Urban nature: What can nature do for people in cities worldwide?
The question has often been asked the other way around, especially in our contemporary era: What can people do for nature? But increasingly, ecologists and conservationists, planners, policymakers, and many others are asking: What can nature do for people? This question has deep roots in urban history. Our City Nature project uses a comparative historical approach to examine the causes and consequences of the tremendous variation in the presence of nature—in a broad array of forms—in cities worldwide. The project began with a multidisciplinary investigation of the distribution of parks and open spaces in the San Francisco Bay Area driven by a counterfactual question: What would have happened if those areas had not been protected? Our investigation then expanded to a comparative analysis of the variation in the presence of parks and other natural areas in the 40 largest U.S. cities and 2,661 neighborhoods in those cities. The investigation has expanded to other cities worldwide on several fronts: visualizing conservation opportunities in urban watersheds in 500 cities worldwide for The Nature Conservancy, an interdisciplinary urban humanities investigation of four Pacific Rim megacities, and preliminary investigations of nature in informal settlements where most global urban growth will occur in the 21st century.
Historically, conservation in cities has been driven by the needs of people. The typical pattern, especially in Anglo-American cities, but with some variation in many other contexts, is that conservation first arises to protect clean water; then commons, especially grazing and forest commons, are enclosed for parks, often for elites; access to a carefully constructed nature is then seen as important for the creation and recreation of good citizens, as in the City Beautiful movement; in the mid-to-late 20th century suburban sprawl gives rise to open space movements to protect aesthetic qualities of natural landscapes; open spaces are then seen as important for protecting biodiversity; and then, again, as sites for provision of ecosystem services. This history provides advocates for conservation with a variety of concepts and tools to address the questions—What can nature do for people? and vice versa—in a wide variety of settings. However, informal settlements, which will absorb nearly all urban growth this century, typically have a very different historical trajectory and context. Historical contingency, which it turns out is crucial in all cities, at every scale, is an especially important variable, challenge, and opportunity in informal urban settlements.