What is the carrying capacity of the earth?

Carrying capacity of the earth "is the maximum population size of the species that the environment can sustain indefinitely, given the food, habitat, water, and other necessities available in the environment [1]". In short, the earth is able to provide everyone with basic needs. 

In fact an equation developed by  Paul R. Ehrlich displays the impact the carrying capacity has on the earth:
I=P *A * T where I is the impact due to energy consumption, P is population, A is the consumption per capita, and T is the technology factor. For example the use of fossil fuels has increased the carrying capacity to the world via sunlight [1].
The image below is an accurate depiction of the carrying capacity if we do not watch our consumption levels.

[2]

Our carrying capacity not only affects humans, but animals and the environment as well.  For instance, hunters have to consider the carrying capacity of animals and how many they are able to shoot. The limited amount of fossil fuels will continue to diminish leading to things shown above flowing out of the bucket.




[1] Wikipedia, 2011. Carrying capacity. 8/27/11. Retrieved from http://en.wikipedia.org/wiki/Carrying_capacity.
[2] Department of Natural Resources, 2003. Retrieved from http://www.dnr.state.mi.us/publications/pdfs/wildlife/viewingguide/eco_carryingcapacity.htm