Ideal human population is 100 billion. Off-planet.

My off planet assumptions are for 200-300 years; that the Moon, asteroids, and free-floating colonies have been settled with lots of people; that Martian life discovery protects Mars from colonization; and that Venus hasn't yet been terraformed. And that there's no Singularity - otherwise all bets are off.* There's lots of room out there in space, and changing some of these assumptions make mine a low-end figure.

I think this is the good way to approach it if you're a space nerd who's deeply concerned about population growth and how little any side of the political spectrum has done to address it. We're not anti-human. Live long and prosper! Just as long as it's mostly out there, where you can't take the sky from me.

On planet Earth, we're messing up big time. What the global ideal population would be depends on trading off numbers against resource constraints. If we don't want resource constraints, want everyone to live like kings, and want minimal harm to the environment, then I think we're looking at 100 million people. If you settle for the median American quality of life with some reasonable technological upgrades to reduce environmental impacts, then we're looking at a billion people, one-tenth of what we'll see in 89 years. For larger numbers with modest environmental impacts, the only way I can imagine an ideal life is if people get most of the high quality of life experiences through virtual reality.

It's a rotten shame that the left in the US has mostly forgotten about the population problem due to some overstatements decades ago, and a fear of doing anything that tar them with espousing a policy that's also espoused for racist reasons by racists. The right is even worse, either ignoring the problem for ideological reasons or dog-whistling racist or fear-inducing reasons to control population. All the above gets magnified tenfold when discussing immigration to the US, where we convert the usually-young immigrants into highly impacting Americans, with descendants.

Maybe we can take the latest milestone of 7,000,000,000 people to do something about population, and even about immigration, without playing into the hands of racists.

*I think we'll pass the Singularity point in less than 50 years.

Random comments I've posted elsewhere

On whether the Singularity's a problem:

Those who deny the Singularity also have to assume a near-future end to Moore’s Law and virtually no improvement thereafter. I think the contrary assumption is more probable, that Moore’s Law will continue to operate and may even accelerate in the 21st Century (and beyond, but that’s not essential).

I think it takes little imagination, that someone, somewhere, will use AI to make our lives better. I don’t expect AI to instantly turn our smart toasters into killing machines, and maybe they never will, but 10-20 Moore’s Law generations after the point of AI sapience, we’ll have little choice over the outcome.

We also might merge with the machines, but again, the biological part won’t be able to keep up with the non-biological part for very long.

On whether the biologists critiquing evolutionary psychology go on to condemn the entire field (I'm going to come back to this, it's relevant to climate denialism):

Carl, I think Coyne would disagree with your statement that he thinks evo psych can’t be done at all. This is from your link to him:

“Now I don’t oppose evolutionary psychology on principle. The evolutionary source of our behavior is a fascinating topic, and I’m convinced that the genetic influences are far stronger than, say, posited by anti-determinists like Dick Lewontin, Steve Rose, and Steve Gould. Evolved adaptations are particularly likely to be found in sexual behavior, which is intimately connected with the real object of selection: the currency of reproduction. I’m far closer in my views on this topic to Steve Pinker than to Steve Gould. And there are many good studies in the field, so I don’t mean to tar the whole endeavor.”

An older one on why the Obama administration took so long to partially fix the Republican War on Science:

One potential reason for delay is that there was an internal battle between this okay document versus pure drivel, this okay document versus something with more heft, or a combination of both. Just speculating.

And on a denialist claim that you can construct a climate model to say anything:

I’m not aware of any climate models that fail to show warming. I think Mr. Calhoun is talking out of his hat. And it’s not like the coal and oil industry is too poor to create a model. My guess is that they’ve fooled around with it privately, but the mangling they have to do to get the outcome they want is so bad that they’ve never trotted it out. Yet more evidence against the denialists, as if more was needed.