A. The giant stone statues of Easter Island in the Pacific Ocean have perplexed archaeologists ever since European explorers first witnessed them three centuries ago. Jacob Roggeveen, the Dutch seaman who gave the island its name in 1722, was amazed by the statues, each of which clearly weighed several tonnes. But as there were no forests on the island, he could not comprehend how people devoid of heavy timber could build and erect something that size. It was also remarkable considering the absence of metal objects for carving and cutting, and the reliance on mere human strength as no draught animals could be seen either. Roggeveen was equally amazed as to how the islanders could have come to colonise such a remote place. Their canoes were leaky and frail, not the sort of ocean-going craft that could survive a three-week sea journey. At the time of his visit, it seemed evident the islanders were living in extremely poor conditions and that there was no cultivation of crops.
B. What was the mystery behind the statues? In the 1970s, the author Erich von Däniken suggested the statues were the work of extraterrestrial beings. It was hard to believe the stones were the work of humans who were more than 2,000 miles from the nearest mainland, so for a short period of time his theory appealed to those fascinated with space travel. But for serious academics, the puzzle of the statues has caused a deep divide. Some archaeologists see Easter Island as an example of what can happen when the lust for material splendour - ever bigger stone carvings in this case - is satisfied at the expense of the environment. Others, meanwhile, take a different view. The island, these scholars argue, suffered at the hands of introduced diseases, notably smallpox, and a slave trade that stole a huge proportion of its indigenous population. At the heart of the debate is the issue of the island's deforestation. There is no doubt that the island was once covered in palm trees. There is also no doubt that something happened that caused the island to become completely denuded over a short period of time. But was it the islanders who triggered this environmental degradation or another event beyond their control, such as the introduction of rats? It is an indisputable fact that rats found their way to the island, although exactly how is a matter of debate.
C. In 2005, the anthropologist Jared Diamond claimed the islanders started building ceremonial statues in an atmosphere of rivalry between the many clans. To move the statues from the island's quarry in the south-east, they needed to cut large logs for the construction of long 'canoe ladders' to carry them to the coast. For its transport alone, each statue would have required several trees to be cut down. As a result of the deforestation, Diamond believes food production fell dramatically. Consequently the population collapsed from perhaps as many as 15,000 to the few thousand that were eking out a living by the time Roggeveen arrived. Smallpox and slavery killed off those who remained, but the islanders were on the way to total collapse even without any European contact, says Diamond.
D. But not everyone is convinced. Professor Terry Hunt, an anthropologist at the University of Hawaii, says: 'There is no evidence that a population collapse occurred before European contact.' He is supported by Professor Carl Lipo of California State University. They argue that Easter Island was colonised by the first Polynesian seafarers nowhere near as early as supposed. They say the first people to arrive came around AD1200, about 400 years later than other scientists have suggested from radio-carbon dating. This makes it implausible for the population to have reached the 15,000 figure that would have caused such a fast ecocide. They also believe the deforestation occurred over a longer period as a result of climate change, and rats probably also played a part. The islanders did not go through a population collapse until after the arrival of Europeans, they say.
E. Hunt has examined new data from the Hawaiian and other Pacific islands that shows that by early historic times the deforestation of Easter Island was already complete, or nearly so. A dense forest of palm trees and shrubs had mostly disappeared and as a result, as many as six land bird species had also become extinct. Crucially, much of the forest damage appears to have been done before evidence of fires on the island. However, almost all of the palm seed shells discovered on the island were found to have been gnawed by rats which would have made them unable to germinate. Evidence from other Pacific islands also confirms how destructive rats can be. However, John Flenley of New Zealand's Massey University, who carried out much of the radio-carbon work on Easter Island, says there is ample evidence for a much earlier arrival of Polynesian settlers. He refutes the arguments of the sceptics: whilst admitting that the Europeans did bring certain disasters, he maintains that Hunt and Lipo are ignoring archaeological, botanical and sedimentological evidence proving the island was transformed from a subtropical rainforest to a treeless landscape. The radio-carbon dating points to an initial colonisation before AD900, Flenley argues. This was ample time for the rapid deforestation, environmental collapse and a population crash, he insists.
F. Why all this is important today is not, of course, lost in the age of globalisation, climate change and a rapidly growing world population in the billions. As Diamond says: 'The parallels between Easter Island and the whole of the modern world are chillingly obvious.'