Humans aren't going extinct any time soon. The world population is projected to level off at 10 billion near 2100.

> Humans aren't going extinct any time soon.

Soon in years, no. Soon in centuries, yes.

Be careful with extrapolation. A few decades ago Malthus thought we were heading for overpopulation.

That is a good point.

And actually it's not all humans who would go extinct, it's modern urban/semi-urban more-liberal people. There are pockets of often-rural highly religious populations that are well above the replacement rate right now. Basically Kamala Harris supporters are going extinct and Donald Trump supporters will populate the future, unless something changes.

In Japan, it's the rural areas that are going extinct while the urban areas are increasing in population. We'll probably see the same thing in the future in the US as well.

No, not unless the US changes its zoning laws drastically. They won't allow new housing in the cities, so the only way to increase population is if hordes of homeless people move in and camp out. However, the urban areas can increase in size, so that large areas are basically gigantic and growing suburbs.

Well even in Japan it's all urban sprawl. Tokyo is the largest metropolis in the world, so if the US follows suit, it would similarly grow outward not upward. Solving zoning law issues seems to be extremely difficult as NIMBYs explicitly vote against solutions as it harms them directly. I understand why they vote that way, but we would need top down solutions which are hard to come by politically.

>Well even in Japan it's all urban sprawl. Tokyo is the largest metropolis in the world

This isn't true (the urban sprawl part): while Tokyo is the largest metro area and does have a lot of sprawl, it's also continuously growing upwards, and not that much outwards because there really isn't much room left on the periphery (ocean and mountains are hard limits). Older, smaller buildings are regularly being knocked down and replaced by new, taller buildings.

Yes, so absent limits like geography, it seems cities will grow outward, and upward only when they hit those limits.

I don't think so at all. Growing outwards only works if you have an instantaneously fast transit system. There's a reason the real estate in central Tokyo is some of the most valuable in the world: because it's close to everything. The farther out you go, the less valuable land is, because it takes time to get to the center (or anywhere else).

This is of course true in American cities too, but zoning laws largely prevent new (and taller) housing construction close to the center, so they have no choice but to build outwards. In Japan, building upwards is much more feasible, only requiring that you acquire some desirable existing property first. (Of course, there are some limits to what you can build on it, but it's nothing like in the US so it's much easier to get approval to build some nicer and/or bigger/taller.)

I live in a depopulating regional capital city of Japan, and we're still building upwards. In the past 4 years or so, I can count at least 7 large (12+ story, 150+ unit) condo buildings that have gone up. People want access to entertainment and short commutes to their jobs.

The thing that needs to change is zoning in cities. We don't let people move into our big cities in the US the way they do in Japan. That's the only change we need.

All of the other species on the planet might disagree.

That's ok. They don't make the rules. We do.