This is a finite planet with a finite resource base

Warning To the People of Earth from Bruce Mohun on Vimeo.
William Rees was the co-founder of the ecological footprint concept. This video puts together excerpts from three of his talks and an interview. The concept of an measuring one's ecological footprint in hectares required to sustain my lifestyle is not an exhaustive metric as it doesn't take all factors into account, but it is still a useful shorthand measure that highlights in a single figure how far our lives are above the carrying capacity of the planet, that is, the degree to which we are stealing such capacity from the poor and from future generations.

"There is no way around this. Any politician who says to you 'there is no conflict between the growth of the economy and maintaining the quality of the natural environment' doesn't know what he or she is talking about. Historically, it has always been this way. The more humans take, the less remains for non-human species."