I don't usually get into abortion debates because it seems pointless. It is essentially a question of where you define the beginning of life, the creation of ovaries with eggs, the moment the sperm fertilizes the egg, the moment the cell divides the first time, the moment it develops rudimentary limbs... Personally I would have to define life as beginning at birth. I can't deny a woman that choice, but it is also a choice that the man is not allowed. The woman can not have the child or have it without the man's say. If the man doesn't want it, and the woman does she can try to force him to give up money. If the man wants it and the woman doesn't want it she can simply have an abortion. It is not a fair situation, but not something I see any kind of fair way to change either.
It has already been stated that population growth really has no connection to abortion. But I think plain old instinct does have a lot to do with it. Whether you think its evolutionary or a natural desire a creator puts into people, most people want to have babies. The maternal instinct is so strong in some women that they feel incomplete without having children. Some societies look down on women who aren't fertile and don't have many children. I think a certain amount of that even goes on in our society. Couples spend thousands of dollars on fertility treatments. You can't change nature, but I think that's an illogical feeling or instinct that may need to suppressed. A person, even a woman, can still be a fulfilled, complete, great contributor to society without having children. I don't plan on having any children, but I think I have some worth.
I also agree with asleif_dufansdottir. We use an enormous amount of energy in this country and then defend it calling it the American way of life. We definitely have luxurious and convenient lives, so of course, other people in the world will strive to have a similar type of lifestyle. If everyone in the world starts living this way, eventually, we will either have to severely cut back our energy usage or we'll have to find it somewhere other than the earth.