cities 2030

Gigalopolises: Urban Land Area May Triple by 2030

Suburbs, slums and city centers may grow by more than a million square kilometers—much of it now home to wildlife

By David Biello

More than half of the world's expected nine billion people will live in giant urban expanses by 2030 as cities and their hinterlands occupy an additional 1.2 million square kilometers, thereby tripling in size. That's an additional 1.35 billion people living in cities, suggesting that urban areas that currently occupy roughly 3 percent of the planet's surface will continue to expand. By comparison, urban areas increased by just 58,000 square kilometers between 1970 and 2000.

In new work published in Proceedings of the National Academy of Sciences, urban environment researcher Karen Seto of the Yale School of Forestry and Environmental Studies and her colleagues first divided the global land area into discrete parcels and, using predicted gross domestic product growth, population growth and urban land area cover in 2000, they projected which parcels had a high or low probability of succumbing to citification over the next few decades. Using that model, 1.2 million square kilometers of land have probabilities higher than 75 percent of becoming citified and nearly six million square kilometers have some probability of going urban.

 

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URBAN GROWTH: If present trends continue, urban areas may triple in size--much as Las Vegas grew over the last several decades as evidenced by these satellite photos.Image: Courtesy of NASA