How Do Changes In the Human Population Affect the Environment?
To what extend do you agree with the statement ‘Population growth has brought social and environmental problems, and human societies through time have been forced to adapt, to find new ways of doing things, or perish’ (Scarre, 2009, p. 40? The World has witnessed a dramatic growth in human population since the last ice age. The warmer climate has reduced the number of hostile habitats and allowed for vast numbers of both wild animals and plants to flourish. However, at some point both the availability of resources and the steady growth of population have become unsustainable (Scarre, 2009. p187).
This essay will look at what happens when production is unable to meet the needs of a growing population and when population growth begins to outstrip the available resources. It will investigate the critical consequences for the environment and on complex societies as a whole. I will illustrate and explain how population growth has contributed to a series of social, health and environmental problems which in some extreme examples has led to the total collapse of human societies. I will also identify those societies that were forced to find ways to adapt themselves to these problems and that consequently flourished.
My analysis will be supported with examples from both the Old World and the New World. Environmental Degradation One common strand found in several ancient societies that experienced a progressive decline or a total wipe out due to population numbers spiralling out of control is that of ecological sustainability. The demise of the Classic Maya, the Polynesia of Easter Island or the Harappans of the Indus Valley to name a few, offer one of the best examples of how population growth can contribute to the collapse of the environment and eventually to an entire civilization.
The demise of the ancient Maya society offers one of the best examples of how population growth has contributed to the collapse of an entire civilization. First and foremost, the Maya World is found in the Yucatan peninsula, a hot and humid area that offers a series of challenges to would be farmers. There is a total absence of large rivers or stream and it has a predominantly dry climate. The Yucatan peninsula consists mostly of karst[1] shaped landscape. Consequently, most of the rain fall is lost, leaving little or no surface water.
Despite the building of artificial reservoirs like those found in the site of Tikal (Webster and Evans pp 626-627), the inhabitants of the Maya lowlands were critically exposed to any major climate adversities such as a prolonged drought. Maya staple diet consisted mainly of corn and a few other small domestic animals such as turkeys and ducks, with an absence of larger animals such as those found in the Old World, horses, oxen or camel or even those found in the Inca empire such as llamas or alpacas, which, not only could be of assistance for food production and transportation but they could also be consumed during times of bad crop seasons.
Furthermore, due to the region’s humid climate, the Mayans were unable to store corn for more than a few months as this would either rot or become infested with parasites. This would prevent them from eating any surpluses accumulated in previous years during periods of severe drought (Diamond, 2003). As more people begun to concentrate in the Copan valley more land had to be cleared to build houses and plant crops in order to feed and house the growing number of people. This brings a series of irreversible environmental issues such as deforestation, soil erosion and man-made drought.
Archaeological evidence in the Copan valley region has shown traits of sediment belonging to that of the hill slopes as a result of clearing the forest to build new settlements and to be used as burning fuel (Diamond, 2003). So here we find perhaps the most damaging consequence for humans of environmental degradation in the long run: Soil erosion. If the soil of arable land becomes either too acidic or like in some cases, toxic, the crop yield will dramatically drop to a point where that land can not be used.
For a society that was made up mostly of farmers (commoners), soil erosion and lost of arable land is going to have some dire consequences from a social point of view which I will discuss later on. The Roman Empire suffered similar fate as the number of people living in and around the cities grew larger. As the empire expanded in the second and first centuries BC,the Romans built many new towns and cities. So food production had to be increased and as a result of this large amounts of forests were cleared for farming.
Just like we saw earlier of with the lowland Maya, the roots of the trees in these forests had previously bound the soil together; once they were gone, every time it rained the loose topsoil was washed away into nearby streams and rivers. This soil was carried downstream and deposited as silt in harbours, river estuaries and deltas, and other coastal areas. Over the centuries this silt built up until many harbours and river mouths became impossible to navigate for large cargo ships.
Transport of food reduced dramatically, transforming previously booming coastal ports poor, prevented transport of food by large ships inland along the river systems, reduced imperial tax revenues and caused food shortages. The accumulation of silt deposits also destroyed the coastal fishing industry, previously a major food source. Lagoons, harbours and estuaries that had once teemed with fish became swamps and marshes where there wasn’t enough oxygen in the water for fish to live. This further impoverished coastal communities and reduced food supplies to a point where shortages became famine.
But whereas the areas or region where the Roman Empire or Mayan laid its foundation did eventually recover from an ecological point of view, other geographical places suffered irreversible environmental changes that last today. The Indus Valley homeland of the Harappan society and Mesopotamia represent some examples regions that to this date the ecological balance is to be restored. Thus, just like we saw earlier with the Roman Empire, the accumulation of silt deposits in coastlines and river mouths also had the same devastating consequences for the Harappans.
Deforestation, fuelled mainly by the use of wood for burning to bake bricks to build settlements and also a burgeoning metalworking and pottery industry was the main factor (McIntosh, 2008) aided by a region that was subject to flash floods during the monsoon season as well as long periods of drought. A common pattern found in all fallen societies was the inability to respond to these problems. Both the Maya Kings and nobles and the Emperor and bureaucrats in Rome, focussed their attention enriching themselves, waging wars, erecting monuments and, ultimately taxing the peasants to support all those activities.
However, no other place suffered more the consequences of environmental degradation than those seen in Easter Island. With an area of only 64 square miles, it is one of the World’s most isolated places, excluding the island from attacks from other people, potential epidemics or natural disasters. The combination of a mild climate together with its volcanic origins providing excellent soil for cultivation made it an ideal place to live. So, you can only guess that at some point population levels would begin to grow at unsustainable levels.
Just like we saw with the Classic Maya, the Polynesian settlers of Easter Island increased their building activity as they were approaching their stage of decline. One of the main characteristics of Easter Island is its monumental statues or Moas, some of them weighed up to 82 tons (Diamond, 1995). The forests of the island would have to be used to transport these massive structures. Social Degradation The advent of agriculture led to the establishment of new farming economies that could support much larger communities.
Larger settlements will not only drive a increase in crop productivity, but they would also become focal points for the exchange of new ideas, practices and ways of improving farming techniques, herding and crafting. Larger settlements would set the bases for craft specialisation and thus the development of increasingly complex societies. With, them, issues of inequalities of wealth and status would lead to the rise of hierarchical societies or “civilizations” of the ancient world (Scarre, 2009).
Social inequalities and social unrest will be the focus of this part of my work, using the demise of the Western Roman Empire, the Classic Maya and the Polynesian society of Ester Island as examples. The Roman Empire can be considered one of the great successes and at the same time failures in human history. I think it offers a prime example of the collapse of a complex society fuelled by a growing population spiralling out of control. Social inequalities became a main feature of an empire that depended heavily on the windfalls of their conquests.
However, with the end of geographical expansion around the second century A. D. there was a correspondent drop in the revenue coming from conquest campaigns. It was during Diocletian’s rule (284 to 305 A. D. ), that the lack of extra revenues filling the Empire’s reserves begun to aggravate the tax burden placed on Roman citizens, especially on small farmers. This was also a period where [2] begun to replace small farms; at the same time, arable land was converted wholesale to pasture land, while much of it was abandoned entirely since its soil had become totally exhausted (Cowell,1980).
Again, we are witnessing the recurring issue of environmental degradation and sustainability, which a few hundred years later will be the downfall of the Classic Mayan societies. So, basically, we get to a point where a large number of peasants were not able to meet the tax requirements imposed by the bureaucrats of the State and at the same time these peasants would be unable to feed themselves, as they had to sell any crop surpluses.
If we assume that at any given time these farmers would have a bad crop yield due to a prolonged drought, plague, etc, we find a situation were farmers would be under conditions of famine. As a result of this we are going to see an exodus from the country side into the cities where most of the grain was stored. We can only assume that, as the Roman Empire begins to enter into their final stages of its decline more taxes would need to be raised to pay for an increasingly disloyal army made of mercenaries and also to support the extravagant lifestyle of an elite minority.
Here we are facing a situation where a large numbers of farmers are going to move to Rome, as well as a significant number of ex soldiers and free slaves. With the vast majority of these people scraping for a living, most of them unemployed and depending exclusively on handouts to feed themselves (Pearson, 2008) we are going to have the development of a social underclass where crime was rife and social revolts were common. Health Deagradation Significantly, it was around 200 BC that malaria seems to have developed in Italy.
The marshes which bred the Anopheles mosquito were man-made. They were created by soil erosion from badly-cultivated sloping lands, which, being deprived of their topsoil, were, by the same token, made largely unproductive. The Pontine marshes supported 16 Volscian towns in the 7th century BC. Five hundred years later, they only supported mosquitoes Scarre, C. (2009). Chapter 5 – The World Transformed: From Foragers And Farmers To States And Empires. In: Scarre, C The Human Past. 2nd ed. London: Thames & Hudson Ltd, London. p187. Webster, D & Evans, S. 2009). Chapter 16-Mesoamerican Civilization. In: Scarre, C The Human Past. 2nd ed. London: Thames & Hudson Ltd. 626-627. Diamond, J. (2003). The Last Americans. Available: http://www. astepback. com/GEP/Diamond,%20The%20Last%20Americans. pdf. Last accessed 14th March 2011. McIntosh, J. (2008). The Indus Valley Today. In: Moore, A and Springer, S The ancient Indus Valley: new perspectives. Santa Barbara, California: ABC-CLIO, Inc. p395-398. Scarre, C. (2009). The Human Past; Retrospect and Prospect. In: In: Scarre, C The Human Past. nd ed. London: Thames & Hudson Ltd, London. P718. Cowell, F. R. (1988). Earning a living. In: Life in Ancient Rome. 3rd ed. New York: The Berkely Publishing Group. p136. Pearson, M.. (2008). The Price of the Empire – The Growth of an Underclass. In: Pearson, M. Perils of Empire and The American Republic. New York: Algora Publishing. p164. Tainter, J. (1988). The Study of Collapse – Resource Depletion. In: Tainter, J The Collapse of Complex Societies (New Studies in Archaeology). 2nd ed. Cambridge: Cambridge University Press. p49. ———————- [1] Karst is a distinctive topography in which the landscape is largely shaped by the dissolving action of water on carbonate bedrock (usually limestone, dolomite, or marble). This geological process, occurring over many thousands of years, results in unusual surface and subsurface features ranging from sinkholes, vertical shafts, disappearing streams, and springs, to complex underground drainage systems and caves. [2] A great landed estate, specially of the ancient Romans. (Source: Oxford English Dictionary)
