Apr 24, 2018 • Easter Island

Rapa Nui

The indigenous name for Easter Island is Rapa Nui. The people of Rapa Nui are called Rapa Nui, and they speak Rapa Nui. Incidentally, their favorite music is Rap a’Nui and their favorite stewed vegetable dish is Rapa-touille. All puns aside, the story of Rapa Nui is a story about the triumph of civilization, of climate change, ecological devastation, and social collapse. It’s a story that bears repeating, in part because so much of what I thought I knew about it was wrong.

Polynesians arrived to the island around 900 AD, and for a time it was good. The land was fertile and fish abundant. They had large forests of giant palm trees with which to make canoes and catamarans. The volcano at the north end of the island was quarried to obtain basalt, an extremely hard rock useful for making fish hooks, farming implements, axes, and chisels. Basalt mines were rare in Polonesia, so the Rapa Nui maintained a trading network spanning thousands of miles of open ocean to exchange basalt with other Polynesian colonies on Pitcairn and Mangareva. Based on the presence of sweet potatoes on the island, it’s possible that the Rapa Nui even made it to South America.

The population grew. They developed a complex hierarchical society and a written language – the only written language in all of Polynesia. They also invented a curious form of megalithic ancestor worship for which they are now best known. The “moai”, as the statues are called, were carved out of tuff using basalt tools. Tuff is essentially compressed ash, and it was mined from the same volcanic quarry. Construction of a single moai took around six months. First, the front face of the statue was carved out of the cliff. Next, the back was excavated, freeing the statue from the mountain. After dragging it down the slope to the base of the volcano, the incomplete moai was stood erect so that the back could be carved. Finally, and most crucially, the moai was walked across the island to its final resting place, typically on a platform along the coast.

Perhaps you think that was a typo. It was not. Modern research has shown that these giant monoliths, some of which weigh over 80 tons, were “walked” across the length of the isand in the same way one might walk a refrigerator across the kitchen. First, the feet of the moai were carved into a large semicircle and angled forward in such a way as to push the center of gravity towards the front. Small groups of men working in perfect unison were then able to rock the moai back and forth using ropes tied around the head and neck of the statue. By adding a slight twist at the apogee, the moai could be advanced across the island at a rate of 200 meters a day. If you don’t believe me, watch this video produced by National Geographic.

Despite the industriousness and creativity of the Rapa Nui, they had two big problems. The first was the Polynesian rat, which they had introduced as soon as they landed. The rats found the nuts of the giant palm trees delicious. The nuts of the giant palm didn’t have a hard protective coating because they had evolved without predators. Combined with logging, the forests started to shrink. The decrease in tree cover, combined with intensive cultivation and strong winds off the Pacific, led to the removal of top soil which decreased farming productivity.

The second problem was the arrival of Europeans to the Americas 3000 miles away. European diseases swept through the native populations of North and South America, killing 90% of the 65 million inhabitants. Lands that had previously been under cultivation reverted to forest as whole tribes disappeared. The sudden increase in forested land led to a sharp drop in CO2 levels, which had the effect of cooling the climate of the entire earth. This led to a period known as the “little ice age”, and it disrupted communities worldwide.

On Rapa Nui, it was the straw that broke the camel’s back. As temperatures dropped, the remaining forests were felled for firewood to keep warm. Without wood to build and repair their boats, they lost access to their fishing grounds, as indicated by the sudden disappearance of tuna bones in the archaeological record. Topsoil erosion continued until the island was mostly barren. The population, which at its height had numbered over 15,000, dropped tenfold to 1,500. The proud Polynesian civilization of Rapa Nui had collapsed.