The Earth is above its carrying capacity!

[AstusAleator]

Lets try to identify all of the factors involved in human population and earth's carrying capacity. I think this could be fun/interesting.
Here's the ones I can think of so far, that have been posted.

population growth
education
populatable landmass
technology
X-factor (human ingenuity, etc)
Culture
Energy availability
Political stability or lack thereof (organization, war, etc)

Can you guys think of any more? Once we identify as many as possible, we can start inferring relationships between them.