World's Cities Are Growing Upward Than Outward, Says Satellite Study

A city usually starts as a small town and grows in area after new buildings are made and boundaries are extended. However, in recent times, taller buildings are seen as one of the elements of any modern city. Now, a new study has revealed that cities are soaring upward at a greater rate than they are spreading out. This new finding can reshape how we use our resources and the environment.

The satellite study, published in the journal Nature Cities, was conducted by a team of Earth scientists, environmental engineers and geomaticists. The team studied two types of satellite data by measuring the footprint and height of buildings or more than 1,500 cities globally from the 1990s to the 2010s. One kind displayed a city's footprint, making it possible to calculate its size in two dimensions. The second kind, which used microwaves, made it possible to estimate city expansion in three dimensions and took skyscraper construction into account for upward growth.

According to the study, cities are increasingly growing upward instead of outward, with Asian cities leading the way. Previously, cities expanded by occupying more territory.

David Wilson, a professor of geography at the University of Illinois Urbana-Champaign, said that the study is "extremely interesting" and the change from horizontal to vertical growth in urban areas has both pros and cons.

"This trend is very positive for promoting sustainability and resource management. Less blocks, neighbourhoods, and communities will require the hand of government to reach out and expend scarce resources for policing, fire protection, and 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."

According to the study, larger cities with a population of more than 10 million people are at the forefront of the vertical transition.

In recent decades, China's urban growth has experienced a remarkable transformation. Wide outward growth was the initial hallmark, but more recently, taller structures are displacing shorter ones as vertical development has taken hold. Nonetheless, Europe's urban growth patterns have not changed much, with outward growth continuing to predominate and vertical development growing at a very slow rate.

Fast upward growth was rare in the 1990s but considerably more typical by the 2010s. Rapid outward development, on the other hand, declined throughout this time.