Cities

Cities can be broadly viewed as spaces in which large numbers of people live and work, and which represent hubs for governments, commerce and services, and transportation. The proliferation and the expansion of cities represent major trends of the twenty-first century. Urban areas today gather 55% of the world’s population. Problems of coordination among states have indeed led observers to look for solutions to be developed by non-state actors, including cities. As local actors, cities generally manage water demand, waste, energy efficiency, and mobility. Direct access to various resources enables them to experiment and adopt innovative environmental policies. Global cities, which attract vast amounts of financial and political resources, are prominent in globalization processes. The question of the effectiveness of cities is often raised, however. In the case of climate change, although numerous promising local policies have propagated, their mitigation effects appear insufficient.