A city’s land use and governance practices are integrally bound up in the climate change issue. Past zoning and land use decisions are key factors because they create the essential circumstances from which climate-related vulnerabilities may arise. Local powers and the larger governance environment will influence what can actually be done, and at what pace. Progress in addressing climate change requires strategic management, science-based policies, efficient financing, jurisdictional coordination, and citizen participation.
The role of urban land in climate change
The built environment or structural aspects of cities, streets, buildings, and infrastructure systems contribute significantly to the emission of greenhouse gases, and can also amplify climate change impacts. The structure, orientation, and conditions of buildings and streetscapes can increase the need for cooling and heating buildings, which are associated with the level of energy use and greenhouse gas emissions in a city. Swaths of impervious surfaces can intensify flooding and are direct determinants of the heat island effect. The presence or lack of street trees and parks, and the extent of wastewater and drainage systems can either impede or enhance the natural processes of evapotranspiration, in addition to amplifying flooding and drought effects.
A city’s natural setting, its urban form and built environments are relatively static factors, but they are subject to future modification through urban planning and management. For example, Shanghai has sought to increase the level of vegetation around the urban core to mitigate the urban heat island; since 1990, urban greenery per capita has increased from 1.0 m2 to 12.5 m2, resulting in decreasing temperatures. In Tokyo, the municipal government has similarly expanded its expenditures on tree planting, park development, and the use of paved surfaces that block heat and absorb moisture.
Stockholm is engaged in a long-term planning initiative to both mitigate and adapt to climate change. The Stockholm Royal Seaport is a new development district with strict environmental requirements on buildings. All buildings will be placed 2.5 m above the average sea level; building materials will be required to resist high humidity; and other requirements call for greenery on roofs, walls, and yards.
These examples represent a starting point for initiatives that local authorities can use to respond to climate change. These initiatives can be pursued through legal and political systems, planning departments, zoning regulations, infrastructure and urban services, real estate markets, and fiscal arrangements. Other specific adaptation and mitigation initiatives related to urban land use include:
• Reduce sprawl by increasing population and building densities, mixing land uses to reduce automobile traffic, and more frequent use of public transit;
• Change building codes to reduce energy use for heating and cooling;
• Restrict land use in areas subject to climate change impacts such as sea level rise and riverine flooding;
• Change building codes and land regulations to reduce damage from climate change hazards, e.g., elevating buildings in flood-prone areas;
• Increase urban tree coverage and vegetation to reduce the heat island effect;
Cities and climate change: The challenges for governance
Local governments face many challenges in their efforts to mitigate and adapt to climate change. For any city, climate is but one of many issues on the local agenda. Governments are also faced with the tradeoffs between current priorities and long-term risks, a situation compounded by the uncertainties that may surround the timing and severity of climate-related impacts in a city.
Most cities undertaking climate plans find themselves constrained by fiscal and policymaking limitations. Jurisdictional conflicts over who can or must take action on a specific mitigation or adaptation initiative can make progress challenging. For example, in Mexico City, administrative boundaries do not align with the city’s geographic boundaries and carbon-relevant functioning. Similar issues exist in Paris, where the Plan Climat de Paris is focused on the 105 km2 area under the direct control of the Maine de Paris, a fraction of the Paris metropolitan region which totals 700 km2 and is under the jurisdiction of three other departements. In Durban, local officials are seeking to ensure that climate change does not get pigeonholed as simply an environmental issue, but instead is more appropriately seen as a development-related challenge.
Despite these difficulties, cities around the world are committing to action on climate change, entering into dialogues with state, provincial, and national governments to discuss their climate policy agendas. Cities are also increasingly focused on data gathering, both to improve internal management practices and to allow for comparison with other cities around the world.
In examining how cities are delivering effective action on climate change adaptation and mitigation, four key factors emerge:
• Effective leadership is critical for overcoming fragmentation across neighborhoods and sectors when building consensus on the climate change agenda in cities;
• Efficient financing is a core requirement for empowered governance in cities; success to date with efforts to confront climate change challenges has been hampered due to deficient financing;
• Jurisdictional coordination across city, state, and national governments is one of the most pressing challenges common to cities worldwide; and,
• Citizen participation can help in development of inclusive local government decision-making on climate change.
