Are cities greener?

[das_nut]

I stumbled across this the other day, and I thought it was rather interesting:

I’ve assembled data on carbon emissions associated with living in different parts of the country. And there are two facts, which I think are important, to come out of that. One of which is that people who live in cities do tend to emit significantly less carbon than people who live in the country, and this is controlling for income and controlling for family size. That’s coming mainly from driving, from the fact that there’s just a lot fewer carbon emissions associated with dense living. It’s not just the move to public transportation; it’s also the drivers within cities — they’re just driving much shorter distances. And then, of course, it’s because of much smaller homes.

The higher price of urban space means that people are living in smaller homes, even with the same family size. And that leads to lower electricity usage, lower home heating usage — and those are the facts that I think make cities seem, at least to my eyes, significantly greener.

- From a Freakonomics podcast last year.

I could see this. There's a few other factors that aren't covered here as well - high density living within cities results in less habitat loss and fragmentation than suburban and rural living. That's important. It's also easier to supply infrastructure to a densely populated area than it is to supply infrastructure to areas that tend towards more sprawl. And cities support mass transit more efficiently than suburban and rural areas.

 

[Lord Snot]

It makes sense. It's not immediately obvious because cities will pump out a lot more carbon than villages, it's only when you calculate the carbon emissions of each person that you see city-dwellers are doing better.

I'm not sure what there is to debate though, what discussions did you have in mind?

 

[beancounter]

I stumbled across this the other day, and I thought it was rather interesting:
- From a Freakonomics podcast last year.

I could see this. There's a few other factors that aren't covered here as well - high density living within cities results in less habitat loss and fragmentation than suburban and rural living. That's important. It's also easier to supply infrastructure to a densely populated area than it is to supply infrastructure to areas that tend towards more sprawl. And cities support mass transit more efficiently than suburban and rural areas.

But what about the carbon emissions from the factories/business the city dwellers work in?

 

[Lord Snot]

But what about the carbon emissions from the factories/business the city dwellers work in?

Where do you think rural people work? Farms, shops (with deliveries, meat products), cities that they commute to.

 

[beancounter]

Where do you think rural people work? Farms, shops (with deliveries, meat products), cities that they commute to.

But there is less density in rural areas than cities, so on a per square mile basis, it would seem like cities pollute more.

 

[Digger]

Makes sense to me. 1000 people spread out over a whole county will have a much larger footprint than 1000 people living in a high-density urban setting, sharing resources and infrastructure, etc.

 

[Lord Snot]

But there is less density in rural areas than cities, so on a per square mile basis, it would seem like cities pollute more.

Not really. If you split up cities and everyone moved to rural locations they would still all have jobs, but they would live in bigger houses and travel further to get to work.

 

[kazyeeqen]

I recognize this discussion.

But there is less density in rural areas than cities, so on a per square mile basis, it would seem like cities pollute more.

Per square mile yes, no doubt. But per person cities are bound to be more effective.

I guess part of the problem is the infrastructure it takes to provide resources to the folks in the city? There will need to be the miners, farmers, loggers, etc and they need to live near their work (in the country) and then there needs to be people working at the restaurants and grocery stores and laundromats where the farmers and loggers and miners work...

So cities are more efficient, but a certain rural population is a necessity, but everyone probably agrees that the suburbs are a big ol' waste of space and resources?

 

[nog]

Not really. If you split up cities and everyone moved to rural locations they would still all have jobs, but they would live in bigger houses and travel further to get to work.

He stated per square mile. So yes, per square mile there may be less human carbon emissions, but per person it is higher.

Also, it's not clear that simply because people live in a rural setting they would live in bigger houses. That completely depends on the area and people.

However, how does one really calculate the per person carbon emissions? Does the farmer get all the carbon emissions necessary to produce and harvest his crop, or miner for mining the metals/minerals necessary for say modern computers, etc, and the end person who consumes said crop, mineral, lumber, house product, only get what? Transportation?

Living in a social community, depending on people who living in cities and rural settings, it's strange to me how we accurately divide up things like carbon emissions. For the various things we use in our daily lives.

All things the same between two people (say habits, products purchased, etc) I could see that in a rural setting one probably has to travel further by car to purchase and return home with the various goods as opposed to someone in the city. Perhaps, but not necessarily travel further to work and less options for public transportation in a rural setting.

 

[das_nut]

However, how does one really calculate the per person carbon emissions? Does the farmer get all the carbon emissions necessary to produce and harvest his crop, or miner for mining the metals/minerals necessary for say modern computers, etc, and the end person who consumes said crop, mineral, lumber, house product, only get what? Transportation?

Here's a different article about that:

According to EIA data, urban U.S. households own an average of 1.8 vehicles each, compared with 2.2 for each rural household. Urban families also drive about 7,000 fewer miles annually than their rural counterparts, saving more than 400 gallons of gasoline and roughly $1,300-$1,400 at current gas prices.

[...]

Similarly, urban families as a whole spend at least $30 billion more for energy each year than their country cousins, but each individual urban family actually spends about $200-$400 less. That suggests that urban homes are more numerous but also more efficient.

So it implies that just looking at households, urban households drive less and use less energy to heat and cool their homes.

ETA: And obviously, the amount of land people use in the cities is less per person. That's just basic statistics - when the population density is higher, each person is going to be using less land. All other things being equal, it's a good thing when people use less land. Most suburban and rural households have larger yards than their urban counterparts. Yards aren't really great for the environment. Yards tend to be an artificial habitat, and don't support native species to the extent that wild areas do. Sure, most people (rural or urban, it doens't matter) will still contribute to habitat loss and fragmentation due to consuming farm foods, but lawns currently consume more land than the entire state of Georgia. That's not good for the environment.

 

[nog]

Here's a different article about that:



So it implies that just looking at households, urban households drive less and use less energy to heat and cool their homes.

ETA: And obviously, the amount of land people use in the cities is less per person. That's just basic statistics - when the population density is higher, each person is going to be using less land. All other things being equal, it's a good thing when people use less land. Most suburban and rural households have larger yards than their urban counterparts. Yards aren't really great for the environment. Yards tend to be an artificial habitat, and don't support native species to the extent that wild areas do. Sure, most people (rural or urban, it doens't matter) will still contribute to habitat loss and fragmentation due to consuming farm foods, but lawns currently consume more land than the entire state of Georgia. That's not good for the environment.

I guess was I was getting at was that rural households probably support the labor class that is harvesting raw materials (including food and living aspects). How does one account for that aspect, the contribution to society, to urban life? If one harvests raw materials and they have to travel further to work site(s) in order to be closer than an urban dweller, does that mean they just use more? Or should the analysis be a little more detailed that reported miles driven? If they live in a rural setting and drive to an urban setting to work, well that's just silly, but what I'm interested in is a more detailed analysis.

I understand that dense population, in general, is more efficient use of immediate resources. I'm just saying it's not so clear cut to generalize for a society dependent on each other, I'd have to see more information to understand than simply basing it off of average number of miles driven.

According to the link in the article, while urban households have less cars per household, more cars are associated with more people in a household (so it could indicate that there are more people, on average, in rural homes as compared to urban homes?) Also comparing the household size to urban status (on the same link), it seems that rural is about the same as a 3 person household (in terms of cars and miles driven), yet urban while having less cars than the two person household, drives as much as an average two person household.

However, from the other link in that article, it breaks down 4 urban status categories, instead of two (so in the vehicle comparison it has urban or rural, in the house comparison it has city, town, suburban, and rural). On the second it has 'self reported', but it's not indicated on the first if that's also the case. I wonder how those two compare. Also in the latter link in the article, it indicates that there are about the same people in city and rural livestyles on average (although more in towns and suburbs and how those two relate to the other data, I don't know).

It's just not so clear cut. To me at least.

 

[das_nut]

I guess was I was getting at was that rural households probably support the labor class that is harvesting raw materials (including food and living aspects). How does one account for that aspect, the contribution to society, to urban life? If one harvests raw materials and they have to travel further to work site(s) in order to be closer than an urban dweller, does that mean they just use more?

But what about using more energy to heat their homes?

According to the link in the article, while urban households have less cars per household, more cars are associated with more people in a household (so it could indicate that there are more people, on average, in rural homes as compared to urban homes?)

Or it could mean that the urban households are less likely to consider more driving a benefit. (Quite literally, where I'm at, driving some places is counter-productive.)

Of course this doesn't matter when we compare urban to suburban and exurban communities, since most of those rely on the city or the surrounding communities for work, and aren't supporting farming or resource extraction. The suburbs clearly are subpar compared to urban areas when it comes to the per capita environmental impact.

 

[nog]

But what about using more energy to heat their homes?

What about it?

Well, let's look at what we can find:
http://www.eia.gov/emeu/recs/recs2005/c&e/summary/pdf/tableus3.pdf

According to that link (and others from here:http://www.eia.gov/emeu/recs/recs2005/c&e/detailed_tables2005c&e.html (which was linked to in the article you recently quoted from)), in general, cities use more electricity and natural gas than rural. Rural uses more wood and propane. In general.

So electricity can be pretty accurate in terms of rating. Wood is measured in 'cords' (not an accurate estimate, varies by how it's cut, stacked, etc as well as the BTUs per type). I would think the propane and natural gas are pretty accurate.

Now, why report in just kWh? Why not look at the energy required to generate that energy? Since most electricity is generated by coal and other fossil fuels, most of that is from coal and other fossil fuels. How many BTUs are lost in conversion to electricity and in transmission?

Now according to:
http://www.eia.gov/emeu/recs/recs2005/c&e/summary/pdf/tableus9.pdf (again from a link in the article)
We have the averages. Although those averages (per household that were quoted on your linked article) exclude the primary electricity and wood (I guess that means heat? I don't know).

Although here:
http://www.eia.gov/emeu/recs/recs2005/c&e/summary/pdf/tableus14.pdf
It's not clear either.

Besides, how does city, town, suburban, and rural fit into urban and rural? Is city, town, suburban the same as urban or just city?


Anyways, I'm back to the, "it's not clear to me."

Or it could mean that the urban households are less likely to consider more driving a benefit. (Quite literally, where I'm at, driving some places is counter-productive.)

It could mean a lot of things and based off those numbers it's difficult to tell what's going on, which was my point.

Of course this doesn't matter when we compare urban to suburban and exurban communities, since most of those rely on the city or the surrounding communities for work, and aren't supporting farming or resource extraction. The suburbs clearly are subpar compared to urban areas when it comes to the per capita environmental impact.

Probably, but I'm not convinced you can easily turn those numbers into per capita environmental impacts. Cities externalize a lot, yet that's not accounted for in those numbers.

I'm not arguing for or against the claims, just that it's not so clear cut as they seem to indicate.

 

[ledboots]

Cities could be considerably greener than they are by growing more food there. There are so many interesting ways people are coming up with to do this, I think it its following to be much more widespread in the near future.

http://m.good.is/posts/good-ideas-for-cities-growing-a-local-food-system-for-st-louis

 

[mlp]

I agree with Nog's posts.

And while I'm not a big fan of suburbia, I have to wonder whether habitat fragmentation is actually worse than the alternative, assuming the alternative is some combination of high density city dwellers supported by super efficient agriculture. Super efficient agriculture results not in habitat fragmentation, but habitat elimination. I've seen the results of that here, over the course of my lifetime. Suburban areas I've lived in are teeming with wildlife compared to what is found in this agricultural area as farming has become more "efficient."

 

[Digger]

Urban dwellers tend to share the cost of things whether they want to or not. Heating a building with 50 apartments is inevitably cheaper than heating 50 separate single-family homes. That kind of thing.

 

[mlp]

Urban dwellers tend to share the cost of things whether they want to or not. Heating a building with 50 apartments is inevitably cheaper than heating 50 separate single-family homes. That kind of thing.

Oh, agreed - multifamily housing is always going to be more energy efficient than single family housing, all other factors (square feet per individual, materials used, etc.) being equal. Subterranean dwellings are the only potential exception that I can think of ATM.