Dirty ‘hoods: Is your neighborhood bad for the climate?
by Tim De Chant.
It’s no secret that cities produce fewer greenhouse gas
emissions per person than suburbs or rural areas—and some cities are better at keeping
emissions down than others. Take New York City: Its dense
urban structure and well-developed mass transit system keeps
emissions well below somewhere like the sprawling and car-dependent Houston. But cities are more than just monolithic
entities; factors like climate, manufacturing, car ownership, and wealth
work differentially between cities and within city boundaries to
influence greenhouse gas emissions.
A review paper published in Environment & Urbanization dug into per
capita emissions data for 100 cities from around the world to see which
variables played a role. The paper’s authors also added a new twist by
dissecting one city, Toronto, to see how rates varied neighborhood by
neighborhood.
Zooming in from the national level to the city itself, the authors
report that Toronto’s metro area has lower emissions than its home province of
Ontario, which itself has lower emissions than Canada as a whole. The
city itself fared better than the surrounding suburbs (not a big
surprise). As they went further, they discovered enclaves of high per capita emissions even within the
city center. The
culprit? Wealth: Residents of tonier neighborhoods drove more and
lived in older, less energy efficient housing, something preservation
groups will surely be dismayed to hear.
The affluence story plays out on the global scale, too: Wealthy cities like New York, Beijing, Frankfurt, and
London have much higher per capita emissions than poor cities like Dhaka
in Bangaladesh or Bangalore in India.
But wealth isn’t the sole the offender. Climate is a large driver,
but that’s not to say we should all ditch jackets and move to the Sunbelt. For example,
Boston still has lower emissions rates than Austin and Philadelphia has lower
emissions than Miami. A city’s source of electricity also plays a role, as do the
qualities of its workforce. Cities like San Francisco and Portland can
lay down such enviable carbon footprints because they tick those boxes
in just the right way. Both enjoy mild climates that all but eliminate
the need for air conditioning. Both are also heavily invested in the
knowledge economy. San Francisco has particularly dense development,
which reduces transportation emissions, while Portland gets a large
portion of its electricity from hydroelectric power.
To encourage cities to trim their per capita emissions, the paper’s
authors argue that governments should look to the success they had with
solid waste reduction. While it’s true that many cities succeeded in
reducing the amount of trash they send to the landfill, the comparison
isn’t apt at this point. Cities pay to dispose of garbage; some do so
handsomely. Currently, there’s no truly global price on carbon
emissions. Never underestimate the ability of money to drive change.
There is some hope, though: Because urban areas produce a large portion
of global greenhouse gas emissions, city governments can take action
that national governments have been hesitant to embrace.
Source:
Hoornweg, Daniel, Lorraine Sugar, and Claudia Lorena Trejos Gómez. 2011.
“Cities and greenhouse gas emissions: moving forward.” Environment
& Urbanization. 23: 207-227.
DOI: 10.1177/0956247810392270
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