The vastness of the size and scope of global cities raises governability issues—both fears and possibilities. The fear is that these large places are political dystopias, either entirely disordered places, or places governed by corporations with little concern for individual rights, communal concerns, or the environment. On the possibilities side, with growing frustration regarding the inability of the traditional nation-state to solve transnational collective-action problems, attention has focused on cities as alternative institutional conduits for international diplomacy and mayors as pragmatists best positioned to accomplish transnational goals. As nation-states and international organizations like the United Nations failed to coordinate efforts to mitigate global warming or eliminate poverty, prominent cities, mayors, and newly created transnational urban organizations were well positioned to step in. Heidi Hobbs was one of the first scholars to notice this. In City Hall Goes Abroad: The Foreign Policy of Local Politics, she writes about how citizens in affluent cities in the United States were passing local ordinances that challenged national policy on questions such as nuclear proliferation and immigration. In addition, the decline in urban aid in the Reagan era motivated US cities to pursue economic development deals. This early research focuses on urban public opinion and economic necessity driving behavior; more recent work focuses on the policy entrepreneurism of prominent global city mayors.
Perhaps the most important contemporary example of the role of global cities and the mayors that lead them is the Climate Leadership Group (C40 Cities), which was founded by London mayor Ken Livingston in 2005. Members include megacities that agree to meet greenhouse gas emission targets for their own cities and have demonstrated an interest in assisting other cities to lower their emissions. The leadership and philanthropic support of New York mayor Michael Bloomberg put the organization on the map, as Michele Acuto makes clear in Global Cities, Governance and Diplomacy: The Urban Link. Perhaps the most visionary statement of the possibility of mayors as global policy players is Benjamin Barber’s If Mayors Ruled the World: Dysfunctional Nations, Rising Cities. Barber—who founded the Global Parliament of Mayors, an international organization that works to coordinate responses to the challenges of urbanization—offers political philosophy and profiles of many global city heavyweights, such as New York City mayor Michael Bloomberg, Lagos (Nigeria) mayor Ayodele Adebowale Adewale, and Delhi (India) mayor Sheila Dikshit.