At the beginning of the 20th century, there were less than 3 billion people on the earth, closer to 2 billion. By all measures that we can come up with right now,. with the lifestyle and consumption pattern of the Western industrial civilization, we can probably sustain about 2 billion people on this earth. We already have over 6 billion. China and India are aspiring to come on as industrial nations, aspiring to the lifestyle of the Western world, and it simply can't happen.