How Population Maximum capacity of the Earth?

Thomas Malthus, the 18th century philosopher said, the power of population is very much on the strength of the Earth to produce subsistence for man that premature death in one form or another must come to mankind.
In his essay, Malthus wrote a grim future of mankind. Humans have a drive that can not be mitigated to reproduce, which will ultimately make the planet experienced over-population and consuming all available resources. In the end, humanity would die of mass starvation.


The question, what is the actual strength of the planet Earth to produce the resources and what limits the number of population of this planet? More importantly, whether the Malthusian vision of the future of mankind is correct?
Excerpted from Life's Little Mysteries, October 13, 2011, many scientists who estimate that the Earth is able to accommodate people up to 9 to 10 billion people. One is Edward Wilson, sociobiologist from Harvard University. He concluded that based on calculations of the Earth's resources.
In addition to the limited availability of clean water, when it's growing concerns over the amount of food that can be produced by the Earth. And this has been predicted by Malthus, more than 200 years ago.
Even if there is maximum efficiency ones, in which all food is grown specifically given to humans (no longer in cattle, which is an inefficient way to convert energy into food energy plants), there are still limitations about how far the quantity of available able to survive.
"If all people agree to be vegatarian, which resulted in no more food for cattle, 1.4 billion hectares of land seluah that can be planted on Earth will only be able to feed about 10 billion people," said Wilson.
1.4 billion hectares of land area will be able to produce about 2 billion tons of grain per year. "It's enough to feed 10 billion vegetarians. However, only able to feed 2.5 billion omnivores because many plants are given to livestock, including poultry, "said Wilson.
That is, 10 billion people is a limit on the population if they want enough food available. However, since it is impossible to make all people stop eating meat, Wison argues, the maximum capacity that can be accommodated Earth humans are not reached 10 billion.
According to Joel Cohen, a population biologist from Columbia University, other environmental factors that limit the capacities of the Earth is the cycle of nitrogen, phosphorus availability and the concentration of carbon in the atmosphere. However, there are very large uncertainties related to the impact of all these factors.
"Frankly, no one knows when or to the point where the maximum number of population will be achieved," said Cohen.
Fortunately, the human race to avoid last day of starvation and over-population as Malthus predicted.
According to the United Nations Population Division, UN agency that monitors the human population, human population will reach 7 billion on October 31, 2011 about this. And if projections are right, we are heading into the 9 billion by 2050 and 10 billion in 2011.
However, in the middle of your journey to the milestone, some scientists predict, the journey of mankind will take turn back.
According to the United Nations, global population trends show that today's families getting smaller. "The empirical data from 230 countries since 1950 suggests that most families experienced a decline in the number of manufacturing children," said Gerhard, Chief of Population Estimates and Projections Sections, United Nations.
Globally, the rate also fell achieving kesuburuan 'replacement level' of 2.1 children per woman. With the average level of this, children born to replace their parents (and fill the space for those who died young).
If the fertility of a truly global reach replacement level, then at the end of this century, human population will stabilize at rates ranging from 9 to 10 billion. In terms of capacity that supported the Earth, we will reach the maximum point, but no longer could be more than that.