The greatest threat to humanity’s ability to survive on the planet is the climate crisis. The most significant change in the way humanity dwells is the move to the city. Without understanding the latter, we will never successfully address the former.

We already know that global growth of cities, particularly in the global south, will entrench and embed people in urban concentrations of informality. If the population of the globe is going to grow by the predicted 2.5 billion people by 2050 then a significant proportion will live in situations of urban residential precariousness or squat in city spaces where labour markets are informal (and invisible to the state) and places where people are vulnerable to environmental hazards, pollution and legal insecurity.

Climate change does not determine these urban outcomes. This is a two-way street, an interplay between the cities of the future and the way the climate crisis plays out. Where the 2.5 billion work and live will determine the metabolism of cities, the carbon footprint of an urban globe.

Negotiations at the COP are brokered between nation states. And while cities are present in Glasgow, they have varied levels of responsibility and devolved powers, variable propensity to make a difference to their own carbon footprint. Never has it been more important to increase our understanding of how people will dwell in future cities in order to shape policy responses to the climate crisis, particularly in cities structured by medium and long term informalities.

The significance of the scale of movement today defines an ethical tension and possible trade-offs between the needs of communities already suffering poverty and an obligation to those yet to be born and others yet to arrive in the city. A commonly used term of ‘climate refugees’ was coined in the 1990s, associated with the environmentalist Norman Myers.  In 2008, the UN  even predicted that there would be between 50 million and 200 million ‘environmental migrants’ by 2010. The phenomenon was often viewed through Eurocentric eyes, wary of the movement of people from one part of the world internationally, implicitly from global south to global north. But the ‘no show’ of the climate migration waves devalued the term, notwithstanding the ‘migration crisis’ of 2015/16 and contemporary events on the Polish border with Belarus.

Yet the scale of migration to the city reboots this narrative. In recent decades, the geographical scale of movement globally, in the global south from the global south is in reality continental. The distinction between internal and international migration begins to melt away in countries such as China and India, when considering the movement of people from Bihar to Mumbai or Szechuan to the eastern seaboard, the Pearl River Delta and the Yangste River city region of Shanghai in the growth of China’s new urban billion.

How we make sense of this interface between climate change and mobilities of people demands a more subtle understanding of the climate crisis – where we take account of how urban growth in the south impacts on the north and the south alike. What this means is that we need to understand those cities and the relationships with the informal sector and government. In particular, it is important to appreciate how the scale of informality provides challenge and opportunities alike. We need to understand how these living breathing cities will have a particular impact on climate outcomes.

We cannot see the urban globe through a lens that privileges cities that look like Dublin, more than Dar Es Salaam. This requires a different kind of thinking about the dynamics of cities. It is a kind of thinking that does not assume the technologies and the science of the global north works in the global south and generates identical social and economic outcomes.

We have to understand that the scale of migrants moving to the cities demands that we see instead through the eyes of those who have not yet arrived and have not yet been born.

By Michael Keith , a Professor in the Centre on Migration Policy and Society and Director of the Future of Cities Network and the International PEAK Urban global research programme on urban futures at the University of Oxford.