10 ms·

Total world landmass: 57,510,000 miles squared. https://en.wikipedia.org/wiki/List_of_countries_and_dependencies_by_area https://en.wikipedia.org/wiki/List_of_

Total world landmass: 57,510,000 miles squared. https://en.wikipedia.org/wiki/List_of_countries_and_dependencies_by_area https://en.wikipedia.org/wiki/List_of_countries_and_dependen... 2500 miles * 2500 miles * pi = 19,630,000 miles squared So that area represents about (19.63 / 57.51 ) 34% of the total world landmass. So 50% of humans live in 34% of the landmass. But harsh and relatively uninhabitable lands make up a large portion of the earth's landmass ( antarctica - 5,400,000, siberia - 5,100,000, canada - 3,511,023, australia - 2,947,336, , greenland - 836,330) = 17.8 million square miles. So the habitable areas are 57.51 - 17.8 = 39.71 million miles squared. So that circle represents ( 19.63 / 39.71 ) 49.4% of the habitable land. So in the end, about 50% of the world population lives in about 50% of the world's habitable land. Astounding huh? It's amazing what some math and common sense and understanding of geography takes away from a clickbait article based on a reddit post. As others have noted, that area is also primed for human habitation due to tons of fresh water rivers flowing from the tibetan plateau and rich fertile land along with year-round planting seasons due to its proximity to the equator.

empath75 7y ago
1/3rd of that circle is water. And a significant amount of it is also Siberia and Mongolia. Double check your math.
- dntbnmpls 7y ago
  > 1/3rd of that circle is water. Fine. Thrown in the saraha desert and a few other inhospitable areas and it'll make up that third. > And a significant amount of it is also Siberia and Mongolia. Are we looking at the same map? Hardly any part of siberia is included ( maybe the a tiny portion of the russian far east ). Feel free to take out the mongolian landmass if you want. > Double check your math. Did and my idea still holds.
  - Jupe 7y ago
    | So in the end, about 50% of the world population lives in about 50% of the world's habitable land. Your math may be accurate, but your assessment of habitable land-mass seems to be off. I know and work with a number of people in Canada, and I've visited many, many times. I'd hardly consider the entire area of Canada "uninhabitable". (Per wikipedia [1], Canada has a total (non-water) area of 3,511,023 sq. mi.) 37 million people live Canada [1]. Also, just a quick visual check indicates that about 1/2 of the area within that circle is ocean. And, the population density of the Himalayas (which is in the circle) is arguably small as well. [1] https://en.wikipedia.org/wiki/Canada https://en.wikipedia.org/wiki/Canada
    - senordevnyc 7y ago
      Doesn’t almost all of the population of Canada live along the southern border? My understanding is that the northern ~80% of Canada is very sparsely populated.
      - Jupe 7y ago
        True [1] But, still I wouldn't consider the entire country to be "uninhabitable" [1] https://www.reddit.com/r/MapPorn/comments/d756ql/population_density_map_of_canada_shows_that_over/ https://www.reddit.com/r/MapPorn/comments/d756ql/population_...
      - flyingswift 7y ago
        I think its something crazy like 90% of people live within 100 miles of the border
        tonyarkles 7y ago
        That is correct. Pretty much the all of the major cities are right around that 100 mile mark. On the coasts that’s because of geography (Victoria, Vancouver, Toronto, Ottawa, Montreal, and the Atlantic provinces). In the prairies we generally have one major city close to the border (Calgary, Regina, Winnipeg) and one further north (Edmonton, Saskatoon, none in MB)
  - code_sloth 7y ago
    You're still assuming ALL of that remaining land area in the circle is habitable. Eg. India has 43% of it's land classified under "others" [0]. A large chunk of that 43% is not likely to be habitable. 0: https://en.wikipedia.org/wiki/Land_use_statistics_by_country https://en.wikipedia.org/wiki/Land_use_statistics_by_country
- scythe 7y ago
  It's more than a third. Roughly half the circle is water. It also contains all of Tibet, the Hindu Kush and the Southeast Asian rainforest (except New Guinea). Furthermore it contains the highly mountainous islands of Japan, Taiwan, the Phillippines and Indonesia. Proclaiming that all or even most of this land is "habitable" is obviously silly if you just look at it: https://media.cntraveler.com/photos/593eedf1f2125a2b5b9ed24d/master/w_768,c_limit/map-reddit-cr.jpg https://media.cntraveler.com/photos/593eedf1f2125a2b5b9ed24d... Any glance at a map of population density will reveal that all of the highest density areas (pink) are within the circle: https://en.m.wikipedia.org/wiki/Population_density#/media/File%3AWorld_population_density_1994_-_with_equator.png https://en.m.wikipedia.org/wiki/Population_density#/media/Fi... This is definitely an interesting phenomenon and not just clickbait. The most likely explanation is that high rainfall in East Asia has allowed high-yield rice cultivation preceding the Green Revolution, allowing East Asia to support much higher population density in preindustrial times than any other region. Europe is too cold, Africa and West Asia too dry, and the Americas didn't have rice. (Although they did have the potato, but it didn't spread outside the Andes without European assistance.)
- namarie 7y ago
  There's also the Gobi Desert.
theredlion 7y ago
> Myers was amazed to find that a circle roughly 2,500 miles in diameter, when placed over the right part of Asia, could hold more than half the world's population. The above is from the article. It says radius in the title and diameter in the article
olalonde 7y ago
So that region is not more densely populated than the rest of the world? That makes me a bit skeptical of your math because it obviously is. For one, you are using habitable land mass for the rest of the world while the circled area is mostly sea water. I wonder how that comment got to the top.
- deleted 7y ago
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- nine_k 7y ago
  It's more densely populated because it has the highest concentration of habitable land. Siberia to the north from there is not inhabited so densely because it has -50°C in the winter and +50°C in the summer. Western Europe, US northeast, etc are also rather densely populated, but are smaller, with less-popuated areas, or with oceans.
  - ReptileMan 7y ago
    I would love to know the region in Siberia in which there is +50 in the summer.
    - nine_k 7y ago
      Oh, sorry, +50 is definitely a typo; +30. Say, Yakutsk is a major city in Siberia with a climate like that.
code_sloth 7y ago
52M km^2 of land on our planet is habitable, after forests, shrubs, rivers and lakes [0]. Total land mass is 149M km^2. So only 1/3 of the world's land is habitable. That's actually ~20M square miles. Your habitable land estimate is already nearly 50% off according to the source I found. The circle covers 50.2M km^2 (4000^2 * pi). I'm going to assume the 2/3 land quotes are good enough an estimate. That makes the land mass inside the circle 33.5M km^2 (2/3 * 50.2). That means that the circle contains just 22.5% (33.5M/149M) of ALL land mass. I couldn't find any quick data source on how much land inside the circle is actually habitable. So I'll apply a few ratios: If X% of the land in the circle is habitable: X = 33% --> 33% * 33.5M / 52M = 21.5% X = 50% --> 50% * 33.5M / 52M = 32.2% X = 75% --> 75% * 33.5M / 52M = 48.3% Your estimations would hold iff >75% of the land in the circle is habitable. [0]: https://ourworldindata.org/land-use https://ourworldindata.org/land-use
Merrill 7y ago
A history of population within the circle would be interesting. The population of China since 2000 years ago appears to have been a series of plateaus with brief periods of increase and a couple of brief decreases. The plateaus represent populations at the limit of agricultural systems. The increases are due to introduction of new systems, such as rice cultivation further north, double-cropping of rice and so forth. The decreases are periods of famine, disease and war. http://www.china-profile.com/data/fig_pop_0-2050.htm http://www.china-profile.com/data/fig_pop_0-2050.htm Possibly other civilizations within the circle follow the same pattern of stability, innovation and crises.
- lottin 7y ago
  If I recall correctly, rice can sustain a much greater number of people per unit of land than any other crop, and this explains why East Asia is more densely populated than any other part of the world.
  - Armisael16 7y ago
    Corn and potatoes each produce around 15 million calories per acre; rice only hits about 11 million. Wheat is significantly worse, at ~4 million.
    - jandrese 7y ago
      The big difference with rice is that you aren't dependent on the weather nearly as much as you are with corn and potatoes. Corn and Potatoes put out more calories per acre when the rains fall at the right times in the right amounts, but rice puts out those calories regardless of the weather. Ultimately you can only sustain a population as large as your food output at the end of a two or thee year long drought.
    - Merrill 7y ago
      The introduction of potatoes led to a rapid population increase in Europe during the first half of the 19th century. https://www.history-magazine.com/potato.html https://www.history-magazine.com/potato.html Sugar cane and sweet potatoes also produce similar calories per acre, depending on the soil, climate, etc. Sugar also has the advantage of being durable to ship. It could be produced in high volumes on tropical plantations and shipped to Europe. Before bulk ocean shipping of food, population was generally limited by calorie production in the local area.
rjkennedy98 7y ago
It clearly says " 2,500 miles in diameter" which makes it 1,250 mile radius. pi * 1250 *1250 = 4,908,738 square miles or ~5 million square miles. That is < 10% of the earths land mass.
- alexilliamson 7y ago
  Yeah this is the error in the parent calculation
- swsieber 7y ago
  It also clearly says "2500 radius circle" in the article title, and the submission title. The article is fast and loose with diameter vs radius later on as well. I can't blame the original commenter for using it as a radius when that's in the title. But I agree, it's actually the diameter and changes the math a lot.
  - humblebee 7y ago
    The distance from Mumbai India to Osaka Japan is ~4000 miles. Both of which are clearly inside the circle. What are you using to assert that the 2500 mile number is the diameter?
- wongarsu 7y ago
  This actually fits with the visual impression you get from the map. It's clearly far less than 50% of the inhabitable land mass
- Abimelex 7y ago
  you also need to map the circle firs to the surface, a circle on a world map is not the same as a circle on the globe.
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Aperocky 7y ago
The circle contains 1/3 ocean and ocean is not landmass. You'll have to revise your calculation. Also, since the circle contains Tibet, desert in Xinjiang and Mongolia, your assumption that all of that is habitable land is even more wrong.
- labawi 7y ago
  The water is a fair point, but GP didn't exclude Sahara, middle east or other deserts, so it would not be proper to exclude Xinjiang or Mongolia.
jariel 7y ago
"So that area represents about (19.63 / 57.51 ) 34% of the total world landmass." 1/2 of said circle is ocean, not land. And some of said land is 'uninhabitable' i.e Gobi Desert. And Canada is 3.8 miles squared, implying that 3.5 of those are uninhabitable is rather off. By that calculation, you'd be excluding most of Quebec and Ontario, which are 'inhabitable' just sparsely populated, in which case much of Tibet and China would be comparably 'uninhabitable' as well.
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dilippkumar 7y ago
> 2500 miles * 2500 miles * pi = 19,630,000 miles squared > So that area represents about (19.63 / 57.51 ) 34% of the total world landmass. So 50% of humans live in 34% of the landmass. I've been telling myself that I have to teach myself Non-Eucledian Geometry, but lacking any real motivation, I've successfully procrastinated for 6 years. The unfortunate itch to be pedantic on the internet will hopefully drive me to learn how to correctly calculate the area of a circle on a sphere. Anybody has a good textbook recommendation?

empath75 7y ago

1/3rd of that circle is water. And a significant amount of it is also Siberia and Mongolia. Double check your math.

dntbnmpls 7y ago
> 1/3rd of that circle is water. Fine. Thrown in the saraha desert and a few other inhospitable areas and it'll make up that third. > And a significant amount of it is also Siberia and Mongolia. Are we looking at the same map? Hardly any part of siberia is included ( maybe the a tiny portion of the russian far east ). Feel free to take out the mongolian landmass if you want. > Double check your math. Did and my idea still holds.
- Jupe 7y ago
  | So in the end, about 50% of the world population lives in about 50% of the world's habitable land. Your math may be accurate, but your assessment of habitable land-mass seems to be off. I know and work with a number of people in Canada, and I've visited many, many times. I'd hardly consider the entire area of Canada "uninhabitable". (Per wikipedia [1], Canada has a total (non-water) area of 3,511,023 sq. mi.) 37 million people live Canada [1]. Also, just a quick visual check indicates that about 1/2 of the area within that circle is ocean. And, the population density of the Himalayas (which is in the circle) is arguably small as well. [1] https://en.wikipedia.org/wiki/Canada https://en.wikipedia.org/wiki/Canada
  - senordevnyc 7y ago
    Doesn’t almost all of the population of Canada live along the southern border? My understanding is that the northern ~80% of Canada is very sparsely populated.
    - Jupe 7y ago
      True [1] But, still I wouldn't consider the entire country to be "uninhabitable" [1] https://www.reddit.com/r/MapPorn/comments/d756ql/population_density_map_of_canada_shows_that_over/ https://www.reddit.com/r/MapPorn/comments/d756ql/population_...
    - flyingswift 7y ago
      I think its something crazy like 90% of people live within 100 miles of the border
      - tonyarkles 7y ago
        That is correct. Pretty much the all of the major cities are right around that 100 mile mark. On the coasts that’s because of geography (Victoria, Vancouver, Toronto, Ottawa, Montreal, and the Atlantic provinces). In the prairies we generally have one major city close to the border (Calgary, Regina, Winnipeg) and one further north (Edmonton, Saskatoon, none in MB)
- code_sloth 7y ago
  You're still assuming ALL of that remaining land area in the circle is habitable. Eg. India has 43% of it's land classified under "others" [0]. A large chunk of that 43% is not likely to be habitable. 0: https://en.wikipedia.org/wiki/Land_use_statistics_by_country https://en.wikipedia.org/wiki/Land_use_statistics_by_country
scythe 7y ago
It's more than a third. Roughly half the circle is water. It also contains all of Tibet, the Hindu Kush and the Southeast Asian rainforest (except New Guinea). Furthermore it contains the highly mountainous islands of Japan, Taiwan, the Phillippines and Indonesia. Proclaiming that all or even most of this land is "habitable" is obviously silly if you just look at it: https://media.cntraveler.com/photos/593eedf1f2125a2b5b9ed24d/master/w_768,c_limit/map-reddit-cr.jpg https://media.cntraveler.com/photos/593eedf1f2125a2b5b9ed24d... Any glance at a map of population density will reveal that all of the highest density areas (pink) are within the circle: https://en.m.wikipedia.org/wiki/Population_density#/media/File%3AWorld_population_density_1994_-_with_equator.png https://en.m.wikipedia.org/wiki/Population_density#/media/Fi... This is definitely an interesting phenomenon and not just clickbait. The most likely explanation is that high rainfall in East Asia has allowed high-yield rice cultivation preceding the Green Revolution, allowing East Asia to support much higher population density in preindustrial times than any other region. Europe is too cold, Africa and West Asia too dry, and the Americas didn't have rice. (Although they did have the potato, but it didn't spread outside the Andes without European assistance.)
namarie 7y ago
There's also the Gobi Desert.

theredlion 7y ago

> Myers was amazed to find that a circle roughly 2,500 miles in diameter, when placed over the right part of Asia, could hold more than half the world's population. The above is from the article. It says radius in the title and diameter in the article

olalonde 7y ago

So that region is not more densely populated than the rest of the world? That makes me a bit skeptical of your math because it obviously is. For one, you are using habitable land mass for the rest of the world while the circled area is mostly sea water. I wonder how that comment got to the top.

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nine_k 7y ago
It's more densely populated because it has the highest concentration of habitable land. Siberia to the north from there is not inhabited so densely because it has -50°C in the winter and +50°C in the summer. Western Europe, US northeast, etc are also rather densely populated, but are smaller, with less-popuated areas, or with oceans.
- ReptileMan 7y ago
  I would love to know the region in Siberia in which there is +50 in the summer.
  - nine_k 7y ago
    Oh, sorry, +50 is definitely a typo; +30. Say, Yakutsk is a major city in Siberia with a climate like that.

code_sloth 7y ago

52M km^2 of land on our planet is habitable, after forests, shrubs, rivers and lakes [0]. Total land mass is 149M km^2. So only 1/3 of the world's land is habitable. That's actually ~20M square miles. Your habitable land estimate is already nearly 50% off according to the source I found. The circle covers 50.2M km^2 (4000^2 * pi). I'm going to assume the 2/3 land quotes are good enough an estimate. That makes the land mass inside the circle 33.5M km^2 (2/3 * 50.2). That means that the circle contains just 22.5% (33.5M/149M) of ALL land mass. I couldn't find any quick data source on how much land inside the circle is actually habitable. So I'll apply a few ratios: If X% of the land in the circle is habitable: X = 33% --> 33% * 33.5M / 52M = 21.5% X = 50% --> 50% * 33.5M / 52M = 32.2% X = 75% --> 75% * 33.5M / 52M = 48.3% Your estimations would hold iff >75% of the land in the circle is habitable. [0]: https://ourworldindata.org/land-use https://ourworldindata.org/land-use

Merrill 7y ago

A history of population within the circle would be interesting. The population of China since 2000 years ago appears to have been a series of plateaus with brief periods of increase and a couple of brief decreases. The plateaus represent populations at the limit of agricultural systems. The increases are due to introduction of new systems, such as rice cultivation further north, double-cropping of rice and so forth. The decreases are periods of famine, disease and war. http://www.china-profile.com/data/fig_pop_0-2050.htm http://www.china-profile.com/data/fig_pop_0-2050.htm Possibly other civilizations within the circle follow the same pattern of stability, innovation and crises.

lottin 7y ago
If I recall correctly, rice can sustain a much greater number of people per unit of land than any other crop, and this explains why East Asia is more densely populated than any other part of the world.
- Armisael16 7y ago
  Corn and potatoes each produce around 15 million calories per acre; rice only hits about 11 million. Wheat is significantly worse, at ~4 million.
  - jandrese 7y ago
    The big difference with rice is that you aren't dependent on the weather nearly as much as you are with corn and potatoes. Corn and Potatoes put out more calories per acre when the rains fall at the right times in the right amounts, but rice puts out those calories regardless of the weather. Ultimately you can only sustain a population as large as your food output at the end of a two or thee year long drought.
  - Merrill 7y ago
    The introduction of potatoes led to a rapid population increase in Europe during the first half of the 19th century. https://www.history-magazine.com/potato.html https://www.history-magazine.com/potato.html Sugar cane and sweet potatoes also produce similar calories per acre, depending on the soil, climate, etc. Sugar also has the advantage of being durable to ship. It could be produced in high volumes on tropical plantations and shipped to Europe. Before bulk ocean shipping of food, population was generally limited by calorie production in the local area.

rjkennedy98 7y ago

It clearly says " 2,500 miles in diameter" which makes it 1,250 mile radius. pi * 1250 *1250 = 4,908,738 square miles or ~5 million square miles. That is < 10% of the earths land mass.

alexilliamson 7y ago
Yeah this is the error in the parent calculation
swsieber 7y ago
It also clearly says "2500 radius circle" in the article title, and the submission title. The article is fast and loose with diameter vs radius later on as well. I can't blame the original commenter for using it as a radius when that's in the title. But I agree, it's actually the diameter and changes the math a lot.
- humblebee 7y ago
  The distance from Mumbai India to Osaka Japan is ~4000 miles. Both of which are clearly inside the circle. What are you using to assert that the 2500 mile number is the diameter?
wongarsu 7y ago
This actually fits with the visual impression you get from the map. It's clearly far less than 50% of the inhabitable land mass
Abimelex 7y ago
you also need to map the circle firs to the surface, a circle on a world map is not the same as a circle on the globe.

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Aperocky 7y ago

The circle contains 1/3 ocean and ocean is not landmass. You'll have to revise your calculation. Also, since the circle contains Tibet, desert in Xinjiang and Mongolia, your assumption that all of that is habitable land is even more wrong.

labawi 7y ago
The water is a fair point, but GP didn't exclude Sahara, middle east or other deserts, so it would not be proper to exclude Xinjiang or Mongolia.

jariel 7y ago

"So that area represents about (19.63 / 57.51 ) 34% of the total world landmass." 1/2 of said circle is ocean, not land. And some of said land is 'uninhabitable' i.e Gobi Desert. And Canada is 3.8 miles squared, implying that 3.5 of those are uninhabitable is rather off. By that calculation, you'd be excluding most of Quebec and Ontario, which are 'inhabitable' just sparsely populated, in which case much of Tibet and China would be comparably 'uninhabitable' as well.

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dilippkumar 7y ago

> 2500 miles * 2500 miles * pi = 19,630,000 miles squared > So that area represents about (19.63 / 57.51 ) 34% of the total world landmass. So 50% of humans live in 34% of the landmass. I've been telling myself that I have to teach myself Non-Eucledian Geometry, but lacking any real motivation, I've successfully procrastinated for 6 years. The unfortunate itch to be pedantic on the internet will hopefully drive me to learn how to correctly calculate the area of a circle on a sphere. Anybody has a good textbook recommendation?