THE ongoing floods paint a stark picture: the traditional monsoon system that has sustained the region for millennia is undergoing dramatic changes. Pakistan is at the epicentre of a climate transformation that is fundamentally altering the nature of monsoon rains and flood patterns across the country. No longer do the monsoons follow predictable patterns, locations, calendar and intensity.

How are the climatic changes redefining Pakistan’s flood landscape? To begin with, research reveals that while the intensity of rainfall has increased exponentially, the number of rainy days during the monsoons has decreased. The changing climate is leading to the geographic redistribution of rain. Monsoons have primarily affected the northern mountainous regions. But recent years show a shift, with greater concentration of intense, heavy rainfall events now occurring in the southern provinces.

This trend marks a departure from the norm where the northern areas received the bulk of the monsoon rains. The southward shift alters the level of flood risks and challenges the existing infrastructure, signalling a transformation in how we experience the weather. It threatens the relevance of some of our flood management institutions, policies and approaches.

Researchers have observed that since 2010, temperatures in Pakistan’s monsoon belt have increased at the rate of 0.18 degrees Celsius annually. This warming has profound implications, as warmer air can hold significantly more moisture: for every 1°C of temperature increase, the atmosphere’s water-holding capacity grows by seven per cent. During the April 2025 heatwave, with temperatures up to 8°C above normal in some places, it translates to a dramatically increased atmospheric moisture capacity, setting the stage for devastating downpours. The intensifying sequence of stronger heatwaves followed by heavy rainfalls has become almost predictable and urgently requires an integrated policy approach.

Climatic changes are redefining the country’s flood landscape.

Let’s review five major trends in recent years:

Non-riverine flooding: The country faces increasing vulnerability to non-riverine flooding. These floods, caused by intense localised rainfall, strike with little warning and overwhelm encroached waterbodies and drainage systems. Recent examples highlight this threat. In 2020, Karachi experienced its worst floodingenter link description here in almost a century when 223.5 millimetres of rain fell in a single day. The 2025 monsoon brought similar devastation as Punjab’s Chakwal district received 400mm in just 10 hours. Urban centres like Lahore and Rawalpindi have seen entire streets turn into rivers.

Addressing non-riverine floods needs a multifaceted approach: enhancing early warning systems, upgrading urban drainage infrastructure and bolstering community disaster readiness. Crucially, the National Flood Protection Plan IV (2015-2025) requires comprehensive revisions to fully integrate cutting-edge climate science, including advanced modelling for the increasing intensity and frequency of precipitation events, to effectively manage these emerging non-riverine flood sources.

Cloudbursts: Sudden, intense rainfall over small areas has become frequent. These extreme events, where rain greater than or equal to 100mm falls hourly, can devastate communities within minutes. Azad Kashmir, KP and Gilgit-Baltistan have seen a rise in flash floods and landslides, triggered by heatwaves in the upper Indus Basin, as seen in the Babusar cloudburst this month. However, some officials, rather than addressing the problem of inadequate infrastructure or limited response capacity, erroneously label all heavy rainfall as cloudbursts, as seen in the case of Chakwal and Islamabad’s Saidpur village. This mischaracterisation undermines credibility and may impede efforts to introduce risk insurance and risk transfer mechanisms.

Koh-i-Sulaiman: This mountain range, separating parts of Balochistan from KP, Punjab and Sindh, has emerged as a deadly source of flash floods. Intense rainfall generates powerful torrents that race into populated valleys, affecting south Punjab’s D.G. Khan and Rajanpur districts. This has led to submerged villages, burst dams and mass displacement, affecting some 700,000 people and inundating over 300,000 acres in D.G. Khan and Rajanpur respectively in 2022. The 2024 torrents recorded flows exceeding 70,000 cusecs. Ironically, these districts offer ideal options to harness floodwaters for nature-based solutions.

Salt Range and barani areas: These areas have seen a notable increase in extreme weather events, including severe floods from intense monsoon rains, frequent heatwaves, hailstorms and occasional higher-elevation snowfall. Together, they underscore growing climate volatility, resulting in greater risks of flash floods, crop losses and community disruptions. While the authorities have responded with emergency measures, local flooding is made worse by the loss of topsoil and the bursting of unregulated private check dams, which damages the ecology.

Urban flooding: Pakistan’s haphazardly growing urban sprawl has become particularly vulnerable to new rainfall patterns. Urban flooding has transformed from occasional inconvenience to regular catastrophe. Cities like Karachi, Lahore, Rawalpindi and Islamabad face severe flooding as drainage systems prove inadequate. The urban heat island effect intensifies rainfall, while rapid urbanisation reduces natural drainage and overwhelms aging infrastructure, often disrupting economic activity.

In all, the changing rainfall patterns alter how water interacts with the landscape. Heat-induced soil hardening reduces infiltration capacity by 40-60pc, meaning intense rains run off the surface rather than being absorbed. This creates a situation where extreme heat events set the stage for more devastating floods. Heavy rainfall also saturates soil, preventing absorption during subsequent storms and compounding flooding during back-to-back rainfall events.

Preparing for the new normal: Pakistan faces a double jeopardy from floods, amplified by heatwaves. Pre-monsoon heatwaves now trigger calamitous non-riverine floods as a first wave, swiftly followed by traditional monsoon riverine floods swollen by upstream heatwaves in India. This paradigm shift creates stark vulnerabilities across all provinces and regions, where some districts face only non-riverine floods while others endure both.

Historically focused on riverine floods, planning must become climate-smart. Non-riverine floods necessitate new strategies: enabling district disaster management authorities to respond promptly, deploying provincial rapid response battalions for cloudburst-triggered flash floods and implementing local, nature-based solutions in places like Koh-i-Sulaiman, the Salt Range and barani areas. The provinces must invest heavily in urban surface run-off and drainage systems. This demands integrating updated climate projections and prioritising multiple flood risks alongside enhancing conventional river flood defences.

The writer is a climate change and sustainable development expert.

Published in Dawn, July 31st, 2025