Peak Population

Peak population and dieback
http://www.postpeakmedicine.com/population.htm
 

 "Dieback" or "dieoff" of the human population is one of those taboo
subjects which you never hear politicians talk about as there are no votes
in it.  But it is important that we discuss it and form some ideas about
what it is, what causes it, how likely it is to occur and what we should do
about it.
  The fundamental underlying concept is that there is a maximum human
population which an ecosystem can carry sustainably.  The ecosystem in
question can be a local ecosystem, such as Easter Island or the formerly
Mayan inhabited region of Central America, both of which experienced
profound dieback as a result of environmental degradation.  Alternatively,
it can be the entire planet.
  At the beginning of the industrial revolution (around 1800) the global
human population was around 1 billion, and these people were on the whole
living sustainably and using only small amounts of non-renewable resources.
Today, the human population is around 6.7 billion and we are using very
large amounts of non-renewable resources, in particular oil, natural gas
and fossil water, to produce our food.  A population of 6.7 billion humans
may therefore be an unsustainable number, which can only be maintained for
a relatively short time until the non-renewable resources are used up.  At
that point, a correction must take place and the population must be reduced
once again to a sustainable level. 
  Let's say, for the sake of argument, that the maximum sustainable number
of humans which the planet can support is 2 billion - twice as many as the
number alive at the beginning of the fossil fuel age.  In order to make the
necessary correction, 4.7 billion people would have to disappear, and this
is what is sometimes referred to as "dieback" or "dieoff".  How might this
happen?
  In earlier, simpler times, a failure of the harvest resulted in dieback
by starvation.  There is archaeological evidence of this happening, for
example, on Easter Island, and it still happens in Third World countries.
In wealthy industrialised countries with more complex societies, factors
other than simple starvation may play a role.  To get some idea what to
expect when a modern industrial society collapses, we can look at the
example of the collapse of the Soviet Union in the early 1990s and what
happened to the population of Russia during this period.
  The population of Russia hit a historic peak at 148,689,000 in 1991,
just before the breakup of the Soviet Union, but then began a decade-long
decline, falling at a rate of about 0.5% per year due to declining birth
rates and rising death rates.  The cause of the rising death rates is
widely debated.  Very little if any was due to starvation, mainly because
the former state-run bakeries continued to function and to distribute bread
as they had done pre-collapse.  The death rate peaked at around 17 per 1000
in 2003 and the birth rate bottomed out at around 8 per 1000 in 1999, but
subsequently both of these indices moved towards a more normal level of 14
per 1000 per annum as the Russian economy improved.  Alcoholism was a
significant contributing factor, although this had been a pre-existing
trend in the population prior to collapse.  Rates of heart disease in
Russia were higher than the European average both pre and post collapse.
The increase in mortality was from multiple causes.
(http://en.wikipedia.org/wiki/Demographics_of_Russia)
  A similar increase in all cause mortality has long been observed in
people subjected to psychological stress.  A recent study found that after
the loss of a spouse, all cause mortality increases by 27% per annum
(citation needed).
  If psychological stress is a significant contributing factor to
all-cause mortality then the high rates of psychological stress apparently
being experienced by populations of post-industrial societies are cause for
concern.  In 2005 10% of Americans were taking antidepressants and 16% of
Americans were taking benzodiazepines.  The levels today are probably
higher.  The reasons for these widespread high levels of psychological
discomfort are unclear but may be related to societal factors such as
fast-paced lifestyles, insecurity of employment and fragmented families and
communities.
  A shortage of fossil fuels may result in an enforced simplification of
life (less commuting to work, more tending vegetable gardens) which in the
long term may reduce psychological stress.  However, in the short term many
people will experience a profound increase in psychological stress because
they are unprepared for the changes being forced upon them.  An increase in
all cause mortality may follow.