It has come to my attention that this blog post is seriously wrong.

Earth's population limit is about 1000 times higher than I thought, because I neglected the possibility of hot radiators on earth and active refrigeration of the living space. https://twitter.com/hereticalupdate/status/1345110220553539584

You can fairly easily fit 10 quadrillion (10¹⁶) people on Earth, all living pretty luxurious lives, without using any magical technology.

Volume becomes the limiting factor slightly before waste heat rejection, which is the opposite of what I said in the post.

Apologies!

With advanced but not physically-impossible materials, you can build a thick 8500km shell around Earth and fit 1 quintillion people with 5000m² of floorspace per person, and just about reject their waste heat using hot radiators too, though people will need to use less power.

I think your personal power consumption would need to fall to 2000W on average to get to 1 quintillion people. But a slight increase in size would give people a little more space and bring the power up to 10kW per person.

I call this "Exa-Earth", as exa is 10¹⁸.

(from @Isaac_A_Arthur 's video on Matrioshka Worlds)

I actually think @Isaac_A_Arthur also missed the possibility of hot radiators