This has been a problem that's been bothering me for some time.

If you have nanotech, that can pull atoms together and make things. What's to stop you from making an assembler that grabs carbon dioxide to make, say food? Or plastic, or papercl... graphite pencils?

Most of our consumables are combinations of H,C,N,O - which we can get from the atmosphere and water... except when everyone else is doing it too. We're unlikely to run out of N and O, but C is in short supply. And if we impact the commons too greatly, we'll starve plants to death - nevermind the fact that we no longer need to grow them for food, and they're just in the way of our new ex-urb palace, to house all those thiings we're making for the mere cost of assembling them.

So, how do you regulate nano-assemblers (and people who might make them) so they don't use up the 'free' atmosphere, and kill the whole plant kingdom (and by extension the animal kingdom shortly thereafter)?


A field of corn will use all the carbon dioxide within a meter of the ground within five minutes at full sunlight. Without atmospheric mixing, and convection currents, those plants would have to stop growing at that point.

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    $\begingroup$ C is not in short supply. In fact, the planet is currently facing critical problems due to a massive oversupply of CO2. A somewhat more realistic problem would be competition between nano-assemblers and plants for sunlight, something we are beginning to see when people put solar panels on the ground, instead of the roof. $\endgroup$
    – jamesqf
    Feb 25, 2015 at 20:10
  • $\begingroup$ CO2 is not currently in short supply, but we also don't have nano-assemblers. Power production didn't use to compete with plants, but as you mention, solar is now competing with plants for sunlight. $\endgroup$
    – user3082
    Feb 26, 2015 at 7:02
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    $\begingroup$ C is not on low supply. Why? take dead animals or plants, and get all the Cs there. $\endgroup$
    – Kristian
    Feb 26, 2015 at 10:45
  • $\begingroup$ Food isn't a problem, carbon briefly locked up, then eaten, then back in the atmosphere. Same with anything "temporary" $\endgroup$ Jun 1, 2015 at 19:14
  • $\begingroup$ I'm failing to understand why this is considered a problem. If you want a full-grown giant sequoia, can't you just have your nano-assemblers create one? I guess the answer to your question is simply to maintain a gene bank and keep the recipes handy. $\endgroup$
    – IchabodE
    Jun 2, 2015 at 21:52

5 Answers 5


While i don't have any actual numbers: The amount of stuff people have and use is tiny compared to the total of matter in this planet (and its atmosphere).

It would eb a reasonable thing to program your nanites to always prefer recycling garbage from attacking any structures.

How do i identify garbage? An easy way would be to check where something is. If it is on a junk yard, it can be used. A bonus here: with nanites, you can recycle everything at a rate of 100%

What if i do not have enough garbage? Well, then we need to designate areas that we think are safe for scavenging. If you take any location on Land and disassemble anything down to at least molecular level, you should find almost anything you need to assemble almost anything else. Since matter is never lost in that process (but only transformed into new shapes), you should not run out of raw materials any time soon, since you recycle anything you don't need any more (including food you digested). If you need some very rare elements, you do the same as we do today: you find a region where those rare are more common, designate a scavenging area, and scavenge.

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    $\begingroup$ Nanites would require legs, and energy sources to move them to the trash, and to move the non-nano-scale item away from the garbage. An atmospheric assembler would not need to move, and could produce items anywhere that there is an atmosphere. Guess which one is easier? CO2 only composes .035% of the atmosphere, and if you bring that percentage down too low, plants are unable to photosynthesize and will die. There is 787 PgC (pentagrams of Carbon) in the atmosphere. $\endgroup$
    – user3082
    Feb 25, 2015 at 17:23
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    $\begingroup$ Sounds like a grey goo apocalypse. Nanites ought not be indivually self-proliferating like bacteria. Instead, large units produce them. They consume stuff where planted and what fed, and don't themselves need to decide what is allowed to be food. $\endgroup$
    – JDługosz
    Feb 26, 2015 at 8:25
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    $\begingroup$ which is easier? Limestone, not air. $\endgroup$
    – JDługosz
    Feb 26, 2015 at 8:26

Maybe some sealed greenhouse facilities, where plants are preserved both as seeds and as specimen.

Or the contrary: nano-machines used only in controlled environments...

Making the assemblers decay and non-self-replicating would be a solution to prevent resource abuse.

Else they could be made so that exposition to certain radiation disables the machines. (Emitters would be like the ultraviolet lamps used in laboratories)


The key is sensitivity. The nanobots need to be aware of the effect their carbon usage has on the world. Obviously each nanobot have very little intelligence and very little ability to measure the world around it, but together they could become very aware of the consequences of their actions and strive to be in harmony with the world.


TL;DR You don't need to worry, you have dastardly human opportunism on your side.


Journal Entry : 14th April, 20xx : We are saved, and I am the one to save us! Yes, you read that right person with no sense of privacy, I finally did it. All problems with Nanite TechTM have been solved. They said I couldn't control atoms, well, stuff that schwarzite down their throats 'CAUSE THEY WERE WRONG! We can pull stuff out of the air and make our food when we want! BYE BYE AGRICULTURE! I AM RICH!
PS : Sales start in two weeks! Better save up pwnsop!

Journal Entry : 1st May, 20xx(same year) : We are doomed, and I am not at fault! Seriously man, people are just batsh*t crazy! Guy walks up to the store, buys a pound of the stuff, then throws it on the Golden Gates. Then the police army has to deal with a few thousand tanks, and mutinies. Some guy bought a truckload and poured them into the ocean, and setting them to making H2O to ethanol, and threw a lighter. SERIOUSLY I AM TIRED OF THE PRESS MEETS. TIME TO NANITE MY WAY TO MOON AND GET THE HELL OUT OF HERE.

Note to self : make a lunar defence system with nanites, powered by hydrogen fusion

Basically, carnage ensues and people are burning more than enough things with nanite made weapons of wars to compensate for the gases consumed.

Also, governments use nanites to rebuild while you rot in a jail :).

Also also, turns out some snotty rich kid beat you to moon.


Impose a carbon tax.

Nowadays, a carbon tax is a proposed tax on factories and power plants that produce carbon dioxide emissions. For every ton of CO2 they produce, the factory would have to pay a couple cents. The idea is that the tax will add up for big polluters and encourage them to cut down on carbon emissions.

You can use this process in reverse. For every ton of CO2 pulled out of the atmosphere, it will cost you a few pennies. If you put that CO2 back, you will get money back. The good thing about this tax is that cycling carbon is fine. If you photosynthesize carbon and then break down the sugars you have made back into carbon dioxide, like a plant would, you don't lose money. There is no point in charging people who do this because there is no overall loss. Household use of CO2 will also not have an effect, so your citizens will not suffer a tax.

Here is how you impose this tax:

You can require that all nanobots are registered and have to log or transmit their CO2 consumption by the ton. This is kind of hard to enforce, but it has the added bonus that if someone tries to use nanobots for evil, you can tell who owns them.

You can also require all CO2 metabolic pathways to be registered and report their usage. Making nanobots requires precision equipment, so only a few manufactures will make them. There will also be services selling nanobot add-ons like a photosynthesis add-on, for example. You can require that these manufactures report usage statistics.

Looking at my answer now, I also see the possibility of charging per the nanobot. If you buy 100 bots or 100 metabolic add-ons, you can calculate how much CO2 they will be expected to pull in their lifetimes. Per unit costs also remove the necessity of cost reporting, in which case you would need receivers everywhere to pick up the reports. But hey, you can use nanobots for that.


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