As I said in another thread, white people have done this to themselves.
I myself, in selfishly acquiescing to the use of NFP for many years (because it was just so easy, got to save a huge portion of my paycheck and take nice vacations, and, ahem, I am a normal heterosɛҳuąƖ male) when I had no excuse, no "grave" or "serious" reason (nor even a "just" or "well-founded" reason), was a part of this problem. (All issues have long been dealt with in the confessional, and I shall not discuss that. I may get the opportunity to do some serious unwanted penance for it one of these days.)
All of us should have been having more children all these years. We shouldn't have been using contraception. There are different schools of thought WRT NFP, but even viewing it as a morally neutral option, that, too, can be abused. In the meantime, other demographics have been having more children. Populations increase exponentially, not arithmetically, as long as they exceed mere replacement level.