This chapter focused on how cities deal with the growing environmental crisis and the challenges of climate change. The 1987 Brundtland report dedicated a chapter to the urban challenge and made explicit the causal link between urbanization and global environmental problems. The World Bank increased its direct involvement in urban environmental management through the creation of programs with the support of UN agencies, bilateral development agencies, national governments of OECD countries, municipal governments, private companies, and civil society. Although great expectations have emerged about cities' role in climate governance, cities often need others like environmental consultancy, engineering or urban planning firms, and energy service corporations for their expertise and experience with similar issues in other cities. The increasing recognition of cities as actors in the international arena has coincided with a changed attitude of multilateral institutions towards sustainable urban development. Cities were approached in nonterritorial terms, as nodes in networks that receive their meaning from network interactions.