To avoid the most horrific outcomes of global warning, greenhouse gas emissions must be reduced by as much as 80 per cent below 1990 levels by 2050. Climate change ranks among the most significant concerns in both developed and developing countries, as reported at the recent meeting of the Global Planners Network in Zhenjiang.
Urban planning is implicated because buildings and transportation account for most emissions and city populations are particularly vulnerable to the impacts of sea level rise and extreme weather events. Technology fixes such as more fuel-efficient cars and robust flood control structures will not prove sufficient.
I treat cities as a potential machine for carbon mitigation through urban planning strategies that reduce emissions and adaptive responses to unavoidable impacts. On the mitigation side, compactness, density, connectivity and mix of land uses provide opportunities for low-carbon transportation, energy and building systems.
Managing the risks caused by increased flooding, wildfires, drought and the exacerbation of the urban heat island effect require both hard and soft solutions, including climate-conscious city and regional plans that incorporate adaptation strategies in the location, intensity and design of new development.
With its partners the American Planning Association and Harvard school of design, the Lincoln Institute of Land Policy brings together planning directors from the 30 largest US cities to deal with a range of topics. Two years ago, climate change went to the top of the agenda. In the absence of a national policy, US cities and states are taking action, notably California.
Its Global Warming Solutions Act 2006 and the recently adopted Senate Bill 375 link emission reduction targets to land-use planning and charges regional agencies with integrating transport and housing plans to achieve them. More than 900 US mayors have signed the mayors' climate protection agreement, based on Kyoto treaty targets. However, without more effective tools to relate emissions to urban form and management it will not be possible to achieve the goals in most cities.
A demonstration project by the Lincoln and Sonoran Institutes and local stakeholders on 712km2 of state trust land near Phoenix, Arizona, is modelling emissions associated with different planning scenarios that could accommodate one million residents over the next 50 years. With the Regional Plan Association of New York, the institute is also completing a pilot project in Bridgeport, Connecticut, which analyses the potential for reductions in a six-city metropolitan planning area.
Armando Carbonell is department of planning and urban form chairman at the Lincoln Institute. He was given honorary RTPI membership in the summer. For more information, please visit www.lincolninst.edu.