Karachi's heat bill lands on the poor

Baba Bhit Island sees outages of up to 18 hours; built-up area up 32% since 2010

KARACHI:

Karachi's built-up area has expanded by about 32% between 2010 and 2025, exceeding 1,400 square kilometres, as agricultural land, rangeland and open spaces have increasingly given way to urban development, raising concerns over the economic costs of heat stress, water scarcity and inadequate infrastructure.

According to an official note by the Space and Upper Atmosphere Research Commission (SUPARCO), satellite-based land-use and land-cover (LULC) analysis shows that the expansion of the country's largest city has significantly altered its surrounding landscape over the past 15 years.

The trend is increasing pressure on the city's natural environment and infrastructure, with potential implications for labour productivity, public health, agricultural activity and the cost of providing essential services.

SUPARCO warned that the spread of built-up surfaces intensifies the urban heat island effect, in which densely developed areas retain more heat than surrounding rural areas. Urbanisation also reduces natural water infiltration and drainage capacity, potentially increasing flood risks during intense monsoon rainfall.

The findings point to a growing economic challenge for Karachi, where expanding settlements and commercial activity are placing greater demands on electricity, water supply, transport and drainage systems.

Concrete expansion raises heat risks

Urban planner M Toheed, associated with the Institute of Business Administration (IBA), said Karachi's green cover had declined by around 40% while built-up areas had increased in the last one and a half decades. The estimate requires further verification through comparable land-cover measurements, but the broader concern is that the city's expanding concrete footprint is reducing its capacity to moderate temperatures.

"The concrete base is building up, and this has serious repercussions on every kind of life here," Toheed said.

The conversion of open and vegetated land into buildings, roads and other paved surfaces can reduce shade and evapotranspiration, increasing heat exposure in densely populated neighbourhoods. The consequences are particularly severe when high temperatures coincide with Karachi's humidity, which limits the body's ability to cool itself through sweating.

Toheed said the impact could become dangerous even before an official heatwave declaration, as residents face rising temperatures alongside inadequate access to water and electricity.

Heat stress also carries an economic cost. Workers exposed to high temperatures may experience lower productivity, while households and businesses face higher cooling requirements and increased pressure on already strained power supplies.

Water, power shortages compound heat stress

Karachi's expanding population has not been matched by adequate infrastructure and green spaces, Toheed said, adding that water scarcity was compounding the effects of rising temperatures.

The problem becomes more acute when electricity outages prevent households from operating fans, pumps and other cooling equipment. Toheed cited areas including North Karachi, Ajmer Nagri, Pahar Ganj and Lyari, where he said prolonged load-shedding was common. He also cited Baba Bhit Island, where outages could last as long as 18 hours. Even the distribution company shuts down electricity supply to Ajmer Nagri on alternative days.

In some neighbourhoods, he said, residents experienced 10 to 14 hours of daily outages, while certain areas faced interruptions lasting an entire day.

These accounts highlight the interaction between heat exposure and infrastructure deficiencies. Without reliable electricity and water, households have fewer options to reduce heat stress, while businesses may face disruptions to working hours and operations.

SUPARCO also highlighted the implications of reduced natural infiltration and drainage capacity, noting that rapid urbanisation could increase flood risk during intense monsoon events. It cited the severe Karachi floods of 2020, when record rainfall and inadequate drainage contributed to widespread flooding.

Over 60% informal settlements

The effects of rising temperatures are not distributed equally across the city.

Toheed estimated that between 62% and 70% of Karachi's population lived in informal settlements, where high population density, limited ventilation and inadequate housing could increase exposure to extreme heat. He said many households had eight or more members and lived in houses with galvanised iron or steel-sheet roofs, which can become oven-like under direct sunlight.

Women and children face particular risks, he added. While some men can leave their homes to sit in open spaces during hot periods, women, children and the elderly may have fewer opportunities to escape overheated indoor environments because of household responsibilities and social restrictions.

The economic consequences extend beyond immediate health risks. Heat-related illness can increase healthcare costs, disrupt education and reduce the ability of workers to earn income, particularly among households that cannot afford cooling equipment or alternative accommodation.

Heat governance and planning gaps

Toheed said heat management remained an underdeveloped area of urban governance in Pakistan, contrasting the country's approach with cities elsewhere that have appointed dedicated heat officers to coordinate public awareness, preparedness and responses to extreme temperatures.

He also argued that Karachi had lagged in household solar adoption despite Pakistan's wider growth in solar energy, citing affordability, rental housing and limited rooftop space as barriers. He estimated that only around 10% of households had solar panels.

The availability of rooftop solar alone would not resolve the city's heat vulnerability, but reliable and affordable electricity could help households maintain cooling during extreme temperatures.

Toheed further alleged that electricity supply obligations under the Heat Wave Management Plan 2017 were not being adequately observed by Karachi's electricity distribution company during heatwave conditions.