New Study Reveals Cities are Growing Upwards Faster than Outwards, Highlighting Sustainability and Equity Challenges

A recent study has uncovered a significant shift in urban development patterns, revealing that cities are now growing upwards at a faster rate than they are expanding outwards. Traditionally, a city begins as a small town and grows in area as new buildings are constructed and boundaries are extended. However, in the modern era, taller buildings have become a defining feature of many urban landscapes. This new finding could have profound implications for resource usage and environmental impact.

The satellite-based research, published in the journal Nature Cities, was carried out by a multidisciplinary team of Earth scientists, environmental engineers, and geomaticists. The team analyzed two types of satellite data to measure the footprint and height of buildings in over 1,500 cities worldwide, spanning from the 1990s to the 2010s. One dataset displayed a city’s footprint, enabling calculations of its size in two dimensions. The second dataset, which utilized microwaves, allowed for the estimation of city expansion in three dimensions, including the construction of skyscrapers for upward growth.

According to the study, cities are increasingly expanding vertically rather than horizontally, with Asian cities at the forefront of this trend. Historically, urban growth involved the occupation of more land.

David Wilson, a professor of geography at the University of Illinois Urbana-Champaign, described the study as “extremely interesting” and noted that the shift from horizontal to vertical growth in urban areas has both benefits and drawbacks.

“This trend is very positive for promoting sustainability and resource management. Less blocks, neighbourhoods, and communities will require the hand of the government to reach out and expend scarce resources for policing, fire protection, and the provision of housing services,” he told Newsweek.

He added, “At the same time, the prognosis for fostering equity in the city is grim. Dramatic increases in vertical development, especially in mega-cities, often signal the realities of downtown gentrification kicking into hyperdrive, a notorious process for displacing and further isolating the poor and the stigmatized.”

The study highlights that larger cities, with populations exceeding 10 million people, are leading the shift towards vertical development.

In recent decades, China’s urban growth has undergone a remarkable transformation. Initially characterized by widespread outward expansion, the focus has now shifted to vertical development, with taller buildings replacing shorter ones. In contrast, urban growth patterns in Europe have remained relatively unchanged, with outward expansion continuing to dominate and vertical development progressing at a much slower pace.

The rapid upward growth that was rare in the 1990s has become significantly more common by the 2010s. Meanwhile, the rate of outward expansion has decreased during this period.