Gringinho I am sorry but you need a lesson in economic Geography. The population of individual countries and the world as a whole is entirely dependant on what type of economy the country or world is in. There are around 6 stages of economies such as agricultural, industrial and technological. The size of population is totally dependant on economy because the type of economy a country lives in dictates their ability to use resources. If you disagree with that than let me ask you. Why hasn't Japan overflooded with population? In fact their population has actually gone down. Why has the population gone down? It has gone down because technology provides the ability of gaining much larger amounts of resources which means that less people and labor are needed. Look at families in economies. The size of American families has gone down in the last century because of the changes in the economy. There may be a shortage of specific resources at some time but there will never be an over population of the world.