i have a very dry sense of humor. for example i do NOT imagine that
sperm is scared.
HTH.
http://en.wikipedia.org/wiki/Overpopulation
"In An Essay on the Principle of Population (first published in 1798),
Thomas Malthus proposed that while resources tend to grow linearly,
population grows exponentially. He argued that, if left unrestricted,
human populations continue to grow until they would become too large
to be supported by the food grown on available agricultural land,
causing starvation which then controls population growth. He noted
that this had happened many times previously in human history and
estimated that this would occur again by the middle of the 19th
century. To avoid this outcome, Malthus argued for population control
through "moral restraint". While arguably he was right about human
history up to his time, he made his prediction for the future exactly
at the time the industrial revolution and a similar revolution in
agriculture caused a large increase in available resources. His
specific predictions for England therefore may have erred because he
used a static analysis, and extrapolated his historical numbers into
the future without considering future factors that could increase the
resource base more rapidly, (for example, the revolutions in
agriculture at his time or later the Green Revolution), although he
correctly predicted that population growth could decline or reverse
with later marriages and "vices" like contraception (see for example,
the demographic transition). The warnings and predictions of Malthus
are commonly refered to as the Malthusian catastrophe.
On a global scale, since the industrial revolution, food production
has sometimes grown faster than human population. However, it has been
argued that other changes impacting Earth's ability to function as a
suitable habitat for human beings, such as global warming,
desertification, overfishing, peak oil, soil degradation,
deforestation, aquifer depletion and other environmental problems
caused by industrialization, will significantly reduce food production
or factors necessary for well-being. Given recent population growth,
this may cause a Malthusian catastrophe.
Among the earlier best-known modern examples of such arguments are The
Limits to Growth (1972) and The Population Bomb (1968) by Paul R.
Ehrlich.
Paul Ehrlich "predicted", "The population of the U.S. will shrink from
250 million to about 22.5 million before 1999 because of famine and
global warming", though it should be noted that between 1950 and 1984,
as the Green Revolution transformed agriculture around the globe,
world grain production increased by 250%%,[13] and the source of his
quote, a 1969 short story called "Eco-catastrophe" reprinted from
"Ramparts" Magazine, was apparently a work of science fiction.[14]
Ehrlich also predicted, "Before 1985, mankind will enter a genuine age
of scarcity . . . in which the accessible supplies of many key
minerals will be facing depletion." [3] According to The Skeptical
Environmentalist by Bjørn Lomborg, Ehrlich's predictions did not
materialise.[15] (See Erlich's answer to his critics and The Ultimate
Resource, by Julian Simon, which challenges Ehrlich's ideas.)
Interestingly Simon himself once stated "We now have in our hands in
our libraries, really the technology to feed, clothe, and supply
energy to an ever-growing population for the next 7 billion years...
We [are] able to go on increasing forever" (Myers and Simon, 1994,
65). These comments have subjected Simon himself to criticism.[16]
In Facing the Limits to Growth the authors of the controversial 1972
study Limits to Growth tell of the difficulty in getting the idea of
the necessity of limiting human population growth past "Entrenched
political, economic, and religious cliques". And they acknowledge that
revision has been necessary, "Because of the long time horizon
involved in our studies, we always realized it would require several
decades to get any perspective on the accuracy of our forecasts",
however, "the basic conclusions are still the same. We have modified
our model only a little to reflect some better data about the effects
of technology on land yields and birth rates."[17]
Between 1950 and 1984, as the Green Revolution transformed agriculture
around the globe, world grain production increased by 250%%. However,
agricultural productivity has declined in many world regions in the
past ten to 20 years due to overdrafting of groundwater (such as has
occurred on the North Plain of China) , overgrazing, extensive slash-
and-burn and resulting soil exhaustion and erosion. The energy for the
Green Revolution was provided by fossil fuels in the form of
fertilizers (natural gas), pesticides (oil), and hydrocarbon fueled
irrigation.[18] David Pimentel, professor of ecology and agriculture
at Cornell University, and Mario Giampietro, senior researcher at the
National Research Institute on Food and Nutrition (INRAN), place in
their study Food, Land, Population and the U.S. Economy the maximum
U.S. population for a sustainable economy at 200 million. To achieve a
sustainable economy and avert disaster, the United States must reduce
its population by at least one-third, and world population will have
to be reduced by two-thirds, says the study. The authors of this study
believe that the mentioned agricultural crisis will only begin to
impact us after 2020, and will not become critical until 2050.[19]
David Pimentel claims that population outcomes for the 22nd century
range from 2 billion people (characterised as thriving in harmony with
the environment), to 12 billion people (characterised as miserable and
suffering difficult lives with limited resources and widespread
famine).[20]
The oncoming peaking of global oil production (and subsequent decline
of production), along with the peak of North American natural gas
production may precipitate this agricultural crisis much sooner than
expected. Geologist Dale Allen Pfeiffer claims that coming decades
could see spiraling food prices without relief and massive starvation
on a global level such as never experienced before.[21][22][23]
The book The Little Green Handbook reasons that in 2050 about 7.7
billion people would be expected to suffer from illness, lack of
adequate sanitation, hunger, and extreme poverty,[9] provided that the
high population estimates of year 2050 are realised.
In his recent book Collapse (2005), Jared Diamond argues that many
earlier civilizations have collapsed due to environmental problems,
and warns of current environmental problems. For example, he argues
that it was overpopulation that led the now recovering inhabitants of
Easter Island (a.k.a. Rapa Nui) to destroy their once beautiful island
paradise.
“ From circa AD 1000 to circa 1650/1700 AD, Rapa Nui's population
increased significantly. Some estimate the population reached a high
of 10,000 or even 15,000. Moai carving and transport were in full
swing from 1400 to 1650, less than 100 years before the first recorded
European visitors to the island. By the late nineteenth century the
population had fallen to a low of 132. Deforestation, civil wars,
European diseases and slave raiding all contributed to the population
crash. Core sampling and archaeology from the island has revealed a
slice of Rapa Nui history that speaks of deforestation, extinction of
native bird populations, soil depletion, and erosion as well as loss
of access to deep sea fish as wood became scarce. From this
devastating ecological scenario it is not hard to imagine the
resulting overpopulation, food shortages, and ultimate collapse of
Rapa Nui society. Evidence of cannibalism at that time is present on
the island, though very scant. Van Tilburg cautiously asserts, "The
archaeological evidence for cannibalism is present on a few sites".
[24] ”
However, he also notes many situations in which humans have managed
their natural resources well"
