Urban islands of heat

Published September 11, 2023

Mushtaq Kharal, a lean man of 48, owns a flat in Lahore’s Johar town. He complains that his flat has no ventilation and, therefore, “it is unimaginable to spend even an hour within it without electricity during the intense heat we have these days.” He is a native of a village around Jatoi city in the Muzaffargarh district of Southern Punjab and frequently travels for work. “In my ancestral house in my village, it is still possible to live without an electric fan because of the green cover, but Lahore, by comparison, is too hot and oppressive to survive without the aid of cooling gadgets,” he concludes.

Those who have lived in Lahore all their lives clarify that the city was much cooler and cleaner a few decades ago. Afzal Rehman, 77, another resident of Lahore who used to live near the Lohari Gate area, says, “The nighttime sky in 1959 had so many stars that standing on the roof of my three-story house, I could see their various clusters and different formations. But now the city is so flooded with pollution, smoke emitting from its factories and traffic and high-rise buildings that only 10 per cent of those stars are visible now.”

Experts say that the intensity of Lahore’s weather could be because of what is known as the “heat island effect” in meteorological science.

‘A Sustainable Cooling Handbook for Cities’, a United Nations Environment Program (UNEP) publication, explains that this effect is caused mainly because of the materials commonly used in urban infrastructure. Houses and industries are made from materials that trap heat, making it impossible for cities to cool down at night. Consequently, the temperature in large cities like Lahore has increased more rapidly than it has for the whole of our planet.

In Lahore, vegetation cover decreased from 60.5pc in 1990 to 47.7pc in 2020 at the cost of urbanisation as overall built-up land increased by 23.52pc

Karachi Urban Lab, a research and advocacy institution associated with the Institute of Business Administration (IBA), a public sector university in Karachi, has done a study that confirms this phenomenon.

“Our study conducted in 2022 observed temperature changes in Karachi over the last 60 years through heat sensors placed at Karachi’s Jinnah International Airport and Pakistan Air Force base, Masroor,” explains Soha Macktoom, an architect who works as an associate director at Karachi Urban Lab. “At the Jinnah International Airport, nighttime temperature was recorded to be 2.6 degrees Celsius higher than six decades ago. The heat island effect has caused this difference.”

A similar study published in 2022 by Nasir Farid, Sajid Rashid, and their group members on the impact of urbanisation on the surface temperature of Lahore in 2020 agrees with this analysis. In Lahore, vegetation cover decreased from 60.5pc in 1990 to 47.7pc in 2020 at the cost of urbanisation. The overall built-up land increased by 23.52pc from 1990 to 2020.

These changes, according to the study, has caused Lahore’s urban area temperature in 2020 to be 2.41 degree Celsius, more than that of its rural surroundings, whereas, in the 1990s, its urban area temperature was only 1.72 degree Celsius higher.

Nadia Ali, 23, who is in the undergrad programme at Punjab University Lahore and is working on her final thesis on the role of media in legitimising commercial housing by sugarcoating as development, has similar views: “Rapid urbanisation has a direct relationship to the deterioration of our environment and its simple example is cities like Karachi and Lahore which have become pollution chambers because heat and pollutants have no way to move out of them,” she says.

Ms Macktoom also explains how urban heat islands make temperature variations in large cities intense and predictable. “This year alone, there have been six heatwave alerts in Karachi in April and June,” she says, adding that the government does not treat such heatwaves as emergencies or disasters because they are not as visibly destructive as floods.

“Our policies and responses are slow to address problems like urban heat islands because not enough research has been done on these islands, and their effects take time to be visible,” she adds.

Aqil Tariq, a researcher working on the heat islands effect at the Mississippi State University in the United States, states that the expansion of cities through high-rise buildings, pavements and housing societies built from concrete materials such as cement and glass is a major cause for global warming as well as urban heat island effect. Both these phenomena, he says, are already affecting people’s health at a large scale while the governments the world over are still struggling to cope with them.

Memoona Ahsan, a healthy woman of 58, a resident of Lahore, and a housewife, started developing symptoms of physical pain right after she shifted to her new house in Wapda Town from Mochi Gate.

She says it took her time to cope with the temperature of her new home. In her old home, she needed neither cooling nor heating because it was made of clay, lime, and stones, but in her new home, made of cement, steel, and bricks, she is forced to use air-conditioning during summers and heaters during winters and the artificial cooling and heating is making her sick.

Ms Ahsan says the old houses were stronger and more resistant to harsh weather conditions. “Even the architecture was smarter as it had plenty of ventilation, windows, and sunlight. Therefore, they were warmer in winters and colder in the summers compared to these new houses built mostly with cement”.

Ironically, she observes that people are advised to stay indoors during heat waves in cities even though urban indoors is hardly any different from outdoors during intense weather. “Not everyone has access to cooling infrastructure and an adequate amount of water to keep themselves cool,” she says.

Dua Sameer, a research associate at the Karachi Urban Lab, agrees. She says people living in urban areas are trapped in heat chambers from where there is no easy escape either indoors or outdoors. “The way we plan and develop our cities are friendly neither to humans nor the environment,” she says. “Concerns about climate change or environment degradation are treated as the grievances of a minor segment of the city which the real estate developers and builders ignore.”

The rapid use of air-conditioners is also alarming because it impacts people’s health, harms the environment, and consumes a lot of energy. “We construct inefficient buildings and infrastructure that traps heat, and to cool our buildings, we are left with the only option of using air conditioners,” says Dr Fiaz Ahmed Chaudary, Director of Lahore University of Management Sciences (Lums) Energy Institute.

The air conditioners put stress on the environment as the ACs throw the inside trapped heat back into the environment, increasing the outside temperature as well. “A motorcycle ride from the city to a nearby rural area is enough to prove that high-temperatures suffocate the urban areas,” he adds.

Lums has been preparing guidelines to change buildings in such a way that less heat is trapped inside the buildings. “Through changing our building codes and employing smart techniques using reflective paints, insulting rooftops, and changing our building codes, we can improve our environment and make our cities livable,” concludes Dr Chaudary.

The writer is a freelance journalist from Lahore working primarily on climate and energy

Published in Dawn, The Business and Finance Weekly, September 11th, 2023

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