Ecological consequences of rapid urban expansion: Shanghai, China

Since China's economic reform in the late 1970s, Shanghai, the country's largest and most modem city, has experienced rapid expansion and urbanization. Here, we explore its land-use and land-cover changes, focusing on the impacts of the urbanization process on air and water quality, local climate, and biodiversity. Over the past 30 years, Shanghai's urban area and green land (eg urban parks, street trees, lawns) have increased dramatically, at the expense of cropland. Concentrations of major air pollutants (eg SO(2), NO(x), and total suspended particles) were higher in urban areas than in suburban and rural areas. Overall, however, concentrations have decreased (with the exception of NO(x)), due primarily to a decline in coal consumption by industry and in private households. Increased NOx pollution was mainly attributed to the huge increase in the number of vehicles on the roads. Water quality changes showed a pattern similar to that of air quality, with the most severe pollution occurring in urban areas. Differences in mean air temperatures between urban and rural areas also increased, in line with the rapid pace of urban expansion, indicating an accelerating "urban heat island" effect. Urban expansion also led to a decrease in native plant species. Despite its severe environmental problems, Shanghai has also seen major economic development. Managing the tradeoffs between urbanization and environmental protection will be a major challenge for Chinese policy makers.EcologyEnvironmental SciencesSCI(E)72ARTICLE7341-346