An international team of researchers has used satellite images to map urban growth between 1985 and 2015. Each image captured 900 square meters of ground, a level of detail that allowed the scientists to study land-use change over time. In a paper in Nature Sustainability , they report that global urban extent has expanded by 9,687 km 2 per year—a rate four times greater than a previous estimate, suggesting an unprecedented rate of global urbanization. Urban area dynamics during 1985–2015 at the global and continent scales. a, Global urban area dynamics over the past three decades. The data were produced using 30 m resolution Landsat data. The slope is derived from linear regression, with an uncertainty range at the 95 th confidence level. b, Slopes of urban area growth over continents. The bottom and upper bounds of the error bars indicate uncertainty ranges (95% confidence interval). Regressions over these […]