Urban development and climate change

Abstract

With growing worldwide concern about global climate change, this article asks two critical questions: What reduction in vehicle‐miles traveled (VMT) is possible in the USA with compact development rather than continuing urban sprawl?; and What reduction in greenhouse gas emissions would accompany such a reduction in VMT? Based on four different planning literatures, the answer to the first question appears to be a 20–40% reduction in VMT for each increment of new development. The answer to the second question is a 7–10% reduction in total transport carbon dioxide emissions by the year 2050 under a plausible set of assumptions.

Keywords:

• development
• climate change
• land use
• transportation
• greenhouse gases

Notes

1. Computed as (−0.074*50)−(1.50*1)−(4.64*1)−(0.068*73)−(2.12*1). The 73 in the preceding formula represents a growth increment of 73%, or 43 years at an average growth rate of just over 1.28% per year.

2. The American Housing Survey reports about 124 million residential units in 2005, while the Census reports a population of about 296 million for the same year, for a ratio of 0.42 units per capita. As household size is not projected to change substantially over the next generation, the Census‐projected population for 2050 is multiplied by the ratio of residential units to the population in 2005 to estimate future residential demand (see http://www.census.gov/hhes/www/housing/ahs/ahs.html).

3. The 1990 Census reports 102 million residential units, while the 2000 Census reports that 96 million survived to 2000, indicating a loss rate of about 6% per decade (see http://www.census.gov).

4. There is no consensus on the actual rate of loss of residential units through demolition and conversion to another land use. The one‐third figure is conservative based on Delphi consensus of experts (Nelson 2006).

5. The US Department of Energy's Energy Information Administration (EIA) conducts the Commercial Buildings Energy Consumption Survey (CBECS) about every five years. The 1992 survey reported 68 billion square feet of nonresidential space excluding industrial space. The 1999 survey (the most compatible in format) reported 58 billion nonresident square feet existing in 1992 surviving to 1999, or an imputed loss rate of slightly more than 20% per decade (see http://www.eia.doe.gov/emeu/cbecs/).

6. This figure includes industrial space (Nelson 2006).

7. This figure assumes about 580 square feet of space per full‐ and part‐time worker. It is the quotient of total nonresidential space (Nelson 2006) and workers. The US Department of Commerce's Bureau of Economic Analysis reported there were 173 million total full‐ and part‐time workers in 2005 (see http://www.bea.gov). In contrast, the CBECS for 2003 estimates 1000 square feet per full‐time worker. The more conservative figure is used.

8. There are, of course, additional localized influences on climate, including the urban heat island effect and related phenomena. The impacts of such effects vary substantially with the characteristics of a specific area (Arnfield 2003, Coutts et al. 2004, Mills 2005, 2007, Pearlmutter et al. 2007).