Overpopulation of hunter gatherers would also destroy the biosphere(without predators or enough diseases, and with the technical achievement of weapons), and so would overpopulation of vegetarian farmers(without enough predators and diseases, and with the technology of the "green revolution").
Fossil fueled industrialized agriculture and transport began the stimulated overpopulation, and the technology of weapons and medicine got rid of predators from wolves to viruses, and increased agricultural output with irrigation and fertilizers along with chemical herbicides and insecticides. They all added with each other for the rapid destruction, pollution, and depletion we see.
The economic system also had its effect of over-consumption promotion, and religions their effects of overpopulation.http://www.worldhistorysite.com/population.html
Seeing it is probably impossible to stop the mid century population crash, the more important thing is to save the biosphere from a mass extinction event caused by human pollution---AETM. That is the serious threat, and may be possible to stop with an 80 to 90% reduction in HGHGs by 2020 or so. Fossil fuel use makes up 70% of that and slash and burn agriculture to feed the overpopulation is 30%. The demand is from overpopulation now.http://www.paulchefurka.ca/CC_Overshoot.html
People's Rights, Planet's Rights Holistic Approaches to a Sustainable Population
"Human population numbers have been fodder for
discussion since ancient times. Aristotle, Confucius, Machiavelli and many others expressed concern about increases in population.
In more contemporary times, the Reverend Thomas Malthus
predicted that population growth would be checked by world hunger, famine, and malnutrition. However, the Industrial Revolution and the rise of fossil fuels usage proved many of his theories wrong.
More recently, in the late 1960s, Dr. Paul and Anne Ehrlich's The Population Bomb echoed similar concerns, though the Green Revolution put off the day of reckoning that Ehrlich feared.
Interestingly, Norman Borlaug, the “father” of the Green Revolution, noted that this effort would only buy humanity a little bit of time.
In his acceptance speech for the Nobel Peace Prize, which he won in 1970, Borlaug said “Most people still fail to comprehend the magnitude and menace of the 'Population Monster'." The New York Times wrote that he was frustrated throughout his life that governments did not do more to tackle population growth by lowering birth rates, and at one point said “If the world population continues to increase at the same rate, we will destroy the species.”
Today the number of humans on Earth number over 7 billion. The mid-range United Nations population projection is for 9.3 billion people by 2050. However, just an average of one half (1.375 instead of 2.75 TFR ) fewer children per woman would reduce that number to 8 billion, with positive effects on health, education, food, water and resource availability.
There are approaches we can take – all grounded in fairness, equality, and rights – that can make a difference in balancing population growth and the health of the planet. It goes beyond numbers and requires a holistic, rights-based approach to talking about population and producing positive changes. Calling it the ‘Population Monster’ or population control won't direct the conversation where it needs to be.
The bottom line is there will remain billions of people on the planet, barring any major catastrophes
, for the rest of this century and far beyond. Finger pointing, denying rights, myopic thinking, and the like will not improve lives or the environment. Global society is confronted by a range of serious ecological, economic, and social issues that require a systemic and holistic path. We are all in this together; let's take an inclusive approach, look closely at how lives may be improved, and put the political and moral will behind doing so."
Barring major catastrophes will be the hardest part. Like world financial meltdown, aquifers depleting, ocean fisheries collapse, Kafla volcano, most oil depleted or too high a price, vastly increased CAGW effects, nuclear war, Cascadia, La Palma, soil depletion effects without petro chemical fertilizers, increased heavy metal pollution, garbage, mass riots, malnutrition effects and diseases.http://collapseofindustrialcivilization ... overshoot/
As for US population factors;
Among the key findings of the FAIR/Pulse Opinion poll:
•By a 53% to 41% margin, voters believe our nation's borders are not secure.
•By a 74% to 21% margin, voters believe the government is not doing an effective job preventing illegal aliens from living and working in the U.S.
•By a 53% to 26% margin, voters believe that illegal immigration is harmful to American workers.
•By a 66% to 11% margin, voters believe that illegal immigration imposes a burden on American taxpayers.
Another good article from a Prof. Emeritus of History;http://www.npg.org/forum_series/Little_ ... 021913.pdf