We have taught ourselves to talk about climate in the vocabulary of catastrophe. Heatwave. Flood.
Fire. Body count. What almost nobody talks about is the heat of an ordinary working Tuesday, and how unevenly it lands. It collects on whoever has the least shelter from it: the fruit vendor, the rickshaw driver, the labourer mixing cement on a plot in Gulshan, the woman standing at a bus stop that has no roof over it.
The 2024 World Weather Attribution figures are worth sitting with for a moment.
The spring heat now moving across Pakistan and India, pushing past 46°C in several cities, has become roughly 35 per cent more likely because of climate change.
Raising tree canopy cover by 10pc lowers air temperature by about 0.8°C
What used to be an anomaly is now something that returns every five years.
Karachi recorded at least ten heat deaths in that period. Reporters found vendors had developed high blood pressure and described the dizziness that came over them at their stalls, because of which they could not work for weeks afterwards.
Nobody here needs reminding about 2015 when more than 1,200 died.
Researchers who went back into the informal settlements afterwards found that outdoor workers in garment and construction trades lose somewhere between 30 and 50 per cent of their productivity in the hottest months. They also found that in poorly ventilated concrete housing in low-income neighbourhoods, indoor temperatures run 5 to 7°C above what people in formal housing experience. Going home, in other words, is not relief. It is a different oven.
A month-long study of about 400 informal workers in Delhi recorded a 19pc drop in net earnings for every one-degree rise in wet-bulb temperature, with losses reaching 40pc on the worst heatwave days, and medical expenses climbing at the same time.
While Karachi is very hot, some measures have been taken to make it more bearable. Along the Clifton coastline, environmentalist Masood Lohar and the Sindh Radiant Organisation have put close to 700,000 trees into what used to be a landfill, using the fast-growing Miyawaki method. The site has measurably cooled its surroundings.
Shahzad Qureshi, who has been growing urban forests here for years, has recorded differences of six to seven degrees between his forested patches and the city outside them at various hours of the day.
A 2019 study from Karachi University’s Institute of Environmental Studies confirmed through instruments what anyone crossing a road at two in the afternoon already knows through their shoes: asphalt, cement and coal tar soak up heat and give it back, and they do it far more readily than lighter surfaces.
The projects mentioned earlier work, but look at where they sit. A handful of locations, most of them in the parts of the city that were never the problem, while green cover across the rest of Karachi remains, by the park department’s own estimate, barely one per cent of the city’s area.
The harder step is to take the same instinct and apply it exactly where it currently does the least good, such as commercial streets and bazaars.
And we do not have to import the basic science. A peer-reviewed study modelled heat mitigation along II Chundrigar Road, using computational fluid dynamics to test how different tree canopy shapes behave under the specific hot and humid conditions of this coast. It found that species selection measurably changes thermal stress at pedestrian level, and it identified which trees actually perform on a commercial corridor here. Thus, there is street-by-street evidence available that can guide a citywide programme instead of the ad hoc planting we keep doing.
The wider literature backs it. A large multi-city analysis found that raising tree canopy cover by 10pc lowers air temperature by about 0.8°C, and a 30pc increase can reduce it by as much as 1.5°C.
Measured at the scale of a body rather than a city, using physiological heatstress indices, full canopy can cut the afternoon heat a person on the street actually feels by up to 3.8°C.
Ahmedabad’s example Ahmedabad’s Heat Action Plan has been running since 2013, the first in South Asia, and it was built from the outset around the people most exposed to heat: street vendors, construction workers, women trading informally.
Its cheapest and best-known component, the Cool Roofs initiative, coats tin and concrete roofs with reflective paint, bringing indoor temperatures down by up to 5°C. Where households cannot afford paint, local partners developed substitutes from coconut husk and recycled paper. A peer-reviewed evaluation in 2018 credited the plan with saving an estimated 1,100 lives per year compared with pre-2013 heatwave mortality.
A tactical, low-cost layer of shade can be organised by traders’ associations and market committees at Empress Market, Lea Market, Sabzi Mandi, or any of the hundreds of informal bazaars in this city.
Ahmedabad then applied the same logic at scale, retrofitting bus and train stations with fans and shade structures.
Our BRT corridors and bus stops, which currently offer commuters nothing whatsoever, could be next.
Retail research has repeatedly found that shoppers will pay roughly 9pc to 12pc more for goods in tree-shaded commercial districts than in comparable unshaded ones, that they travel further to reach them, and that they stay longer once they do.
In a bazaar, footfall is a vendor’s daily income. Traders ought to be the loudest advocates for shading their own streets. n The writer is an architect and an urban planner currently leading her own practise, “Beyond Facades”.
Email: hello@beyondfacades.studio
Published in Dawn, The Business and Finance Weekly, July 20th, 2026