It is important to remember that overpopulation is a figure rather than a number.
Overpopulation is a matter of impact.
That said, I wouldn't be sanguine about the consequences if the 20th century rate of population growth is repeated in the 21st century. I wouldn't assume that humanity would definitely make the advances in ecoefficiency and social evolution necessary to deal with that sort of growth rate. The figures all measure use, or non-use. It's an internal thing that motivates people to head to the beach, mountains, forests and countryside. I've been to places where you can walk for days without seeing another human.