Out of House and Home
by Peter Tyson
Can what happened on one small island in the South Pacific serve as a cautionary tale for the entire planet?
To see just how clearly a growing human population relies on and impacts its natural environment, one need look no farther than Easter Island, the South Pacific isle with the famous stone statues known as moai. I have been doing a lot of reading about the fate of Easter in preparation for an upcoming trip, and, as the geographer John Flenley and archeologist Paul Bahn write in The Enigmas of Easter Island, "it is a story with an urgent and sobering message for our own times."
Easter Island is the most isolated piece of inhabited land in the world. A speck of volcanic rock only about twice the size of Manhattan, it lies roughly 2,250 miles northwest of Chile and 1,300 miles east of Pitcairn Island (of Mutiny on the Bounty fame). When, as most scholars believe, the first Polynesian settlers arrived from the west about the middle of the first millennium A.D., they found a pristine tropical island. Covered in a palm forest, it resounded with the cries of 25 or more species of nesting seabirds and at least six land birds. Though its soils were low in nutrients, the island bore a wide coastal plain well suited for cultivation of the taro, yam, sweet potato, and other crops these pioneers brought with them and which became their staples.
The population grew slowly at first, then more quickly, reaching a peak around the middle of the second millennium A.D. of anywhere from 10,000 to 20,000 people. By this time, the Rapanui, as the islanders are known, had developed a complex society of chiefdoms and elaborate stone architecture epitomized by the moai. Beginning around 1600, however, Rapanui civilization began to fall apart, and by the mid-19th century, it had all but disappeared.
After decades of painstaking work, a host of archeologists, ethnographers, and other specialists have painted a comprehensive picture of what transpired on Easter Island. And the parallels between what happened there and what is occurring today in the world at large—albeit more slowly and on a much vaster scale—are, as the evolutionary biologist Jared Diamond has put it, "chillingly obvious."
Trees of life
One could argue that Rapanui culture and society rose and fell with the fortunes of the island's trees. Studies of pollen and charcoal from extinct plants have shown that, before people first arrived and well into the early centuries after settlement, a subtropical forest blanketed the island. Among its species was the world's largest palm tree. It outsized even the giant Chilean wine palm, today's biggest, which grows to 65 feet tall and a yard in diameter.
On Easter Island, the Polynesian word rakau ("tree," "wood," "timber") meant "riches" or "wealth." This is not surprising, for the Rapanui used trees and their products for almost everything. They ate the fruits of the trees as well as the birds that lived among them. They thatched their houses, which looked like upended boats, with palm fronds. They fashioned bark-cloth clothing. They burned firewood for cooking and for keeping warm on winter nights, which on Easter Island can drop as low as 50°F. They built oceangoing canoes and crafted harpoons to spear dolphins and pelagic fish such as tuna. And they used some combination of log rollers, sleds, and/or levers, along with rope made from tree fibers, to transport and erect the hundreds of moai that once stood around the edges of the island, their brooding faces gazing inland.
Archeologists have deduced that clearing of trees for crops and other uses began soon after the first Rapanui arrived and was largely over by 1600. In a recent article for The New York Review of Books, Diamond called it "the most extreme example of forest destruction in the Pacific, and among the most extreme in the world: the whole forest gone, and all of its tree species extinct." (A single endemic tree, the toromiro, survived in botanical gardens in Sweden, after some seeds germinated that the ethnologist Thor Heyerdahl had collected from the last surviving specimen, and someday the tree may again grace Easter's grassy slopes.)
The end of the forest had devastating consequences, both directly through the loss of the trees' raw materials and indirectly through what those products allowed the Rapanui to do. Archeologists have found, for example, that by 1500, porpoise bones all but vanish from the island's refuse heaps. Common dolphins weigh up to 165 pounds and live far offshore, yet the Rapanui had clearly found a way to fish for them: in garbage remains at an early site on the north coast, porpoise bones constitute more than one third of all bones. Experts infer that the Rapanui must have built sturdy, oceangoing canoes out of the now-extinct trees. Without the trees, that rich food source fell frustratingly out of reach.
By 1872, the number of Rapanui had plummeted to just 111 individuals.
The expanding population put other food sources under extraordinary pressure. Garbage heaps show that seabirds and shellfish declined over time, and the six species of land birds, including two rails, two parrots, a heron, and a barn owl, went extinct. Their end came probably through a combination of hunting, loss of their forest habitat, and the stealing of their eggs by the Polynesian rat, the only animal to survive in abundance in the wild. (The rat forestalled any comeback by the vanishing trees: every fossil palm nut that experts have turned up on the island had been nibbled by rats in such a way as to preclude germination.)
Even as the forests dwindled, Rapanui chiefs intensified food production, eager to create surpluses to support the carving of ever-larger statues. But that practice stressed an already fragile agricultural system built on marginal soils and insufficient water. "The removal of the forest may have reduced localized rainfall and lowered the productivity that was needed for corporate work efforts and by a large and growing population," says Christopher Stevenson, an archeologist with the Virginia Department of Historic Resources who has done years of work on Easter Island. "They reached a threshold where their economy took a really severe hit."
To us today, the most obvious manifestation of that hit is the crash of the moai culture. Oral tradition holds that the last moai was erected in 1620. With the religious basis of their power severely weakened or gone, the chiefs and priests who had held sway on the island for centuries were overthrown by military leaders around 1680. The society collapsed into civil war, and rival factions began toppling moai; the last erect statue recorded by European visitors was seen in 1838. (All standing statues today were re-erected in modern times.)
In the decades before the Dutch explorer Jacob Roggeveen "discovered" the island on Easter Day, 1722—hence the island's name—the Rapanui began to go hungry. Out of desperation, they may even have turned to cannibalism. Though Stevenson says the population had begun to rebound by the time Roggeveen's sails appeared on the horizon, contact with outsiders over the next century and a half spelled doom for the Rapanui through introduced diseases, slave raids, and other impacts. By 1872, the number of Rapanui had plummeted to just 111 individuals.*
Metaphor for disaster
Can Easter Island be seen as a microcosm of our planet today? Should we regard its shocking collapse as a cautionary tale of the utmost gravity? In the world at large, we are deforesting our land, overfishing our oceans, causing the extinction of large numbers of species. We are watching our topsoil disappear by the millions of tons each year. We are starting to fight over ever-scarcer freshwater. We are overconsuming our resources as if there were no tomorrow, or future generations. One would have to be in denial not to see those "chillingly obvious" parallels to Easter Island.
"The message is clear," says José Miguel Ramírez, a Chilean archeologist who served as superintendent of Rapa Nui National Park from 1993 to 1999. "In the past, some people on Easter Island, namely the ruling class, were able to destroy other people and their homes, but now some societies can destroy everything, and for the same reason: power and greed. The only difference is the scale—from a little island to the whole planet."
Some scholars take issue with the notion of seeing Easter's fate as a metaphor for disaster. Jo Anne Van Tilburg, one of the leading archeologists of Easter Island, considers it "a projection of Western values which emphasizes the self-destruction of the Rapanui culture over the actual, near-annihilation of it by contact with the West." Yet such cross-cultural contact, one might argue, is precisely the reason why we should be concerned. Again, Jared Diamond:
Thanks to globalization, international trade, jet planes, and the Internet, all countries on Earth today share resources and affect each other, just as did Easter's eleven clans. Polynesian Easter Island was as isolated in the Pacific Ocean as the Earth is today in space. When the Easter Islanders got into difficulties, there was nowhere to which they could flee, or to which they could turn for help; nor shall we modern Earthlings have recourse elsewhere if our troubles increase. Those are the reasons why people see the collapse of Easter Island society as a metaphor, a worst-case scenario, for what may lie ahead of us in our own future.
Tragic tale of Easter Island gets new twist
By Ker Than
Updated: 5:44 p.m. ET March 9, 2006
The first settlers on Easter Island didn't arrive until the year 1200, up to 800 years later than previously thought, a new study suggests.
The revised estimate is based on new radiocarbon dating of soil samples collected from one of oldest-known sites on the island, which is in the South Pacific west of Chile.
The finding challenges the widely held notion that Easter Island's civilization experienced a sudden collapse after centuries of slow growth. If correct, the finding would mean that the island's irreversible deforestation and construction of its famous Moai statues began almost immediately after Polynesian settlers first set foot on the island.
The study, conducted by Terry Hunt of the University of Hawaii, Manoa and Carl Lipo of California State University, Long Beach, is detailed Thursday in the online version of the journal Science.
The conventional story
According to one widely held view, a small band of Polynesian settlers, perhaps no more than a few dozen people, arrived on the Easter Island sometime between A.D. 400 and 1000.
The settlers lived in harmony with the environment for hundreds of years, and the population slowly grew. Some scientists estimate that at its height, Easter Island's population may have been as much as 20,000 people.
Around 1200, the story goes, the inhabitants began cutting down the island's subtropical trees and giant palms in large numbers to build canoes and to transport the giant stone statues, which started going up around this time.
The large-scale deforestation led to soil erosion, and over a span of several centuries, the island's ability to support wildlife and farming was compromised. People began to starve. In a last-ditch effort at survival, they became cannibals.
The collapse of both the island's ecology and civilization was so complete that by the time the Dutch arrived in the 1700s, Easter Island was a sandy grassland void of nearly all its native wildlife; its human inhabitants were reduced to a starving population of 3,000 or less.
This is the story pieced together by researchers over the past several decades, but Hunt and Lipo think it is wrong.
No Garden of Eden
Crucial to the conventional account of events on Easter Island is the time when settlers first arrived. If colonization didn't begin until 1200, then the island's population wouldn't have had time to swell to tens of thousands of people.
"You don't have this Garden of Eden period for 400 to 800 years," Hunt said in an accompanying Science article. "Instead, [humans] have an immediate impact."
Also, the few thousand people Europeans encountered when they first arrived on Easter Island might not have been the remnants of a once-great and populous civilization as widely believed. The researchers think a few thousand people might have been all the island was ever able to support.
"There may not have actually been any collapse," Lipo told LiveScience. "With only 500 years, there's no reason to believe there had to have been a huge [population] growth."
Europeans and rats to blame
The researchers also dispute the claim that Easter Island's human inhabitants were responsible for their own demise. Instead, they think the culprits may have been Europeans, who brought disease and took islanders away as slaves; and rats, which quickly multiplied after arriving with the first Polynesian settlers.
"The collapse was really a function of European disease being introduced," Lipo said. "The story that's been told about these populations going crazy and creating their own demise may just be simply an artifact of [Christian] missionaries telling stories."
At a scientific meeting last year, Hunt presented evidence that the island's rat population spiked to 20 million from the years 1200 to 1300. Rats had no predators on the island other than humans, and they would have made quick work of the island's palm seeds. After the trees were gone, the island's rat population dropped off to a mere 1 million.
Lipo thinks the story of Easter Island's civilization being responsible for its own demise might better reflect the psychological baggage of our own society than the archeological evidence.
"It fits our 20th-century view of us as ecological monsters," Lipo said. "There's no doubt that we do terrible things ecologically, but we're passing that on to the past, which may not have actually been the case. To stick our plight onto them is unfair."