The built environment and the ecosphere: A global perspective

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 thinking about urban form and function. Buildings account for 40% of the materials and about a third of the energy consumed by the world economy. Combined with ecocity design principles, green building technologies therefore have the potential to make an enormous contribution to a required 50% reduction in the energy and material intensity of consumption globally. The needed dematerialization increases to 90% in the high-income countries. Such enormous gains in material productivity are unlikely in the absence of significant ecological fiscal (tax) reform. Ironically, then, the most effective path to green buildings and ecocities may be intensive lobbying for higher taxes on primary energy and materials.