Extinction

Adapted from Jared Diamond, “Easter’s End,” Discover, August 1995, 16(8), pp. 63-69.

Among the most riveting mysteries of human history are those posed by vanished civilizations.… Among all such vanished civilizations, that of the former Polynesian society on Easter Island remains unsurpassed in mystery and isolation. The mystery stems especially from the island’s gigantic stone statues and its impoverished landscape, but it is enhanced by our associations with the specific people involved: Polynesians represent for us the ultimate in exotic romance, the background for many a child’s, and an adult’s, vision of paradise.…

Easter Island, with an area of only 64 square miles, is the world’s most isolated scrap of habitable land. It lies in the Pacific Ocean more than 2,000 miles west of the nearest continent (South America), 1,400 miles from even the nearest habitable island (Pitcairn). Its subtropical location and latitude — at 27 degrees south, it is approximately as far below the equator as Houston is north of it — help give it a rather mild climate, while its volcanic origins make its soil fertile. In theory, this combination of blessings should have made Easter a miniature paradise, remote from problems that beset the rest of the world.

The island derives its name from its “discovery” by the Dutch explorer Jacob Roggeveen, on Easter (April 5) in 1722. Roggeveen’s first impression was not of a paradise but of a wasteland.… The island Roggeveen saw was a grassland without a single tree or bush over ten feet high.… Their native animals included nothing larger than insects, not even a single species of native bat, land bird, land snail, or lizard. For domestic animals, they had only chickens.

European visitors throughout the eighteenth and early nineteenth centuries estimated Easter’s human population at about 2,000, a modest number considering the island’s fertility. As Captain James Cook recognized during his brief visit in 1774, the islanders were Polynesians (a Tahitian man accompanying Cook was able to converse with them). Yet despite the Polynesians’ well deserved fame as a great seafaring people, the Easter Islanders who came out to Roggeveen’s and Cook’s ships did so by swimming or paddling canoes that Roggeveen described as “bad and frail.”…

With such flimsy craft, Polynesians could never have…traveled far offshore to fish. The islanders Roggeveen met were totally isolated, unaware that other people existed.… Not a single Easter Island rock or product has turned up elsewhere, nor has anything been found on the island that could have been brought by anyone other than the original settlers or the Europeans. Yet the people living on Easter claimed memories of visiting the uninhabited Sala y Gomez reef 260 miles away, far beyond the range of the leaky canoes seen by Roggeveen.…

Easter Island’s most famous feature is its huge stone statues, more than 200 of which once stood on massive stone platforms lining the coast.ⁱ At least 700 more, in all stages of completion, were abandoned in quarries or on ancient roads between the quarries and the coast.… Most of the erected statues were carved in a single quarry and then somehow transported as far as six miles — despite heights as great as 33 feet and weights up to 82 tons. The abandoned statues, meanwhile, were as much as 65 feet tall and weighed up to 270 tons. The stone platforms were equally gigantic: up to 500 feet long and 10 feet high, with facing slabs weighing up to 10 tons.…

The islander had no wheels, no draft animals, and no source of power except their own muscles.… To deepen the mystery, the statues were still standing in 1770, but by 1864 all of them had been pulled down, by the islanders themselves.… The statues imply a society very different from the one Roggeveen saw in 1722. Their sheer number and size suggest a population much larger than 2,000.…

Easter Island 1860 lithograph

Easter Island’s mysteries have spawned volumes of speculation for more than two and a half centuries. In the 1950s, [Thor] Heyerdahl argued that Polynesia must have been settled by advanced societies of American Indians, who in turn must have received civilization across the Atlantic from…societies of the Old World. Heyerdahl’s raft voyages aimed to prove the feasibility of such prehistoric transoceanic contacts. In the 1960s the Swiss writer Erich von Däniken, an ardent believer in Earth visits by extraterrestrial astronauts, went further, claiming that Easter’s statues were the work of intelligent beings who owned ultramodern tools, became stranded on Easter, and were finally rescued.

Heyerdahl and Von Däniken both brushed aside overwhelming evidence that the Easter Islanders were typical Polynesians derived from Asia rather than from the Americas and that their culture (including their statues) grew out of Polynesian culture.… They [also] spoke an eastern Polynesian dialect related to Hawaiian and Marquesan, a dialect isolated since about A.D. 400, as estimated from slight differences in vocabulary.… [In 1994,] DNA extracted from 12 Easter Island skeletons was also shown to be Polynesian.…

Evidence lets us imagine the island onto which Easter’s first Polynesian colonists stepped ashore some 1,600 years ago, after a long canoe voyage from eastern Polynesia. They found themselves in a pristine paradise.… Pollen records show that destruction was well under way by the year 800, just a few centuries after the start of human settlement.… Not long after 1400 the palm finally became extinct, not only as a result of being chopped down but also because the now ubiquitous rats prevented its regeneration.… While the huahua tree did not become extinct in Polynesian times, its numbers declined drastically until there weren’t enough left to make ropes from. By the time Heyerdahl visited Easter, only a single, nearly dead toromiro tree remained on the island, and even that lone survivor has now disappeared.…

The fifteenth century marked the end not only for Easter’s palm but for the forest itself. Its doom had been approaching as people cleared land to plant gardens; as they felled trees to build canoes, to transport and erect statues, and to burn; as rats devoured seeds; and probably as the native birds died out that had pollinated the trees’ flowers and dispersed their fruit.… The destruction of the island’s animals was as extreme as that of the forest.…

In place of these meat supplies, the Easter Islanders intensified their production of chickens, which had been only an occasional food item. They also turned to the largest remaining meat source available: humans, whose bones became common in late Easter Island garbage heaps. Oral traditions of the islanders are rife with cannibalism;ⁱⁱ the most inflammatory taunt that could be snarled at an enemy was “The flesh of your mother sticks between my teeth.”…

The first Polynesian colonists found themselves on an island with fertile soil, abundant food, bountiful building materials, ample lebensraum, and all the prerequisites for comfortable living. They prospered and multiplied.

After a few centuries, they began erecting stone statues on platforms, like the ones their Polynesian forebears had carved. With passing years, the statues and platforms became larger and larger, and the statues began sporting ten ton red crowns — probably in an escalating spiral of one upmanship, as rival clans tried to surpass each other with shows of wealth and power. (In the same way, successive Egyptian pharaohs built ever larger pyramids. Today Hollywood movie moguls…in Los Angeles are displaying their wealth and power by building ever more ostentatious mansions.… All that those buildings lack to make the message explicit are ten ton red crowns.) On Easter, as in modern America, society was held together by a complex political system to redistribute locally available resources and to integrate the economies of different areas.

Eventually Easter’s growing population was cutting the forest more rapidly than the forest was regenerating.… As forest disappeared, the islanders ran out of timber and rope to transport and erect their statues. Life became more uncomfortable — springs and streams dried up, and wood was no longer available for fires.

People also found it harder to fill their stomachs.… Crop yields also declined, since deforestation allowed the soil to be eroded by rain and wind, dried by the sun, and its nutrients to be leeched from it. Intensified chicken production and cannibalism replaced only part of all those lost foods. Preserved statuettes with sunken cheeks and visible ribs suggest that people were starving.

With the disappearance of food surpluses, Easter Island could no longer feed the chiefs, bureaucrats, and priests who had kept a complex society running. Surviving islanders described to early European visitors how local chaos replaced centralized government and a warrior class took over from the hereditary chiefs.… By around 1700, the population began to crash toward between one quarter and one tenth of its former number. People took to living in caves for protection against their enemies. Around 1770 rival clans started to topple each other’s statues, breaking the heads off. By 1864 the last statue had been thrown down and desecrated.

As we try to imagine the decline of Easter’s civilization, we ask ourselves, “Why didn’t they look around, realize what they were doing, and stop before it was too late? What were they thinking when they cut down the last palm tree?”… Any islander who tried to warn about the dangers of progressive deforestation would have been overridden by vested interests of carvers, bureaucrats, and chiefs, whose jobs depended on continued deforestation. Our Pacific Northwest loggers are only the latest in a long line of loggers to cry, “Jobs over trees!”… Their children could no more have comprehended their parents’ tales than…eight year old[s]…today can comprehend…tales of what Los Angeles was like 30 years ago.

Gradually trees became fewer, smaller, and less important.… No one would have noticed the felling of the last small palm.…

By now the meaning of Easter Island for us should be tellingly obvious. Easter Island is Earth writ small. Today, again, a rising population confronts shrinking resources. We too have no emigration valve, because all human societies are linked by international transport, and we can no more escape into space than the Easter Islanders could flee into the ocean. If we continue to follow our present course, we shall have exhausted the world’s major fisheries,ⁱⁱⁱ tropical rain forests,^iv fossil fuels,^v and much of our soil ^vi by the time…every day newspapers report [the] details.^vii, viii…

Corrective action is blocked by vested interests, by well intentioned political and business leaders, and by their electorates, all of whom are perfectly correct in not noticing big changes from year to year. Instead, each year there are just somewhat more people, and somewhat fewer resources, on Earth.

ⁱ Just how these monuments, or moai, were carved, transported, and erected (pic) has been the subject of an intense and long-standing scholarly debate.
— Jo Anne Van Tilburg and Ted Ralston, “Engineers of Easter Island,” Archaeology, 6 Nov/Dec 1999.

ⁱⁱ Every Easter Islander knows that his ancestors were kai-tangata, ‘man-eaters.’ Some make jokes about it; others take offence at any allusion to this custom, which has become in their eyes barbarous and shameful. According to Father Roussel, cannibalism did not disappear from Easter Island until after the introduction of Christianity. Shortly before this, the natives are said to have eaten a number of men, including two Peruvian traders. Cannibal feasts were held in secluded spots, and women and children were rarely admitted. The natives told Father Zumbohm that the fingers and toes were the choicest morsels.
— heretical.com, “Cannibalism in Polynesia: The Demise of Captain Cook,” at http://www.heretical.com/cannibal/polynesi.html.

ⁱⁱⁱ More than 70 per cent of the world’s commercially important fish stocks are either over-exploited, depleted, slowly recovering or close to the maximum sustainable level of exploitation, according to the United Nations. UN statistics show that consumption of fish worldwide has increased by 240 per cent since 1960.
— “Depleted fisheries sound alarm for Earth Summit,” The New Zealand Herald, 23 Oct 2002, IUCN: The World Conservation Union, at www.iucn.org/news/wssd/nzh26aug.pdf.

^iv “Today only two percent of the original ancient forests are left.”
— ¡TchKunG!, “Clearcut,” Post World Handbook.

^5v The amount of the world’s remaining oil reserves is equal to 1/8 of the volume of Mt. Fuji.^*
— Gaia Press, “Ecological Unit,” 1998, at http://global.horiba.com/gaiapress_e/eu/eu10/eu10_1.htm.

^* The volume of Mount Fuji is approximately…12 x 10¹² ft³
— Ole Eichhorn, “Critical Section - Really Moving Mount Fuj[i],” 17 Sep 2003, at http://w-uh.com/articles/030917b-really_moving_Mou.html.

^vi It has been estimated that 20 [percent] of the world’s cultivated topsoil was lost between 1950 and 1990.
— “soil erosion,” Hutchinson’s Encyclopaedia, at http://www.tiscali.co.uk/reference/encyclopaedia/hutchinson/m0024281.html.

	NASA handout photo showing the thickness of the ozone layer over the Earth’s South polar region. The US government is coming under increasing pressure from its own companies to sign up to the Kyoto protocol on climate change, EU Environment Commissioner Margot Wallstroem said. (AFP/NASA)

^vii In 2000, NASA said the ozone hole expanded to a record 10.9 million sq miles. This is three times the size of Australia or the United States, excluding Alaska.
— “Ozone hole keeps growing,” Sky News, 22 Aug 2003.

^viii The world’s biggest producer of greenhouse gases,^* the United States, has pulled out of the Kyoto agreement on reducing carbon dioxide emissions.^†
— “Depleted fisheries.”

^* The phrase “greenhouse gases” is a misnomer, said [Mr. Henry Hengeveld of Environment Canada], because they function less like greenhouse glass than an insulated blanket. The blanket absorbs heat radiation that would otherwise escape into space, and recycles it back into earth’s system.…

Scientists have observed and modeled global temperature change in line with what’s happened in the past and found the models to be reasonably reliable for making predictions.… Continents will warm more than oceans and high latitudes will warm more than low latitudes. By about 2050, the North Pacific is projected to warm by 1-2°C, while parts of the North Atlantic are expected to cool because of changes in ocean circulation. Changes in precipitation levels and distribution will be significant, with precipitation projected to increase in the tropical and sub-tropical Atlantic and in the Arctic, and to decrease over the American Southwest and other regions.

All of this will change ocean dynamics and salinity. As the climate warms, we’ll see a more El Niño pattern around the world. By 2090, the Arctic could warm by as much as 20°C, resulting in removal of most of the sea ice. The tropical Pacific is projected to warm by 4-5°C, and there will be further warming in the North Pacific as well, while the North Atlantic will either not warm or could remain still cooler than today.

Much of the increase in rainfall will take place over the oceans, with little change or less rainfall over many mid- to low-latitude areas of the continents. This will affect fresh water flux into the oceans. The key thing affecting the ocean system is thermohaline circulation. This affects both salinity and temperature, creating different densities in ocean water and driving water movement. In the North Atlantic, strong sinking areas push deep water south and allow warm surface currents to move from tropical regions to the north, creating the gulf stream effect that warms Northern Europe. Increased high-latitude fresh water flux and changed temperatures will slow down that process and temperatures in Northern Europe would warm much less than other continental areas. Although the results of six models vary widely in specifics, they all show slowdowns in the current system resulting from global warming.

Warming will also affect surface winds and currents, which will in turn affect pressure systems. But there’s a lot of uncertainty as to how this will impact regional systems. Regarding El Niño, although most models have insufficient resolution to properly simulate its behaviour, a German model with an embedded high resolution tropical ocean submodel has suggested that mean temperature changes will increase the variability of El Niño and La Niña intensities, with a bias toward a greater increase in the latter.
— “Henry Hengeveld, Environment Canada: Climate Change and the Ocean Environment — Understanding the Science,” Pacific Fisheries Resource Conservation Council, 2002.

^† The Kyoto Protocol was reached at a United Nations conference in Kyoto, Japan, in 1997. It was intended to reduce the amount of greenhouse gases emitted by developed countries by 5.2 percent of their 1990’s levels, during a five-year period from 2008 to 2012. A total of 122 nations have ratified or acceded to the pact, according to the United Nations.
— Erin E. Arvedlund, “Russia, on Path to W.T.O., Signs Trade Deal With Europe,” The New York Times, 21 May 2004.