The Family Proclamation states the following: We declare that God's commandment for His children to multiply and replenish the earth remains in force.
So, we are a people of reproducing. We marry, we have children, we increase the world's population. What affect does this have on the world? What about concerns of over-population? Ask most LDS people what they think of over-population, and they will tell you it's a myth, that the Earth's problems aren't caused by an excess of people, but by improperly distributed resources. I whole-heartedly agree, but do we practice what we preach?
How many people can the Earth support anyway? To save time and for convenience, I'm going to rely on this article for my information. I encourage you to read the article.
The point of the article is that the Earth can sustain the amount of people currently on it, but only if we stop consuming at our current rate. Unsustainable practises and over-consumerism are destroying the world and the brunt of the blame lies on members of the Western World. Mormons are no exception, despite the preachings of several church leaders, past and present.
The fact is, the culture of Mormonism and the doctrine don't always match up, and I think this is definitely a case where that applies. Mormon culture adores the rich and ambitious. Sometimes this manifests itself subtley, and sometimes with such blatantly ignorant statements such as "poor people obviously aren't righteous or they wouldn't be poor" and "people who live in poor countries were less righteous in the pre-existence." It makes me think that the Book of Mormon really was directed at us, considering the ad naseum warnings of the "pride cycle". The Nephites repeatedly succumbed to pride, classism, and the "wearing of costly apparel."
Back to the point, I don't think wealth and consumption are nearly as venerable as people seem to think they are. If we really are all about the family (and having children), if we really do believe that the Earth is our inheritance, if we really do believe that everyone on Earth is one of God's children, then why do we take more than our piece of the pie? Why do we uphold an unsustainable and exploitative culture of commercialism? Aren't we supposed to me in the world, but not of the world? I think we should all be striving to be a "one Earth" type of person. That is, I would like to live in such a way that if everyone lived the way I do, we would only need one Earth.