6 ■ CITIES AND CLIMATE CHANGE
diff erence. Th e implication for mitigation in cities is that although cities can
certainly learn from one another when developing and implementing mitiga-
tion strategies, specifi c solutions and mitigation measures may not be easily
transferable or directly relevant for other cities.
The Importance of Urban Form for Emissions
Perhaps of greatest interest for urban planners and managers is the issue of urban
form and density. It has long been known that denser cities tend to have lower per
capita energy consumption (see, for example, Newman and Kenworthy 1989) and
therefore lower per capita emissions, and within a given city, per capita emissions are
lower in the denser parts of the city. Although this received wisdom has been ques-
tioned (Mindali, Raveh, and Salomon 2004), these correlations have been confi rmed
in recent work, including from the symposium papers and from research cited in
the World Development Report 2010 (World Bank 2010a). Yet urban form is shaped
over longer time horizons, through planning, policy, and investment decisions.
In the chapter “GHG Emissions, Urban Mobility, and Effi ciency of Urban
Morphology,” Bertaud and others use the examples of Mumbai, New York City,
and Singapore to show how price signals—including energy prices and carbon
market–based incentives—are a key factor in reducing GHG emissions from urban
transport, in combination with land use and transport planning and policies. Th ey
suggest that monocentric cities and density can be managed with the right policies
and that emissions from monocentric cities can be reduced if demand for trans-
port between suburbs and the center increases. In their examination of the factors
explaining diff erences in demand for urban transport, the authors consider how
signifi cant reductions in GHG emissions from urban transport can be achieved
through technological change to reduce carbon content and through a shift in
transport mode from private cars to public transit. Th e use of energy pricing based
on carbon content would promote both of these changes.
Th e demand for urban transport also depends on urban spatial structures.
Bertaud and others go on to show how in all three cities, spatial policies, includ-
ing fl oor area ratios (FARs), have played an important role. New York City and
Singapore have been able to maintain a high level of transit share by mandating
high FARs, prioritizing and improving connections to public transport, ensur-
ing high levels of amenities that make downtown areas attractive, and promot-
ing mixed-use developments located at integrated transport hubs.
Governance Matters for Climate Mitigation in Cities
Armed with a growing understanding of their GHG emissions, many cities are
already at the forefront of the mitigation challenge, with subnational eff orts in