The South Asian monsoon is a life-giver for 2 billion people. The regular rains from June to September nourish the crops they eat and temper the region’s searing heat. But you can have too much of a good thing. This summer, for the second time in three years, record-breaking cloudbursts in the Himalayas made the monsoon deadly for millions of people across Pakistan. With as much as half its summer harvest once again lost, the country is increasingly seen as more vulnerable to climate change than any other.
Floods pouring out of the rain-drenched western Himalayas and through Pakistan in August and September killed a thousand people and forced the evacuation of 2.5 million more, mostly poor villagers. Hundreds of miles of roads and flood defenses, along with dozens of bridges, were washed away the length of the Indus River, from the mountain province of Khyber Pakhtunkhwa, through the country’s breadbasket of Punjab, to the world’s largest irrigated area hundreds of miles south in the desert province of Sindh.
More than 4,000 villages were inundated. For many of the villagers there was a sense of déjà vu. They were still recovering from an even more intense “super flood” in 2022, when a third of the country was under water, with 33 million people impacted and total damage and economic loss put at $30 billion by the World Bank. Thousands of residents of Karachi, a megacity of 20 million people, have now been flooded out of their homes for the third time in five years, and the business district shuttered.
Some models predict extreme daily rainfall in the region will become up to 50 percent more intense if the world warms by 2 degrees C.
The repeated disasters, on top of a rising trend of exceptionally intense monsoon rains over the past two decades, are leading climate scientists to fear the worst.
“Pakistan is a hotspot for increases in extreme rainfall” and is “undoubtedly on the front line of climate change,” says Friederike Otto, a climate scientist at Imperial College London, and founder of World Weather Attribution, an international collaboration assessing the causes of extreme weather events. The country has “acute vulnerability to frequent extreme rainfall,” and faces an “urgent need to reduce vulnerability.”
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There is now little doubt that rainfall patterns in northern Pakistan and neighboring northwest India are becoming ever more extreme, and that climate change is the root cause, says climate scientist Mariam Zachariah, also of Imperial College London. “Today, similar spells of monsoon rain are expected in the region on average about once every five years.”
Some climate models predict extreme daily rainfall in the region will become up to 50 percent more intense if the world warms by 2 degrees C, says Michela Biasutti of the Lamont-Doherty Earth Observatory at Columbia University.
A 2025 global assessment of recent extreme weather events sponsored by the German government found Pakistan, the world’s fifth most populous nation, more vulnerable to climate change than any other.
Flooded farmland in Pubjab Province in early September.
Jahan Zeb / AP Photo
What is going on?
First, the thermodynamics. Global warming means the atmosphere can hold more moisture — about 9 percent more for the current 1.3 degrees C warming, according to a well established law known as the Clausius-Clapeyron relationship. During the monsoon, this extra moisture is released in increasingly intense cloudbursts, especially when the moisture-laden winds rise over the Himalayas, cooling the air.
“Monsoon storms are now forming in a warmer atmosphere that holds and dumps far more moisture in short bursts, causing flash floods and landslides,” says Akshay Deoras, a meteorologist at University of Reading. “As extreme events grow more frequent, we’re flying blind into disaster.”
Zachariah says the cloudbursts are unexpectedly severe. “Climate models show an increase in extreme rainfall intensity [in South Asia] of about 12 percent, but observational datasets indicate a stronger trend of approximately 22 percent.”
One reason why reality is outstripping predictions is that the hotter monsoon is not the only driver. Another factor is changes in the wider atmospheric circulation, scientists say. More storms are tracking east from the Mediterranean Sea into Asia, driven by a shifting subtropical jet stream.
Temperatures in Pakistan’s mountains this summer reached 119 degrees F, triggering a series of glacial lake outbursts.
These storms, known to meteorologists as western disturbances, used to be largely a winter phenomenon, bringing much-needed rains for farmers in India and Pakistan. But in the past 20 years, they have become much more frequent in summer too, says Deoras, coinciding with the onset of the monsoon with disastrous effect. “Think of the monsoon as a loaded water cannon, and western disturbances as the trigger,” he says. This year, “this trigger was pulled with force, drenching several states.”
And it is not just rain. There are other loaded water cannons ready to unleash floodwaters, say geographers. The mountains of northern Pakistan are home to the world’s largest concentration of glacial lakes — some 7,000. These lakes form when steep-sided river valleys carrying monsoon rains and meltwater from glaciers are blocked by debris from landslides that are often triggered by melting permafrost.
As the summers get hotter, more landslides occur, and the lakes grow more numerous and bigger. Eventually, they burst, creating torrents of water that rush downstream.
Flash floods caused by a glacial lake outburst destroy a bridge in Hassanabad, Gilgit-Baltistan Province, in 2022.
AFP via Getty Images
This summer, temperatures in Pakistan’s northern mountains reached record levels. In the city of Chilas at 3,800 feet in Gilgit-Baltistan, they hit an unprecedented 119 degrees F. The heat triggered a series of glacial lake outbursts in the region.
In late August, one caused a wall of water to sweep through the villages of Talidas and Raushan. With no official warning alarm, hundreds of lives were saved only because a shepherd in the mountains saw what was happening and phoned home in time for villagers to evacuate. Next time, people living downstream may not be so lucky. According to a recent global analysis by British geographers, some 2 million Pakistanis are exposed to potential future glacial lake outbursts. Half of them live less than less than 10 miles downstream of vulnerable lakes.
With a range of factors in play, the August floods in the western Himalayas and Punjab were the worst on record, according to the U.N. Office for the Coordination of Humanitarian Affairs. And downstream damage has been considerable. On the flatlands of Sindh, several major levees were breached in September, engulfing fields of cotton and sugar. In all, NASA’s Earth Observatory reported that as much as three-quarters of the country’s farmland may have been inundated. Early estimates suggest the loss of rice and other crops worth $3.5 billion.
“Every submerged village… every family camped under tarpaulins on a hot roadside is a reminder that climate inaction has human faces.”
But this is no one-off. A pattern is emerging of repeated flood damage that is permanently undermining Pakistan’s ability to feed itself. The 2022 floods in Sindh caused the country’s largest freshwater lake, Lake Manchar, to overflow across an area of cropland the size of New Jersey. And in 2010, monsoon floods displaced 20 million people and caused billions of dollars of damage, when the swollen Indus abandoned its normal course for 200 miles. Other floods across Pakistan in 2011, 2012, 2020, 2023, and 2024 would have been major stories in most other countries, but seem like the new normal there.
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“These are not irregular events anymore,” says Tariq Aziz, an environmental scientist at the University of Agriculture in Faisalabad. “Every submerged village, every washed-away bridge, every family camped under tarpaulins on a hot roadside is a reminder that climate inaction has human faces.”
Of this year’s floods, he warns that unless the government acts fast to drain fields and remove mud in Punjab, farmers will be unable to get onto their fields in October and November and plant their next crop of wheat, which provides more than half of the country’s calorie intake. The resulting losses “could be devastating” for the farmers and the nation’s food security alike, says Aziz.
The heart of the problem lies in more intense rainfall being driven by climate change for which industrialized nations are overwhelmingly responsible. But scientists and policy analysts alike say that Pakistan is making itself more vulnerable by failing to adapt to the new climate realities.
For one thing, houses continue to be built in all the wrong places. According to a 2023 report by UN-Habitat, which promotes sustainable design for urban areas, some 30 million Pakistanis, 40 percent the country’s urban population, live in unplanned informal settlements, many of them along riverbanks and on floodplains. Often those homes are built of mud that quickly washes away in floods. The country’s National Disaster Management Authority estimates that more than half of this year’s flood deaths happened when people were crushed in their collapsing houses.
Meanwhile, engineers continue to drain wetlands and barricade floodplains to make room for urban developments and construct embankments and bridges that reduce the capacity of river channels. As a result, water is rushing down rivers faster, creating flood bottlenecks where defenses are overwhelmed.
Muhammad Ehsan Leghari, a member of the Indus River System Authority, a government regulatory agency, recently complained that an urban development authority building what it calls a “sustainable riverfront city” in Lahore is paving the floodplain of the Ravi River, “turning absorbent areas into concrete, inviting devastation.” Lahore, home to 14 million people, is largely built on the Ravi floodplain and suffered extensive flooding this summer.
Water infrastructure was designed according to assessments of flood risk that are “obsolete and meaningless.”
Further downstream, Leghari warned, a buildup of sediment, much of it linked to deforestation, had “elevated the River Indus riverbed, reducing the river’s flood-handling capacity by 17.75 percent,” thus worsening recent floods.
“Pakistan must think long term,” says Aziz. “Floodplain management is essential — restricting construction in high-risk zones, restoring wetlands, and maintaining embankments.” But he sees few signs of that happening.
Instead, even as this year’s floods spread, a blame game began. Pakistan’s planning minister Ahsan Iqbal accused neighboring India of “using water as a weapon” by releasing water from dams on Indus tributaries that flow into Pakistan. It was true that India released water from the Thein and Bhakra dams, and that this worsened cross-border flood surges. But India gave notice and had little alternative. Otherwise, the dams would have collapsed, unleashing much worse floods, says Daanish Mustafa, a geographer at Kings College London and author of past reports on Pakistan’s flood response strategy for the U.N. Development Programme.
The real problem, Mustafa says, is that dams, barrages, and embankments in both countries are designed according to assessments of flood risk that are “obsolete and meaningless.” Today’s floods are more severe than anything envisaged when the infrastructure was built, much of it during British colonial times.
A mud house destroyed by flooding in Balochistan Province in 2022.
Fida Hussain / AFP via Getty Images
So, who will pay for repairing the damage from Pakistan’s repeated inundations and for flood-proofing the country for the future?
Pakistan and other nations will use the Belém climate conference in Brazil in November to push for a “loss and damage” fund that is capable of compensating them for climate disasters. Formally operationalized two years ago, the fund has so far been pledged nearly $1 billion — less than a tenth of the cost of just the most recent Pakistan floods — but has received less than half that and has not yet paid out anything.
The picture is slightly better for funding for adaptation of infrastructure to cope with future now-inevitable climate change. But Mustafa says his own country is among many pushing for the wrong kind of adaptation. It appears bent on seeking “expensive loans from international donors to upgrade the [existing] infrastructure,” he says.
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That might help in the short term. But what is really needed, he says, is to restore natural means of flood amelioration, such as wetlands and river floodplains unencumbered by ever-expanding urban developments. “The point is to allow the rivers space to flow,” he says. But “the present Pakistani engineering establishment is loath to allow this to happen.”
Pakistan, a country of 250 million people, is a case study in how vulnerable many of the world’s poorest people are to climate change that now seems unstoppable. But it is also set to be a case study in whether the world can come up with the right strategies to reduce their risks.
