The best illustration of the concept, imo, is that with sustained 1.3%/year world population growth, we'll reach a population density of 1 person per square meter of land in only 780 years.
In 50 years at 1.3% growth we'll basically double our population, and go from about 8000 m^2 per person to 4000 m^2 per person. After 780 years, the growth starts adding up, you can play with the numbers.
So we should be at roughly 25,336 meters / person currently. (But remember that plenty of that is more-or-less unlivable--Siberia and the like.)
In 50 years, the population will have increased by a factor of exp(.013 50) = 1.91554, so in the next 50 years population will roughly double, so that number will go down to about 13k meters/person.