CITIES ARE at a crossroads, confronting historical challenges posed by rising populations, accelerating climate change, increasing inequity, and - all too often- faltering livability.
As rural migrants to cities adopt city-based lifestyles, they tend to use more resources as their incomes rise and their diets shift from starchy staples to a greater share of animal products and processed foods. This in turn, drives land clearance for livestock grazing and fodder.
People care about their cities and often are motivated to protect and improve their urban homes. Cities can harness that passion to help advance a sustainability agenda, perhaps more easily than national governments or corporations can.
Perhaps the biggest single step that cities can take toward a sustainable future is to create economies that greatly reduce materials use, recirculate most materials, and rely largely on renewable energy. "Green infrastructure" - the use of natural areas to provide economic services - can also help cities avoid building costly new water management facilities, can recharge aquifers, and can provide flood protection. Ensuring that decisionmaking is transparent and participatory ensures that no community is left behind.
The path to a sustainable city starts with a vision; a well-crafted vision can rally public support and mobilise civic energy for a long-term urban makeover.