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IMAGE: Distribution of large cities in the world with greening built-up area (BUA), and greening built-up areas in Yangtze River Delta (YRD) city cluster
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Credit: The University of Hong Kong
The world has experienced dramatic urbanization in recent decades. According to the latest report from the United Nations (UN), the global population in 2018 was 7.6 billion and the urban population was 4.2 billion. By 2050, the global population is expected to soar to 9.7 billion, with 68% of the population living in urban areas. (Note 1)
In the first-ever study on the characteristics of urbanization in large cities around the world, researchers at the Department of Civil Engineering of the University of Hong Kong (HKU) analyzed cities' urban built-up areas (BUAs) expansion, population growth and greening BUA changes, and revealed a hugely uneven pace of urbanization in those cities in the last two decades. They warn against major challenges posed to sustainable development if the urban problems are not dealt with in a timely manner. The findings have been published in Nature Communication.