Most of the talking going on about earth's population is based off of now debunked theories from a book called the
Population Bomb by Ehrlich.
Critics have compared Ehrlich to Thomas Malthus for his multiple predictions of famine and economic catastrophe. The leading critic of Ehrlich was Julian Lincoln Simon, a libertarian theorist and the author of the book The Ultimate Resource, a book which argues a larger population is a benefit, not a cost. To test their two contrasting views on resources, in 1980, Ehrlich and Simon entered into a wager over how the price of metals would move during the 1980s. Ehrlich predicted that the price would increase as metals became more scarce in the Earth's crust, while Simon insisted the price of metals had fallen throughout human history and would continue to do so. Ehrlich lost the bet. Indeed such was the decline in the price of the five metals Ehrlich selected, Simon would have won even without taking inflation into account.
In Ehrlich's books, many predictions are made, for example, The Population Bomb begins "[t]he battle to feed all of humanity is over. In the 1970s the world will undergo famines -- hundreds of millions of people are going to starve to death," while in "The End of Affluence", Ehrlich stated, "One general prediction can be made with confidence: the cost of feeding yourself and your family will continue to increase. There may be minor fluctuations in food prices, but the overall trend will be up". According to Ehrlich, the United States would see its life expectancy drop to 42 years by 1980 because of pesticide usage, and the nation's population would drop to 22.6 million by 1999 [1]. Criticizing Ehrlich on similar grounds as Simon was Ronald Bailey, a leader in the wise use movement, who wrote a book in 1993 entitled Eco-Scam where he blasted the views of Ehrlich, Lester Brown, Carl Sagan and other environmental theorists. While of the repeated theorizing Simon complained "As soon as one predicted disaster doesn't occur, the doomsayers skip to another... why don't the [they] see that, in the aggregate, things are getting better? Why do they always think we're at a turning point -- or at the end of the road?"
In his book Betrayal of Science and Reason, Ehrlich discussed these earlier predictions of his and re-affirmed his stances on population and resource issues.
Ehrlich also has critics on the political left. These include Betsy Hartmann, author of the 1987 book Reproductive Rights and Wrongs: The Global Politics of Population Control & Contraceptive Choice. Hartmann accuses Ehrlich and other environmentalists who focus on population control of misanthropy, and believes that such focus is antithetical to activism on issues of social class and feminism.
There has been much criticism of the book from demographers today (chiefly Phillip Longman in his 2004 The Empty Cradle) who argues that the "baby boom" of the 1950s was an aberration unlikely to be repeated and that population decline in an urbanized society is by nature hard to prevent because of the economic liability children become.
The Skeptical Environmentalist by Bjørn Lomborg disputes many of the claims in the book.
Various Indices of Economic Freedom claim that lack of property rights, not high population density, is the real cause of famine. Thus, countries such as China, India, South Korea, and Botswana were able to eliminate their famines by adopting property rights. Likewise, countries such as Ethiopia, Zimbabwe, and North Korea created famines when they abolished property rights. Ehrlich's book does not explain why South Korea is so much better off than North Korea, but an analysis of property rights explains this difference very well.
Basically, the fact that mankind has learned how to produce enough food to feed everyone has increased due to the panics that the book created. However, while those changes were indeed good the theories themselves were so flawed that the scientific community dropped them long ago. And yet those same theories, now so long debunked, fuel the private philosophic wars of those who have nothing better to do with their lives.
Will reply when I get back. 
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