Redefining the City: From Growth Engine to the Frontier of Global Governance

Cities were once a byproduct of the industrial age, but have now become the main stage of human civilization. With more than half of the global population living in cities, urban development is no longer just a local planning issue but a core thread for understanding the global economic, political, and ecological future. It is no accident that the OECD has made urban development a major policy area—it signals that the international governance system has begun to confront a long-underestimated fact: the success or failure of cities will determine the rise and fall of nations and even the direction of the global order.

For the past few decades, cities have been widely regarded as engines of economic growth. Agglomeration effects, economies of scale, innovation spillovers... These concepts shaped a linear view of urban development: as long as population and capital keep pouring in, cities will automatically bring prosperity. However, this logic is hitting its limits. Traffic congestion, housing crises, social fragmentation, and the fragility of infrastructure in megacities have made "growth" itself questionable. The question of urban development has shifted from "how to grow" to "how to grow in a sustainable, inclusive, and resilient way."

The "urban development" that the OECD focuses on actually contains a deeper agenda: How can cities achieve net-zero transition amid climate change? How can digitalization enhance governance capacity without exacerbating inequality? How can infrastructure investment serve long-term social returns rather than short-term political interests? These questions are no longer confined within city boundaries; they directly concern national competitiveness and the provision of global public goods.

At the same time, the relationship between cities and states is undergoing a subtle restructuring. In the traditional political framework, cities are subordinate units within the national system, with their power derived from the authorization of the central government. But today, with globalization and regionalization proceeding in parallel, cities increasingly resemble independent international actors. They set their own climate goals, sign inter-city cooperation agreements, and even voice positions on foreign policy that differ from those of the central government. The rise of this "city diplomacy" is both a complement to and a pressure on national governance failures—it forces states to rethink the place of cities in their strategic landscape.

From the Global South to the Global North, urbanization paths are diverging. In Asia and Africa, rapid urbanization has not yet fully coupled with industrialization, and cities must simultaneously address the dual challenges of population explosion and job creation. In Europe and North America, cities face the difficulties of renewing existing urban stock, population aging, and aging infrastructure. This diversity means that no single model of urban development is applicable anymore. The policy learning and comparative research advocated by the OECD precisely provide a pragmatic framework for dialogue amid this diversity.What is even more noteworthy is that cities are becoming the front line of climate action. Cities around the world consume most of the energy and emit most of the greenhouse gases. But it is precisely this highly concentrated flow of resources that makes cities the spatial units with the greatest leverage for emission reduction. Many cities have already set more ambitious carbon neutrality targets than their national governments, and are carrying out practices in areas such as building energy efficiency, transportation electrification, and the circular economy. These efforts by cities are not only technological experiments, but also governance experiments—they demonstrate that, in the absence of global coordination, subnational actors can still drive substantive change.

Digitalization has opened another door for urban governance. Artificial intelligence, the Internet of Things, and big data endow cities with unprecedented capabilities for sensing and response. But the introduction of technology is never neutral. Digital governance may bring efficiency, but it may also bring surveillance and exclusion. How cities can safeguard civil rights while becoming smarter, and how they can prevent algorithmic bias from entrenching social injustice, are among the most critical governance issues of the next decade. The OECD's attention to artificial intelligence and digital government happens to intersect with urban issues, and this intersection will become a new frontier for urban development.

The future of urban development, in the final analysis, is a repositioning of public strategy. Cities no longer need more grand narratives; they need more precise institutional design, more effective fiscal tools, and more resilient governance structures. From affordable housing to public transportation, from green infrastructure to community participation, every seemingly technical detail conceals a value choice about "for whom the city is built."

When international organizations begin to treat urban development as a core issue, this itself is a sign of the times: cities are no longer merely a statistical category within nation-states, but a key platform for global affairs. On this platform, issues of climate, economy, technology, and social justice converge, and cannot be solved by any single sector alone. Urban development is rising from a "planning problem" to a "civilizational issue."

Future urban policy must move beyond the traditional growth-oriented framework and shift toward a development logic aimed at long-term resilience. This means that the indicators for measuring urban success are no longer merely GDP and population, but comprehensive dimensions that include ecological carrying capacity, social mobility, and governance quality. The research and standards accumulated by the OECD and its member countries provide a foundation for this transformation, but true change still requires the courage and wisdom of cities themselves in practice.

Cities are the collective works of humanity. They have never been as important as they are today, nor have they ever been as fragile. Redefining urban development is redefining the boundaries and possibilities of human cooperation.