Beyond city expansion: multi-scale environmental impacts of urban megaregion formation in China

Environmental degradation caused by rapid urbanization is a pressing global issue. However, little is known about how urban changes operate and affect environments across multiple scales. Focusing on China, we found urbanization was indeed massive from 2000 to 2015, but it was also very uneven, exhibiting high internal city dynamics. Urban areas in China as a whole became less green, warmer, and had exacerbated PM2.5 pollution. However, environmental impacts differed in newly developed versus older areas of cities. Adverse impacts were prominent in newly urbanized areas, while old urban areas generally showed improved environmental quality. In addition, regional environmental issues are emerging as cities expand, connect and interact to form urban megaregions. To turn urbanization into an opportunity for, rather than an obstacle to, sustainable development, we must move beyond documenting urban expansion to understand the environmental consequences of both internal city dynamics and the formation of urban megaregions. Massive urbanization in China caused overall environmental degradation: environmental quality in old urban areas was generally improved but adverse impacts were prominent in newly urbanized areas.

Automated summary

The environmental degradation caused by rapid urbanization is a pressing global issue. In the case of China, the massive and uneven urbanization from 2000 to 2015 resulted in overall less green and warmer urban areas with exacerbated PM2.5 pollution. However, the environmental impacts differed between newly developed and older areas of cities, with adverse impacts being more prominent in newly urbanized areas. Additionally, as cities expand and connect to form urban megaregions, regional environmental issues are emerging. Understanding the environmental consequences of internal city dynamics and the formation of urban megaregions is crucial in turning urbanization into an opportunity for sustainable development.