In an analysis of the costs of sprawl in Canada, Walker and Rees used a metric called the
ecological footprint that converts, for comparative purposes, all energy, materials, and other resources
associated with different built environments into equivalent land area requirements. The authors found lot
size to be a very important factor in the analysis because lot size determines house frontage, which in
turn dictates the length requirements for infrastructure such as local streets and electricity, communica
tions, and water and sewage lines.
Walker and Rees's study also provides a breakdown of the resource requirements of these differ
ent dwelling types. It indicates that only 53 percent of the ecological footprint of a detached house is
related directly to the type of housing, while 44 percent is related to its associated travel requirements,
with an additional 3 percent associated with the need for municipal infrastructure. This finding corre
sponds quite well with a recent Finnish study on the effects of urban form on GHG emissions a continu
ation of that country's urban sprawl is compared with a 30 year scenario based on locating new housing
much closer to employment and regional activity centers.
The study suggests that 48 percent of the
reduction in GHG emissions from this more compact spatial development would come from efficiencies
brought about by district heating of residential and service buildings, another 48 percent would come
from reduced passenger travel within each commuting region, and an additional 4 percent savings would
be due to a reduced need for supporting municipal infrastructures.
B. Possible Policy Instruments
Policy actions that have been proposed to curtail the worst effects of
sprawl encompass a variety of smart growth initiatives.
include land use zoning ordinances to encourage higher density, mixed use (residential, commercial,
recreational, light industrial) land developments; promotion of urban designs based on gridded street
plans and other compact and readily accessible local street systems; the provision of more pedestrian and
cyclist friendly pathways;
and the use of green areas such as small urban parks and tree lined streets
to act as carbon sinks and to help break up the well documented heat island effect that often accom
panies asphalt, concrete, and other heat absorbing surfaces.
Efforts to impact the future form of entire
metropolitan areas include the application of urban growth boundaries, as well as the use of financial
incentives to build housing subdivisions or employment centers at infill sites within the urban boundary.
Both of these approaches limit the common practice of leap frog development that leads to the
Towards a Climate Friendly