Cities at the climate crossroads: can growth be sustainable?

Can cities continue to grow without destroying the planet? A new study from the Institute of Environmental Science and Technology at the Universitat Autònoma de Barcelona (ICTA-UAB), Spain, offers insight into this complex issue. While there is no general answer to the question of whether sustainable urban growth is possible, as it depends on local physical conditions and development levels, what is clear is that continued urban growth is not desirable everywhere. More sustainability will require rigorous planning, effective governance, and a critical reassessment of dominant development narratives.

Although cities are key players in the fight against climate change, their economic, demographic, and spatial growth continues to generate severe environmental impacts that are difficult to control. Amid the rise of economic approaches such as green growth, degrowth, and post-growth, this new study warns of the lack of clear empirical evidence on their real effectiveness in urban contexts.

Published recently in Nature Cities, the research provides the first overview of the debate on economic growth and the environment in cities. To this end, it draws on empirical evidence from disciplines including urban economics, environmental governance, urban planning, and climate and sustainability science.

The article comparatively reviews three contemporary approaches to urban growth: green growth, which relies on technology and efficiency to reduce impacts; degrowth, which advocates reducing production and consumption to preserve ecosystems; and post-growth, which proposes deprioritizing GDP in favor of well-being and sustainability.

These approaches are analyzed across four dimensions of urban growth—economic, demographic, spatial, and environmental—considering both their impacts and political feasibility.
“The main contribution of the study is a comparative conceptual framework that helps understand how different forms of urban growth interact and what implications they have for the future of cities,” says Charlotte Liotta, researcher at ICTA-UAB and lead author of the study. Through this framework, researchers examined real-world examples of cities experimenting with alternative approaches, such as Barcelona’s superblocks and Amsterdam’s doughnut strategy.

No One-Size-Fits-All Solutions
The study does not advocate a single vision of growth but neutrally and evenly analyses the strengths and weaknesses of each approach. “One of the main conclusions is that empirical evidence on the decoupling of economic growth and environmental harm in cities remains limited, which calls for caution regarding the promises of green urban growth,” notes Jeroen van den Bergh, ICTA-UAB researcher and co-author of the study.

At the same time, the research questions certain degrowth proposals that advocate reducing the size of urban centres, arguing that large cities are not intrinsically unsustainable: their density and scale can offer real environmental benefits—such as improved public transport and more efficient housing—if properly planned.

Regarding population growth and urban expansion, the article warns of their environmental consequences if not strictly managed, including increased consumption and emissions, biodiversity loss, and soil sealing.

Against simplified views of urban development, the authors advocate for a more critical, integrated, and evidence-based perspective. The study does not aim to close the debate but rather to provide tools to better understand it—recognizing that sustainable solutions will always depend on the political, social, and environmental context of each city.