Transhumans that replace eating with breathing

Question

We are in a far future setting where humans (or transhumans I should say) achieved two things:

1. be able to modify themselves genetically to the point where they can have completely different organs to what we have now
2. be able to customize the earths atmosphere to their needs without causing unwanted side effects (like global warming)

The goal is now that nobody has to eat anymore in the way we do now and the plan is to get the necessary nutrients from breathing the customized atmosphere. This can either work by having nutrients directly in the air or the components are in the air so when the transhumans breathe, their new and specialized organs can produce any necessary nutrient. Removing the necessity to drink is not a priority. If they can get their water supply from their atmosphere it is a nice bonus but if they drink it like we do now it is also okay.

My question is: Can this be possible given the two assumptions above?

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There are a few potential problems I can think of with this method of nutrient supply:

• breathing may not be efficient enough
• the constant access to food may be a problem
• the needs for nutrients vary too much to have one atmosphere composition that works for anyone anywhere anytime
• the air would be so heavy that it would get too dense in low altitudes or that only people living in low altitudes would have access to food
• other organsims may reproduce incredibly fast in this nutrient rich atmosphere

Answer 1

The current atmosphere is just fine

As you're aware, plants are mostly carbon, and they get it entirely from carbon dioxide in the atmosphere. They get extra nutrients from the soil, but in much lower quantity. Since you allow drinking, you should be able to enrich the water with all the minerals needed. Clearly trees exist, so the mechanism for converting carbon dioxide and minerals to organic matter is out there. The only problem is it requires huge amounts of energy, so trees need a huge surface area for photosynthesis.

If you can replace photosynthesis with wireless power, you're all good.

You'd need a huge network of power plants, which we already have. Additionally you want power transmitting antennas all around the world. We sort-of have this capability with mobile networks, but it's incomplete and they don't send enough power. But this should be a doable engineering feat if we chose to do it. Finally you need a custom organ that includes a giant coil to efficiently capture power. Once you have the energy you need an equivalent to photosynthesis to go from electric energy to organic compounds. And that's about it.

Final note is that our current breathing rate should also be sufficient. When you lose weight you are literally burning fat, with the exhaust CO2 going through your blood and out of your lungs. All the weight you lose goes through your lungs or the water you pee. Thus the throughput of CO2 going through your blood and out the lungs should also work in reverse and let you grow at about the same rate as losing weight.

Answer 2

While possible, I don't think that a society of transhumanists would do what you're proposing as it would be a massive waste of resources. Saturating the entire atmosphere with enough "nutrients" to make it practical for transhumans to use would be a colossal effort and probably completely destroy all native ecosystems. Most air never gets inhaled by humans anyways since the vast majority of "air cycling" on Earth is done by plants.

If you want to eliminate the need for transhumans to eat regularly, then maybe only make them take supplements while they're growing of if they need to repair themselves. For energy needs, batteries along with wireless charging could be the solution or people could grow nuclear reactors inside themselves and swallow a vial of tritium every couple decades or so.

Additionally, I think that any society of transhumanists would be rather diverse with different people choosing different upgrades or enhancements. It's possible that people would need highly customized or specialized diets for their specific body parts and adapting a one-size-fits-all solution might not be the right call.

Answer 3

This will be a massive undertaking, and is probably not economically viable enough. As other answers pointed out, saturation the entire atmosphere with nutrients is near impossible, and a gigantic inefficient waste. But even if it can be done, this will not negate the need for food production, as the nutrients will still need to come from somewhere.

This will also need to be taken over by a sitting government entirely, the production as well as the distribution, as this is not really an opt-in kind of situation. Either everyone will need to do it, or nobody can. So not only will you need a gargantuan amount of resources, you will also need to unify the earth under a communist regime. As plenty of examples have shown us, communism doesn't always work the best, because of human nature. If you genetically modify humans, their mentality is where you would need to start.

On top of all this, there is the cost of genetically modifying humans. This can't be done to just a few humans, as they will need to effectively repopulate the earth. That is if their gene modding doesn't have any averse effect on human physique to begin with, especially their reproductive ability. And if the modified gene is carried on through reproduction to begin with. Forced evolution like that will not be easy.

You could offset it by only allowing this in enclosed spaces, perhaps as large as (domed) cities. But this will still be a huge undertaking nonetheless. And anyone not living in the city (or travelling) will not have access to food, as all of it is used to supply the cities. All in all the convenience of food consumption is unlikely to ever be so big an issue that it will need a solution like this.

Answer 4

https://en.wikipedia.org/wiki/Radiosynthesis_(metabolism) - "eat" PU238 once every 20 years or so, the stomach equivalent produces melanin which, in its activated metastable form, is circulated by the blood stream to carry the necessary energy into the cells. Biochemistry is no longer needed as a source of energy, all the other supporting processes are tuned to maintain the brain and reproductive organs. Like photosynthesis, except at higher energy levels and not limited by the surface of skin that can see the sunlight.

Answer 5

They’d be filter feeders that eat highly dense pollen.

The transhumans you describe sound very much like the Astomi from Orion’s Arm.

They’re filter feeders who live in specialised space habitats that include plants that produce large amounts of pollen that they feed upon. They do this by using a layer of fine hairs that cover their bodies that collect an amount of pollen before retracting under the skin so that the pollen can be digested before extruding again. Since the human body doesn’t have enough surface area to make this a viable feeding strategy on its own, they supplement this with a symbiotic “flower” implant on their backs that greatly increases the surface area available for them to feed with.

Answer 6

Have you thought about making these humanoids undergo photosynthesis? That way, they can get many of their nutrients without even the need for air, just sunlight. I'm no biologist, but it seems like your people would then only require water and the air we know.

Furthermore, it seems like your second point counters any issues that might arise.

EDIT: As you pointed out to me, photosynthesis does not provide enough energy to sustain a human, so that possibility flies out the window.

To answer your question, though: It seems like your two stated facts, that these transhumans can pretty much adapt themselves to any environment and that you handwave the risks of pumping the air full of nutrients, this idea should work. This constant access to food might be unhealthy to individuals who require less energy, like children, so keep that in mind.

So: It works, you just gotta make it believable.

Answer 7

This is not realistically possible, unless your transhumanism includes serious cybernetics, in which case "breathing" would stop being a thing anyway. The vast majority of the food you digest serves as fuel. Your body reacts this fuel with an oxidizer taken from the air to provide the energy you need to survive and maintain the high activity of an animal.

If your "solution" is to mix this fuel into the air at densities sufficient to support human activity, then you have a reactive fuel-air mix that would ignite and potentially kill everything in the world at the first lightning-strike, or if someone lit a match in the open.

If your "solution" is to remove the oxidizer from the air, then you've simply switched from eating fuel to eating oxidizer, which requires even more biological changes, as our carbon-based systems are not designed to chow down on solid / liquid oxidizers.

If your solution is to forgo the fuel entirely and switch to photosynthesis, you don't get enough energy. There's a reason plants are virtually inactive. You need roughly 8MJ (2000 food Calories, which is actually 2,000,000 calories) per 24-hour period to survive. Sunlight averages roughly 160 Watts per square meter over the course of a day, which translates to 14MJ per square meter per 24-hour period. If you can capture sunlight with 100% efficiency, you need to have a cross-section of 0.6 square meters exposed to the sun throughout the day. Photosynthesis only captures 6% of the sun's energy (it's 60% efficient within the wavelengths it absorbs.) so you would need 10 square meters exposed to the sun throughout the daytime to capture enough to survive on chlorophyll. Photoelectric panels are 20% efficient, and have a theortic maximum of 33% efficiency. If you powered your transhumans with maximum efficiency solar panels, they'd need to average 1.6 square meters of skin facing the sun throughout the day. The entire body of a healthy adult has approximately 2 square meters of skin, which translates to less than 1 square meter that can be faced in any one direction.
To make this work your transhumans would need large bat wings made out of photoelectric materials (and some efficient way of converting electrical energy into biological energy), and would have to lie with them spread out toward the sun throughout the day time. (So, it might be possible, but everyone would have to ask whether it was realistically worthwhile.)

If your solution its to replace all the messy bits with metal and power yourself with electricity, then there's not much point in breathing (other than using air for cooling).