Cities: the crucible of climate change

Geographically, vulnerability is hugely skewed across space. There are vulnerable neighborhoods, regions, and countries. Within any city, vulnerable populations are exposed to landslide, heat wave, and flood risks. These populations tend to cluster in densely populated areas where housing is cheaper. There is a significant geographical distribution of vulnerability that is closely linked to economic and social factors, shaping how it manifests across space and time.

Economically, vulnerability is manifest through uneven access to resources and the impact of markets. A prime example is the impact of climate change on food security; climate change impacts food production, leading to inflation and price spikes. The poorer a person is, the greater the proportion of their income they spend on basic needs, making them more exposed to these consequences.

Vulnerability to climate change is shaped by economic, social, and geographical factors, which influence how it is distributed across the world. At the same time, vulnerability exists at every scale. It is present in every neighbourhood, city, country, and region. No part of the world is immune: all places contain vulnerable populations and face the dilemma of adapting to climate change in ways that make communities safer and more equitable for everyone.

Cities are growing for multiple reasons. They are expanding spatially, absorbing surrounding areas, but they are also destinations for large-scale migration. This is especially evident in rapidly growing cities across Africa and Asia, where urban populations have increased dramatically—sometimes tenfold in size within a single generation over three or four decades. Many people living in these cities have moved there themselves and can therefore be considered lifetime migrants.

Climate change will be a key driver shaping how this urbanisation unfolds. It will influence whether cities develop in ways that are sustainable, safe, and resilient. Cities are the crucible of where climate change will occur and the crucible of where we need to adapt.

Take the city of Chattogram in Bangladesh, which grew from 1.5 million to 5.5 million people in 40 years. City authorities there recognize that climate change affects the port, coastal areas, and high-density migrant neighborhoods. The dilemma is to provide good infrastructure and stable employment while protecting citizens of this growing city from environmental changes and climate hazards. City planners believe that the quicker they integrate new migrant populations into the city, the better the chances of building a safe and resilient city for everyone. This process, led by government and non-government organizations, enhances the ability of these populations to have a voice in what the future city looks like.

To enable people to move, we must maximize agency and dignity. People choose to move. It is driven by aspiration and shaped by social contexts. Migration has occurred across all parts of the world and throughout generations. To view migration as a failure of adaptation overlooks the agency of individuals who actively choose to move. It can, in fact, be part of a positive strategy and an intergenerational bargain within families.

People moving because of climate change must be enabled to do so with dignity, ensuring they are not discriminated against in labor or housing markets. Another hidden consequence is the impact on people's identity. Fishing communities, for example, are defined by their harbour ports—places where people have built their lives, cultures, and heritage through fishing. As the impacts of climate change intensify, alongside overfishing and other forms of environmental change, this occupational identity and sense of cultural identity are increasingly at risk. These types of places need to be supported through the dilemmas of adaptation, even when that involves difficult transitions—such as exiting the fishery, moving away from long-held identities, and rethinking the future economic viability of these communities.

However, a great deal of cooperation also takes place outside this formal international framework. Countries often work closely with their neighbours. In the context of climate change, this includes agreements—such as those between Australia, New Zealand, and Pacific Island nations—where populations have long moved between countries and are now collaborating on climate-related challenges. These arrangements can involve facilitating migration, return migration, visa access, and other forms of mobility as part of a long-term response to climate change.

This is both a positive and appropriate approach. Many migration flows are focused on neighbourhoods. There is a gravity effect in migration, and so it does not need to be global agreements. Agreements between neighbouring countries to cooperate on climate change adaptation, and even on free movement between these countries, seem appropriate.

The consequences of climate change also affect transboundary resources—those shared between countries. Rivers flow across borders, and sea ice extends across national coastlines. There is a common assumption that climate change will inevitably lead to conflict over these shared resources. However, both historically and in the present, there is as much cooperation as there is tension. Countries frequently work together to manage transboundary resources in the face of climate change. In many ways, the potential for geopolitical conflict is linked as much to processes of decarbonisation—such as moving away from oil—as it is to the direct impacts of climate change. In practice, we are just as likely to see cooperation as conflict.

When we consider the consequence of climate change and the displacement of people, this is indeed a major issue. It must be addressed in ways that preserve dignity, allow people to have choice, and enable people to remain where they wish to stay.

The core issue, therefore, is not only about international displacement across borders—important as that is—but about allowing people to have choice, aspiration, and dignity to live where they feel they have a future.

Editor’s note: This article has been faithfully transcribed from the original interview filmed with the author, and carefully edited and proofread. Edit date: 2026