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Comment by danhor | Hacker News Reader

No doubt it's greener, but not by an order of magnitude. Looking at the car: A large part of emissions are produced during manufacturing, especially for electrical cars. Driving less helps, but not an order of magnitude. Same with heating. A heat pump just needs (generally speaking around) 1/3 of the energy, so you really need a large size differential to get to an order of magnitude.

People living in a large city also have better access to an airport, which generally leads to more flights and more emissions (in total still less, but not great).

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It's order of magnitude, easily.

For example - if you live in a commie-block - you don't need and often you don't have the option to own multiple cars per family. Often you don't own a car at all. Parking space is at premium and walking/public transport solves most of your transporting needs anyway.

So that's the difference between producing 1.75 cars per family vs let's say 0.75 in the city. And then driving let's say 5000 km per year vs let's say 30 000 km per year. And changing these cars every 3 years vs every 6 years.

Heating is another thing. Surface area of my block is maybe 4 times the surface area of a detached house. But it houses 16 times more people.

But that's nitpicking. The big thing is infrastructure.

How many km of roads, cables, pipes, etc do you need per 1 detached house vs 1 flat in a commie block? How much concrete and steel do you use for that? How much energy is spent building and maintaining that infrastructure over the years?

My 4-stories commie block houses 16 families in a plot that would be roughly equivalent to a plot where 1 detached house would stand in the countryside. And it's pretty low-density as far as city planning goes. You could easily make it much denser. There's a small park and a playground in that plot of land.

So that's ~1/16th the infrastructure to service the same number of people compared to the countryside. And building the infrastructure is cheap compared to maintaining it for decades. The real unsustainable part of suburbia is maintaining all the extra infrastructure that low population density housing requires.

If anything - 1 order of magnitude was an underestimate.

I didn't follow the car replacement schedule line. Why would a suburbanite replace cars every three years vs six for a block dweller? Both of those seem extremely short to me.

If you don't use a car much you don't need to replace it as often?

I‘m baffled that you in all seriousness think that it‘s a good idea to live like that. It‘s less resource consumption, ok (for now at least). What about all the downsides to humans? Constant noise. Being exposed to people all the time. Pollution (by that I mean trash on the streets)? What about the pandemic? People had serious mental health issues during that time, that lived in places like you describe, because their appartements were tiny and they weren‘t allowed to go out.

I don‘t know man, to me you describe a real dystopian future. Just because it‘s a solution, doesn‘t mean it‘s the best/right solution.

Sounds like you’ve never lived in a block of flats before. There’s nothing dystopian about apartment blocks.

For us theirs is no constant noise. The flats have excellent sounds insulation between them so you can’t hear neighbours, and height means there’s zero road noise, or noise from people outside. Our flat is substantially quieter than any detached house I’ve ever stayed in, except perhaps houses deep in the English countryside where there isn’t another human for miles.

There’s also very little pollution. High density house means high density tax revenue, so the local authority is substantially better funded than any rural authority, meaning our roads are clean and free of litter and rubbish, and in excellent mechanical condition because the local authority operates an aggressive maintenance schedule.

For space, we have miles of car free paths and parks, which can all be reach without crossing a main road. It’s substantially easier to walk our dog off lead here than it is in suburbia, where you’re stuck to tiny pavements and the constant fear of a speeding driver.

Every time I stay in the country side I feel trapped, unable to go anywhere without getting in car. I can’t just put a coat on, go outside, and just walk somewhere pleasant, get a coffee, sit in a park, walk along the river, do some quick shopping, or grab transit to visit a friend. Instead the countryside forces me get in a car to go anywhere, something I would rather not do, and certainly not something I consider freedom.

Fun fact - nights in the countryside were louder than in the city. Dogs are barking whenever anything moves near them and then for 15 minutes a wave of barking goes through the village.

Meanwhile in the cities if you don't happen to live near a big multi-lane road - it's basically silent.

Also - what kind of a city has trash on the streets?

> I don‘t know man, to me you describe a real dystopian future.

It's hilarious to hear that I and almost everyone I know have been living in a dystopia our whole lives.

Looking at heating: There are still (admittedly fewer each year) people heating with coal, often with district heating. This results in approx. 1kg of CO2 emissions per kWh of heat (with losses due to the distribution) (gas heating is 200g per kWh).

The german electric grid has a carbon intensity of approx. 500g per kWh. If you supplement this with a local solar installation that (let's just say) halves the carbon intensity and have a great heat pump setup with a COP of 5 it results in 50g per kWh. This means you can heat 20 times the amount of the worst-case commie-block dweller with coal district heating before it gets even. And even though commie blocks aren't bad, I'd expect modern houses to have much better insulation (at least in Germany) than original commie blocks (worst [reasonable] case, remember).

In cities there is generally less infrastructure per person, but even though there are less road, cable, pipe kms per person, the ones are bigger and/or more heavily used, needing more maintenance and more frequent replacements.

In Germany public infrastructure accounts for 800kg of CO2 per person, while heating and warm water account for 2.2t of CO2. Public infrastructure is important, but so large to matter so much (and remember, this includes things like public service and military that isn't effected by your living style).

Electricity consumption at 0.5t and food at 1.7t are not that different for urban vs rural areas. Other consumption at 3.4t is hard to classify.

Looking at the statistics in Germany (http://www.mobilitaet-in-deutschland.de/pdf/MiD2017_Ergebnis..., page 48) people living in metropolis drive roughly half as much as people living in very rural regions. This is significant, but hardly an order of magnitude. Just because you live in a metropolis doesn't mean you live in a commie block, but I find it hard to imagine it gets down 1/6th. Even people without a car (not only not owning one, but not having access to one) in a metropolis drive 1/7th of people in very rural areas (but commie blocks are certainly not without cars). So this is hardly an order of magnitude.

A car replacement rate of every 3 years also sounds very high to me (ignoring company cars, but that doesn't change in either case), I think 5-6 years at least is more likely for suburbs and maybe a bit higher for commie-block dwellers but I wouldn't be surprised if it's the same.

This was only looking at CO2 (since it's easy to find numbers) and it's undoubtedly true that on average living in dense housing is more sustainable than suburban sprawl or even rural living. But an order of magnitude is huge and much harder to reach.

And since energy usage & emissions are heavily shaped by factors beyond "how dense do you live", it's harder to speak beyond the average. Someone living in the commie block that flies once a year from germany to new york and back produces more CO2 emissions from these two flights alone (~2.5t) than the average german with his mobility (~2.2t).

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