Despite accounting for less than 3% of global terrestrial area, cities have had an outsized impact on our approach to planetary boundaries, affecting biodiversity, materials consumption, and energy consumption. 

Studies show that cities have become responsible for 78% of carbon emissions, accounting for as much as 76% of global energy use, 60% of residential water use, and 76% of wood used for industrial purposes. 

At the same time, cities house significant infrastructure and population, which not only drives cities' significant environmental footprint but also heightens their vulnerability to climate change impacts, particularly for urban poor communities. More than half the world now lives in cities, with urbanization rates increasing rapidly. In fact, urban-poor communities in cities like Jakarta, Delhi, Karachi, Manila and Lagos now represent some of the most vulnerable communities across the globe by key climate indices. 

Cities, with their dense populations and critical infrastructure like power grids, transportation, and water systems, are highly vulnerable to climate change impacts, exacerbated by the loss of natural ecosystems. Urban expansion often destroys green spaces, wetlands, and forests, which naturally mitigate floods, regulate temperatures, and store carbon. 

Construction in Nairobi City

Construction in Nairobi City. Photo: Susan Onyango/ WRI

This degradation amplifies on one hand climate risks, as cities lose natural buffers against storms and heatwaves, leading to increased flooding, urban heat islands, and service disruptions; and on the other hand heavy economic loss as nearly half of GDP from cities around the world – over $31 trillion USD – is lost. 

Emerging towns, municipalities, and local city actors worldwide are transforming this narrative by showing the potential of cities to respond to climate demand by integrating nature-based solutions (NbS) and preserving natural landscapes. 

While not a new concept, NbS has gained significant traction in recent years. By weaving NbS, such as parks, garden roofs, and green stormwater management, into the fabric of urban development, cities are creating livable spaces that are not only environmentally sustainable but also more equitable and economically vibrant. 

For instance, cities like Kigali in Rwanda, Dire Dawa in Ethiopia, and Johannesburg in South Africa are implementing gender-responsive NbS, including urban tree planting, reforestation, afforestation, and agroforestry. These efforts aim to address climate impacts such as urban flooding, landslides, soil erosion, and biodiversity degradation. 

Seedlings for urban tree planting in Johannesburg

Seedlings for urban tree planting. Photo: Nikara Mahadeo, WRI

Cities are increasingly becoming a focal point for challenges, vulnerabilities, and solutions related to people, nature, and climate. Africa, the fastest-growing region on the planet, is particularly affected. By the turn of the century, nearly half of all people born will be African. By 2050, over 60% of Africans will live in cities, which will collectively be home to more than a quarter of the world's urban population. Yet, more than two-thirds of the infrastructure African cities need has not been built. 

Addressing these vulnerabilities presents an opportunity to integrate Nature-based approaches into critical socio-economic infrastructure. This integration can provide numerous co-benefits for the continent, promoting resilient urban development. Failure to act could result in catastrophic global consequences as our climate changes. 

Where is the capital for urban nature solutions? 

Meeting the continent’s urban development needs will require an estimated $130–$170 billion annually. Urgent reforms are necessary to mobilize the financing required to build sustainable and resilient cities. 

The theme of the African Development Bank Annual Meetings for 2025 Making Africa’s Capital Work Better for Africa’s Development,” was a call not for aid or rescue, but for financial recalibration. It reflects a growing recognition that Africa’s transformation will be driven by better use of its resources to benefit its people. 

A recent report from World Resources Institute and the World Bank, developed in collaboration with the African Development Bank, highlights the growing momentum of nature-based solutions in sub-Saharan Africa. 

The most comprehensive repository of nature-based initiatives on the continent, the study leverages data to explore and identify trends in where nature-based solutions are being implemented and how they are being financed. 

Between 2012 and 2023, nearly 300 new resilience projects based on nature secured over $21 billion in funding in Africa. From 2012 to 2021, these projects increased consistently at an average annual rate of 15%. 

While the number of nature-based solutions projects is growing, we find a striking trend: only 16% have been implemented in cities. Multilateral Development Banks funded 70% of projects, especially green-gray ones, often with support from national governments and multilateral donors like UNEP, UNDP, GEF, and the Green Climate Fund. 

Types of Lead Project Developers

Few projects were mainly funded by the private sector, showing a need for greater engagement to scale up financing. This is despite the potential of nature-based solutions to address multiple urban challenges from disaster preparedness to water management, public health, air quality, safety, equality, and even job creation. 

More investment in urban nature-based solutions, such as natural water retention and green-gray drainage, is needed. 

How Can We Catalyze More Finance for Nature-Based Solutions in African Cities? 

Development finance institutions play a crucial role in enhancing resilience in African cities. Here are some ways African Development Bank and similar development finance institutions can help finance resilience in African cities facing challenges related to climate change, urbanization, and infrastructure development. 

Bring the Private Sector to the table

Development finance institutions can significantly boost climate finance for NbS by deploying blended finance models to de-risk private sector investments, unlocking substantial capital for urban resilience. 

By offering guarantees, first-loss facilities, or concessional loans, development finance institutions can attract private investors to fund nature-based solution projects integrating green infrastructure, such as urban wetlands or reforestation, with traditional gray infrastructure. 

The African Cities Water Adaptation Fund (ACWA Fund), launched by WRI at COP27, exemplifies this approach. It aims to leverage $5 billion for water resilience solutions in 100 African cities by 2032 through grants ($222 million) and direct investments ($288 million). 

By partnering with initiatives like the ACWA Fund, development finance institutions can scale investments in nature-based solutions, ensuring African cities tackle climate challenges like flooding and heatwaves while fostering economic growth. 

Traditional and innovative finance, including guarantees, carbon credits, and green bonds, piloted by the AfDB through tools like the Adaptation Benefit Mechanism and the Africa Carbon Support Facility, currently under development, can unlock the finance cities need to accelerate resilience. However, cities also need investments in upstream project development and policy alignment. 

Mainstream Nature-Based Solutions in Urban Development 

Nature integration is fundamental to urban resilience. It helps manage stormwater, reduce urban heat, and filter pollution while building socioeconomic resilience. As development finance institutions look to fill the infrastructure gap in African cities, they must treat nature-based solutions as core infrastructure on par with roads and pipelines, investing capital accordingly. This can be achieved by expanding city-focused programs like the AfDB’s Urban and Municipal Development Fund, which supports project preparation, urban planning, and resilience strategies, and building local capacity to develop bankable NbS projects like urban green spaces or watershed restoration. 

The African Cities Water Adaptation Platform, a WRI-led coalition of 24 institutions, complements this by providing technical assistance to cities like Kigali and Johannesburg, helping design and finance NbS projects. By integrating NbS into sectoral investments like water, transport, and energy, development finance institutions can ensure resilient urban development, responding to the needs of the 70% of African cities facing severe climate risks like droughts, flooding and landslides. 

Strengthen Municipal Financial Capacity 

Enhancing municipal financial management is pivotal for scaling NbS. Development finance institutions can lead by supporting initiatives like the AfDB’s Municipal CFO Initiative, building financial expertise in African cities. Empowered municipalities can access and manage funds for NbS projects, such as urban tree planting or permeable pavements, ensuring sustainability. Empowering cities can look like well-defined property rights and tax systems, cadastral data and improved municipal financial management. Through technical assistance and credit enhancement tools, DFIs can help strengthen financial readiness. 

Through partnerships with coalitions like the ACWA Platforms, DFIs can foster governance structures and monetary systems that equip city governments with the capacity to bridge the $66 billion annual funding gap for water and sanitation, ensuring NbS are prioritized. 

Invest in Green-Gray Infrastructure 

WRI’s research shows that the most significant investments in nature happen when accompanied by investments in grey infrastructure. Green-gray infrastructure combines natural systems and engineered structures to help climate-vulnerable cities achieve a range of benefits. Programs like WRI’s Green-Gray Infrastructure Accelerator offer technical assistance to 11 cities in sub-Saharan Africa in integrating NbS with traditional infrastructure. Combining mangrove restoration with seawalls, for example, enhances flood protection while supporting biodiversity. Other examples include wetlands, levees, bioswales, and urban green spaces. The Accelerator provides technical assistance across project stages, ensuring tailored solutions with co-benefits like job creation. Development Finance Institutions can draw on the joint AfDB and Global Center on Adaptation’s Africa Acceleration Adaptation Program, which integrates NbS into $7 billion worth of infrastructure investments, to scale support to programs like the Accelerator and amplify green-gray solutions addressing Africa’s $100 billion infrastructure financing gap. 

Convene and Align Stakeholders

As conveners, development finance institutions can align stakeholders by supporting platforms such as the African Urban Forum, fostering collaboration on urbanization challenges. They can also support the ACWA Platform, uniting cities, research institutes and private sector actors to advocate for water resilience solutions, guided by the 2030 Joint Agenda for Urban Water Resilience. By coordinating donor efforts and building partnerships, development finance institutions can enhance the enabling environment for NbS, ensuring equitable access to benefits for vulnerable communities, where only a fraction of climate investment supports urban water services. 

If Africa’s capital is to work better for its development, it must be directed toward the places where risks are highest and opportunities for transformation are greatest: our cities. Urban resilience, especially through nature-based solutions, is not just a climate or environmental issue; it is a capital allocation and development effectiveness issue.