That mostly seems like an artifact that first world countries are much more urbanized than third world countries. Wealthy consumers generate much more carbon per capita in general.

New York City may produce more emissions than Papau New Guinea. But I don't think moving people from Manhattan to Vermont would lower emissions. Just the opposite in fact.

A person's carbon footprint is directly related to their wealth/income. If 80% of wealth/income is in cities, this isn't surprising.

Further, the definition of "city" can include a lot of sprawl in places like Houston, Phoenix, and even Beijing and Tokyo.

Even further, can you cute your source? I'm skeptical of both numbers. And it would be very easy to cherry pick either side of these numbers.

For example, a lot of concrete is pored in cities to build mid/high rises. Concrete produces a fuck-ton of carbon. Is this amortized over the expected lifespan of the building? Where is the carbon cost accounted for? A lot of the carbon is emitted in rural areas. But is it all just lumped into the city because that's where it's used? That seems unfair. A lot of rural wealth comes from natural resource extraction used to build and power cities...

Most power plants and factories are outside of cities. Yes, they mostly power the city and produce goods for the city -- but their providing a lot of income/wealth to rural areas...

For citation here are two sources:

50% of population: https://ourworldindata.org/urbanization#how-urban-is-the-wor...

70% of emissions: https://www.c40.org/why_cities

This is based on the concept of a "consumption emission", which is an interesting concept. The point being that cities (especially western cities) have seen their emissions drop due to de-industrialization, but consumption has increased (hence your statement about carbon footprints correlating to wealth/income). To say that cities impacts are smaller when they just outsource all of their carbon impact is disingenuous.

From your source: It usually incorporates the population in a city or town plus that in the suburban areas lying outside of, but being adjacent to, the city boundaries.

GGP suggested that suburban living is greener. How does the 50%/70% support his point if cities include the suburbs?

> Further, the definition of "city" can include a lot of sprawl in places like Houston, Phoenix, and even Beijing and Tokyo.

Is it the case that you get to cherry pick which urban center is a real city based on how green it is?

The point is, there's likely a certain density at which it gets progressively more green to live in. If you're treating all cities equally, there's hardly a point in distinguishing between cities and small towns. There's not much of a difference between Omaha, Nebraska and Podunk, Kentucky. There's a gigantic difference between Manhattan and Yonkers.

I wouldn't be surprised if Dallas is "less green" than small towns in Italy, even adjusting for income/wealth. I would be surprised if the same is true when you compare to inner Tokyo (Shibuya).

One thing that would be interesting to know -- high rises can use a ton of energy to heat & cool. And the taller they get, a significant portion of the building is just stairs and elevators. I wouldn't be surprised if density gets "less green" at a certain maximum. Manhattan & Shibuya could very well be past that point.

>One thing that would be interesting to know -- high rises can use a ton of energy to heat & cool.

Sure, but how does that compare to the energy needed for lots of smaller buildings, which can provide the same floor space to the same number of people? I suspect the high rise is more efficient: it has far less surface area on the outside. The more surface area that borders the unheated/uncooled outside, the more energy you need to expend.

>And the taller they get, a significant portion of the building is just stairs and elevators.

Again, how does that compare to smaller buildings? Once you get past 1 floor, you're going to have to use space for stairs and elevators. You can't have a city with 1-floor buildings; the sprawl would be ridiculous.

>Manhattan & Shibuya could very well be past that point.

Have you been to Shibuya? Buildings really aren't that tall in Tokyo, especially in Shibuya. Remember, Tokyo (and pretty much all of Japan) is a highly tectonically active area, with frequent earthquakes. Manhattan has no earthquakes and has a huge layer of bedrock under it; it's basically the most idea place on the planet for building skyscrapers, except for being close to the sea (because of hurricanes, but these are rare because it's pretty far north). There are some reasonably tall buildings in Tokyo, but nothing like the 100-story behemoths in Manhattan.

Yeah, skyscrapers have a lot of stairs and elevators, but I'm pretty sure switching to a bunch of smaller buildings and replacing the stairs and elevators with roads and automobiles is not going to come out ahead on environmental impact.

There are a lot of articles talking about this. Here's one I grabbed:

https://www.citylab.com/life/2012/04/why-bigger-cities-are-g...

I think in the statistic you cite, 'city' includes both the urban part and the sprawling suburbs. You'd also want to compare apples to apples: someone living a very green life in a "western" city is still likely to live a more carbon-intensive life than someone doing subsistence farming.

I suspect it's more about wealth, people in cities earn and spend more. In general the more you spend the bigger your carbon footprint.

Carbon emissions aren't the only impact humans have on the environment. As one other commenter pointed out, the further humans sprawl the more we encroach on wildlife habitat.

This trope of environment === greenhouse gases in the atmosphere is dangerous.

There are significant demographic issues to account for, especially when looking at such high level statistics. Your breakdown also doesn't take into account the inverse land-use factor. High density in one location allows for lower density elsewhere, with additional environmental effects.

Think of it this way: The smaller area humans occupy, the more can be untouched wilderness.

Directly touching sure, but what about indirectly touching. If those city dwellers are all using more carbon and creating more pollution, then they may touch more wilderness.

Of course, they do not, but still....

People in cities have much shorter and less car driven commutes than in suburbs or rural.

Everything is near and there is public transport.

So how they would use more carbon is very hard to see.

yeah, that might be true if we built cities where the only means of transportation was public transit. But I'm thinking of all those skyscrapers in SF, and how many folks make 1-2 hour commutes to work in them.

If there were more housing close to those skyscrapers; if it were legal to build it, those people would have shorter commutes - and occupy less land to boot.

Instead, San Fran is one of the NIMBYest cities on the planet and so all those people are forced to come in from further afield.

The skyscrapers themselves are pretty eco-unfriendly as well, frequently built as essentially a giant greenhouse with heavy heating & cooling loads to maintain comfort.

I suppose you might look at some technical discussions of whether you're better off with a larger area built up to 6-10 stories or something like that, than fewer, taller skyscrapers, but in general, that denser environment keeps cities from sprawling out, and is more friendly to people walking around.

I prefer the more European style of 2-8 stories, like here: https://goo.gl/maps/poabxNny8r8Jq46v7

But I think the broader point stands.

Many european cities max out at 8 stories simply because they were built before the advent of elevators, or the design aesthetic started before the elevator and they're keeping new neighborhoods consistent.

4 floors is mildly inconvenient on foot but 8 floors is becoming a real chore for people over 40.

Almost no buildings beyond 4 floors (5 the way Americans count them) lack elevators in Germany or Austria at least. I suspect it's the same elsewhere in Europe.

That seems counterintuitive to me. I'd expect only having one or two walls exposed to the outside (maybe 3 if I'm on the top corner) would reduce the amount of energy I lose to the environment compared to a house with 5 sides exposed. Plus a skyscraper can use a larger and more efficient system than a single family home.

Right, but your family home is likely insulated to at least R-13 in the walls and R-38 or better in the attic while an all-glass skyscraper is probably something like R-2. A tall & thin skyscraper also has an uncompelling surface to volume ratio.

This is also a factor or density right? There are more people leaving per square meter in a city than there are in rural areas.

Wow, what a way to play with statistics.

I wonder where those people not living in the city go to work or at school...

Oh, wait!

Rome is a city with less than 4 million inhabitants, they become almost 6 millions during a normal workday.