Science tells us that the land area on the earth is today 58 million square miles. Over 6.5 billion of us live there. If we have these numbers correct, on average a little over 100 humans live on a square mile of the earth's land.
Humans are almost everywhere. They are remarkably adaptable, living in a wide range of climates from freezing artic to tropics, from deserts to jungles, from lowlands to mountains, and from elegant to humble. This capability to make any place a home is contained in the verse from 150 years ago by John Howard Payne, "Be it ever so humble, there's no place like home."
Humans now have a challenge that is an outgrowth of their success at abundantly increasing in numbers. They must cope with being constrained to the finite size of the planet earth. Seeing how many people can fit on the earth is the planet equivalent of seeing how many people can fit into a phone booth or into a car. A clown car in the circus surprises us to see how many people can be contained. Nevertheless there are limits.
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