Urban land expansion: the role of population and economic growth for 300+ cities

Global urban populations are projected to increase by 2.5 billion over the next 30 years. Yet, there is limited understanding of how this growth will affect urban land expansion (ULE). Here, we develop a large-scale study to test explicitly the relative importance of urban population and Gross Domestic Product (GDP) growth in affecting ULE for different regions, economic development levels and governance types for 300+ cities. Our results show that population growth, more than GDP, is consistently the dominant determinant of ULE during 1970-2014. However, the effect of GDP growth on ULE increases in importance after 2000. In countries with strong governance, economic growth contributes more to ULE than population growth. We find that urban population growth and ULE are correlated but this relationship varies for countries at different developmental stages. Lastly, this study illustrates that good governance is a necessary condition for economic growth to affect ULE.

Automated summary

The growth of global urban populations will have a significant impact on urban land expansion, with population growth being the dominant factor. However, the importance of GDP growth in urban land expansion has increased since 2000. In countries with strong governance, economic growth plays a bigger role in urban land expansion than population growth. The study also highlights the correlation between urban population growth and urban land expansion, which varies across countries at different developmental stages.