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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 super volcano 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 meager 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 Europebetween 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 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, especially 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 ofEuropequadrupled 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 (Raven, 1997). 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 (Shils, Shike, Ross, Caballero, and Cousins, 2006). The population of the UKwould approximately double every 50 years over the entire 19th century. The population of theUnited States would go from 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 have 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 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, 2005).

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 theEaster 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

            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 many 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 theChernobylnuclear 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 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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