The geography of carbon dioxide emissions

Economists Ed Glaeser and Matthew Kahn have written a new paper estimating the differences in carbon emissions across different metropolitan areas.

Using a hypothetial household with 2.62 members and $62,000 in average yearly earnings, they attempt to calculate how much carbon dioxide this household would emit in a given metropolitan area.  They estimate household emissions from driving, public transportation, home heating and electricity (which includes air conditioning), and they factor in the relative cleanness of the region's electricity supply.   

Their findings are not all that surpising:

• "Per capita emissions generally are lowest in Western metropolitan areas and highest in Southern ones.  Metropolitan areas in the Northeast and Midwest fall in between these two extremes."
• "All told, if the social cost of one ton of carbon dioxide emissions is $43, then the annual environmental damage associated with an additional home in greater Houston is more than $500 greater than the damage for a new home in greater San Francisco."

Car-dependence obviously plays a large role, but often not as large as electricity consumption:  The typical Houston MA household emits 3,000 more pounds of CO2 per year from driving than does the typical San Francisco household.  But the typical Houston household emits 23,000 more pounds per year than the SF household due to extra electricity use.  As we all know, air conditioning is expensive. 

Their tentative conclusion is that perhaps we should make it easier for households to move from Texas to California, rather than vice versa:

This work is far too preliminary to be a sound basis for particular policies.  However, it does emphasize the contradictions of current American land-use policies.  Local land-use restrictions cannot stop development in the nation as a whole.  They simply have the ability to move development from one area to another.  Our current land-use restrictions tend to stop development in those areas, like California, that are environmentally friendly and to encourage it in areas, like Texas, where households produce more carbon dioxide.  Within metropolitan areas, land use restrictions often push development out towards the urban fringe where energy use is highest.  Our results do suggest that it makes sense to look for policies that would encourage building in more enviornmentally friendly cities and discourage it in areas that have the greatest carbon dioxide emissions.

Comments

[M1EK]

Such an additional analysis would have to incorporate more of the concept of the marginal production of a watt of electricity. For instance, a new resident to Houston is going to use coal-powered electrons, sure, but so is a new resident of San Francisco (the hydro power is already completely spoken for, and no new watts are coming along).

It also should account for the regional differences in vehicle 'choice' - do you suppose California really wants a bunch of people moving in driving Hummers and pickups on the 101?

[DSK]

I wonder, with electricity costs rising, if more new houses will be built with smarter cooling features like whole-house fans and air exchangers. I had these in my 70s era house growing up, and it amazes me that few modern houses have them. Even no-basement places like Houston could save energy by having them. I know that in Austin the Americorps greenbuilding program uses whole-house fans (or did a few years ago, anyway), but I don't think they use air exchangers.

[The Overhead Wire]

Or perhaps they'll start building them with dog runs in the center again for a breeze. Building design is a lost art. In regards to alternative energy capacity. I will note that here in California it has been written into law that coal only be 3% of our energy in 2010. Over 50% of our energy comes from low GHG sources including Nuclear, Hydro, Wind, and Solar. Recently there is a project in the desert to build a thermo solar farm that will power 400,000 homes. http://www.engadget.com/2007/07/09/california-to-get-worlds-largest-solar-farm/

[M 1EK]

Jeff,

However, when you guys buy on the spot market, as you had to do quite often during the Enron Fiasco, you don't get to choose what kind of electrons you buy, and they're quite likely to be coal (natural gas otherwise).

Hence, the marginal watt in CA is dirty, just like it is in Texas.

[The Overhead Wire]

Very true. If and when (i'm sure we'll see another crazy energy year soon) that happens we will have to buy from other states like Nevada that have excess capacity. And outside of California it's predominantly coal and ng. I hope however that changes soon.

[M1EK]

It can change with a ton of solar - but I'm amazed at the fact that they're pushing it more in San Francisco than in the interior areas (or at least as far east as Silicon Valley). There just can't be enough hours of sunlight in San Fran proper to make it worthwhile to subsidize solar installation, even in California, can there?

[The Overhead Wire]

Well my landlord has solar on the top of our Victorian and he powers his unit with it. My neighborhood however is sunnier than most. If you live on the otherside of Twin Peaks there is much more fog.