Planet Rapa Nui

This is the story of a prosperous civilization which consumed without control the resources of their place, to such a point that these resources nearly disappeared, conflicts between people popped up and the civilization lost its greatness. Are we talking about human civilization on Earth today? Near future will tell us how things will evolve, but let’s see here what happened to the inhabitants of Easter Island, the small island in the Pacific, in the middle of last millennium.

Symbolic Moais

Rapa Nui is the name of Easter Island in local Polynesian language. Jacob Roggeveen (1659-1729) reached the island in 1722, the day of Easter - thus the name - and while exploring the island, the Dutch navigator could observe what is today the symbol of the island : the moais. The moais are huge megalithic figures representing the ancestors of the island clans. They were carved from the volcanic rock of the island, and then transported to their final place somewhere on the coast. The erected ones can be up to 10 meters high and weight 86 tons. They all look towards inside the island.

The first residents settled on the island in a period that is not clearly defined, due to few data available ; this period is between 400 AD and 700 AD. The explorers came from west, from the Marquesas islands in nowadays French Polynesia. At that time the island was the home of one of the highest palm trees on Earth and of several bird species. From then, the population adapted to the environment and rose slowly. Between 900 and 1300 the human population of the prosperous society started to increase more rapidly, reaching possibly 15 000 inhabitants. Also during this period more and more moais were erected by the different clans of the island.

Easter Island is a volcanic island. It lies 3 500km west of continental Chile

From around 1300 the Rapa Nui people started to face an issue : the number of trees, which represented a key resource, turned to be insufficient! Three main causes explain this slow disappearance of the trees.

Tree lessons

Firstly, the islanders had developed much technology - not only related to the wood - and trees were used a lot during everyday life by the growing population. They were used to build boats or to transport the moais for instance. Actually the moais turned to be the subject of a competition between the clans. Higher and higher, bigger and bigger. More and more wood was cut to displace the moais. The problem is that the Polynesian cut the trees without control and did not replant. They over-consumed the resource and forgot about the day after. This can be lesson number one : the resources are rarely unlimited, and today human being is over-consuming the natural resources of the planet.

The scientists or the historians are not certain about which technology was used to transport the moais. Nevertheless, whatever the technology, wood and cordage was employed. (Pictures : P. Pavel)

Secondly, a forest can be fragile. As more and more trees were cut, the whole ecosystem became poorer to such a point that the forest collapsed by itself. This is close to the concept of tipping point that we mentioned in a previous article. The Rapa Nui people did not cut the last tree! The forest turned to be more and more fragile, damaging also the soils and the fauna. This can be a lesson number two : nature is fragile, humankind should stop to overuse and must anticipate. Scientists talk about a risk of runaway climate change : the situation could reach a point from where changes will accelerate and will be irreversible.

Thirdly, a proliferation of rats could also explain the loss of the trees. The rats eating the seeds and the roots prevented the proper development of the forest. This can also be a lesson : the invasive species can be a threat for the local environment. The recent abrupt climate changes on Earth promote these invasions. Large flooding, droughts or forest fires allow new species to settle and potentially disturb. For instance global warming could bring malaria back in Europe in the next decades.

The end of an era

During 17th century, the consequences of the loss of the trees became critical on Easter Island. The islanders adapted to it but the trees were vital to the society. Population went down. Famine came, but also cannibalism. Conflicts between the clans appeared and some historians even talk about wars. The clans started to pull down the moais of the adverse clans and there is actually not a single moai that was not brought down. Still today lots of the moais of Easter Island are down. The Rapa Nui people carved around 900 moais but less than 300 were transported to their final place on the coast. Most probably due to the lack of wood.

Some moai have a pukao on their heads. The pukao is a kind of hat and is made
of a specific volcanic rock. On the right, a pukao in front of fallen moais.

“Easter Island is a laboratory where you can observe how men used, destroyed and adapted!” This is one of the first things Sonia Haoa told us. Sonia has been an archeologist working on Easter Island for 35 years and particularly she has an excellent knowledge about the use of the stones by the Rapa Nui people. 

“I do not like to say that what happened was a brutal collapse, because it took time for the forest to disappear. It was more like a slow and tough adaptation to a poorer environment… the end of an era for the Rapa Nui people”, says Sonia. “The islanders were isolated from the rest of the world. This island was their small planet!" Sonia adds : "they have always showed a great capacity of adaptation to the fragile environment of the island. For instance after the loss of the forest, they understood that they had to pay even more attention to their soils, and they turned to be remarkable managers of stone gardens. Stone was available in great quantities on the island, and they successfully used it in order to improve yield.”

 



In the garden of her office Sonia replanted Toromiro which is an endemic species to Easter Island. The plant once disappeared entirely from the island but was kept in a botanical garden in Sweden.
We met Sonia on February the 15^th.

The other Earth… that we do not have

“Today men lost the contact with the nature and the resources. So many people do not know where the food or the goods they buy come from. People lost their ability to observe”, Sonia adds.

  

Nowadays human society consumes lots of natural resources without control and without anticipation. The experience of Rapa Nui can be related to the current excessive deforestations that occur all around the world, releasing huge quantities of carbon dioxide and impacting the water availability for instance. We can also mention the example of bluefin tuna overfishing in the Mediterranean Sea. So many bluefin tuna is caught that it could disappear from this sea in the next years. 

Sonia comments : “how is it that humankind does not react though we are aware of the ongoing change and the resulting risks? Today information is available, technology is also available!” According to the World Wildlife Fund (WWF), if human beings do not change their relation to the natural resources, humanity will need a second planet Earth by 2030. Another planet that we do not have.

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Torres del Paine, the role of the forests

“Plant a tree, plant a tree” they say!... What about also protecting old trees?

The Chilean National Park Torres del Paine is an outstanding piece of nature, composed of mountains, glaciers, lakes, rivers and native forests. It is one of the most visited places in Chile.

A large fire started in the middle of Torres del Paine Park last December the 27^th, causing major environmental damages. The park partially re-opened on the 4^th of January and we were there two days later. At the gate of the park, a forest ranger told us : “This fire is a catastrophe. Most of the rangers working here are local people, the situation has severely affected the surrounding community.”

More than 170 km² were burnt down ; 36% of burnt area was native forest. The fire represents one of the biggest destructions of forest of these last decades in Chile. Even at the beginning of February, the fire was not yet completely under control. 

Forests dry up

Climate change increases vegetation fire risk since extended periods without rain brings droughts, such as El Niño in the Pacific Ocean. Additionally this fire risk rises due to land-use change, like deforestation. A declining trend in precipitation has been observed in southern Chile in the past decades. This, combined with the exceptional hot summer 2011-2012, created the conditions for a large and persistent fire in Torres del Paine. 

Forest fires occur from human or natural causes. Human causes include accidental fires or intentional fires such as : farmers establishing new plantations, small and controlled fires by forest keepers to prevent larger fires or even criminal fires. Torres del Paine fire started as an accident caused by a visitor of the park.

“There is no smoke without fire” 

Forest fires release big quantities of carbon dioxide which is one of the greenhouse gases that contribute to climate change. Carbon is stored in the trees as they grow. Many decades are necessary to store large quantities of carbon in forests ; however in just a few days of fire it can all be released. One hectare of tropical forest that is burnt down approximately releases 500 tons of carbon dioxide. 

Preserving the forest allows to retain great quantities of carbon dioxide : planting new trees is good, protecting old ones is even better!

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Some figures about Forests and Climate Change 

Every year 130 000 km² of forest disappear. This is equivalent to the surface of Greece.

Forests on Earth contain as much carbon as the entire atmosphere.

There is more carbon in forests and soils than in all the oil reservoirs of the planet.

In the Amazon, the estimated human health cost of fires increased from 3.4 million US Dollars in 1996 to 10.7 million US Dollars in 1999 (Cardoso de Mendonça et al., 2004).

National Park Torres del Paine.

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