Populations tend to grow exponentially, which is why the growth rate is defined as R in P = AeRt, where A is the population at time t=0, and P is the population at any other time t. If the average growth rate is greater than zero, then the population will grow exponentially forever, which is sadly impossible. Here’s why:If the population could grow forever, then eventually the total mass of Humans would be greater than the mass of the Earth, which makes no damn sense. The population could grow forever if we found a way to colonize other star systems. We’ve had a lot of visits from reddit.com with a little confusion over the line “populations tend to grow exponentially” (my bad). The less that resources are available, the more the population will tend to level off.