Rewriting Easter Island's history

At the height of the now cooling debate on global warming, activists sometimes pointed to remote Easter Island as a society that deliberately destroyed its environment. Unless we lifted our game, we were told, we will devastate this world, just like the Easter Islanders devastated their island – in particular, by cutting down all the trees as part of the effort to carve, transport and erect the statues that are a feature of the island.

After this short sighted exploitation, the islanders fought a series of civil wars in medieval times over what resources remained, with those wars and their aftermath eventually destroying the culture that built the statues.

This rather grim story is colourful and, for those pre-disposed to believe in the evils of industrial development, it has the ring of truth. As a cautionary tale it has the additional advantage that the general public are aware of the Easter Island statues, but only a handful of scholars know anything much else about the island, let alone anything about the theories concerning the statues. So this version of events was seldom questioned What happened on Easter Island will happen to us all, so why don't we have a carbon tax?

The trouble with this argument is that the above scenario depends heavily on the ideas of Jared Diamond, a professor of geography and physiology at the University of California, and those ideas should properly be seen more as contested speculation, with recent discoveries making them look shaky indeed. This is not to say that Professor Diamond is wrong. As I'm not an archeologist and have never been to the island, I am not in a position to pronounce on any theory concerning it. But I am entitled to complain about the way Professor Diamond has presented his theories - as if they are established fact, rather than his own ideas which require a lot more evidence before being allowed into the text books.

I was certainly fooled when I encountered them in Diamond's popular book Collapse: How Societies Choose to Fail or Survive (Viking Press, 2005). In this book, a follow on from his best selling Guns, Germs and Steel, (Vintage, 1997). Diamond presents a number of examples of known collapses of civilisations, including the Norse colonies on Greenland, the Mayas in Central America, the Anasazi in what is now the American South West, and the society on Easter Island.

There is a lot more in the book including some material on Australia which is there mostly because Diamond has spent some time in Australia, including a sabbatical at the Australian National University, and says that he likes the place. Despite the title of the book he does not think we about to collapse but believes we are doing various things wrong. However, while his observations on soil and agriculture have some value some of his comments on politics and history in that chapter can only be described as nutty.

To examine that chapter briefly, at one point he says that Australia's agricultural productivity was so poor that it had to subsist on "regular food subsidies" sent from Britain which did not cease until the 1840s. What? A quick check of any history text shows that the first governor, Captain Arthur Phillip, faced immense difficulties in getting agriculture established in a different climate and different continent and with an understandably sullen workforce. He hoped that the first and second fleets would have more food instead of, as it turned out, sick convicts. He had to send out twice for supply ships – once from what is now South Africa and another from India – before the stituation stabilised. Diamond seems to have confused all subsequent shipments of convicts, which did end in the 1840s, with food shipments. The suggestion that the British authorities regularly exported food in any quantities all the way to Australia in that period is absurd.

At another point, he says that the "Australian constitution gives a disproportionate vote to rural areas". Again, what? The Federal rural gerrymander, which was swept away by the newly elected Whitlam government in the early 1970s, never had anything directly to do with the constitution. It was arranged through government instructions to the Australian Electoral Office. Perhaps Diamond is confusing the West Australian state constitution, which still deliberately gerrymanders the state upper house towards rural interests, with the Federal constitution.

There is a great deal more I could say. Diamond does not seem aware of the detailed rural production and farm income statistics kept by the Australian Bureau of Agriculture Resources Economics and Sciences, or international comparisons of agricultural subsidies, or of the agriculture trade figures collected by the Australian Bureau of Statistics. Nor does he understand that agricultural economics often dictates that certain products (such as orange juice, which he mentions) are best produced in different countries. If he had taken time to study any of those sources, the reader might have been spared some of his lectures on how agriculture in Australia is too costly to be economic, and that really we should not bother with it.

The problems cited above are not just slips, they are howlers. As a journalist who has written on agribusiness from time to time over the years, I was unimpressed. And this is a best seller?

The chapter on Australia dissuaded me from reading parts of the book dealing with present-day matters, or from reading his popular Guns, Germs and Steel, but I did look at the chapters in Collapse on Greenland, Easter Island, the Anasazi and the Maya civilisations believing, like all his other readers, that Diamond was simply retelling what is generally understood about those collapsed civilisations. As he is also an engaging writer, this was no great task.

At first glance his summary of the rise and then extinction of the Norse colonies on Greenland, accorded with what I understood to be the orthodoxy. The Norse settled Greenland during what is now known as the Medieval Warm Period (temperatures around those of present times), but then would not or could not adapt to the much colder conditions of the Little Ice Age, including adapting the clothing and hunting techniques of the Inuits.

But a look at other sources indicates that the orthodoxy had changed, and that some of Diamond's assertions are doubtful. For example, he insists that the Greenland Norse did not eat fish, citing as evidence a lack of fish bones in what amounts to Norse rubbish heaps carefully analysed by scholars. He supposes that there was a previously unknown cultural taboo against eating fish. No other scholar seems to agree with him and, in any case, isotopic analysis of the bones found in Norse graveyards indicate that they did. Further, the analysis shows that more of the Norse food came from the ocean, over time, and less from their farms, as the climate changed, until 80 per cent of their diet was from the sea. In other words, they did adapt. (C-14 dating and the disappearance of Norsemen from Greenland, Europhysics News, May/June 2002.) In addition, although there is evidence of individuals being driven to desperation in one farm excavated, in another scholars, led by Dr Jette Arneborg, of the Danish Museum in Copenhagen, suspect that the inhabitants simply packed up what they could take with them and left. (New York Times, May 8, 2001. In online comments Arneborg is scathing of Diamond, although Diamond quotes her extensively.)

The black plague in Europe in the 14^th century wiped out one third of Europe's population and offered new economic opportunities, so rather than go native, and the Inuit lifestyle was no bed of roses, the Norse may simply have moved to Greenland's near neighbour, Iceland. In those days, of course, emigrants did not fill out visa forms or postal change of address cards, they simply left. A point in favour of the argument is that only bodies found in the Norse settlements excavated have been deliberately buried and there is no sign of a final collapse.

Diamond insists that they had no boats so they could not move, whereas scholars think they did have boats, and explains away the absence of starved corpses by one means or another.

Another strand to the emigration argument is that at the time ivory from African elephants was displacing the more expensive ivory from Walrus tusks, which was Greenland's main source of trade at the time. (Scholarly papers have been published in the journal Arctic Anthropology.)

None of this is definitive, of course, the mystery of the vanishing Norse colonies will be kicked around for many years yet, but it does make more sense than the failure to adapt scenario. This was all known before Diamond wrote Collapse, but he does not trouble his readers with the information.

And now we arrive at the chapter on Easter Island, which is the main source of the sensational theory outlined at the beginning of the article. Magazine articles preceded the book and other scholars – notably by academics John R Flenley and Paul G. Bahn who wrote Easter Island, Earth Island – have speculated about a collapse in the Eastern Island culture predating western contact. But most references for the collapse story are to the chapter on Easter Island in Collapse. In any case, it is by far the most detailed.

Diamond seems to have spent some time on the island, which is indeed isolated. South America is 3,000 kilometres to the East and Pitcairn, the closest habitable island, 2,000 kilometres to the West. Despite this isolation quite a parade of scholars have found their way to the island, including others less distinquished than Diamond but with their own theories. Thor Heyerdahl of Kon-Tiki expedition fame in the 1940s claimed that Eastern Polynesia, which includes Easter Island, was first inhabited by white skinned people fleeing from South America who built the statues. That race was conquered by stone age North Western American Indians. Scholars paid very little attention to Heyerdahl at the time, and DNA testing has since conclusively disproved his ideas. In the 1960s Erich von Daniken climed that the statues were the work of an advanced alien race. (Von Daniken's theories may be nonsensical, but his books sold millions. Sceptics would be a lot richer if they were not sceptics.)

Diamond says that after arriving in 900 AD (or CE in the new style) the Polynesian settlers started cutting down the island's trees in part to make the ropes, rollers and levers needed to move the monstrous statues that are a feature of the island. This was done, he says, at the behest of their priests and chiefs who wanted to erect the statues to demonstrate their own power. When all this destruction caused the island's ecosystem to collapse, the connection the chiefs claimed with the gods was shown to be false, Diamond says, and they were overthrown by military leaders called Matatoa. The island's society degenerated into civil war. The islanders started to live in caves for protection and even practised cannibalism, so that there was only a remnant by the time a Dutch explorer made the first European contact in 1722. As is widely acknowledged the subsequent history of Easter Island is very sad. European contact introduced diseases, and slave raiders took away most of the population that was left.

That is the dramatic tale that Diamond has to tell and there are points in its favour. The island is known to have been covered by trees for thousands of years, but had lost at least a large part of that cover by the time of European contact (the very early accounts are contradictory). It's known that the islanders started to live in caves, the island is littered with spear points and a human bone, cracked to extract the marrow, Diamond says, was found among a number of other bones. Island folk tales also talk of fighting long ago.

A closer look at the material he presents, however, suggests that much of what he puts forward is speculative. Thus: "The increase in statue size with time suggests competition with rival chiefs commissioning the statues to outdo each other". He draws parallels between their behaviour and the apparent urge of major Hollywood players to build ever bigger mansions.

Diamond's theories are also very strongly disputed by academics in that field, notably Benny Peiser an anthropologist from Liverpool John Moores University. Peiser says that the Easter Islanders adapted well to their environment, making statues every few years. The reason they stopped making the statues is the obvious one, the onslaught of European diseases and mass abductions by slave traders which destroyed the society. (From Genocide to Ecocide, The Rape of Rapa Nui, Energy & Environment, 2005.) He says that the islander tales of fights in the distant past relied on by Diamond for his theories have been shown to be confused communal tales of far more recent fights with the slave trader gangs. The original culture was all but destroyed by diseases and slave raids, Peiser says, and by the time the folk tales were written down by missionaries they had been heavily influenced by an influx of Polynesian settlers from other islands. The spear points and cave living period can all be dated to after European contact, when the islanders were defending themselves against slave raids. He also describes Diamond's suggestion that the islanders practised cannibalism as "absurd" given that they were still well able to fish.

As Peiser is now executive head of the very sceptical Global Warming Policy Foundation, activists have dismissed his criticism as politically motivated – as part of an orchestrated sceptical attack on Diamond's theories. However, they have been unable to think of any handy political excuse for dismissing another of Diamond's major critics, Terry L. Hunt, a professor of archaeology at the University of Hawaii, who has conducted several digs on the island. He says archaeological evidence clearly points to that the main cause of the demise of the island's tree cover as rats, introduced by the islanders, eating the seeds of trees before they could germinate. Further, at least a part of the island still had trees by the time of first European contact. (American Scientist, October 2006.)

This does not mean the islanders were angels who dared not touch a tree. They certainly helped out the deforestation process by cutting down trees There just does not seem to be any real evidence that they blindly cut down everything at the behest of their chiefs, as Diamond alleges. As noted, the island's culture was all but destroyed so there is no direct evidence on why the statues were built or over what period, and there are difficulties in carbon dating them. Hunt adds that the island's population grew to about 3,000 and remained stable, without any sign of a collapse triggered by deforestation.

Hunt's work is, in turn, part of a major overhaul of scholarly thinking about the islands of Eastern Polynesia in that they now believe the first settlers arrived in the thirteenth century AD, or much later than 900AD date which Diamond uses. (High-precision radiocarbon dating shows recent and rapid initial human colonisation of East Polynesia, Janet M Wilmshurst, Terry L Hunt and others, Proceedings of the National Academy of Sciences, February 1, 2011). Should that much later date be accepted scientists will have to completely revise what they thought they knew about the interaction between humans and the animals they introduced, with the environment on various islands.

Diamond has since bitten back pointing out, amongst other things, that there is evidence that the islanders affected their environment. Perhaps, but the original thesis was that they destroyed their environment through short-sighted exploitation. Again, please note, this is not to say that Diamond is wrong, but only that the world has paid far too much attention to his theories. Until he can point to hard proof, such as an archaeological dig by an independent scholar which shows substantial evidence of a collapse of the island society pre-dating western contact, there is no reason to pay any more attention to these theories than, say, suggestions that the seige of Troy really occured in England, or that the Arc of the Covenant is in Ethiopia. There is nothing to really contradict those notions, but not much to confirm them either. In any case, as we have seen, Diamond's track record in other chapters in Collapse, is mixed to say the least. Had he been on the other side of the global warming debate, any one of the previously mentioned howlers in the chapter on Australia would have spawned whole web sites dedicated to attacking the man.