While the myth of the collapse persists, a team of researchers shows that the population of Easter Island (Rapa Nui) experienced a continuous increase until the arrival of Europeans in 1722.
The moai statues are sometimes presented as the symbol of the excessiveness of the Pascuans by the defenders of the myth of the collapse.
According to the theory of ecocide, the Pascuans, inhabitants of Easter Island, would have cut down all the trees, to develop agriculture and to help erect their famous giant statues , the moai . This overexploitation, coupled with the invasion of rats, fond of palm seeds, would have led to the disappearance of the subtropical forest that covered the island before the arrival of its first inhabitants, between the 12th and 13th centuries. Finding themselves without trees to build the canoes that allowed them to fish, the population of Easter Island would in turn have sunk.
It's a famous sprinkler story, popularized by Jared Diamond in 2005 in his book Collapse:How Societies Decide Whether They Die or Survive , which sounds like a warning in these times of global warming. But, beyond its moralizing function, is this story accurate? Has the population of Easter Island collapsed?
Easter Island would have experienced decades of drought
Nothing is less certain, according to recent research. If the massive deforestation of the island is proven, in particular by the analyzes of pollen residues, scientists agree more and more on the importance of climate change. In the first half of the 17th century, the island would have experienced decades of drought, an episode that would correspond to a chronic oceanic phenomenon still observable in the Pacific, known as El Niño Southern Oscillation (ENSO). The Pascuans would not be the cause of the disappearance of the forests of their island, and would even have survived it.
According to the theory of ecocide, the Pascuans, inhabitants of Easter Island, would have cut down all the trees, to develop agriculture and to help erect their famous giant statues , the moai . This overexploitation, coupled with the invasion of rats, fond of palm seeds, would have led to the disappearance of the subtropical forest that covered the island before the arrival of its first inhabitants, between the 12th and 13th centuries. Finding themselves without trees to build the canoes that allowed them to fish, the population of Easter Island would in turn have sunk.
It's a famous sprinkler story, popularized by Jared Diamond in 2005 in his book Collapse:How Societies Decide Whether They Die or Survive , which sounds like a warning in these times of global warming. But, beyond its moralizing function, is this story accurate? Has the population of Easter Island collapsed?
Easter Island would have experienced decades of drought
Nothing is less certain, according to recent research. If the massive deforestation of the island is proven, in particular by the analyzes of pollen residues, scientists agree more and more on the importance of climate change. In the first half of the 17th century, the island would have experienced decades of drought, an episode that would correspond to a chronic oceanic phenomenon still observable in the Pacific, known as El Niño Southern Oscillation (ENSO). The Pascuans would not be the cause of the disappearance of the forests of their island, and would even have survived it.
In any case, this is what researchers from Binghamton University in New York say in a study published in the journal Nature . The objective of this team was to confront the theory of demographic collapse with archaeological data, through statistics, and more precisely the method of approximate Bayesian calculations. This method, which was already used in the field of genetics, makes it possible to consider the demographic curves generated by the empirical data (201 carbon-14 datings) to compare them with the models obtained "theoretically", by introducing variables.
Here, four models were thus used for comparison with the model obtained by the empirical data, which made it possible to model the demography by taking into account, respectively:the evolution of the number of palm trees, the evolution of the climate, these two parameters and none of these two parameters. Without this technique, the approximate C14 dating does not make it possible to study demography in relation to environmental and climatic changes. It would indeed be necessary to use the likelihood function, which would be impractical. Finally, if the method of approximate Bayesian calculations did not allow the researchers to decide on the influence of a particular parameter, all the models agree on the constant increase in the population of the island until l arrival of the Europeans in 1722 (then, according to the models, there would then be a decline or a plateau). This is enough for the researchers to conclude that there has been no demographic decline on Easter Island, despite the climatic upheavals.
The myth of the collapse is crumbling
Other studies had already come to the same conclusion, after proving that the diet of Easter Islanders had remained the same after the period of global warming (which indicates that they did not experience a food crisis) and that the erection of statues continued even after the discovery of the island by Europeans in 1722.
Contacted by Sciences et Avenir , Catherine Orliac, research director at the CNRS, recalls that “the Rapanui, ingenious horticulturists, knew how to adapt brilliantly to the climate changes caused by the ENSO phenomenon ”. Among the elements which make it possible to prove it, the accounts of European explorers of the 18th and 19th centuries, such as James Cook, Frederick William Beechey or Jean-François de Lapérouse, describe horticultural arrangements:straw spread over the fields to protect from the sun and retain moisture, dry stone walls built to protect the gardens, or even furrows dug to capture running water.
But how to explain the anchoring of the myth of the collapse despite the proliferation of studies contradicting it? Already, the number and size of the moai , characteristic of Easter Island and its first inhabitants, have long led to overestimating the number of the latter. Furthermore, according to Carl Lipo, one of the team's researchers, today the link between climate change and a demographic catastrophe is established automatically, without the populations' ability to adapt being taken into account, and this especially for those who preceded us:“I there is a natural tendency to think that people of the past weren’t as smart as we are “, he said in a statement.