How big a population can the USA support?

Interesting … if everybody stood elbow to elbow, the entire world’s population could fit within Los Angeles city limits … Nation Geographic made that point some years ago … just thought that an interesting analogy …

Arcologies are silly. If you’re going to make your buildings that large, why make them all one building? And if they’re multiple buildings, then it’s not what people call an “arcology” any more, it’s what we call a “city”.

What if we become able to synthesize food, like vat grown meat substitutes and such? Wouldn’t that be a game changer?

Where do the feedstocks for the food vats come from, and where does the energy come from?

Farming is a low tech way of converting solar energy into food. Sure there are ways to synthesize arbitrary organic molecules from inorganic stocks, but how can that compete with farming?

And I agree with Chronos about arcologies. A city in one building? What’s the purpose of that? A city is already an arcology, just with modular replaceable subunits. An arcology that covers 10 city blocks is no more efficient than 10 city blocks worth of buildings.

It seems to me that an arcology would be somewhat more energy efficient, at least in the winter; summer I’m not sure about. Between the thermal mass of a really big building, plus the body heat of all the people, I doubt that the middle part would need any heating during the winter.

The Mall of America at 5.6 million square feet of space has no central heating system and it is in freaking Minnesota where it gets super-cold for months of the year. The heat is provided by passive sources like body heat, lighting and skylights. The biggest problem is getting the temperature down into the comfortable range even during the winter.

http://minnesotaconnected.com/lifestyle/local-businesses/did-you-know-the-mall-of-america-has-no-central-heating_178620/

However, when I hear questions like this, it sends chills down my spine. The world can “support” a metric shit-ton of people but only for a few generations at best and maybe not even that at this point. My position is that the world is already vastly overpopulated and almost all environmental problems, especially global climate change, are directly tied to that simple fact. Even if you disagree, I have never heard a good argument why adding MORE PEOPLE would be a good idea in the first place. I realize that wasn’t the direct question but I still think it is important. Over what time-scale are we talking about? The world is expected to have 9.7 billion people by 2050 already. That may not seem like a huge increase over the 7+ billion people we have now but the difference is about the same as the entire population of the world in 1940 when seismic problems were already well underway.

Here’s another take on the challenges of limit case population density: Everybody Jump Even Cecil weighed in on this one: If everyone in China jumped off chairs at once, would the earth be thrown out of its orbit? - The Straight Dope

:smiley:

Or Zanzibar.

How much land it takes to stand on, how much land it takes to build housing and industry as we do now, and how much land, water, energy, and food it takes to support those folks have three very different answers.

e.g.

Antarctica is 5.4 million square miles. The USA is a mere 3.8 million square miles. There is no friggin’ way we could move the current populace of the USA to Antarctica and survive, feed ourselves, etc., as we do now. Despite gaining an additional 42% more land to build on.

See the cite in my previous post for how little land it takes for everybody to stand. That’s not the relevant measure of merit.

Clearly the US has lots of uninhabited land. Alaska, the desert Southwest, the North central areas, etc. They could be settled more densely than they are. But you can’t plop down a new Los Angeles with 10 million people in, say, eastern Colorado, unless you can source water for them.

To a first approximation, we’re already overusing the water resources of our part of the continent. IOW, as Shagnasty says, we’ve exceeded our long term carrying capacity right now. And every year we do so we sentence some future generations to a land with even less carrying capacity than the number we’re exceeding today.

IOW using made up numbers: Right now we’re 325 million living on land that can’t support more than 250 million long term. If we keep this up for another 100 years, the revised long term capacity forward from then will be more like only 150 million. Our great grandkids better like population shrinkage; they’re gonna need it.

wait what?
Who are we relocating and why?

An arcology would be incredibly more energy efficient. Think of all the cars that wouldn’ tbe driving around.

Hardly. If Westerners had the same carbon footprint as people in poor countries, we’d probably be fine. It’s not overpopulation but overuse of resources by a relatively tiny fraction of the global populace.

I don’t see the fundamental difference between those two things. “Go be poor like the 3rd world” isn’t a realistic solution. Asia and Africa are rapidly developing. Africa is expected to produce over 1 billion more people in the next few decades. Do you really think that many of them will want to continue living in poverty or develop a lifestyle that more closely matches a Western one?

The fundamental problem is that birth rates drop sharply as standards of living rise but we don’t have enough resources right now to support 7+ billion people at the level that requires. Unfortunately, I don’t have a solution and I don’t think anyone else does either. China is the only major country that has come up with one so far.

If we’ve got a billion more people in North America, the only way to feed them is through massive energy use which means we can’t cut down on our fossil fuel use. More CO2 means more ice melting, which means rising sea levels.

So in any future world where North America has an extra billion people must also be a world where the Gulf Coast looks like this:

I’ve always used “arable” to describe potentially cultivatable land, but poking around online I see mostly lists of land used for cultivation. Cultivated land has decreased and yield has increased.

Doesn’t chicken like that end up in canned chicken soup and frozen chicken enchiladas and chicken pet food?

I find it hard to believe it’s simply discarded because it was miscut.

Aren’t you forgetting nuclear power?