rights—to the Indus. Shah showed me a draft. It calls the Indus “an ecological marvel” with “value aside from its utility to humans.” It points out that the Quran calls all the Earth “a mosque.” It proposes checks on hydro projects, pollution controls, and a fund to restore the river.
The proposal is too radical to become law. But something needs to shift along the Indus; something like the old reverence needs to return. The alternative, in which the river continues to be squandered and new weather gods add to the chaos, is too scary to contemplate.