The human population is rapidly urbanizing, leading many observers to conclude that humans are leaving nature and the countryside behind. This is a perceptual error consistent with the technological optimism inherent in the prevailing expansionist cultural worldview. By contrast, ecological analysis reveals that modern cities are actually increasingly dependent on the goods and services of nature. This fact is merely obscured by technology and urbanization itself. Typical high-income cities appropriate the productive and assimilative capacity of a vast and increasingly global hinterland, resulting in an ‘ecological footprint’ several hundred times larger than the areas they physically occupy. In the next 27 years, the urban population alone is expected to grow by the equivalent of the total human population in the 1930s. This will double the 1970s urban presence on the Earth. Unfortunately, the conventional development path is biophysically unsustainable, calling for a radical transformation of our thinki...