Africa’s urban centers are heating up, a direct result of rapid expansion and rapidly growing population. Cities like Lagos, Nairobi, and Accra are growing at unprecedented rates. But this growth comes with an environmental cost: rising temperatures.
The Intergovernmental Panel on Climate Change (IPCC) projects that heat exposure in Africa will increase significantly over the coming years. By the 2060s, the number of days with temperatures exceeding 40.6°C could reach 45 billion person-days, tripling the exposure rates seen between 1985 and 2005.
This heat disproportionately affects residents in informal settlements. These areas often lack basic services and infrastructure. Poor housing conditions exacerbate the impact of heat.
For instance, a study in Akure, Nigeria, found that poorer neighborhoods experience higher heat exposure than wealthier ones. While 78% of households in affluent areas had air conditioning, only 22% in poorer areas could afford such cooling solutions.
Urbanization amplifies heat. Replacing natural landscapes with concrete, asphalt, and high-density housing intensifies the urban heat island effect.
This phenomenon causes cities to retain more heat than surrounding rural areas. Temperatures in urban spaces can be several degrees higher, impacting air quality, energy use, and human health.
In Lagos, for instance, the average temperature is consistently higher in the city center than in outlying areas. Similar trends are seen in Nairobi and Accra. The dense, built-up environment traps heat, increasing discomfort and health risks, particularly for vulnerable populations.
Efforts to mitigate heat
To counteract rising temperatures, many cities are adopting green infrastructure solutions. These include rooftop gardens, urban forests, and cooling centers. The goal is to make urban areas cooler and more sustainable.
Rooftop Gardens
Rooftop gardens are increasingly common in Nairobi, where some commercial and residential buildings are turning rooftops into green spaces. This approach helps lower indoor temperatures by providing insulation from the sun. Studies show that a building with a rooftop garden can reduce internal temperatures by as much as 2°C.
But Nairobi faces challenges. Green rooftops require regular maintenance, which can be costly. Still, the immediate benefits of reduced heat are evident. Residents also report improved air quality around these buildings.
In Lagos, vertical greening systems are being tested, using high-density polyethylene pipes to grow vegetables on building walls. Residents have reported that these gardens not only yield fresh produce but also help cool their homes, with temperature reductions of up to 5°C recorded in areas where these systems are installed.
Urban Forests
Urban forests are offering another solution. By planting trees within city limits, cities can create natural shade, reduce heat, and improve air quality. Accra has launched a notable urban forestry initiative, aiming to increase the city’s green cover by 10% in the next decade.
Trees lower surface and air temperatures through shade and evapotranspiration, where water evaporates from leaves. This effect can reduce temperatures by up to 5°C in shaded areas. In Accra, urban forests have already made a noticeable difference in some neighborhoods.
However, urban forests require space. Accra’s program had to negotiate with landowners and developers to reserve green spaces in new developments. Funding remains another obstacle, as planting and maintaining trees in an urban environment demands consistent resources.
In Freetown, Sierra Leone, a project to plant one million trees aims to combat heat stress and improve air quality. Such initiatives are scientifically proven to effectively lower surface temperatures and enhance the overall urban environment.
Community Cooling Centers
In Lagos, community cooling centers are now available to the public. These air-conditioned spaces provide relief during extreme heat events. Residents without access to cooling at home can use these centers to escape the heat. While not a permanent solution, these spaces offer temporary relief and reduce heat-related illnesses.
Yet, maintaining cooling centers is costly. Power outages, a common issue in Lagos, further complicate the centers’ reliability. Limited funding also means that cooling centers are only in select neighborhoods, often missing the poorest communities who need them the most.
In Nairobi, local leaders are advocating for more cooling centers in informal settlements, recognizing the need for safe havens for vulnerable populations, especially the elderly and children, who are more susceptible to heat-related illnesses.
Hits and misses of green infrastructure
Green infrastructure, despite its promise, has limitations. Each approach—rooftop gardens, urban forests, cooling centers—comes with benefits and challenges. A study from the Nairobi Institute of Climate Adaptation found that while green spaces can reduce temperatures, they don’t eliminate heat stress. The same report highlights that temperature reductions vary based on city layout, vegetation type, and climate.
Data from Accra’s forestry program shows that while the initiative lowered local temperatures, it also faced resistance from developers who argued that green spaces reduce available land for housing. In Lagos, research indicates that cooling centers provide essential relief but are underfunded and understaffed.
Green projects like these require considerable investment, but funding remains a challenge. The World Bank estimates that African cities will need $40 billion annually to adapt to rising temperatures and other climate-related impacts. Without adequate resources, these initiatives risk stagnation.
Equity in access to cooling solutions
The effectiveness of these green infrastructure projects is supported by data. Studies indicate that urban greening can lower both air and surface temperatures.
For example, tree shading in Akure has led to reduced air conditioning use, saving households up to $218 annually on energy costs.
Furthermore, community engagement plays a key role in the success of these initiatives. Residents in informal settlements possess valuable insights into their local environments.
By involving them in the planning and maintenance of green spaces, cities can enhance the effectiveness of these projects. Training residents in micro-gardening techniques empowers them to take ownership of local green initiatives.
A major concern with green infrastructure is equitable access. Often, marginalized communities are the first to face extreme heat but the last to benefit from cooling initiatives. In Nairobi, lower-income neighborhoods have fewer green spaces and no access to rooftop gardens or cooling centers.
Equity-focused projects can help address this gap. In Accra, for example, a local NGO partners with the government to plant trees in low-income neighborhoods. In Lagos, city officials are considering subsidies to expand cooling centers in underserved areas.
