"One-fifth of your current use..."

"To act justly is to take no more than one's fair share of the Earth's resources, including the capacity of the atmosphere to absorb carbon dioxide without causing major climatic change. Simply take the population of the Earth and divide it into the available resources; the resultant number will tell you the share of resources you can fairly claim. Unfortunately, if you are an average American, this number will be approximately one-fifth of your current use."

"Think hard about the most important personal decision you will make: Whether to bring children into the world. It's easy to think of overpopulation as a moral failing of other people, other religions, other continents. But if you have more than one or two children, overpopulation is a moral problem in your household. No one 'deserves' more children than anyone else; in fact, affluent Americans may have difficulty claiming even equal rights to children, given the global impacts of our lifestyles and life spans. Overpopulation in a time of climate crisis creates terrible problems of distributive justice; overpopulation coupled with overconsumption creates injustice that is exponentially worse."

From Moral Ground: Ethical Action for a Planet in Peril edited by Kathleen Dean Moore and Michael P. Nelson (Trinity University Press, 2010).