I thought about going that route with my earlier rough calculations, but I wasn’t sure at what point I was no longer taking about “earth’s carrying capacity.” Even then, I think stuff in orbit around earth is fair game.
No room for an ecology of course.
Cite?
We are overcrowded and resources are not well distributed, some of that is due to greed & politics.
But, I have not heard that the world is actually overpopulated at this moment, except by people who feel there are too many of “those people”.
Could power generation by nuclear fusion take us beyond the solar energy flux limit with a relatively modest technological advance? I’m not sure what the plausible reactions and fuels are.
If someone were making the argument “People are starving therefore we have too many people” then you might be right. But that’s not the argument.
We irrigate our crops with water from underground aquifers, at a rate MUCH faster than the aquifers can replenish themselves. Almost every aspect of modern farming requires energy input in the form of fossil fuels, at a MUCH faster rate than it took the fuels to accumulate in the first place. We use artificial fertilizers so fast that, by some estimates, we can only keep it up for another 30 years or so before we face shortages of the raw materials needed. That’s just three examples. Currently, we manage to feed such a huge population by using strategies which succeed in the short term but cannot possibly continue indefinitely. If switch to sustainable methods which actually CAN be continued indefinitely, we’d have a smaller amount of food.
Just how many people could be fed with that smaller amount of food depends on many factors, including distribution of resources, greed, and politics. It also depends greatly on what percentage of the diet would be meat, and to what extent we are willing to push aside other species to make room for our farms. But you’d be hard pressed to think up a scenario where we could SUSTAINABLY feed 7 billion people with proven technology*, let alone 10 or 12 billion, even if you completely eliminate greed. I think it’s much more likely that we could only feed about 2 billion people that way.
That’s what I mean when I say we are overpopulated. It’s got nothing to do with how many people are hungry in Africa.
*I’m assuming we won’t have Star Trek style replicators, for example.
Just to add, PLEASE don’t take my question as a cue to sidetrack this thread with cold fusion polemics, or anything like that. I was asking in terms of broad theoretical principles, of where fusion might take us in (say) 300 years. I think hydrogen from water is all that’s needed as fuel, in principle? So is it plausible that energy production from fusion could reach the order of magnitude of solar energy flux?
This one will do better in IMHO rather than GQ.
samclem, moderator
Or they travel mostly to China and India
If you’ve ever looked at the wide open spaces of places like Nevada and thought “wow, there’s room here for 10 times as many people”… consider this. Earth currently has 7.1 billion people, sharing 57 million square miles of land. That’s about 125 people per square mile. Let’s think about that for a minute.
Imagine yourself and 124 other people sharing one square mile of land, like a tiny island. That’s 640 acres. Only about 10% of Earth’s land surface is cropland, plus another 20% is pasture. So you’d be growing all your crops on just 64 acres, and raising all your cattle on just 128 more. You’d have about 10 acres devotes to streets and houses, and about 160 acres of forest. Of the remaining 278 acres, the vast majority of it would be unusable. Some if it is desert. Some of it is steep mountains. Some of it is swamp. There would be about 18 acres leftover that’s usable but currently unproductive.
Right now, you’re managing to feed 124 people on this island, using aggressive farming techniques which can’t be sustained forever. How many more could you feed if you increased your cropland from 64 acres to 82 acres? How much would that help? How about if you chopped down all the forest, another 160 acres? Could you double your food production? How long could you keep it up?
Now do you still think it’s possible to feed 10x as many people as we currently have?
Keep in mind that there haven’t always been 124 people on this tiny island of yours. A hundred years ago, only 30 people lived on this island.
Right now our food comes primarily from the sun, carbon dioxide, and water. You could make edible reduced carbon some other way, using another energy source (and probably the same starting materials), but I’m not sure at what efficiency. See articles returned by an “artificial photosynthesis” search. With current technology plus fusion, your best bet might be to just generate light at optimum photosynthesis wavelengths and let indoor plants or algae do their thing.
That whole post was an insightful analysis, thanks.
It’s worst than I thought.
Let the purge begin!
Why do you think that solar flux is insufficient to provide enough food for the world? Currently most of the light that gets through the reflective cloud layer hits the oceans; cover the oceans with algae-vats and you could easily support 100 billion.
Sure, we could use fusion as a source of energy to power our civilisation, assuming that fusion ever becomes feasible; but photovoltaics could power the world adequately. 173,000 terawatts of light hits the Earth on average at all times; 10,000 times more power than we use in our worldwide civilisation. If we used just 1% of that power to supply the needs of the population we could support 100 billion humans at high levels of comfort.
But there would be no reindeer, no whales, no elephants. Do you want to know the Earth’s carrying capacity for humans, or the Earth’s carrying capacity for humans plus a diverse biosphere? These are very different figures.
I think there are two parallel conversations here, one about more realistic questions of feeding the world in the forseeable future, and another one about theoretical ultimate bounds in the far distant future. The possibility of exceeding solar flux arose as part of the latter.
Thank you for paying attention.
One word cannibalism. Americans start eating exotic mystery meat
What do you think goes into hot dogs? Cemeteries are A LIE, SHEEPLE!
I do know that some sources of fertiliser such a guano deposits on islands have been mined out and in some countries aquifer levels are dropping due to high withdrawal rates.
Economics will drive the production of manufactured products with the result of more costly food, and that will be an issue. Aquifer depletion is fairly common in many areas. Humans are taking out water faster than it gets back in. that is also something that is a fairly important problem over the relatively near term.