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HUMAN POPULATION GROWTH
Growth of Human Population
Human population growth has been marked by a much steeper growth rate in recent
times owing to the unique stability and sustenance factors developed over thousands of years.
These include efficient neutralization of natural calamities, better immunity against diseases,
better medical care, better food provisioning and an easier lifestyle. In the absence of these
factors, human population remained relatively stable, growing little in numbers over thousands
of years.
The Toba supervolcano event dated at about 70000 B.C. is considered a major natural
disaster that prevented the human race from expanding beyond the 1 million mark. In fact due to
a combination of other factors this number would remain steady until the introduction of
agriculture in about 11th millennium, when the food problem was alleviated to some extent from
the otherwise meagre options of hunting and gathering. The population density of the times was
low owing to the lifestyle. It is estimated that by the first millennium AD, the population was
nearing about 300 million people. Out of these about 60 million people lived in the roman
empire.
A string of diseases (plagues) would create additional bottlenecks in the growth of
population. For example the Justinian plague would cause the demise of about 50 percent of the
population of Europe between the 6th and the 8th centuries. Then the 14th century Black Death
pandemic would reduce the population of the world from being 450 million to about 350 million,
pushing growth back by nearly 200 years. Plague and wars would have differential effects across
the world. The population of China would go from being around 123 million in 1200 AD to half
that number by 1393 owing to the Mongol invasion as well as plagues. As European colonizers
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would move into the new world, they would carry with them diseases from the old world which
would have a devastating effect on native populations. As much as 90 percent of the native
American population perished from such diseases.
Life Expectancy factors
The agricultural and the industrial revolutions are prominent events that marked the
improvements in average life expectancy, specially for children. Nutritional demands were all of
sudden met with far greater ease. Where records were kept, for example in London, the
percentage of children dying before reaching the age of five years went from 74.5 percent to
being only 31.8 percent. Just between 1700 and 1900 AD, the population of Europe quadrupled
from being 100 million to being over 400 million.
After the revolutions would be the advent of compulsory vaccinations which would again
make an enormous difference in the mortality rate. There were improvements and strides made
in cleanliness and the field of medicine saw the introduction of antibiotics and anesthesia. For
example, Penicillin would revolutionize the medical field being the first drug to be effective
against historical diseases such as Syphilis. The techniques for surgery improved after the
introduction of anesthesia and once microorganisms were realized as being the cause of all
infection. Hospitals were segregated as separate buildings where patients would come to procure
care (instead of the traditional way of rendering care in the patients’ own homes). There would
be cleaning and sanitizing routines introduced, including sterilizing of instruments and washing
hands became routine. Also in the nutritional field, pasteurization of milk would be started,
killing all pathogens potentially present. The population of the UK would approximately double
every 50 years over the entire 19th century. The population of the United States would go from
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being 5.3 million in 1800 to being 106 million by 1920.
In the Soviet Union, disasters such as wars and famines would have a negative impact on
population growth all the way into the 20th century. By 1945, it is estimated, 90 million people
there were lost to these disasters. Current demographic trends are negative other there owing to
changing attitudes and government policies. The population in the Indian subcontinent,
estimated at about 125 million in 1750 has reached to above 1.2 billion as of today – continuing
to increase owing to continued development and advances in medical care. China’s numbered at
about 430 million by 1850 is estimated at over 1.3 billion. Cultural changes have affected
various places differently. For example in war ravaged areas, people tend to be having more
children to reduce the risk of losing all their children. Some cultures in areas of the world
including middle east strongly favor male children (“more sons-more guns”) and go to great
lengths at ensuring a tilted sex ratio, which has contributed to greater growth rates over there.
Attitudes in the west have been crafted in part from the child provisioning requirements (child
support etc.) and a stronger law presence that has ensured a more balanced growth rate.
Ecological Footprint and Carrying Capacity
The ecological footprint of human civilization has consistently increased as their demand
of the Earth’s ecosystems has gone up. Earth’s ecological capacity to regenerate its ecosystems
has long lagged behind the rate at which humans have been invading and consuming resources.
These resources include food sustenance and other needed resources and assimilation of
whatever waste products necessary for our lifestyle. The ecological footprint for 2007 was about
1.5 earths. Therefore half a planet extra would be needed to keep replenishing what humans are
consuming. Ecological footprint is sometimes measured in global hectares. In 2006, per
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biologically productive person, the area required was 1.8 gha (global hectares). Demonstrating
the effect of lifestyle on usage, the average area for an American was 9.0 gha, compared with
only 1.8 gha for a Chinese citizen.
Carrying Capacity
Also called the maximum environmental load, the carrying capacity is defined as the
maximum number of a species that can be sustained for an indefinite period of time given the
food and resources available in the environment. In this regard, the carrying capacity is uniquely
defined for any species. When speaking in terms of humans, who are not only dependent upon
the environment, but also on the variables of adequate medical care and sanitation, those
concepts are also considered (Gausset, Whyte, and Birch-Thomsen,005)
Unbridled Continued Growth
From an unbridled continued growth of our population, the ecosystems that we are
dependent upon would become overstressed. Their capacity to return to a stable equilibrium
would be at stake when we will consider the celerity with which this growth happened. Some
stressed ecosystems may never return to their regenerative state; others may take an exceeding
amount of time to recover from the ecological shock, as we are seeing in the Easter Island.
As the carrying capacity is reached, our life style would immediately start to decline for
more and more people to be accommodated then on. This will give rise to stresses among
geographical regions and cultures. In the end, this will give conclude in a culture war owing to
the differential life styles that we are accustomed to.
Size of Population and Environmental Degradation
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Overpopulation can result in a variety of stresses. These include mismanagement of
resources, haphazard human intervention, advent of diseases from mismanagement, over
pollution and mismanagement of waste. Social confusion and upheaval along with the
introduction of destructive, invasive and foreign species can further contribute negatively to
ecosystems.
Mismanagement of resources comes about from the need for quick requisitioning of
resources. Shortcuts may be resorted to, for example in a lot of regions, landfills in the last few
decades followed lax standards leading to problems such as leaching and contamination of
underground soils and aquifers. Likewise, environmental damage may come about from
not taking enough precautions in a quest for fast development. We saw this happen with the
Chernobyl nuclear disaster where there were few safety levels developed and deployed. Rapid
deforestation for employing more land in agriculture to feed more and more people (or for
exporting purposes) has had a severe impact on resident species and destruction of ecosystems as
a result.
Likewise, introduction of foreign or invasive species can cause a deleterious impact on
the native flora and fauna of a region. Higher population levels also mean that diseases find
sanctuary in the midst, degrading the quality of life and needing more global hectares per capita
for making up. Social upheaval causes disorganization and a general degradation in the law and
order situation, causing further damage to the environment.
Environmental restoration projects and efforts must take into account the size of the
human population interacting with the ecosystem because that population size will continue to
interact with the ecosystem and will be reliant on it. The greater the size, the harder it will be for
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the ecosystem to regenerate. Therefore the success of the project will depend upon careful
provisioning for the size of the population.

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