How much habitable land is there on earth per person?

What is the total area of habitable land on Earth? And how much habitable land does that leave one person? We’ll use the value r = 6400 km as the radius of Earth. According to the corresponding formula for spheres, the surface area of Earth is:

S = 4 * π * (6400 km)^2 ≈ 515 million square km

Since about 30 % of Earth’s surface is land, this means that the total area of land is 0.3 * 515 ≈ 155 million square km, about half of which is habitable for humans. With roughly 7 billion people alive today, we can conclude that there is 0.011 square km habitable land available per person. This corresponds to a square with 100 m ≈ 330 ft length and width.

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42 comments

  1. I came up with approximately 3 acres of land for each of the 7 billion people on earth.

    155,000,000 kilometers of land on earth of which half supposedly is habitable. So 77 million square kilometers translates to 19 billion acres of land. 19 billion divided by a population of 6-7 billion people means each man, woman and child can have 3 acres of land to live on. Overpopulation is a liberal lie.

    1. It takes 23 acres to provide food per person, without the heavy concentration of population in cities, highly mechanized farming and irrigation there would not be enough unoccupied arable land to farm and provide food. At this point we can still maintain however our resources are finite potable water, arable land, affordable energy and all other resources there are limits if we haven’t reached the limit we will eventually. From 1950 2.5 billion on earth to 2015 7.2 billion 4.7 billion additional people in 65 years, 2050 10 to 11 billion on earth 4 billion additional people in 35 years, how much land will there be per person in the year 2050 ? Every 3 seconds a child is born, every 11 seconds 1 person dies, 4 to 1. With life expectancy increasing the 11 seconds will rise and birth rate attrition will decline. We do have a population problem if not now very soon.

      1. Hahaha are you serious a family of 4 if managed correctly can live off 1/4 acre this includes all the food they need and meat from rabbits and chooks . I dont know where you did your math but 23 acres man you couldnt eat that much in a year no matter how much you tried thats roughly 5000 kgs of food per person per year even on a very conservative estimate its 2000 kgs per person 6 kgs of food per person per day i think not….

      2. Peasant market gardening is the most productive land use not highly mechanized farming. Mechanization increases monetary profit by cutting down labour costs not by increasing yield with the consequence that labour intensive farmers are priced off the land. Our first world lifestyle is the chief problem. Yes, if you imagine a world human population which always grows you will be able to foresee a time when it will be unsustainable under any system, however there is no guarantee that population will continue to grow and the level of waste in our current culture is phenomenal, actually astounding so that should be where our attention should be focussed.

      3. It takes 23 acres to provide food per person

        It’s absolutely possible to raise enough food to sustain a family of five on one’s own three acres – though of course people would have to quit demanding beef and start accepting rabbit.

        If overpopulation ever became a real thing, people would have to start taking some responsibility for their own food production; we simply could not afford the wasted space. Every lawn would be viewed as a place that ought to be growing fruit. Every rooftop would have a greenhouse, where existing but largely unused technology enabling small-scale high-yield automated vegetable gardens would become common. Kids would learn in school how to grow hydroponics under LED lights, instead of how to man the community garden. We’d stop wasting food, and we’d stop paying farmers to not grow food.

        We’d start eating native plants; instead of demanding Honeycrisp apples we’d learn to accept fruits that grow without heavy inputs and demanding special handling. We’d stop being so picky and we’d stop throwing away so much food. Pigs would replace garbage disposals.

        We do not need 23 acres per person.

      4. Your incorrect sir on statement in which you stated that it takes/requires 23 acres per person to sustain themselves, for one it only takes an acre per head of cattle, in that acre it would, easily, be possible for hydroponics garden, and a suitable area for poultry (eggs, white meat), those not interested in poultry could farm fish in the same amount of space. it would also be possible to suppliment the cows feed by growing some grains in before mentioned garden

    2. true. As a lie is insufficient food. The poorest countries are the biggest exporters of food (as percentage to their GDI). The source of the problem is not lack of resources, but greed and envy (lack of empathy)

    3. I don’t think that’s 3 acres for each person to have their house on; that’s 3 acres to get all their food from.

      Setting aside the fact that “habitable” and “arable” are two very different things, lets assume an ideal world where each persons’ three acres has fairly healthy soil and stable enough weather to grow edible crops – which gets less and less common with the increasing effects of climate change, but I digress. Anyway, that means each person would have to live on a yearly diet of oh, say, around 250 pounds of wheat (most Americans average around 350 pounds a year), OR just over 1300 pounds of corn (which sounds like a lot but the average American eats about 1800 pounds of corn and derivatives yearly), OR about three and half cows (and good luck milking half a cow).

      So you could live like that, and you’d be closer to how the majority of the human population lives, but your lifestyle would be closer to serfdom in Mideival England than anything most first world countries would call “acceptable conditions to raise my kids in”.

      And of course, those numbers up there are all based on professional, large-scale agricultural techniques that are designed to yield the most food possible. There’s no telling what YOU, Average Random Person, will be able to eke out of your new plot of land that statistically exists somewhere deep inland with no hope of imports or trading because nobody’s keeping the infrastructure going if everyone is busy failing at barley production.

      My point is not just that we’re producing and consuming food at a globally uneven rate, though we are – my point is that as people who are affluent enough to spend time discussing this stuff online, our perception of many aspects of the global situation is badly skewed. And blaming our misperception on “liberals”, or anyone but ourselves, is irresponsible. All politics aside, there’s no denying these are scary numbers to consider.

      1. This misses the point that the average American or Briton (like myself) lives an absurdly wasteful lifestyle in an absurdly wasteful destructive disconnected insane commercial culture. Our culture is the problem, where we surrender our personal discretion and responsibility to an almost entirely accidental political structure. There is no reason for us to respect the financial structures and political institutions that guide us into this apparent mass suicide and yet we seem unable to create a more intelligent social structure.

      2. You’re entirely missing the fact that we ARE surviving, and doing quite well as a whole, with almost 7.5 billion people on earth, which translates to about 3 acres per person. This includes the vast areas of the earth that are basically untouched by man – just fly over China, Russia, Canada, much of Africa, South America, Africa, and Australia – and even areas in the US to see the millions of acres of land untouched – or at least very lightly inhabited.
        There are so few people on the earth, including the productively of the oceans that make up 70% of the earth, that the entire man- caused global warming is such a laughable lie. How egotistical to think that humans have that much effect!
        Yes, we are to be good and wise stewards – which means not falling for every politically motivated crazy idea. By the way, we can not produce carbon – the earth is a closed system, the carbon has always been here and always will be.

      3. We are not all surviving (well or at all) and we are having a devastating and utterly unnecessary impact on some very large areas of rich wild life. In my opinion there is no danger to the Earth, she is old enough and bad enough to look after herself and in the short term there is little danger to the Human Race, we are brilliantly well adapted survivors. My efforts are not to save the World or the Human Race but to live better which we obviously can do. Most famine is avoidable, deforestation is a scandal since mature forest supports more life than any other land use and we are apparently happy to poison whole rivers just to help some self-obsessed business tycoon buy a bigger yacht. Go to the Riviera or one of their other haunts and take a look at the vile prancing slugs (prancing slugs, look you!) any culture that produces that is ready for change.

      4. Land does not need to be of good quality. You can grow tomatoes in a PVC pipe under LED or sodium lights, and doing so uses less water than tomatoes grown in the ground.

        Also, it isn’t a case of house OR food production; if overpopulation ever becomes a real issue, earth sheltered housing and rooftop greenhouses will become a big thing.

    4. Paddy Mendea concludes ” There is plenty of world FOR US if we learn to live better. But, many others wisely state ond observe : “” Yeah, never mind the 6.5 million other species of land animals…” YES, what kink of a skewed WORLD we would be living in if beautiful forests , wild plants and animals were ELIMINATED so that we “HUMANS” COULD be the ONLY inhabitants of this wonderful BLUE planet !!??

      1. Thank you Dusan. My idea of living better is of a wholly harmonious existence. The most productive land use in terms of life (not merely human life) is, as far as I’ve been able to gather, mature forest such as rain forest or the ancient forests of Transylvania in Europe. My hope for the future is that we will learn to live upon the products of such forests instead of clearing them. The idea of humans living alone in the world is not only monstrous it is also profoundly unrealistic. If a better future is to be made it must first be imagined. The seeds, fruits, leaves, sap and pollen of trees can all be harvested without killing the trees.
        There is also the possibility of making floating gardens on the open ocean where currently very little grows. We could easily all live here in a world which we tend instead of exploiting it. My love to all the other people who care.

      2. Good point…..I think I will breed some of the lovely animals on my land in a manner that is sustainable harvesting some of them for food and making sure that others are healthy and happy, maintaining the population so when next year comes around we can do it all over again.

  2. Maybe I’m missing something, but I believe your surface area formula may need adjusting. It appears the surface area is overstated…

  3. An important issue in respect of population reduction is that throughout European history shrinking populations have been accompanied by instability and civil war. The wasteful cultures we are talking about are organized along European lines.
    Peasants produce surpluses. Give small amounts of land to a large number of poor people and put in place structures to allow them to bring their surpluses to market.
    Whenever this debate makes it to the mainstream media in Britain no-one ever challenges the idea that mechanization and food technology produces more food – this is untrue it only produces more profit.
    It produces profit because that is what it is designed to do.
    Labour intensive farming produces more food but because labour costs are high it produces less profit and so is priced off the land.
    There is plenty of world for us if we learn to live better.

  4. You like the numbers?
    I got some numbers.
    10 kJ per day is sufficient intake (as food) for an active adult human.
    So 7 billions need 70,000,000,000,000kJ per day.
    Big number.

    Wikipedia gives a figure of 1.361 kW/m^2 for the solar constant so that’s 1361 Joules per second striking one square metre of the Earth’s surface.

    If we convert seconds into days we get 1361 times 60 times 60 times 24 equals 117,590,400 Joules per square metre per day.

    We can divide 70,000,000,000,000 by 117,590,400 easily enough to get 595,287.

    So the sunlight which falls on 595,287m^2 or a little over half a square kilometre is enough for all the humans to live.

    The problem is only to convert the vastly abundant energy into a form we can eat or use otherwise.

    A solvable problem chiefly of efficiency.

  5. ive heard that the population will only go upto 10 billion. so that leaves 2 acres each. i say we all live in big apartment buildings so as to maximize plants and animal life habitats and parks and nature. eat low or no animal product diets. create an effecient and low consumtion and waste life and culture. conserve water and energy.

    1. We could build into hillsides so as to leave the surface available for growing and have us on the scene to tend what grows so that it meets our needs. It isn’t natural for us to have a lot of meat in our diet and that is far and away the most wasteful type of food production so cutting down on meat production would immediately reduce our (artificial) problems.

  6. don’t forget vertical farming (think of multi levelled buildings full of crops possibly set up in some sort of Aquaponic configuration) can reduce the actual surface area required on the ground required, so that 2 acres estimate of can be significantly requced.

    1. Mist this before I wrote my first comment, what about a multi leveled buildings with a manure pit, a wet/dry separator, a moisture cleaner to get fresh water again, the next 10 floors for animals to get egg’s, milk, butter and meat, the next 20 floors for crop, all moisturized with the fresh water, fertilized with the dry substance from the manure.
      Of course all computerized, so about 10 people can do the handwork and maintenance!

    1. Mathematics is an abstraction of reality (abs-tract = out of-drawn). It is concerned with making statements which are, as nearly as is possible, STRICTLY true.
      When people talk about “reality” in this way they usually mean social, legal, business or political limitations which are conventional, man-made and subject to the fashions of the moment…

      …and not particularly real.

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