So, what has happened to the point I made in my very first post about Easter Island being a parable to today’s society? Well today’s post will look into just this. Already we can see the potential impacts deforestation had on Easter Island (depending on whether you support Jared Diamond’s theory, or Hunt and Lipo’s theories), yet the underlying cause of deforestation, as proposed by Diamond, is population expansion.
It may (and should) be clear by now that the theories behind Easter’s collapse are highly contested. Population expansion, as suggested by Jared Diamond and many other scholars COULD be a cause behind Easter Island’s demise, but it should be obvious that t his is only one side to the argument. Theories already discussed, such as the rat theory, and theories to come, for example, the arrival of the Europeans and slave trade are also supported by archaeological and anthropological evidence, and are no less important. I am only saying this because it is easy to be caught up in the more popular idea that the Easter Islanders caused their own demise….’suicide’, without looking at all the arguments and evidence. That said, I will investigate a couple of papers that suggest population expansion was the cause behind the Easter Island collapse.
The Malthus prediction that:
‘Population growth would eventually lead to natural resource depletion, economic decline, starvation, violent conflict and population decline’
seems remarkably close to the Easter Island story suggested by Diamond.
Bologna and Flores (2008) implement a mathematic model that explains the rise and fall of Easter Island. The model considers the interaction between natural resources and population, and generates an estimation of the civilisation’s collapse time. The diagram below shows the model predicted population and amount of resources.
They predict a population increase to 7000 by AD 1400. This estimate is similar to those made by Bahn and Flenley (1992) from the pollen record, and by Diamond (2007) and Rainbird (2002). In addition, this peak population is also supported by the fact that moai construction peaked between 1100 and 1400 A.D. Moai construction indicates the presence of a large population since their construction requires intensive labour, and it also suggests a complex society that were able to organise such large-scale projects.
Bologna and Flores use their model to determine the civilisation’s equilibrium point where humans can coexist with the available natural resources indefinitely. They estimate the equilibrium population size to be around 2000 people, as it was around 1175. Meith and Bork (2005) suggest that sustainable agriculture existed up until A.D 1300, perhaps implying that humans and natural resources were in equilibrium. Considering the year 1175 falls into this phase of sustainable agriculture, Bologna and Flores’ predicted equilibrium population size seems entirely likely.
The model then shows a population decline to 2000 by 1600 A.D that coincides with a sharp drop in resources, as shown by the diagram.
However, Wolcott and Conrad (2011) advocate that using the interaction between humans and resources to drive the model is not accurate, and the influence of soil erosion must be factored into population estimates from mathematical modelling. Their research proposes that population decline occurred because soil erosion caused agriculture to fail, which can be seen in the diagram below.
Either way, both studies show the general trend that Malthus predicted, where population increased past the equilibrium population size, resources were depleted (with the help of soil erosion causing agricultural failure), causing population decline. Bologna and Flores conclude by stating:
‘The model could be, with the opportune changes, applied to the planet…of course there are many differences but surely the planet can be considered an isolated system as Easter Island was’
which sums up not only their view, but many other scholars as well. Of course, as I have already mentioned, this popular viewpoint is only one side of the story…there is much more to be discovered and told about Easter Island yet!
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