Energy & Environment

When seeking the city solution on climate, don’t forget the suburbs

Daniel Kammen

Our cities have the potential to be a key climate change solution. Already they are hot-beds of innovation in local and global approaches to the nexus of sustainability and quality of life.  People who live in cities drive less, use less energy to heat, cool, and light their homes, and even their water and sewer lines are shorter and require fewer resources. (See related, “The City Solution.”)

But all of those advantages – and the ability to save more land for nature and agriculture – will be cancelled out if our cities are ringed with suburbs that are profligate in their use of energy and resources. In my laboratory – the Renewable and Appropriate Energy Laboratory (RAEL) — at UC Berkeley’s Energy and Resources Group, we decided to take a closer look at whether cities in the United States really are helping to shrink the nation’s carbon footprint. (See related Quiz: What You Don’t Know About Cities and Energy.)

Our results, just published in Environmental Safety & Technology, should give urbanization advocates kudos for what well-designed urban cores can do. But it also should give them pause, to not forget the suburbs. Population-dense cities indeed are contributing fewer greenhouse gas emissions per person than other areas of the country, but these cities’ extensive suburbs essentially “take back” the climate benefits of their cores.  We are not talking just about commuting, either.

U.S. suburbs, in fact, account for half of all U.S. household greenhouse gas emissions, even though they house less than half the population. Taking into account the impact of all urban and suburban residents, large metropolitan areas have a slightly higher average carbon footprint than smaller metro areas.

The bottom line: Cities are not islands. They exist in a complex landscape that we need to understand better, both theoretically and empirically.

We wanted to present in a visually striking way the impacts and interactions of our energy, transportation, land use, shopping, and other choices in both cities and suburbs. It is plain to see the trends at our interactive carbon footprint maps for more than 31,000 U.S. zip codes in all 50 states at: http://coolclimate.berkeley.edu/maps.

map

“Metropolitan areas look like carbon footprint hurricanes, with dark green, low-carbon urban cores surrounded by red, high-carbon suburbs,” says Christopher Jones, the doctoral student who worked with me on the project. “Unfortunately, while the most populous metropolitan areas tend to have the lowest carbon footprint centers, they also tend to have the most extensive high carbon footprint suburbs.”

In fact, the average carbon footprint of households living in the center of large, population-dense urban cities …

Read more on the National Geographic blog “The Great Energy Challenge.”

See related science article, “Suburban sprawl cancels carbon-footprint savings of dense urban cores,” on the UC Berkeley NewsCenter.

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Comments to "When seeking the city solution on climate, don’t forget the suburbs":
    • Elise Mills

      Thanks very much for creating & sharing this tool –
      I’m curious what makes Arkansas stand out as having a lower average household carbon footprint. I’m not so surprised to see the west generally have lower numbers – nor state of NY, but I am a bit surprised by Arkansas. Do they have specific laws or have they invested in their infrastructure in some way to have this impact?

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    • Anthony St. John

      Dan, this was published last night on the Huffington Post: “California Has Driest Year Ever — And It May Get Worse

      It’s time to accelerate our efforts to implement better ways to protect long-term future quality of life.

      Large-scale fusion energy generation is what is imperative for a worldwide solution, but we need help from social scientists to overcome our mental limitations that prevent us from making the right things happen in the meantime.

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    • Dan Kammen

      Hi Anthony, agreed that transformational, and not just incremental, changes are needed. In addition to changing the face of our suburbs, I’ve also been arguing that we need to give ourselves not only an energy makeover, but also a financial one. See this op-ed for example.

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    • Anthony St. John

      Dan, thank you very much for your feedback and continuous efforts to protect our civilization from calamity.

      Today I also commented on Steven Weissman’s recent post:

      “— evolutionary biologists tell us our brain has not evolved enough to save the long-term future of our civilization.”
      (See “Can we adapt in time?” Sept/Oct 2006 CALIFORNIA magazine.”)

      Thus we are prevented from implementing the ultimate solution of fusion-power plants because of our mental limitations and what Sir John Maddox documented as “— strategies eventually adopted internationally are usually burdened by the compromises required to override the vested interests of many of the participants” in his “Avoidance of Calamity” chapter of his book “What Remains to Be Discovered.”

      We must find a better way or our failure to evolve far enough beyond Pan troglodytes will overwhelm our ability to survive our failures to meet the challenges of change that Will and Ariel Durant documented in their Story of Civilization” which has caused all other civilizations to fail.

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    • Anthony St. John

      Dan, the most inconvenient fact of life today is that the current rate of increase in atmospheric CO2 has taken us far beyond the “350 or Bust” level, and has taken control of our future out of our control using any methods based on our past experience.

      We require a whole new lifestyle for 7+ Billion people with rapidly declining resources in a new era of increasing chaos.

      And no one really seems to be able to convince the powers that control the United Nations to implement the required solutions in time to prevent earth from turning into another Mars type environment.

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