Pakistan Heatwaves and Urban Heat Islands: Understanding the Crisis and Building Cooler Cities

When Cities Become Furnaces

Pakistan is one of the most climate-vulnerable countries on earth, and its cities are feeling this in the most direct way possible: through extreme and increasingly deadly heat. Heatwaves in Pakistan have grown longer, more intense, and more frequent over the past two decades, and the urban heat island effect is amplifying this danger for tens of millions of people living in Karachi, Lahore, Multan, Islamabad, Peshawar, and dozens of smaller cities across the country.

Understanding how urban heat islands form, why Pakistani cities are especially exposed, and what practical interventions can reduce heat stress is not just an academic exercise. For environmental professionals, urban planners, public health officials, and policymakers, this is one of the most urgent applied challenges of the decade.

What Is an Urban Heat Island?

An urban heat island (UHI) is a condition where a city or densely built area records significantly higher temperatures than surrounding rural or semi-rural land. The effect is driven by several reinforcing factors.

- Reduced vegetation: Trees and plants cool the air through evapotranspiration. When green cover is replaced by concrete and asphalt, this natural cooling disappears.

- Heat-absorbing surfaces: Dark rooftops, paved roads, and concrete walls absorb solar radiation and release it as heat throughout the day and into the night.

- Waste heat from human activity: Air conditioners, vehicles, industrial processes, and generators all release heat directly into the urban environment.

- Reduced airflow: Dense building layouts can block wind corridors that would otherwise carry heat away from built-up areas.

- Altered hydrology: Hard surfaces prevent rainwater infiltration, reducing the evaporative cooling that moist soil provides.

In well-documented cases globally, urban cores can be 3 to 8 degrees Celsius warmer than nearby rural areas during peak heat periods. In Pakistani cities, where baseline temperatures are already extreme, even a few additional degrees can push conditions beyond the threshold of human survivability without cooling infrastructure.

The Pakistani Context: A Country Built for a Different Climate

Pakistan's urban population has grown rapidly. According to the Pakistan Bureau of Statistics, more than 36 percent of the population now lives in urban areas, and that share continues to rise. Much of this urbanisation has been unplanned or informally developed, meaning that cities expanded without the green infrastructure, building codes, or cooling systems needed to manage heat safely.

Several factors make Pakistani cities particularly vulnerable to the urban heat island effect.

Low Urban Green Cover

Karachi, Pakistan's largest city, has seen dramatic losses in tree cover over the past several decades due to construction, road expansion, and informal settlement growth. Studies by urban researchers have documented green cover in parts of Karachi falling well below the 10 to 15 percent minimum generally recommended for urban livability. Lahore has faced similar pressures despite periodic tree-planting campaigns.

Energy Poverty and Cooling Access

Many low-income urban residents cannot afford air conditioning or reliable electricity to run fans. Load shedding, which remains a serious problem in many Pakistani cities, cuts power precisely when demand for cooling is highest. This creates a situation where the most economically vulnerable populations bear the greatest heat burden, often sleeping on rooftops or in poorly ventilated rooms during the hottest nights.

High-Density Informal Settlements

Katchi abadis and informal urban settlements are common in all major Pakistani cities. These areas typically have high building density, minimal open space, few trees, and roofing materials such as corrugated metal that absorb and radiate heat intensely. Residents in these neighbourhoods face compounded risk: high ambient temperatures, poor housing quality, and limited access to health services.

Industrial and Traffic Emissions

Cities like Lahore, Faisalabad, and Karachi carry significant industrial and vehicular pollution loads. These emissions contribute to a localised warming effect and also degrade air quality, making it harder for the body to cope with heat stress through normal respiratory and cardiovascular responses.

Landmark Heatwave Events in Pakistan

The 2015 Karachi heatwave remains one of the deadliest heat events in Pakistani history. Temperatures exceeded 44 degrees Celsius for several consecutive days during Ramadan, when many residents were fasting and avoiding water. Official estimates at the time placed the death toll above 1,200, though independent researchers and health workers suggested the actual figure was considerably higher. The event exposed the absence of any coordinated urban heat emergency response system.

More recently, the pre-monsoon period of 2022 saw extreme heat across Sindh and Balochistan, with Jacobabad and Sibi recording temperatures among the highest reliably measured anywhere on earth that year. While Jacobabad is not a megacity, the conditions it experienced illustrate the upper boundary of what urban populations in Pakistan's hottest regions may face as climate change progresses.

The IPCC Sixth Assessment Report on Impacts, Adaptation and Vulnerability specifically identifies South Asia as a region where wet-bulb temperature thresholds dangerous to human health are being approached or exceeded with increasing frequency, a finding directly relevant to Pakistan's urban heat challenge.

Regulatory and Policy Framework

Pakistan's environmental governance framework, anchored in the Pakistan Environmental Protection Act 1997 and its provincial equivalents following the 18th Amendment, does not yet contain specific provisions targeting urban heat islands as a distinct environmental hazard. However, several related instruments are relevant.

- The National Climate Change Policy and its associated frameworks acknowledge urban vulnerability to extreme heat as a priority area.

- The Climate Change Act 2017 (now superseded by the Climate Change Authority Act 2017 and subsequent legislative developments) established institutional mechanisms for climate planning that include urban resilience considerations.

- Provincial building codes, where enforced, contain provisions that can reduce heat absorption, including minimum setback requirements and in some cases reflective roofing standards, though enforcement remains inconsistent.

- The Environment Protection Departments of Punjab, Sindh, KPK, and Balochistan have authority under provincial EPA legislation to regulate land use activities that affect environmental quality, which in principle includes urban greening and heat-related planning.

It is worth noting that urban planning in Pakistan is primarily governed through local government frameworks and development authorities such as the Lahore Development Authority and the Karachi Development Authority, which operate with considerable independence from environmental regulatory bodies. Bridging this gap between environmental management and urban planning is a structural challenge that professionals in both fields need to engage with directly.

Practical Interventions: What Actually Works

There is a growing evidence base on what reduces urban heat effectively. Not all interventions are equally applicable to Pakistani conditions, but the following have demonstrated results in comparable contexts.

Urban Forestry and Green Cover Expansion

Street trees, urban parks, and green buffers along roads and waterways reduce surface and air temperatures measurably. Shade from a mature tree can reduce surface temperatures on pavements and walls by 10 to 20 degrees Celsius. Pakistan's Ten Billion Tree Tsunami programme, while primarily targeting forest and peri-urban areas, has created institutional mechanisms that can be adapted for denser urban greening if urban local governments are engaged.

Cool Roofs and Reflective Surfaces

Painting rooftops white or applying reflective coatings is one of the most cost-effective heat reduction measures available. Pilots in Karachi carried out by community organisations and the Karachi Metropolitan Corporation in selected neighbourhoods demonstrated meaningful reductions in indoor temperatures. Scaling this requires subsidy or incentive mechanisms for low-income households who cannot afford even modest upfront costs.

Green Infrastructure in New Developments

Requiring minimum green cover, permeable paving, and shading structures in new construction and development approvals is a straightforward regulatory measure. Environmental Impact Assessments under the PEPA 1997 framework and provincial IEE/EIA regulations could be strengthened to require heat impact assessments for large urban development projects, particularly in cities already experiencing high baseline temperatures.

Heat Action Plans

Ahmedabad in India developed one of the world's first municipal heat action plans following a deadly 2010 heatwave. The plan included early warning systems, cooling centre networks, public communication, and coordination between health and municipal authorities. Several Pakistani cities have begun developing similar frameworks, but implementation capacity and interagency coordination remain barriers.

Reducing Waste Heat

Transitioning urban transport toward electric vehicles, improving building energy efficiency to reduce air conditioning loads, and shifting industrial operations toward cleaner technologies all reduce the waste heat added to urban environments. These are longer-term transitions but should be embedded in urban development planning now.

The Role of Environmental Professionals

Environmental professionals in Pakistan are positioned to contribute to urban heat resilience across multiple domains: conducting urban microclimate assessments, strengthening EIA processes to capture heat-related risks, advising on green infrastructure design, engaging with development authorities on planning standards, and building the evidence base through monitoring and research.

There is also a communication role. Heat deaths in Pakistan are frequently undercounted and underreported because heat is not always recorded as the primary cause of death. Raising awareness among health professionals, community leaders, and the public about heat stress recognition and response is part of the broader environmental professional mandate.

The UNEP Sustainable Cooling Handbook for Cities provides a practical reference that environmental and urban professionals in Pakistan can draw on when advising local governments or designing interventions.

Conclusion

Pakistan's heatwave and urban heat island challenge is not a future risk. It is a present crisis that is already costing lives, reducing productivity, and deepening inequality in cities across the country. Addressing it requires coordination across environmental management, urban planning, public health, and energy policy, precisely the kind of cross-disciplinary work that environmental professionals are trained to support.

PAEP brings together professionals working across these intersecting fields. Whether you are working on EIA practice, urban greening policy, climate adaptation planning, or community-level resilience programmes, PAEP's network and professional development resources can help you connect with peers tackling the same challenges and stay current on evolving practice and policy in this area.

Frequently Asked Questions

Q1. What is an urban heat island and why does it matter for Pakistani cities?

An urban heat island is a condition where built-up urban areas record significantly higher temperatures than surrounding rural land, due to heat-absorbing surfaces, reduced vegetation, waste heat from human activity, and restricted airflow. In Pakistani cities, where summer temperatures already reach extreme levels, the urban heat island effect adds further dangerous heat stress, increasing the risk of heat-related illness and death, particularly for low-income residents without access to reliable cooling.

Q2. Which Pakistani cities are most affected by the urban heat island effect?

Karachi, Lahore, Multan, Faisalabad, and Hyderabad are among the cities most affected, given their population density, limited urban green cover, high industrial and traffic activity, and in some cases, geographic conditions that reduce natural cooling. Smaller cities in interior Sindh and southern Punjab, such as Sukkur and Rahim Yar Khan, also experience extreme baseline heat that is worsened by urban development patterns.

Q3. Are there laws in Pakistan that address urban heat islands specifically?

There is currently no specific legislation in Pakistan that addresses urban heat islands as a distinct environmental hazard. However, the Pakistan Environmental Protection Act 1997, provincial EPA legislation, the National Climate Change Policy, and provincial building codes all contain provisions relevant to managing heat-related risks in urban environments. Environmental Impact Assessment regulations could also be strengthened to require heat impact analysis for major urban development projects.

Q4. What is a cool roof and how effective is it in Pakistani conditions?

A cool roof uses white paint, reflective coatings, or light-coloured materials to reflect solar radiation rather than absorbing it as heat. In Pakistani conditions, where rooftop temperatures on dark surfaces can exceed 70 degrees Celsius during peak summer, cool roofs can significantly reduce indoor temperatures and lower the heat radiated back into the urban environment. Community pilots in Karachi have demonstrated practical benefits, though scaling the approach requires financial support mechanisms for low-income households.

Q5. How can environmental professionals contribute to reducing urban heat in Pakistan?

Environmental professionals can contribute by conducting urban microclimate assessments, strengthening EIA processes to include heat risk analysis, advising development authorities on green infrastructure standards, supporting the design and implementation of municipal heat action plans, and building public and institutional awareness about heat stress. Research, monitoring, and cross-sector coordination are also areas where trained environmental professionals can add direct value.

Q6. What is a heat action plan and does Pakistan have one?

A heat action plan is a coordinated municipal or provincial framework that prepares institutions, health systems, and communities to respond to extreme heat events. It typically includes early warning systems, public communication, cooling centre networks, and protocols for health and emergency services. Some Pakistani cities and provincial governments have begun developing heat action frameworks, but comprehensive, well-resourced, and consistently implemented heat action plans remain limited, and this is an area where significant policy and professional effort is still needed.