Exponentials can get away from you a lot faster than you might expect. For instance if we sustained a 1% annual population growth for another 13000 years the total volume of all living people would be more than the total volume of all the space within 13000 light years of Earth.
So unless we get faster than light travel or we greatly reduce the amount of space into which you can physically cram a living human we are under 13000 years away from a pretty hard upper limit.
Make more realistic assumptions than speed of light expansion of humanity and that limit gets a lot shorter even with growth rates quite a bit lower than 1%.
> if we sustained a 1% annual population growth for another 13000 years
And if we sustained a 0.03% annual population reduction rate (like South Korea recently experienced) there would be less than 100 people on Earth after just 600 years.
So I agree that exponentials can get away from you a lot faster than you might expect, but I also think that trying to predict cultural norms 13 millennia from now is likely to be counter-productive.
Per the article, actually about 100-1000 times beyond current capacities.
In a way I agree that the feasible limits, even on Earth, may be orders of magnitude larger (say, in terms of population, perhaps) than we currently have. But the current rate of growth in any case is probably unsustainable because of imbalances like co2 emissions. I do think it's feasible to change to renewable energy in the short term, if only political motivation was a bit higher (please, go out and vote focused on climate change, folks!). If I were to lay out a strategy for humankind, I'd say we should focus on climate change for the next few decades, and then we can resume growing (to avoid possible collapse).
Limits to technology are actually non-trivial due to the atomic nature of objects, limited number of chemical elements with limited range of properties, etc.. Intelligence itself isn't free and keeping the Great Self-sustaining Rube Goldberg contraption working is not trivial. It's very hard to predict what limitations we can overcome -- see Moore's law slowing down. Some limits we've almost reached such as luminous efficacy (LEDs in lm/W). Soon we'll be faced with the question of whether we want to make Earth into a Caves of Steel landscape (ending most natural life to create a hyper-efficient human/machine habitat) capable of sustaining more humans or a Solarpunk landscape (preserving natural ecosystems) with a more limited population. I think there's a large degree of arrogance to the first, because I don't feel competent enough to evaluate the true value of animal lives, supposing a large quantity of animals are sentient, and they have intrinsic scientific and cultural value. I think this requires an exercise in imagination from all of us. In any case, it's probably a great idea if we could at least keep the oceans, rainforests, and major national parks healthy.
One crazy dream I have is to colonize not Mars, but Mercury. In Mercury solar energy density is crazy high. There's even some thermal energy from the solar thermal gradient. You can dig to get to nice temperature ranges and be safe from radiation, all this works well since the planet is tidally locked and therefore doesn't rotate, there's no diurnal variation. You can build a crazy Cave-of-Steel there and live your life in a cramped cell playing video games (or [insert activity]), if that's what your vision of heaven is.
Diamond-based molecular nanotechnology, combined with fusion and high efficiency solar as sources of power will make all of our technology and infrastructure carbon sinks. By the end of this century I expect we will be concerned about CO2 going too low and causing a glacial period.
PS Mercury is too far in-system to be that useful. It takes less energy to get to/from the outer planets than it does Mercury. The cold traps on the poles are interesting though--mercury potentially has all the raw material needed for a self-sufficient industrial colony.
You have suggested in the same comment that somehow we will have nearly limitless carbon-negative energy but also that the amount of energy to get to Mercury is too high to make the trip worth it. This does not follow from the initial assumption.
A lot more Mercury than sum of all asteroids. On the scale of "this century" this may only matter for von Neumann probes building a Dyson swarm, but that's not a 0% possibility and you did ask for a reason.
Eh, if it's economical to have the sinks at that scale, we probably won't turn them off for the same reason we "could" turn the CO2 sources off but don't.
The ideal setup is probably CO2 levels quite a bit higher than today’s, but with a sunshade filtering out UV-B wavelengths. All of earth would be habitable, but without major weather swings.
Higher CO2 levels will result in vastly more arable land, mostly from the reduction of deserts and the warming of permafrost. Higher CO2 levels make agricultural crops grow faster and bigger. Higher CO2 levels (within the range I was talking about) has no effect on human respiration. Ideal for plants is good for us too.
"They found that if the outdoor CO2 concentrations do rise to 930 ppm, that would nudge the indoor concentrations to a harmful 1,400 ppm.
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In fact, at 1,400 ppm, CO2 concentrations may decrease basic decision-making ability by 25%, and complex strategic thinking by around 50%, the authors found."
Ok I didn't mean to imply maximally ideal. 300-400ppm CO2 would be a tremendous boon to both agriculture and most biodiverse wild ecosystems (e.g. jungles & forest tundra, not deserts). It would also warm polar regions more than it does equatorial regions, making northern Alaska, Canada, Russia, and Scandinavia more tolerable to large-scale, year-round human habitation, as well as Antarctica and Greenland (the resulting sea level rise being an issue tho).
