Sprawling Shanghai

Geographers who have studied the growth of China’s cities over the past four decades tend to sum up the pace of change with one word: unprecedented.

Via earthobservatory.nasa.gov

In 1960, about 110 million Chinese people—or 16 percent of the population—lived in cities. By 2015, that number had swollen to 760 million and 56 percent. (For comparison, the entire population of the United States was about 325 million people as of March 2017.)

The surge in urbanization began in the 1980s when the Chinese government began opening the country to foreign trade and investment. As markets developed in “special economic zones,” villages morphed into booming cities and cities grew into sprawling megalopolises.

Perhaps no city epitomizes the trend better than Shanghai. What had been a relatively compact industrial city of 12 million people in 1982 had swollen to 24 million in 2016, making it one of the largest metropolitan areas in the world.

Sprawling Shanghai

For more than four decades, Landsat satellites have collected images of Shanghai. The composite images above show how cities in the Yangtze River Delta have expanded since 1984. Note how Suzhou and Wuxi have merged with Shanghai to create one continuous megalopolis.

These “best-pixel mosaics” are made up of small parts of many images captured over five-year periods. The first image is a mosaic of scenes captured between 1984 and 1988; the second shows the best pixels captured between 2013 and 2017. This technique makes it possible to strip away clouds and haze, which are common in Shanghai.

A 2015 World Bank report noted that 7,734 square kilometers in the Yangtze River Delta Economic Zone—which includes Shanghai, Suzhou, Wuxi, and several other cities—became urban between 2000 and 2010. That is an area equivalent to 88 Manhattans. During that period, population in that zone increased by 21 million people.

See more images of Shanghai by clicking here.

NASA Earth Observatory mosaics by Joshua Stevens and Jesse Allen, using best pixel mosaics generated by Google Earth Engin with Landsat data from the U.S. Geological Survey. Caption by Adam Voiland.

Landsat 5 – TM
Landsat 8 – OLI