Climate action in fast-growing cities
28 February 2023
In the margins of global climate politics, small-scale experimental initiatives are reducing carbon emissions. Vanesa Castán Broto is researching how local responses in the world’s fastest-growing cities reshape our understanding of climate action.
Climate action in fast-growing cities

Cities are on the front lines of the growing risks associated with climate change, such as coastal flooding, extreme heat, and storm surges. Despite these looming challenges, “when looking at climate change literature, I realized that the fastest growing cities, which are often located in the global south, have not received much attention,” says Vanesa Castán Broto. “There is a real gap in understanding what climate change policy and action means in rapid urbanization contexts and how this will affect the next decades.”

Global cities like London and Toronto are leading climate debates, Castán Broto observes. “The influential C40 Cities Climate Leadership Group, for instance, is very inclusive in many ways but in their view, cities are places with a government that functions well and has access to resources. For many fast-growing cities in Asia or Africa, this does not count. The local government sometimes does not even reach the whole territory and does not have many resources.”

Still, in such places far from international policy arenas, action to tackle the adverse effects of global warming is taking place, often involving many different actors. “In theory, you always need to have institutional support if you want to achieve outcomes at scale”, Castán Broto says. “We question that: perhaps there is an impact that we do not yet know how to measure. Perhaps there are new ways in which we can understand climate action by looking at rapidly urbanising areas.”


How did you select the ‘ordinary’ cities that you are studying?

“I selected the cities by looking at the UN World Urbanization Prospects database. At first, I selected all cities under one million people with a growth rate of over four per cent, narrowing the study down to 113 cities. However, the 2018 update of the population data showed that rapid urbanization was intensifying more than previously thought. I had a list of hundreds of cities with the same search criteria. Since studying so many cities was not feasible, I had to narrow down our search and eventually select 140 cities as a sample, all of which are in Africa and in Asia. Take, for example, the countries of Mozambique and Malawi that I have visited recently. In the city of Mzuzu in the north of Malawi, rapid urban growth is creating hybrid forms of organization, urban and rural at the same time, which is causing conflicts between traditional leaders and the local state government.“

For such a large-scale study, what are your data sources?

“For the theoretical part, I am looking at how these rapidly growing cities are represented in the global narrative of climate change, and how key policy ideas such as ‘responsibility’ and ‘action’ are conceptualised. The second data set concerns specific initiatives that originated in global cities and are ‘travelling’ to fast-growing cities; we follow urban climate innovations such as Bus Rapid Transit (BRT) systems or solar home systems to see how they change from one location to the next, and how the context shapes their implementation.

The third pillar focuses on the 140 cities that inspired the project and looks at what kind of climate actions are happening there. For each city, we created a database of climate initiatives using 14 different search languages. Local researchers helped us to trace these initiatives, triangulating information with policy reports and newspaper articles. My team collected 1500 initiatives, which we then revised down to 851 projects that contain some evidence of social or technological innovation. Some initiatives are particularly fascinating – for instance, when they take advantage of local resources – and we then study them more deeply during our fieldwork.”

Could you give a few examples of interesting initiatives?

“In Lobito, Angola, we are looking at a project that aims to restore the mangrove forest, which was motivated by local concerns that the flamingos would disappear. Activists took up the concerns about the loss of biodiversity and connected these to climate change. They created alliances with all kinds of businesses and with other initiatives, such as local actions for waste collection, wetland restoration, and sustainable fishing. In Quelimane, in the north of Mozambique, we are studying a bike-sharing initiative, again a project that focuses very much on using local resources. We have also worked together with researchers in the Philippines, looking at innovations in rapidly urbanising areas such as urban agricultural projects in informal settlements and projects that seek to improve water sanitation systems. Providing such an infrastructure is crucial where the population is growing rapidly.”

What novel insights has your research produced so far?

“When we reviewed the global climate policy documents, we noticed a shift in discourse, from climate motivation to climate action. During COP27 in Sharm el-Sheikh, it also became evident that we are now in a moment in which everybody wants to see action and results. This has created a different landscape and a new understanding of ‘acting for climate change’. Similarly, we are observing changes on the ground. People have concerns about their direct environment and want to move forward, so they develop innovative actions related to their daily lives. This type of innovation – ‘mundane innovation’ – is becoming very common and is a direct response to people’s concerns.

Surprisingly, however, communities have a very small role in climate change action, which is most often initiated by the local or national government, so called ‘top down’ projects. There is very little leadership of communities in these initiatives, while research has shown that they are often effective in delivering action that reduces both vulnerability and carbon emissions. This is a missed opportunity in the pathway towards sustainable futures. Until now ‘mundane innovation’ has not permeated any public forum, and place-based ideas about how to act against climate change are too often excluded from global climate change policy.”



Vanesa Castán Broto is Professor of Climate Urbanism at the Urban Institute, University of Sheffield. Vanesa serves as a Lead Author for the Intergovernmental Panel on Climate Change (Working Group II, Vulnerability, Impacts and Adaptation), and she directs the interdisciplinary project Community Energy and Sustainable Energy Transitions in Ethiopia, Malawi and Mozambique (CESET), funded by the UK's Global Challenges Research Fund. Vanesa has published widely on cities and climate change governance and on the governance of energy transitions, including her book Urban Energy Landscapes (Cambridge University Press).

Project information

Low Carbon Action in Ordinary Cities
Climate action in fast-growing cities
Vanesa Castán Broto
Host institution:
Urban Institute, University of Sheffield
United Kingdom
Call details
ERC-2018-STG, SH2
ERC funding
1 393 979 €