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A 2010 National Geographic video talks about 7 billion people (the Earth's population at the time). At timestamp 1:57, the video claims that

standing shoulder to shoulder all 7 billion of us would fill the city of Los Angeles

Some rough math I did using the land areas of the US state of Oregon (248,849 km^2) and the city of Los Angeles (1215.97 km^2) from Wikipedia suggests that you would need to fit ~28 people per square meter to get everyone to fit in Oregon and ~5676 people per square meter to get everyone to fit in LA.

This seems impossible, even if you limit this to the adult population (4.630 Billion as of 2005, according to Wikipedia), you're still hitting ~18 and ~3807 people per square meter in those two areas respectively.

Is there some other way they got to this number that I'm not seeing??

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    i suspect they also took some liberties with the math (such as assuming both areas are flat and have no buildings or any other things on them like trees), but maybe this is wrong and you can pack people more densely if you account for vertical stacking as would be present in high-rise buildings
    – DeveloperACE
    Oct 18 at 20:23
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    I’m voting to close this question because it is based on a simple calculation error. Skeptics.SE is not "fix my maths".
    – gerrit
    Oct 19 at 6:21
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    @gerrit why? The question (seems to be) asked in good faith and received proper answer, which is accepted. What is the benefit of closing the question? I'm genuinely wondering.
    – pinegulf
    Oct 19 at 9:57
  • Using the wrong factor in area conversions is a common error, so I'm on the fence on this. It does have some illustrative quality.
    – Fizz
    Oct 19 at 10:52
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    I think it is a legitimate Skeptics.SE question, because there is a notable claim, the OP is (in good faith) dubious about whether it is true, and has provided their reasoning (which is useful for targeting answers). The fact that the answer turns out to be relatively shallow with enough eyeballs shouldn't invalidate the question.
    – Oddthinking ♦
    Oct 19 at 14:16

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Is there some other way they got to this number that I'm not seeing??

Yes: they actually got the math right. I mean this with the greatest of respect, but you've simply gotten the calculations wrong.

You seem to have calculated this under the assumption that 1 sq.km = 1,000 sq.m. This is off by three orders of magnitude: a sq.km by definition measures 1,000m x 1,000m = 1,000,000 sq.m. This means your estimate of ~5676 people per sq.m is also off by three orders of magnitude. In order to pack all of humanity into Los Angeles, you would actually only need ~5.676 people per sq.m, which is much more plausible.

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    Put another way, 1215.97 sq km is 1.215 billion sq m.
    – Schwern
    Oct 18 at 21:13
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    This is a reason our questions here are not supposed to include original computations (original research) by the questioner...
    – GEdgar
    Oct 19 at 1:09
  • I guess I deserved that downvote both for the obvious math error and the oversight of not reading the guidelines.
    – DeveloperACE
    Oct 19 at 1:40
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    @GEdgar: it doesn't extend to "highschool algebra", which this is. skeptics.meta.stackexchange.com/questions/1080/…
    – Fizz
    Oct 19 at 10:57

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