Collapse of the Easter Island ecocide theory: to what extent does opinion influence research?

The idea that Rapa Nui (Easter Island) society collapsed as a result of over-exploitation of the island’s environment has become a widely held belief. But is this view supported by evidence, or is it opinion?

What did the Easter Islander who cut down the last palm tree say while he was doing it?” Like modern loggers, did he shout “Jobs, not trees!”?‎

This often quoted line comes from Collapse: How Societies Choose to Fail or Succeed[1. Diamond, J. M. (2005). Collapse: How societies choose to fail or succeed. New York: Viking.], the celebrated 2005 book by Jared Diamond which draws lessons for today from the role of environmental factors in the collapse of past societies. Rapa Nui (Easter Island) has fascinated people from around the world because of it’s massive stone figures, the moai. In Collapse, Diamond concludes that the people of Rapa Nui destroyed all of the island’s forests within a few centuries of arrival, leading to widespread environmental degradation. This caused the society to collapse into conflict, cannibalism, and self-annihilation with less than 700 people remaining when Captain James Cook visited the island in 1774.

The “Easter Island ecocide” theory put forward by Diamond quickly became a widely promoted mantra, particularly among environmentalists, despite being challenged in the paper “”From Genocide to Ecocide: The Rape of Rapa Nui””[2. Benny Peiser (2005). From Genocide to Ecocide: The Rape of Rapa Nui. Energy & Environment, 16, 513–540.] soon after the publication of Collapse. Paper author Barry Peiser argues that Diamond’s significant concern for the future and its impacts on the environment clouded his judgement:

The fundamental flaw in his treatment of Easter Island is that he approaches the problems of its evolution and history with the zeal of an environmental campaigner, and not with the dispassionate detachment of a scientist.

However, Peiser is a well-known climate science skeptic who is Director of the Global Warming Policy Foundation, described as “the United Kingdom’s most high-profile climate denier group”. This contributed to rejection of his views in regard to the Easter Island ecocide theory.

The next major challenge to the Easter Island ecocide theory came in the 2011 book The Statues that Walked: Unraveling the Mystery of Easter Island[3. Hunt, T. L., & Lipo, C. P. (2011). The statues that walked: Unraveling the mystery of Easter Island. New York: Free Press.] by Terry Hunt and Carl Lipo, who paint a very different picture:

Far from irresponsible environmental destroyers, they show, the Easter Islanders were remarkably inventive environmental stewards, devising ingenious methods to enhance the island’s agricultural capacity. They did not devastate the palm forest, and the culture did not descend into brutal violence. Perhaps most surprising of all, the making and moving of their enormous statutes did not require a bloated population or tax their precious resources; their statue building was actually integral to their ability to achieve a delicate balance of sustainability. The Easter Islanders, it turns out, offer us an impressive record of masterful environmental management rich with lessons for confronting the daunting environmental challenges of our own time.

Central to Diamond’s Easter Island ecocide theory is the conclusion that the islanders deforested the island not just for agriculture, but to use the trees to help transport the moai. This assessment was first put forward in the 1992 book Easter Island, Earth Island[4. Bahn, P. G., & Flenley, J. (1992). Easter Island, Earth Island. New York, N.Y.: Thames and Hudson.].

However, Hunt and Lipo argue that the moai were “walked” vertically from quarries to their final locations, rather than being slid or dragged horizontally across the ground with the assistance of timber. They show that it can be done in a real-life demonstration.

Environmentalist Mark Lynas discussed Hunt and Lipo’s conclusions in a blog post, in which Lynas was heavily critical of Diamond:

Falsely accusing the islanders of killing and eating each other is bad enough. But it gets worse. Whilst the conventional narrative blames the islanders for committing a kind of collective ecological and social suicide (hence the term ‘ecocide’) this reading of history is almost certainly perpetuating a monumental injustice. For the Easter Islanders were indeed subject to a genocide — but it did not come from within. Instead, visiting ships brought epidemics of new diseases which wiped out the majority of the population — with most of the remnants later carted off in slave raids.
It is grimly ironic that Jared Diamond, of all people, missed — or misread — this more realistic version of history, given that it forms the central thesis for his earlier and much more convincing book ‘Guns, Germs and Steel’.

In a subsequent blog post, Lynas gives Diamond the right of reply. Diamond hits back at the criticism, saying that:

Unfortunately, the web postings don’t recognize the compelling reasons why Hunt’s and Lipo’s conclusions are considered transparently wrong by essentially all other archaeologists with active programs on Easter Island.

Diamond goes on to detail what he sees as those compelling reasons, drawing on research findings to support his views. He dismisses Hunt and Lipo’s view that rats had a role in deforestation, rejects their date for the settlement of Rapa Nui, describes their view that the moai were moved vertically (walked) as being implausible, and rejects their view that collapse occurred only after European contact. He finishes by stressing the core message from Collapse: that the collapse of Rapa Nui society was due to the over-exploitation of the environment, and that there are lessons in this for today.

In a further blog post, Lynas allows Hunt and Lipo to respond to Diamond’s rejection of their criticism. They begin their response with:

We are hardly surprised that Jared Diamond would write that we are “transparently wrong” about Easter Island. He has a vested interest in defending his “ecocide” storyline published back in 1995 in Discover Magazine and again in his bestselling book Collapse. We acknowledge that Diamond has much at stake here. But so do the Easter Islanders. So too does the field of archeology. And so too does the truth.

They then address the reasons why Diamond described their views as being wrong. They provide a much more detailed and extensive response than Diamond does in his rejection, and also draw on a wider range of evidence.

Following the publication of The Statues That Walked, the evidence against the Easter Island ecocide theory has continued to mount, and this new research was the focus of a BBC documentary hosted by archaeologist Dr Jago Cooper.

In a paper published in the Journal of Archaeological Science[5. Mulrooney, M.A. (2013). An island-wide assessment of the chronology of settlement and land use on Rapa Nui (Easter Island) based on radiocarbon data. Journal of Archaeological Science, 40, 4377–4399.], anthropologist Mara A. Mulrooney analyses radiocarbon data from Rapa Nui to conclude:

The results of this study suggest that Rapa Nui settlement and land use exhibit continuity rather than punctuated, detrimental change during the late pre-European contact period.

In the paper “Challenging Easter Island’s collapse: the need for interdisciplinary synergies”[6. Rull, V., Cañellas-Boltà, N., Sáez, A., Margalef, O., Bao, R., Pla-Rabes, S., Valero-Garcés, B. and Giralt, S. (2013). Challenging Easter Island’s collapse: the need for interdisciplinary synergies. Frontiers in Ecology and Evolution, 1:3.], Rull et al. examine paleoecological and archaeological evidence to conclude:

Our observations agree with Mulrooney’s (2013) argument of gradual social change and challenge the current paradigm of a human-driven ecological catastrophe causing a social collapse around AD 1000–1200 or later. Both archaeological and paleoecological evidence point to a new view of Easter Island’s history.

On the basis of the growing body of new research, it does appear that Diamond’s influential Easter Island ecocide theory is the product of his opinions about environmental and societal decline rather than being evidence-based, as climate science skeptic Peiser had asserted soon after Diamond published Collapse.

To assist better understandings in the future, Rull et al. propose in “Challenging Easter Island’s collapse: the need for interdisciplinary synergies” that “scholars from disparate disciplines, working together, may enhance the scope and the soundness of historical inferences.”

The emerging field of Resilience Thinking[7. Folke, C., Carpenter, S. R., Walker, B., Scheffer, M., Chapin, T. and Rockström, J. (2010). Resilience thinking: integrating resilience, adaptability and transformability. Ecology and Society 15(4): 20.] is also likely to offer insights into how Rapa Nui society was able to adapt to environmental change:

Resilience thinking addresses the dynamics and development of complex social-ecological systems (SES). Three aspects are central: resilience, adaptability and transformability. These aspects interrelate across multiple scales. Resilience in this context is the capacity of a SES to continually change and adapt yet remain within critical thresholds.

Image source: Easter Island Moai by Nicolas de Camaret is licenced by CC By 2.0.


Originally published at RealKM.