'Smart growth" projects across the country aim to jam people into high-density housing near mass transit systems.
Proponents think this will make people abandon their automobiles, reducing greenhouse gas emissions. But new research shows "stack-and-pack" housing is an ineffective way to reduce carbon dioxide levels.
Researchers at the University of California Energy and Resources Group in Berkeley used Census, weather, economic and transportation data — 37 variables in total — to estimate greenhouse gas emissions from the energy, transportation, food, goods and services consumed by U.S. households.
They calculated "household carbon footprints" for more than 31,000 U.S. ZIP codes (of approximately 43,000 total) in all 50 states and found that a "10-fold increase in population density in central cities yields only a 25% reduction in greenhouse gas emissions."
In other words, the number of people living in cities such as Los Angeles, San Francisco, Chicago, Miami, Philadelphia and New York would have to increase 10 times — from 1.5 million in Philadelphia, for example, to 15 million — to yield a 25% reduction in CO2.