# Thread: How much inhabitable land?

1. How much inhabitable land is there on Earth? By inhabitable I mean either natural food sources and/or the potential for agriculture, where a basic shelter and fire is all you need to protect you from the elements.

I've been looking and I found 2 figures

148,940,000 and 29,242,234
I'm assuming the larger one is the amount of total land excluding oceans, and the smaller one is the amount of actuall inhabitable land.

I can't find what data these figures where derived from so any help would be appreciated.

I'm trying to calculate how much land everyone would have if divided equally amongst all inhabitants, so if this has been determined we can skip all the other stuff.

My only concern is the definition of "inhabitable," since some places are only inhabitable during some seasons, and other places can be made inhabitable rather easily. For now I will settle for the least amount of land considered inhabitable.

2.

3. Are you really looking for arable? That is, land where productive crops can be grown.

Not sure "Inhabitable" has a well defined definition sufficient to answering your question. In jest, I don't consider Southern Florida or Coastal Georgia inhabitable during the summer, yet even the moon could be inhabited with enough technology help. Without technologic we've evolved to live in a pretty limited areas of the subtropics some tropical places.

4. Not just crops but also animals or bugs that we could eat, wild fruits and other plants to forage etc. Florida has lots of stuff to hunt and forage.

Take for example the Inuit, they survive mostly on meat, but also some plants. They don't have very long life spans, but life has been sustained for a very long time there.

so far my best estimate is about 50 sq feet per person, but this doesn't seem right at all. That's 7x7 and change. Are huge cities really that dense? Yikes, I'm claustrophobic thinking about it.

5. Originally Posted by marcusclayman
so far my best estimate is about 50 sq feet per person, but this doesn't seem right at all. That's 7x7 and change. Are huge cities really that dense? Yikes, I'm claustrophobic thinking about it.
I'd guess we probably talking 5-10 acrea to support a single person just in land necessary to feed us. The city density is only possible because we transport everything in.

We don't have to guess as much though. I'd be surprised if we coundn't find some figures for land that's useful for crops. Less confident for your other criteria.

"148,940,000 and 29,242,234 "
What are the units?

6. liters... jk

they must be square kilometers

the larger number was a part of a post saying something like "there is x surface on earth, and y is ocean and so x-y=z" But there is a lot of land that is not inhabitable, some of the land is not actually land but is rivers and lakes as well.

7. Originally Posted by marcusclayman
liters... jk

they must be square kilometers

the larger number was a part of a post saying something like "there is x surface on earth, and y is ocean and so x-y=z" But there is a lot of land that is not inhabitable, some of the land is not actually land but is rivers and lakes as well.
Ah but there are cultures who DO live close to exclusively on rivers and lakes so they would, by your parameters be included.

To me your definition is broad enough that the only land area on earth what would not be included would be the ice sheet of Antarctica inland from the cost where the dominant lifeforms are algae and very tiny insects. All other land areas have the prerequisites if one works for them.

8. There is a research station at the South Pole in which scientists live and work, 12 months of the year. There is no more inhospitable area on Earth, so this means 100% of the land area on Earth is habitable.

Of course, we understand that is not your meaning. If we exclude mountains, Arctic and Antarctic regions, and severe deserts, we are left with about two thirds of the Earth's land surface that is habitable, though sometimes barely so. If we look only at land area that is easily cultivated, that drops to about half.

These figures are flexible, and controversial. If we pipe fresh water into a desert, it becomes habitable. If we find a big aquifer under a desert and tap it for irrigation, it becomes habitable. Iceland, by many measures, is not habitable. Yet, using geothermal energy and glasshouses, they grow bananas! The right technology would make Antarctica habitable.

9. alright, thanks skeptic.

so if we count half of all land as inhabitable, about 75million square kilometers fits this description

divided by 10 billion people(to make room for future population growth)

is about 82 square feet(sorry I prefer to use the english system)

which is not neerly enough to survive on, which is what I'm trying to determine

10. I think you're off by a factor of 1,000.

11. The land area of the Earth is just under 150 million square kilometres. Allowing for 10 billion people and half the land area being 'habitable', we get 15,000 square metres per person. An area of 150 metres by 100 metres. (If you prefer imperial measures, allow for this as 150 by 100 yards - close enough). Or a little less than 4 acres each.

That is ample to provide sufficient food. If we were to grow all food as hydroponics, we could provide sufficient food to provide for 10 billion people on 1 million square kilometres, which is a small part of what is available.

12. Yes. I make it just over 80,000 square feet per person, which is roughly two acres.

13. alright thanks, that makes me feel a little less claustrophobic

so people just don't know what they are talking about, me trying to spread propaganda and/or fear, when they talk about global overpopulation

14. so people just don't know what they are talking about, me trying to spread propaganda and/or fear, when they talk about global overpopulation
Hang on there, you made a simple math mistake. That doesn't mean overpopulation isn't a problem. The average square footage per person is a pretty meaningless number. You need to look at total resources and total impacts.

For instance, it's been estimated that if the population doubles, the amount of waste generated will grow by a factor of twelve (sorry don't have reference but can find it later), due to increased standard of living of the new and existing population. That's a problem.

15. I suspect an optimum population level would be around one to two billion. Catch 22 is that to get there we need a declining birth rate and the way to achieve that is to raise standards of living, which just consumes resources much more rapidly.

16. There is no optimal population size. There are just too many damn variables affecting how those people will live. For example : a higher population means more geniuses, and hence more potential for human development. Obviously, there are practical limits to this.

Controlling population is currently very simple. There is no need for draconian measures such as China has enforced. Developed nations (excluding immigration and the more rapid reproduction of recent immigrants) have a growth rate that represents less than 2 children per woman. Japan for example, is now less than 1.5, and the Japanese government is frantically trying to induce women to have more kids. Many European countries are similar. The USA has a growing population, but only because it has so many immigrants, and so many recent immigrants from developing nations having too many kids.

The bulk of the increase in population is coming from developing nations, and most of that is actually a kind of 'left over' population explosion. That is, mostly, each couple are not having too many kids (world average for developing nations is 2.5 kids per woman). However, from the population growth last generation, there are a lot of kids reaching reproductive age, and their production of 2.5 kids per woman will keep the population growth going. In many ways, the population explosion is over, and we are dealing with the shrapnel!

However, there are still a few countries that produce more children than their share, and we should take action to help them reduce population growth. This happens because the women have no way of reducing their family size to the 2 kids per woman that surveys show they actually want.

All that is needed to bring the world to the point where population stops growing and starts to shrink, is to provide birth control materials to all women everywhere. This is something that George Bush specifically banned as part of foreign aid. Obama is reversing that decision. Along with the rest of the developed world, this aid to assist birth control should help considerably.

17. Along with the rest of the developed world, this aid to assist birth control should help considerably.
The UN prediction of around 9 billion people already considers such effects, so barring some horrific pandemic we might as well accept that the population is going to be much larger than it is today by the end of this century.

18. Bunbury
While that is correct, you need to bear in mind that UN demographics allow for a wide range in its possible predictions. Final maximum population size could be anything from 7 billion to 14 billion, though the extremes are unlikely.

By providing aid in birth control, we can help to keep the maximum size down towards the lower end of the range of predictions.

Check the UN ideas on www.un.org/popin

19. Skeptic, I'm not disagreeing with you. I agree it's pointless to think in terms of an optimum population. I'm just suggesting that instead of complaining that the population is too big we should all accept that the population will be bigger in the future and think about how the world can accommodate such a huge population with a decent standard of living in a sustainable way.

20. The scary part is there's little doubt that using our current tech we can probably support a much larger population for a while by unsustainable means.

Of course in the long run it's ultimately the sustainable number that's we're after--and it's possible that we've all ready exceeded that number.

21. It all depends on our definition of 'sustainable'. Personally, I could envisage a future society of 100 billion plus people, all eating vegetarian food grown by hydroponics, with fertilisers coming from recycled sewage. Nothing unsustainable there. Sad about the loss of all that wilderness, though.....

22. Originally Posted by skeptic
For example : a higher population means more geniuses, and hence more potential for human development. ..
This isn't logical Jim. To develop fully genius requires proper development in the womb and during childhood and adolescence. In an overpopulated world where many have insufficient quality food potential geniuses will not attain that potential. Of those who do many will be unable to make a significant break out of the poverty they find themselves in.
There is no optimal population size.
Of course there is. All you have to do is to define the desired standard of living, determine the resources required for that and calculate how many can be sustained at that level.
If you wish to say that no agreement can be reached on the desired standard of living you will find that is an entirely different argument.

23. John
The idea that more population means more geniuses is not original with me. It is part of Prof. Julian Simon's philosophy (economist), and obviously it is a logic that works only when those people genetically genius have the opportunity to develop that potential.

I stand by my statement that there is no optimum population size. The thing is that the variables that determine this 'optimum' change so rapidly that no single figure lasts long enough to have much meaning. In addition, everyone has a different set of values, and so everyone will have a different idea of 'optimum'. I have even read missives by people who think the optimum human population size is zero. Thus any idea of optimum is so variable as to have no real meaning.

24. Originally Posted by skeptic
The thing is that the variables that determine this 'optimum' change so rapidly that no single figure lasts long enough to have much meaning. In addition, everyone has a different set of values, and so everyone will have a different idea of 'optimum'. ....... Thus any idea of optimum is so variable as to have no real meaning.
The same could be said of the Inter Bank Lending Rate, but that sure as hell as a massive impact on all of lives, as the current economic crisis amply demonstrate. The point is an optimum can be defined that is the optimum for the specified conditions.

25. Originally Posted by skeptic
John
The idea that more population means more geniuses is not original with me. It is part of Prof. Julian Simon's philosophy (economist), and obviously it is a logic that works only when those people genetically genius have the opportunity to develop that potential.
Pretty interesting. Though in addition to opportunity, is nutrition which will limit their potential, lot of potential geniuses today are handicapped by childhood mal nutrition, as well as a nurturing environment that will make him want to do good--rather than become a Somali pirate kingpin, the next violent religious extremist etc.
--

I agree that optimum is also pretty hard to define and highly transient because of a variety of factors. While Western meat consumption already far exceeds what's possible for the entire global population--that all could change with development of affordable palatable "test-tube" meats as just one example. Another example is how much progress the US has made in reducing soil erosion, by adoption of no-till farming techniques in the past twenty years.

26. Lynx
You are absolutely correct about the importance of nutrition. What we need to be working towards is a global society (not a world government) in which everyone is adequately nourished. The technology for doing this already exists, and the population is well within the limits that permit this goal to be achieved.

28. yeasts, mushrooms and insects are very efficient sources of protein

they are relatively cheep, completely sustainable and operations can be very compact

29. gth
I have said this before, and I will, no doubt, have to say it again. World population is no longer exploding. It is still increasing, but that is a residue of the previous 'explosion'. The United Nations demographers predict a maximum of 10 billion (plus or minus a couple) by about 2050. Your calculations should be based on this figure.

30. Like gth759k I was interested in the study pretty much the same way.. however eventually and based on the historical basis, we can never be so close to the future prediction (specially the far future) of the population on earth.

We can decide that by calculations as gth explained without considering the other essential influential elements, which would make our predictions holds more realistic results than just calculating numbers... and Im refering by that to the possibilies of the arising of spreading deadly virsus, or maybe a total human war (which is a common possibilty).

So I wouldnt worry much about the over population, I believe it will never exist, unless humans turned into robots or that earth turned into .. something else not moody as I am. :wink:

Evenif it happens.. the only logical conclusion is the same: war --> death --> regaining nature balance.

Just poped out on my mind now.. I`ll quote it from the Jurrasik park movie: :" Life always find away". 8)

31. The proposied "space coliny" population to area was 1.8 Square Miles for every

1000 people , including food, shelter, and energy requirements ;acordingly,

32. I see this is an old thread but I just found it and would like to keep this discussion going if anyone else has any input or a response to the following info.

I am very interested in getting a "good" (best, right) answer to this question.

(it seems to me we all should be)

I don't have the link right now but I found this on prodigy "bignum" (big numbers)

"Surface Area of the Earth

Earth has a surface area of 196,940,400 square miles, slightly less than a perfect ball with a diameter of 7913.5 miles (which is the mean diameter of the Earth - see "Prove it" under 103).

The surface area of the seven continents and all the islands of the world is about 57 million miles, while the total area of the six habitable continents (Antarctica excluded) is around 52 million square miles.

Including Antarctica , over one fifth of the globe's land mass is under water (oceans, lakes, rivers, etc.) or ice. This leaves about 45 million square miles of exposed land.

The human population on earth has crossed six billion. If we distribute all the exposed land evenly among all mankind, 133 people would have to share one square mile. What that means is that every single person on Earth, man woman and child would have close to five acres of land for his or her use. More precisely, each person would get 209,000 square feet of land, or a square plot of land 457 feet on each side.

Not all this land can be used beneficially however. A significant portion of the Earth's exposed land is unhabitable or cannot be used for any agricultural purpose. Large portions lie in the far north. Large portions are extremely arid. Large portions are very mountainous. In sum, only about one fourth of all the land on earth, or somewhat more than 12 million square miles, is arable.

Today, over half of the arable land in the world is in fact not under cultivation. Bringing the unused land into service in many cases would require huge investments of money and effort, and would do considerable damage to the environment. For example, only about 28% of the arable land on the African continent is used for growing crops. Immense tracts of forests or jungles would have to be cleared to bring the rest of the arable land on that continent to productive use.

Thus, only about one eighth of each imaginary plot of land distributed to each person is land which is under cultivation. In effect, each person has a piece of land about 26,000 square feet (a square 161 feet on each side or just a bit more than ½ an acre) at his or her disposal on which to grow all that he or she needs."

I know it is a completely different calculation process but A professor Sugata Mitra posted this on his blog "barefoot in the head"

http://sugatam.blogspot.com/2007/10/...ted-world.html

Thursday, October 04, 2007

There are 6 billion people on Earth. That is 6,000,000,000.

Imagine a plot of land 20m x 20m, that is 400 square metres. I think one person can have a very decent sized room, say 10m x 10m plus a garden with a pond in the remaining 300 square metres. Enough to keep a few animals, grow some rice and vegetables and a few trees and plants.

If each human on Earth were to have 400 square metres, it would need 2400,000,000,000 square metres of land. That is 2.4 trillion square metres.

One square Kilometre is 1 million square metres (1000 x 1000 metres). So, 2.4 trillion square metres is 2.4 million square Kilometres. 2,400,000.

That is a stretch of land that could be, for instance, 2400 Km x 1000 Km.

Smaller than Mexico.

Who says its a crowded world?"

Thanks in advance for any responses!

33. Originally Posted by clever9
Who says its a crowded world?"

Thanks in advance for any responses!
who's going to be the first to claim his 400 m² in Antarctica - or the caldera of an active volcano ?

34. All the good caldera's have been taken by super villains :/

35. Ok, just read this with interest. Does it matter how much land is inhabitable? At the end of the day, if population is increasing, it will run out. Sometime. We are a greedy species, and I don't mean that in a over-consumtion way, but rather in a greedy algorithmic way. We don't, as a whole, care about the long term. In the year 2800 or whatever the best prediction for 1 human for 1 sq m is, I'll be long gone, as will any of my descendents that remember me, I care about the value of life I can offer my immediate offspring etc.

Slightly cynically or not, politicians only care about their term, or re-election, no one is going to set any draconian measures at this point.

But, using a bacteria multiplying analogy, it they double every minute and are totally filling a set area by the end of the hour, when do they, if they are intelligent bacteria, realise that they're running out of space? When they've covered 1/16th of the total area, or rather 4 mins before total coverage?

What I am trying to say that if we continue to have any positive growth, we will run out of room; timings may differ but it is a mathematical fact that it will happen. How do we stop it? Better education? What, like developing cures and treatments for malaria or aids, thereby adding fuel to the growth rate? We tend, again because we're greedy, to use education to improve standards of living (if its true that the way we live is a higher standard than, say, 100 yrs ago....i mean stress levels here, rather than HD tv!). We can't devolve, but it is clear that way before we get to few sq m each, war, famine, illness will have a horrible levelling manner, in the same way that a population of animals even without predators will fluctuate about a certain level.
Just my thoughts......

It is the way of evolution that we will either adapt, or suffer some kind of culling event. We won't go extinct as a species, but at some point a large portion of the human race is going to be killed off somehow - unless we adapt, e.g. by colonising other planets.

37. 400 m^2 isn't going to feed a person. It takes five to ten times that to feed someone and lots more if you eat meat of inefficient animals like most Americans. There are some interesting alternatives, such as verticle farming which might help this, but regardess we're already probably beyond a sustainable population.

38. The ignorance of most people on human population growth!

I have posted numerous times to correct the fallacies above. The population explosion is over! Current population growth is simply the world playing catch up, and the growth rate is slowing.

50 years ago, the average fertility in the third world was 5.5 children per couple. Today it is 2.5 and falling. Numerous surveys show that women in third world nations want only 2 children on average. The United Nations have suggested from their models that world population will reach about 9 billion by 2050 and then either stabilise or fall.

39. Originally Posted by Lynx_Fox
400 m^2 isn't going to feed a person. It takes five to ten times that to feed someone and lots more if you eat meat of inefficient animals like most Americans. There are some interesting alternatives, such as verticle farming which might help this, but regardess we're already probably beyond a sustainable population.
I eagerly refer interested forum members to the BBC documentary:

"A Farm for the Future"

According to testimony in the video, some people are harvesting enough food to feed seven people from one acre. Using http://www.metric-conversions.org/ar...are-meters.htm, I get 1 acre = 4046.856 m², or about 578 m² per person. This is within the range of decrementation, as it were, to a figure of 400 m². If we, humanity, were to continue to develop this potential, and/or to use technology to build vertically, or eventually to convert skyscrapers for food production, is it not reasonable to imagine us greatly surpassing the needs of every living soul?

40. Originally Posted by marcusclayman
Not just crops but also animals or bugs that we could eat, wild fruits and other plants to forage etc. Florida has lots of stuff to hunt and forage.

Take for example the Inuit, they survive mostly on meat, but also some plants. They don't have very long life spans, but life has been sustained for a very long time there.

so far my best estimate is about 50 sq feet per person, but this doesn't seem right at all. That's 7x7 and change. Are huge cities really that dense? Yikes, I'm claustrophobic thinking about it.
There is 5.239 acres of land for every human on earth,wether it is habitable or not is up for debate.

41. Let's assume the continent of Antarctica is not, and the Gobi Desert, and the Sahara Desert. But the real issue isn't land to live on. It's land to grow crops on, or "arable land". We'll more likely run out of food rather than run out of space.

42. acres, square miles, square kilometers
jeez
roughly 148,000,000 square kilometers of land, of which 16 million is covered by glaciers(and ice caps), about another 14 million of deserts. (1/2 of which ar virtually uninhabitable, leaving 125 million square kilometers for us(including some that is really cold. At 247 acres per sq kilometers that's about 36.5 billion acres, of varying productivity. Which means we're getting by on a tad over 5 acres per person. and suffering a global obesity epidemic on that. yummy

43. i'll bump this thread, with interest.

to skeptic's repeated (and reasonable) point that the world population is no longer "exploding", it is increasing at a net rate of about 200,000 persons *per day*, which is roughly the population of tacoma or akron. i prefer to think of these new people as 60kg "dumb bombs" plummeting to earth with a resounding thud. in that image, the earth is certainly being *bombarded* with human life -- two or three thuds every second.

an increasing death rate might reduce the total population increase, but we have bill gates promising a global cure for malaria and sergei brin promising to feed the planet with frankenmeat, so we have science working hand in hand with venture capitalism to keep the increase going. (one should ask: why?)

this new population will also need a new 200,000 population city sized infrastructure *every day*. the calculations linking population to arable land only assume that food must be grown: there is no allowance for roads to join people, nor pasture for the animals used for transport (assuming we're off carbon fuels in the future), nor accommodation for growing textile and timber crops or for the manufacture of necessary goods, nor the area for rivers and streams, natural habitat to recycle waste and percolate runoff into the water table. what about mining and power generation and waste disposal? schools and hospitals and workplaces? and there will be continuing procreation -- unless the global population already universally adheres to strict birth limitation, then the parents' 5 or 10 or 50 acres are going to be divided among the children.

nor is the limited agricultural assumption valid, as it makes no accommodation for the rotation of crops, the diversity of foods necessary for good nutrition (in particular, healthy child development), the wide variance in climates and crop varieties across "arable" land, annual variations in weather, the effects of crop diseases and pests, all of which will produce wide variations in welfare across individual farms.

of course: there is technology and the bombardment of geniuses to pave the way smooth to infinite growth. unfortunately technology inherently means complexity -- social infrastructure requires control infrastructure -- and as human population grows all human societies, on average, become more complex. more diverse, more politicized, more regulated, more encumbered, more crowded, more regimented, more trammeled by guard rails, security gates, video surveillance, directive signage, security personnel. the conflict is between the bucolic 5 acre vision of a pastoral area the size of mexico and all the technology necessary to keep the bombardment going. the promise is that technology will solve problems: no one asks what that technology will be, or who will own it.

the fundamental question is not "how many people could live on the planet?" but: "WHY?" why are 10 billion people inherently better than 2 billion, or 1 billion? on the merits of population numbers or population density alone, why is china or india a better human existence than canada or australia? on what grounds would people in australia say to themselves, "oh, how i wish my country were more like bangladesh"?

the only answer i have heard so far is "we don't have a choice, the world will necessarily have 10 (plus or minus 3) billion people, we just have to adjust to that fact." however that is another way to say we are a trapped species, we have no real command over our future, at best we can only adjust to our population confinement, endure the inherent limitations in freedom and independence that greater numbers of people will impose. we accept that we are slaves to population growth and proles working to solve the problems created by our gonads.

44. True! In the words of Izacc Asimov, " humanity is fucking itself to death."

45. Originally Posted by drollere
the fundamental question is not "how many people could live on the planet?" but: "WHY?" why are 10 billion people inherently better than 2 billion, or 1 billion?
Strawman argument. Only a few groups would argue that 10 billion are better than 2 billion.

Originally Posted by drollere
the only answer i have heard so far is "we don't have a choice, the world will necessarily have 10 (plus or minus 3) billion people, we just have to adjust to that fact." however that is another way to say we are a trapped species, we have no real command over our future, at best we can only adjust to our population confinement, endure the inherent limitations in freedom and independence that greater numbers of people will impose. we accept that we are slaves to population growth and proles working to solve the problems created by our gonads.
It is a political decision. Politics is the science of the possible. To achieve a rapid cessation of population growth and a reduction to 'suitable' levels would involve impositions. These would be impositions on religious and personal freedoms and on what are presently understood to be fundamental human rights. They would require that we pretend human instincts do not exist. Accepting the growth while seeking to minimise it offers the best chance of achieving a balanced, sustainable population level in the medium term - the next 500 to 1000 years.

46. In theory, you could have more than one or several layers of habitable space on a given surface, by having several layers of underground or both sea surface and undersea area used. Upper level could use solar power and lower levels use geothermal energy.

47. In theory, you could have more than one or several layers of habitable space on a given surface, by having several layers of underground or both sea surface and undersea area used.
Only if people stop eating. Food has to grow somewhere.

48. "Only if people stop eating. Food has to grow somewhere."
You could have several underground levels of hydroponics below, as well as food grown above such as rooftop agriculture and hydroponics in giant blimps

49. You could have several underground levels of hydroponics below, as well as food grown above such as rooftop agriculture and hydroponics in giant blimps
You can't get away from it that easily. Rooftop agriculture where the roof is the covering for a multistory building containing many hundreds, if not thousands, of people just won't cut it. People who currently live in cities rely for sustenance on the surrounding land - or on food transported from far away places.

It is true that a suburban environment can be self-sufficient in food grown on the land surrounding houses and roadsides, especially if they use a food forest arrangement to get maximum output from each unit of water and fertiliser. It's not true for multiple housing arrangements in cities.

Everyone could grow some of their food - even in their own kitchens they could keep a small plot of herbs and small greens for salads, along with artificial lighting and hydroponics and the like in a dedicated growing area. But if you wanted to raise enough poultry and rabbits as well as fish and vegetables and mushrooms in space set aside within a block of apartments as well as on its roof you would lose a lot of the living space for the crowded occupants. And you still haven't grown any grain for the people and the chooks, nor any bedding/ straw/ growing medium for animals and fungi. And where do you grow fruits and nuts, let alone coffee, tea, cocoa and vanilla? Any notion of eating meat or dairy products from animals larger than a goat would be completely out of the question for absolutely everyone.

The space on the surfaces of the planet needed by each one of us is much, much larger than the spaces we live and work in. Consider how many kilos of grain each person requires and translate that into hectares of land (acres for those working in old money).

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