The matter of overpopulation is not in my mind the literal meaning of
the word. I believe that few scientist fear that there will not be
enough square footage to place individuals on the earth. However, the
land usage is what is important. For population to be sustainable you
must realize that a city is not self subsistent. If you cut of the city
from the rest of the world, say with an imaginary glass dome, the city
would die. There would be huge famines, and eventually pollution would
also begin to wipe out the inhabitants. So in response to your emphasis
on the fact that there is a lot of square feet on the earth for people
to fill, I would invite you to examine how much land we all use outside
of our living areas. Not only for food, but for waste disposal, energy
(gas, coal, etc.), and living. This may bring light to the problem of
overpopulating the earth..
I appreciate the fact that you recognize the problem is not overcrowding. Clearly you have moved beyond the ordinary "pictorial" approach to this issue. The question of land use outside of cities (where there are vast expanses of relatively empty land) is an important one. Does it not seem to you that with the help of modern science we have been able to make it highly productive? In fact, so productive we currently have an agricultural glut rather than a food shortage. That appears to be particularly the case on the most densely populated continent (Europe). The same over-production seems to apply to energy and minerals as well.
Please let me know if you have data which contradicts those statements.
Fr. Phil Bloom