Hence, it is probable that the carrying capacity of the planet has been underestimated.
I so much agree with this @gentleshaid. coupled with the fact that people must die at a particular age, I dont think earth will ever exceed its carrying capacity. There always seem to be some sort of balance, no matter how the world's population grows
The current figure is an hypothetical one. No one can correctly estimate the resources of the earth. Hence, it is quite difficult to put a figure on the carrying capacity.