By Victoria Ogechukwu Ujam
For Latifat Ojo, the heat became an unexpected complication in her recovery from a Caesarean section at a government hospital on Lagos Mainland.
In early March 2026, she spent nights in a general ward where air conditioners and fans struggled to keep the room comfortable. When electricity failed, the hospital relied on solar power to keep the fans running.
The doors were left open to allow air into the ward and help mothers and their babies sleep.
But that brought another problem.
Mosquitoes entered through the open doors, leaving some mothers awake through the night, using hand fans to keep air moving around their babies.
After she was discharged, Latifat said excessive sweating became another challenge. Sweat repeatedly reached her surgical wound, prompting her to return to the hospital several times for wound cleaning. She said the wound took about three months to heal.
Her baby also developed a skin rash. “This year, the heat was after my life,” Latifat said.
Her experience does not establish that heat caused her prolonged wound healing or her baby’s rash. But it offers a glimpse into what extreme heat can mean for people who have little control over their immediate environment.
For millions of other Lagos residents, escaping the heat is even more difficult.
They have to walk to work, wait for buses, change transport connections, trade in open markets or spend hours outdoors to earn a living.
And as Lagos grows hotter, researchers are trying to determine exactly where the heat is worst, who is most exposed and whether the evidence can eventually lead to changes in the places where people live and move.
The rising cost of extreme heat
At a recent Hotsteppers training session in Lagos, Barbara Rubiell, a researcher at the University of Cambridge and member of the Hotsteppers research team, presented evidence showing the scale of Nigeria’s heat exposure.
According to figures presented at the training, people in Nigeria experienced an average of 33 heatwave days in 2024, with 85 per cent attributed to human-induced climate change.
Rubiell also estimated that Nigerians experienced an additional 465 hours per person of at least moderate heat-stress risk during moderate exercise that year.
The economic consequences are significant.
Heat exposure was associated with about 31.9 billion potential labour hours lost in Nigeria in 2024, with agriculture accounting for the largest share.
The figures do not mean every Nigerian experienced the same level of heat exposure. But they underline a growing reality: extreme heat is no longer simply an issue of discomfort.
It can affect people’s ability to work, exercise and move safely through their daily lives.
In Lagos, where millions depend on walking and public transportation, that makes the physical environment through which people travel increasingly important.
Not everyone experiences Lagos heat equally
The city’s rapid urbanisation has also changed how heat is distributed.
Research cited by the Hotsteppers found that the area affected by significant urban heat-island intensity in Lagos expanded from 254 square kilometres in 1984 to 1,572 square kilometres in 2016.
Urban heat islands occur when surfaces such as concrete and asphalt absorb and retain heat, making built-up areas considerably warmer than greener surroundings.
The esearch also shows that some densely developed areas can be up to 7°C hotter than nearby greener and wealthier suburbs.
For residents of densely built neighbourhoods, limited tree cover, poor ventilation and heat-absorbing surfaces can make exposure harder to escape.
This creates a question that is more important than simply asking whether Lagos is getting hotter:
Where is the heat concentrated, who is exposed to it, and what can be done about it?
That is the question Hotsteppers Active Lives in Hot Spots is attempting to answer.
Mapping heat where people actually move
Hotsteppers is a three-year climate and health research project examining heat exposure among people who walk, cycle and use public transportation in Lagos.
Its first phase of mobility mapping covers 11 priority transport corridors, including areas around Yaba, Oshodi, Mile 2, Ojota, Ikorodu and Marina-CMS.
The objective is not merely to create another map showing where temperatures are high.
Researchers want to understand how people experience heat as they move through the city.
A satellite image may identify a road or transport facility. It may not show that passengers wait outside a designated bus shelter because there is insufficient shade, or that pedestrians must walk long distances between transport connections under direct sunlight.
This is where technical data and local knowledge intersect. A commuter knows where passengers wait when a bus stop has no shade.
A trader knows which part of a market becomes unbearable in the afternoon. A cyclist knows which routes expose them to prolonged heat.
A pedestrian knows where a journey becomes physically exhausting. Hotsteppers plans to combine those experiences with technical measurements.
During its participatory mapping phase, scheduled for September 2026, researchers known as Citizen Scientists, or Cityzens, are expected to work with communities to document walking and cycling routes, public transport connections, heat hotspots, waiting areas, shade, public spaces, movement patterns and people’s experiences of heat.
The hope is that this combination of scientific evidence and community knowledge will help identify where interventions are most urgently needed.
That could include additional trees and shade, better-designed transport waiting areas or improvements to walking and cycling routes.
But there is an important caveat. A map cannot plant a tree, build a bus shelter or redesign a road.
Whether the evidence generated by the project influences transport and urban-planning decisions remains to be seen.
Heat and pollution: a double burden
The problem becomes even more complicated for people walking or cycling along congested roads.
They can be exposed to extreme heat and polluted air simultaneously.
Evidence presented during the training suggested that a combination of increased active travel, reductions in fine particulate pollution and cooling transport corridors by 1–2°C could potentially prevent between 50 and 100 premature deaths annually.
That figure is a modelled potential benefit, not an outcome achieved by Hotsteppers.
Its significance, however, is that relatively modest changes to the urban environment could potentially produce several health benefits at once.
The challenge is turning those possibilities into measurable interventions.
Why journalists are part of the experiment
Hotsteppers is not only collecting data. It is also investing in journalists who can scrutinise and explain that evidence.
During a three-day training programme, journalists were introduced to the health consequences of extreme heat and air pollution, scientific evidence, mapping technologies, data and solutions-oriented approaches to climate reporting.
For reporters, the training offers tools to interrogate evidence that can otherwise appear inaccessible.
A journalist who understands satellite imagery, thermal imaging, geographic information systems and temperature sensors is better positioned to ask what a heat map actually shows—and what it leaves out.
The journalist can also connect technical measurements to the people experiencing the conditions those measurements describe.
The Hotsteppers Media Network is expected to provide journalists with continued access to researchers, experts and emerging findings from the project.
The objective is therefore not simply to produce more stories about rising temperatures.
It is to ask harder questions: Where is the exposure greatest? Who bears the greatest burden? What interventions are being proposed?
Who is responsible for implementing them? And, most importantly, do they work?
The real test begins after the maps
Hotsteppers has begun building evidence about the problem. It has not yet demonstrated that its research will produce cooler or safer environments.
That distinction matters. The project plans to combine technical measurements with community-generated knowledge and build a network of journalists capable of examining the findings.
But what happens after the data is collected? Who will use the maps? What happens when researchers identify a severe heat hotspot?
Will transport authorities redesign exposed waiting areas? Will urban planners use the findings to improve tree cover or walking routes?
Will the project be able to demonstrate that its recommendations resulted in physical changes—and that those changes actually reduced people’s exposure to heat?
There are also questions about community participation.
Residents are expected to contribute knowledge to the mapping exercise, but whether they remain involved after data collection—and whether they see improvements in the places they helped document—will be an important measure of the project’s impact.
And because Hotsteppers is a three-year project, its longer-term value will depend partly on what remains after it ends: the data, relationships with communities and journalists, and the willingness of public institutions to use the evidence.
Ultimately, success cannot be measured simply by the number of maps produced or journalists trained.
The harder test is whether the evidence changes the places where Lagos residents walk, wait, cycle and connect to public transport—and whether those changes make their daily journeys cooler, safer and healthier.
Latifat’s experience occurred inside a hospital ward rather than on one of the transport corridors being mapped by Hotsteppers.
But the underlying question is the same: What happens when people have nowhere to escape the heat?
For a new mother recovering from surgery, inadequate cooling made an already difficult recovery harder. For a commuter, it may mean standing under direct sunlight at an unshaded bus stop.
For a trader, it may mean working for hours without relief.
For a cyclist or pedestrian, it may mean physical exertion under intense heat alongside polluted traffic.
Hotsteppers is attempting to identify where those burdens are greatest.
Its maps may show where Lagos is hottest. But the real measure of success will be whether anyone acts on what those maps reveal.
