Well, as you said it's hard to say, whats right and whats wrong. But I think these statistics saying that humanity will be doubled in 60 years are wrong.
Many countries in Africa experience now, what Europe experienced a couple hundred years ago. The medication gets better and more kids survive. They soon will adapt to this like Europe did and the population will stabilize and not grow as much as now per year.
RE: Contemporary Issue: Overpopulation