Cities Have Doubled in Size Globally in the Last 20 Years, Study Says

Stephen Chen reports the findings of a new study from researchers in China ad published in Science Bulletin earlier this month. The key finding of the research: "The collective size of cities more than doubled over the past two decades in an unequal pace of expansion across the globe…"

"Measurements based on satellite images suggest the total size of urban areas increased from nearly 240,000 sq km (92,700 square miles) in the year 2000 to almost 520,000 sq km (200,000 square miles) in 2020," explain Chen.

The continent with the fastest rate of expansion: North America, with 3,921 square kilometers of developer land added every year over that time period. Chinese cities, infamous for a quick rate of urbanization and expansion, "trailed closely behind with a 73,300 sq km increase in total."

The research team behind the study created a new tool to define boundaries of cities, acknowledging the inaccuracies of previously extant automated processing tools, according to the article. The researchers also credited the quick rate of urban expansion in North America and China to people seeking more space to live in the relatively undeveloped expanses of the country and an intensive use of automobiles.

The news about the expansion of urban areas follows closely on the heels of news that the United Nations has updated its definition of urban, as compared to rural.