> No one says that, ...

Malthusians do, and have, for more than 200 years. Two hundred years.

Now, if we keep growing our population, then yes, eventually the Malthusians must and will be right. And perhaps that eventually is now. It's worth exploring that, even if Malthusians are like the boy who cried wolf.

But I'm skeptical that we're finally at our and the planet's limit for the simple reason that population is already predicted to go flat and then begin declining very soon.

Europe, North America, Japan, Australia, Russia, China, India, Iran -- all of these are below replacement rate fertility now or nearly there and getting there fast. Much of Latin America is well on its way there too. That leaves places like Nigeria, for example, as having high fertility rates, but even there it's a pretty safe prediction that fertility will eventually go down.

Decreasing fertility correlates very well with GDP per capita, and it's understood how wealth has caused low fertility rates. That dynamic need not be universal, but it's a pretty safe bet.

Meanwhile, Malthusians have been perennially wrong not only because they've failed to predict or accept the reality of low and declining fertility rates, but also because they've consistently failed to predict or accept the market's ability to adjust to demand growth. So far we've always found ways to produce more food and so on -- no, there's no guarantee that we will continue to be able to, but the fact that total population will peak soon then begin declining means we probably won't need too much more in the way of food production revolutions.

Malthusian also complain about pollution but don't seem to understand that more wealth == cleaner environment -- not at first, maybe, but certainly at some point. Just look at Haiti vs. the Dominican Republic: Haitians are so poor that they cut down their tree for firewood, while Dominicans are wealthy enough that they do not -- same island, same climate, different stories. Or look at the U.S.! In the 1930s river fires were so commonplace as to not be news. In the late 40s river fires were rare enough that they made Time magazine's cover. Now they're even rarer. Those are just some examples. Of course, most Americans have no idea how clean the U.S. is because they've not been to, e.g., Beijing, but that's good anyways: we can always get cleaner.

> ... because having as many kids as you like seems to be considered a basic human right. But imagine Earth with a stable 10% of our current population.

If some family wants to have six children, in a country that has below-replacement fertility rates, that won't move the needle. These are macro trends.

What you write comes across as rather ominous: a threat to impose Chinese-style family planning rules. Not only is it a very bad idea (ask China!) but it's also quite tyrannical, and completely unnecessary given the macro fertility trends.

How do you imagine we'll get to 10% of the current population anyways? War? Draconian family planning? Something worse? How much time do you think we can afford to let pass before we reach that 10%? Centuries? Decades?? If you say "centuries", it might happen naturally. Saying "decades" would strongly imply that you must have some truly awful ideas for how to make it happen.