… And they were expert stone carvers Stone mound for statues
Building their statues was a monumental feat: The statues were sculpted directly from quarries in the sides of mountains And were lugged as much as 14 kilometres to their places of honour along the shore. Collapse: How Societies Choose to Fail or Succeed, Jared Diamond
The first ones measured 8 to 12 feet high… Competition built up between rival clans The size of the statues increased in a spiral of one- upmanship. The last ones built were over 30 high. The biggest of all measured 70 feet and weighed 240 tons! Partially completed statue abandoned in quarry Kon-Tiki: Across the Pacific by Raft by Thor Heyerdahl
But without levitation machines how could they have transported them?
That question baffled researchers for a long time But the consensus is that the Rapa Nui people built long slides out of timber leading to the ceremonial sites. The statues would then have been placed on rollers made from tree trunks and guided into place. Thor Heyerdahls team re-enacts erection of moai Kon-Tiki: Across the Pacific by Raft by Thor Heyerdahl
This statue moving activity would have made a significant contribution to deforestation.
The Rapa Nui population grew …Reached a peak of 10,000 to 20,000 And by the year 1500…
Shortly after, statue building came to an end… …there were 887 statues in different stages of completion. Hundreds of uncompleted statues were simply abandoned in the quarries and their stone chisels were dropped on the ground.
All statue carving had stopped. someone had cut down the last standing tree. Only shrubs and grasses were left.
The population crash: After the rich ground cover had washed away the springs dried up There was a drastic drop in food production The vast flocks of birds coming to roost on the island had disappeared
With no more wood… They could no longer build replacement boats. Porpoise hunting, their main source of meat, came to an end. They couldnt rebuild deteriorating homes - the Rap Nui resorted to living in reed huts and in caves. They lost their main source of heating and cooking fuel.
Starvation was rampant Fighting broke out over the diminishing food supply Desperate, they even resorted to cannibalism Winter temperatures were as low as 5°C. Without firewood, children and the aged suffered. Social order was in shambles. Vandals toppled rival clans statues There was a massive die-off
Then came the Europeans: It was on Easter Sunday of 1722 Dutch Admiral Jacob Roggeveen arrived He found 3000 people living in destitute conditions
Then 52 years later, Captain Cook visited the island By then the population had dropped to about 2000. The only animals to be seen were chickens. The warring clans were in constant battle.
Over the next century: Mostly due to contact with Europeans, the population plunged to a low of 111
Wow! How could that happen when the island had so much to offer its people at the start?
Its simply that the Rapa Nui population exceeded the islands CARRYING CAPACITY CARRYING CAPACITY is how many organisms a territory can support indefinitely without degradation of the life support systems of that territory.
CARRYING CAPACITY OF THE EARTH When it comes to humans, carrying capacity can be reduced by the type of food they chose. For example, a meat diet requires much more land and energy input than a grain diet. It takes about 7 kg of grain to produce one kg of steak So if a population decides it wants a meat diet, the carrying capacity would be less than if it were satisfied with a boring granola diet.
Lifestyle has an influence on CARRYING CAPACITY PER CAPITA Square feet of living space Cars, motorhomes, boats Miles driven Airplane, cruiseship and ecotour trips Tools, electronics, cookware etc., etc. Depletion of natural resources Destruction of biodiversity Future cropland compromised Earlier Peak Oil All of of these… …influence these All of these effects reduce carrying capacity
So lets re-define CARRYING CAPACITY a bit: CARRYING CAPACITY of the Earth is how many humans it can support indefinitely at a certain lifestyle and a certain level of technology without degradation of the life support systems. The same planet can support more people with a modest lifestyle and low technology than people with an extravagant lifestyle and high technology. i.e.:
A population can exceed the carrying capacity of its environment – what we call overshoot. Overshoot becomes possible when a species encounters a rich and previously unexploited stock of resources that promote its reproduction.
Invariably, after a population overshoots, a massive die-off of the species follows.
St. Matthew Island During WW2 the US Coast Guard released 29 reindeer on this remote island as a back-up food source for their men. Lichen mats 4 inches deep which had taken centuries to grow covered the island. Since there were no predators, the food supply allowed the reindeer population to reach 6000 by 1963. www.dieoff.org
Within three years of the reindeer having reached peak population, their numbers were slashed to 42 miserable, emaciated specimens. The graph at the right shows how rapidly and sharply a population can crash when it overshoots. Lichen is slow growing, so the carrying capacity was much less than 6000 reindeer.
i Like the St. Matthew Island reindeer, industrial age humans have encountered a rich and previously unexploited stock of resources that promoted their reproduction – PETROLEUM!
Canada is huge, so I guess that it must enjoy a very large carrying capacity, right?
Distinction between area and carrying capacity: Yes and no. If we stood everybody up shoulder to shoulder, we could pack the population of the whole world on Prince Edward Island. But we humans need more than space for our two feet:
Distinction between area and carrying capacity: We need room for our cities and farms.
Distinction between area and carrying capacity: We depend on vast areas of land to support the complex biological systems we need for our sustenance.
Distinction between area and carrying capacity: Biodiversity requires large, uninterrupted expanses of land. Biodiversity enables us to discover and develop new medicines and edible plants.
Distinction between area and carrying capacity: We need space to extract the resources to build schools, universities, theatres, cinemas, auditoriums, arenas, conference centres, machinery, instruments, vehicles.
Distinction between area and carrying capacity: We need rivers for canoeing and fishing, forests for hiking and hunting, beaches for lounging and swimming, fields and mountains for communion with Nature.
Distinction between area and carrying capacity: And a technological society needs vast areas of bog, swamps and mangrove to absorb and neutralize its chemical effluent BogSwampMangrove
Distinction between area and carrying capacity: We need large expanses of natural forests: …to maintain underground water tables through slowly percolating rainwater …to prevent soil erosion and mudslides by holding soil together …to purify the air and absorb air pollution
Distinction between area and carrying capacity: And remember, that only a small portion of Canadas surface is suitable for crops and much of that is covered by roads and buildings. www.hort.purdue.edu/.../v4-015a.html In a cold climate we use more resources. The more resources a population uses, the lower the carrying capacity. Green areas represent cropland Canadian winters impose many needs.
Distinction between area and carrying capacity: And remember, Canada must provide its citizens with food, housing, clothing, heat, transportation, as well as the infrastructures to provide education and health care.
The exploitation of oil was a one-shot affair that enabled us to triple agricultural yields: The vast amount of oil that Nature had put aside for us millions of years ago has artificially increased the Earths ability to provide us with food.
In other words, oil artificially tripled the Earths carrying capacity. Its as though oil provided us with acres of land that werent there – phantom acreage, as Catton would put it in his ground- breaking book*. *Overshoot, William R. Catton, Jr.
…How? Because oil provided the: - resources to build laboratories and technology to develop high yielding grains - energy to run the machinery enabling one farmer to feed 100 people - chemicals to make fertilizers and pesticides, thus tripling yields - energy to pump ground water for irrigation - energy to transport food from the producer to the consumer - energy to dry grain and preserve food, thus preventing large losses
All of these factors artificially increased food production – temporarily.
But when oil becomes rare, food production will plummet – just at a time when population is at its largest!
If we cant convince our government to take action, we may not be able to bring renewables on line fast enough…
…And if we have to resort to 19 th century technology, will we be able to feed Canadas growing population?
And if ever we had to resort to using draw animals instead of tractors… …then wed need to develop 25 to 30% more cropland just to grow the feedstuffs to nourish the animals.
The Easter Islanders no longer had seaworthy vessels that would enable them to escape to another island. They had no place to go.
…and neither do we. We dont have space vessels that would enable us to escape to another planet.
The next chapter looks at the parallels between the behaviour of the Rapa Nui population and that of our technological society. Are we much smarter? Find out in Chapter 5. Click icon for Chapter Choice