What is the total amount of indoor area in the world? And how fast is it growing?
I doubt that you are going to find an accurate answer to this question. By the time you managed to get everyone to fess up the details (never would happen), they would have changed. I think that it is safe to say that it is increasing, but I don’t know anything more exact.
Well, nobody knows the exact human population of the world, but that doesn’t stop people from making estimates, right?
Guestimate 6.5 Billion humans. Habitiable space alone would be well ino the hundred Billions. Take on the warehouses, work facilities et.al. The number would be well into the trillions of square footage for total world…