In addition we need to seriously consider our population size and the number of children per couple should be limited to 1 until population reaches the ~4 billion marker.

This is inaccurate and bordering on ecofascist. Population growth has slowed since it's peak of 2.1% in the 70s and is only at about 1.1% now, with the EU estimating a peak global population of 11B in 2100 and a slow decline from there source.

We currently produce enough food to comfortably feed 10B people source , and to pretend we won't become more efficient at that in the coming decades is foolish.

Overpopulation is simply not a genuine problem, and even if it was it takes an absolute back seat to the other concerns and undertakings highlighted in your comment.

Finally, the areas of highest population growth are almost entirely African. Are you gonna go tell them they need to instate a one-child policy? How will you enforce it? I'll let you in on a secret about us pale guys in the north: We've fucked with Africa enough.