Here is another thought for the math people, concerning our resources. One of the resources that is becoming increasingly scarce in our modern time is fresh water. There are of course many reasons for our diminishing water supply from over use, pollution, and waste, but here is one I think no one considers, us.
My thoughts are as follows:
1. The human body is, I beleive, 75% water.
2. Our population has increased drastically from early civilization