LATEST UPDATE: November 26, 2011

• The Rise and Fall of Easter Island

In his book "Collapse", Jared Diamond mentions the rise and fall of the population of Easter Island. This Easter Island case is often used as a fable to reflect what could happen to our world if we continue business as usual and do not consider the limitation of the resources that we currently use. The story is also described in Chapter 1 in the course book. In a sense, Earth - the isolated habitable planet in the solar system - is like Easter Island, the most remote place on Earth. The story is summarized here:
• Easter Island is the most remote island on the planet, with the closest other island, Pitcairn, being > to the west 2000km and Chile > 3700km to the east. With only 165km² (64 mi²), it is relatively small. At a latitude of 27° S, the island is close to the subtropical divergence zone along which many deserts lie. But being an ocean island and Maunga Terevaka having a maximum elevation of 507m (it's a shield volcano), Easter Island receives about 1000mm (44") of rain annually (though this can vary). The island has high temperatures and humidity. In principle, one could expect that Easter Island has some kind of forest and water but it is a desolate place with poorly drained and marginal soils, no permanent stream, no terrestrial mammals. Some permanent water is available in little lakes within the volcano caldera. It turns out that the island has not always looked like this.
• Polynesian seafarers (about 25-50 or so) found a paradise with lush palm forests when they first arrived at the island around A.D. 400. They began to settle the island and use its resources. They brought some food staples, such as bananas and yams which appeared to be the only adequate staples for the relatively harsh conditions on the island. The Polynesians also brought chickens. The population thrived, using the wood of the palm trees to build boats for fishing, to cook, and to transport their Moais, large basalt statues that can still be found along the perimeter of the island.
• Pollen and other soil analysis revealed that a first sign of decline emerged in about 800AD and the last tree was gone by 1400AD, when about 10,000 people inhabited the island. By that time, first signs of a change in diet emerged in the waste disposal piles (e.g. discarded bones). The bones of porpoises were replaced by remains of shellfish, snails and bird eggs. Evidently, the people could not go out to sea far enough to catch the larger fish.
• Soon after, crop failures and soil erosion started to happen. The rats brought to the island by the settlers ate the seeds, and the people started to eat rats and insects, after all the chickens were gone and apparently unable to go out to sea anymore because there was no longer wood to build boats. The population declined dramatically after that.
• When Dutch explorers first visited the island in 1722, they found about 2000 people living in caves (no more wood to build houses) in a primitive society engaged in warfare. The island was completely desolated and people practiced cannibalism.
• It appears that human activities so overwhelmed the environment that it was no longer able to support the greatly enlarged human population.
• This example shows us what could happen if we are not carefully using our resources, some of which we take for granted but may last only a few more decades, after our ancestors have been using them for thousands of years.
• There is still scientific discussion going on about some details how things happened. Some scientists suggest that not the people are responsible for the demise of the palm forest but that the rats ate the seeds so fast that the forest couldn't grow back. Some scientists argue that the settling people didn't come from Polynesia but from Chile. Some scientists argue that climate changes may have caused droughts and triggered the crop failures. And some scientists argue that the timing of events is not exactly right. But the bottom line is ultimately the same, in that the island witnessed the collapse of a once thriving society, mostly due to unwise, or ignorant, management of the environment.
There is some indication, that with most of the most important fisheries depleted nearly beyond recovery we are now going down the food chain and collect smaller species that were once considered unworthy of harvesting....... squid anyone?

• References

• ⁽¹⁾"Collapse" by Jared Diamond, 2005. Penguin Books, ISBN: 0-14303655-6; paperback/ 2004 ISBN:0-67003337-5; hardcover