How much of the world is paved over?

Discussion in 'Earth Science' started by Epictetus, Apr 26, 2012.

  1. Epictetus here & now Registered Senior Member

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    Don't it always seem to go that you don't know what you got til it's gone? Can anyone tell us (estimate for us) about how much of the earth's land surface is urban; that is, asphalt, sidewalks, buildings, city residences, even suburban development?

    I would imagine it's much less than one would suppose. Many of us don't get out of the city much, and it's easy to forget how much of the world, while not pristine is at least free of Seven-Elevens and parking lots.
     
  2. keith1 Guest

    Modern structural footprints can be large in metro areas, but they need constant tending.
    If we all moved away, they would disappear rapidly back into the ever-shifting environ.

    Cobblestone streets are lasting structures. I saw some hardwood ghost-town streets that were there for at least 110 years of hard winter rains. Pyramids in both Egypt and Americas were almost entirely buried and forgotten within a short period of time.
     
  3. leopold i miss my coco. Valued Senior Member

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    i'll take a stab at this and say it's less than 5 percent.
     
  4. adoucette Caca Occurs Valued Senior Member

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  5. Buddha12 Valued Senior Member

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    75 % of the earth is water. 20 % is land that is uninhabitable. That leaves about 5 % for human useage and perhaps less than 1/8 % are paved, if that.
     
  6. adoucette Caca Occurs Valued Senior Member

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    No, about half the land area is habitable.

    As of the year 2000, about 37 percent of Earth's land area was agricultural land, another 30 percent of the world's land area is forested, so that's habitable, so no, there is far more available to us.

    http://www.learner.org/courses/envsci/unit/text.php?unit=7&secNum=2
     
  7. Trippy ALEA IACTA EST Staff Member

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    Using this Source we can infer that 167,000 km[sup]2[/sup] of the surface of the earth is occupied by urban areas with a population >500,000

    Alternatively, using the income section we can infer that 223,000 km[sup]2[/sup] of land area has an urban population. This is about the same size as Minnesota (or Laos).

    Apparently once you exclude Oceans, deserts, high mountains, and some other landforms, about one eighth of the earths surface is habitable.

    So this leaves us with two figures.
    0.35% of the earths habitable land area is occupied by urban areas.
    0.04% of the earths surface is occupied by urban areas.

    Urban areas, I believe, in the context of the source I provided being areas of >400 people/km[sup]2[/sup]

    However, it's worth noting that the definition of what constitutes an urban area varies from country to country.
     
  8. Epictetus here & now Registered Senior Member

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    Sorry Great Buddha. If about 20% is land is uninhabitable (closer to 30 %, but all right) I think you mean to say that that leaves 80% for human use.
    So aside from arable land, and the fact that not all of it is used any way, I mean only area "being areas of >400 people/km2", as Trippy puts it.

    And Trippy, that's great! Laos or Minnesota? So what if we all went to live in one big city the size of Minnesota and let the rest of the world heal? How much surrounding farmland would we need? About ten times that size?

    How about half of us live in half of Minnesota, and half in half of Laos? That way we can have away games.

    I thank the rest of you for your contributions so far too. Keep them coming!
     
    Last edited: Apr 27, 2012
  9. adoucette Caca Occurs Valued Senior Member

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    And it might help to consider:

    Wilderness areas still cover close to half the Earth's land, but contain only a tiny percentage of the world's population, finds a new report from Conservation International. The 37 wilderness areas identified in the report represent 46 percent of the Earth's land surface, but are occupied by just 2.4 percent of the world's population, excluding urban centers.

    http://www.ens-newswire.com/ens/dec2002/2002-12-05-06.html
     
  10. Buddha12 Valued Senior Member

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    So all of Antartica, all of the North Pole and the Tundra areas, mountains, deserts, and other inhospitable places don't amount to more than 25 % of the land? It would seem to me that if you included all of those areas that humans are not able to actually use due to a multitude of reasons then there is far less, about 5 % , that can actually keep humans alive for planting, irrigation and dwellings.
     

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