Once human population increases to the point where it begins to threaten the life of the planet, its self-defense mechanism will kick in to bring the population back to a more healthy level. Either that or humans will learn more restraint. . . not really sure which is more likely

So we can have a massive shortage of women which will (likely) result in significant social problems?

Realistically, for centuries there have been people predicting doom and gloom in the near future because of over-population and humans have beaten the odds by becoming far more productive than was anticipated. If we were able to make better use of the land in the world that is currently being mismanaged in third-world dictatorships we will (probably) be able to support twice as many people worldwide, I suspect that development of unexpected technology (like inexpensive greenhouses) will probably double production per acre over the next 50 to 100 years, and spreading democratic capitalism throughout the world will result in prosperity that will naturally bring down the birth rate to a very slow growth after we factor in for much longer life-spans.

Well, my graphic is population ecology, yours is community (or interactions) ecology.

But you're completely right, when you exceed the carrying capacity there's a little negative bounce (Is correct to say that in English?). Like in my graphic, you see they exceed K, then there's a negative bounce, and there are positive and negative bounces until N (population number) is flat. The problem is, the bigger you exceed K, the bigger the negative bounce is going to be. It is possibly to exceed it by so much, that the negative bounce will be so intense that the population can't recover.

But we have to remember, Humans are not just one population, we are more of a metapopulation (spatially separated populations of the same species which interact at some level) so, when talking about metapopulations, it's almost impossible that all the population that take part of it will dissapear at the same moment.

Finally, Humans will go extinct before we kill all of other species. Most of species living on high depths will overlive us. Most arthropods will overlive us. Most mosses and lots of stress tolerant plants with flower will beat us. There are species that are quite resistant.So, Humans will go extinct before we kill the world.

Earth is already over populated... I should be the only man on earth.

You sir are educated, thank you for sharing this before I did because some opinions made me laugh out loud.

I think when a country gets too populated.....pull a china. Governments should try to get its people to have only 1 kid per family. Give incentives like tax cuts and other things to move this movement along.

Lack of women = less opportunity for reproduction :P

But seriously, disincentive-based population control measures would work better in cultures that have gotten past the notion that only a son is any good for a family

But there is more to that in China than simply more boys being born than girls. Yes there is a slightly higher chance that a boy will be born than a girl but the figure has hovered at around 50 more boys than girls per 1000 (globally) for decades which would only account for 5,000,000 of the 100,000,000 or so more males than females currently populating China. This means there have to be other factors involved. The biggest of these is the Stigma with not having a son, which with the One child policy in China results in couples to not want daughters, This causes many would be parents to abort upon finding out that their baby is a girl, or failing that some even resort to infanticide and will likely do so until they get a son, or until they give up and just accept a girl I suppose, which has caused the massive imbalance in China's population.

Wow that many eh? I would have never guessed it had that big of an impact. 

Yeah I agree more of this. Only problem is we can't force countries to adopt policies like this without starting some kind of conflict. Hopefully all the fast growing countries that are causing overpopulation like India, Pakistan, Bangladesh, and basically all of Africa adopt one-child policies. 

"The population has been growing continuously since the end of the Black Death, around the year 1400."

That is false.