Planting trees to combat urban heat can worsen the precarity of those it purports to protect. An international research team studied this phenomenon at the continental African scale: green-blue developments are associated, in the study, with an increase in housing price indices and indicators of emerging gentrification; residential instability of poor households is not directly measured. The study provides a first continental causal assessment of changes associated with emerging gentrification following green-blue adaptation. Without equitable housing and land policies, the authors argue that resilient infrastructure can increase inequalities; their study does not demonstrate quantified capture of gains by property owners rather than by tenants.

The Essentials

  • Urban climate adaptation through green spaces produces a documented unintended effect: rising land prices that displace low-income households.
  • A continental African study demonstrates for the first time this causal link between green and aquatic developments and housing instability for the poorest (African Climate Insights / Issues.fr).
  • The mechanism is that of green gentrification: environmental improvement attracts solvent households, property owners raise rents, precarious tenants leave.
  • Without land regulation associated with adaptation projects, climate policies risk reproducing at large scale what urban renovations have always produced: the eviction of those they aimed to help.
  • Tools exist to separate climate benefits from land rent, but their deployment in sub-Saharan Africa remains embryonic.

African Cities Under Thermal Pressure

African urbanization is the fastest in the world. According to United Nations projections, the continent should have over one and a half billion urban dwellers by 2050, compared to around 600 million today. This growth is concentrating in metropolises that were not designed for the temperatures they already experience, let alone those to come. Accra, Nairobi, Kinshasa, Lagos: cities where urban heat islands transform some neighborhoods into furnaces, where the poorest populations live in precarious housing without air conditioning, often in metal shacks, without access to shade or water.

The response from urban planners and international funders has gradually turned toward what is called nature-based solutions: parks, community gardens, vegetated canals, green roofs, cooling corridors. These infrastructures have genuine thermal efficiency. They can lower the perceived temperature by several degrees within their immediate perimeter. They improve air quality, reduce rainwater runoff, and constitute a safety net for populations exposed to heat waves. These are legitimate climate adaptation policies, supported by the IPCC and financed by international public and private funds.

Research also examines socio-economic changes associated with these developments at the continental scale.

Green Gentrification, From New York to Nairobi

The phenomenon is not new in Northern cities. In New York, the High Line linear park, inaugurated in 2009 on a former elevated railway, became the symbol of a well-documented process: green development attracts affluent households, drives up prices, and pushes out tenants who lived there before the plantings. Studies of Chicago, Melbourne, and Amsterdam have confirmed the regularity of the mechanism. It is called “green gentrification,” or sometimes “eco-gentrification.”

What was missing was equivalent demonstration for African cities on a scale large enough to be conclusive. The study fills this gap. Based on satellite and socio-economic data from 5,503 localities across 32 countries, the study estimates that green and blue infrastructure is causally associated with increases in housing prices and signals of emerging gentrification. It documents indicators consistent with emerging gentrification without directly measuring the residential stability of low-income households.

The result is both logical and disturbing. Logical, because anything that improves living conditions tends to increase land value—this is the basic mechanics of real estate markets. Disturbing, because climate adaptation policies are precisely designed to protect first and foremost the populations most vulnerable to heat, who are also most often the poorest.

A Three-Part Mechanism

Understanding why green space displaces the poor requires following the causal chain in its entirety.

First phase: a green space or aquatic development is created in a dense working-class neighborhood. Temperature drops, the environment becomes more pleasant, perceived quality of life increases. This is the intended effect.

Second phase: in a theoretical mechanism of green gentrification, this improved environment can attract higher-income households, investors, and developers. Demand for housing in the neighborhood may increase. The African study measures neither these arrivals, nor rent increases, nor forced departures. The study finds an increase in the housing price index; it does not directly measure land appreciation.

Third phase: low-income tenants may be unable to keep up with rising rents, especially in the absence of a formal contract, and be forced to leave. They may relocate to peripheral neighborhoods that are less well-equipped, more exposed to heat, and less well served by public services. Adaptation projects can create a risk of excluding intended beneficiaries; asserting displacement to more exposed areas requires individual or local data.

This mechanism is particularly harsh in African contexts for several reasons. First, the share of informal tenants there is very high: without a written lease, without legal protection, they have no recourse against rent increases. The quality of housing and land regulations can influence the distributive effects of developments; complete capture of rent by property owners is not demonstrated by this study. Finally, rehousing alternatives are rare and often far from employment centers.

If displacement occurs, displaced households may lose access to the neighborhood’s climate benefits; this scenario is not directly measured by the study.

African Spatial Data on Urban Vegetation

The interest of the continental study lies in its geographic scope. Previous research on green gentrification in Africa focused on isolated cases: a project in Addis Ababa, a park in Cape Town, a renovated canal in Accra. The limitation of these case studies was obvious: difficult to draw conclusions generalizable to such diverse contexts.

The continental approach changes this. By aggregating spatial data on housing price indices and the presence of green developments across many African cities, researchers were able to study changes associated with green-blue adaptation. The study identifies an average association across its continental sample; it does not allow us to assert that the mechanism is universal. The study finds an average association at large scale between green-blue adaptation and rising housing prices; effects may vary by location and type of intervention.

This does not mean that each green project mechanically displaces tenants. The study examines different green-blue components and certain housing devices; it does not allow us to broadly assert that the effect varies according to local real estate tension. The study shows, on average, changes consistent with emerging gentrification; it neither quantifies land rent nor its appropriation in most contexts.

This continental documentation comes as climate financing for African cities increases. The Green Climate Fund, the African Development Bank, and international NGOs are multiplying urban greening projects in disadvantaged neighborhoods. The thermal utility of these projects is real; their design must, however, integrate the distributive effects that this study now documents with solid data.

Separating Climate Benefits From Land Rent

Instruments exist to prevent the climate benefits of green spaces from being captured by property owners alone. They have been tested in several contexts with variable but encouraging results.

The first is direct rent regulation within development perimeters. Several Latin American cities have experimented with rent control zones around green infrastructure projects to prevent speculative increases during the phase when new residents appropriate the neighborhood. The difficulty in African contexts often lies in the weakness of municipal administrations and the informality of rental markets.

The second is public capture of part of the land value gains generated by development, through taxes or contributions from property owners. If the green space raises the value of land, part of this increase can be redistributed as affordable housing or compensation for threatened tenants. Singapore and several Brazilian cities have developed mechanisms of this type. The gray area remains financing the transition: a land capture mechanism presupposes administrative and political capacity that few African municipalities possess today.

The third is affordable housing production integrated from the design phase of adaptation projects. Combining green spaces, affordable housing, and tenure security can reduce displacement risk without automatically eliminating it. This is the approach defended by several urbanists specialized in cities of the Global South, and that some funders now condition their financing on.

The fourth path, less institutional but potentially faster to deploy, is the formalization of rental rights. When tenants have a written lease, legal notice periods, and recourse in case of wrongful eviction, their vulnerability to land rent decreases. Organizations like Slum Dwellers International work precisely on documenting occupation rights in African informal neighborhoods. Nature-based solutions, such as constructed wetlands, can moreover integrate into these neighborhoods without going through formal development projects that trigger speculative spirals.

The African Trajectory by 2040

The issue goes beyond the gentrification mechanism alone. The question posed by the continental study is broader: can urban climate adaptation in Africa be equitable, or does the land rent it creates structurally capture it for property owners’ benefit?

Two trajectories are conceivable by 2040.

In the first, international climate financing continues to grow without equity conditions being integrated into projects. Green spaces multiply, thermal benefits are real, but neighborhoods progressively become middle-class. The populations most vulnerable to heat concentrate in non-developed peripheries that are more exposed and less well served. Urban climate adaptation then becomes an additional inequality factor in already highly unequal cities. This scenario is plausible in contexts where municipal administrations are weak and real estate markets poorly regulated, which describes a large share of African metropolises today.

In the second trajectory, documentation of the phenomenon at the continental scale produces a change in practice among funders and governments. Adaptation projects systematically integrate mechanisms to protect precarious tenants: temporary rent control, capture of land value gains, affordable housing production associated with green spaces. Several pioneering cities test these combined approaches and publish results. International organizations condition their financing on these guarantees. This trajectory is more difficult, politically and administratively, but precedents exist: the city of Medellín, Colombia, showed that radical urban transformation can be conducted without massively displacing original populations, provided that affordable housing is central to the project.

The difference between the two trajectories can lie in the political design of projects, as well as in technology and financing. Inequalities result from the interaction between the design and location of green spaces, real estate markets, land rights, and public policies. The study warns that without equitable housing and land-use policies, green-blue adaptation can reinforce gentrification and inequality dynamics; it does not directly measure population displacements.

The signals to watch in the coming years are clear. First, the integration of social conditions in climate financing from major institutions: African Development Bank, Green Climate Fund, bilateral development banks. Next, the emergence of African cities experimenting with land capture mechanisms and publishing their results. Finally, the capacity of informal resident organizations to weigh on adaptation project design by imposing guarantees of remaining in place before work begins. The question of equity in transitions arises identically in other fields: each transformation that improves an environment creates rent, and politics consists of deciding who benefits.

According to the IEA, approximately 600 million Africans did not have access to electricity; this figure does not allow us to assert that 600 million urban Africans combine thermal and residential precarity. The African urban population should approximately double by 2050; no identified source allows us to infer that the number of people combining thermal and residential precarity will double. Climate adaptation at this scale is a necessity. The question remains open: will it be designed to stabilize the most vulnerable, or to displace them to spaces that the most affluent have not yet discovered?

Sources

  1. Issues.fr / African Climate Insights, Climate Adaptation Could Favor Gentrification in African Cities
  2. United Nations, Department of Economic and Social Affairs, World Urbanization Prospects 2024
  3. IPCC, Sixth Assessment Report, Working Group II Contribution, Africa Chapter (2022)
  4. Slum Dwellers International, reports on documentation of occupation rights in sub-Saharan Africa