1. Earth’s Carrying Capacity PEAK OIL AND THE FATE OF HUMANITY Mr. McCarthy’s adaptation of PEAK OIL AND THE FATE OF HUMANITY Chapter 4 – The Fate of Easter Island By Robert Bériault

2. To start this story we have to go back in time to 500 AD… to one of the most isolated places on Earth: Easter Island. Easter Island The land of the Moai

3. It was an uninhabited sub-tropical paradise 240 square miles 2300 miles from the Chilean coast to the east 1300 miles from the Pitcairn Islands to the west

4. A group of Polynesian settlers arrived by boat around 500 AD Archaeologists estimate that there were no more than 100 people The island was known as Rapa Nui

5. Large palm trees flourished along with 17 species of other trees These were suitable for making logs, planks and dugout canoes

6. They came equipped… They brought with them chickens, pigs and Polynesian rats. They planted banana trees, taro root, and sweet potato.

7. The Islanders started to cut down the giant palms to build houses and dug-out canoes.

8. They supplemented their diet from the sea There were no reefs around Easter Island, and therefore few small fish. The main catch was porpoises which they caught from their large wooden canoes.

9. Conditions on the island made for an easy life They had time on their hands for religious ceremonies.

10. They held ceremonial dances and feasts

11. Stone mound for statues bases … And they were expert stone carvers

12. 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 miles to their places of honor along the shore.

13. How big were those statues?

14. Partially completed statue abandoned in quarry At first they only measured 8 to 12 feet high… But 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 ft. high. The biggest of all measured 70 feet and weighed 240 tons!

15. 240 tons is the equivalent weight of 200 school buses

16. But without levitation machines how could they have transported them?

17. 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.

18. This statue moving activity would have made a significant contribution to deforestation.

19. The Rapa Nui population grew And by the year 1500… Reached a peak of around 20,000

20. …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. Shortly after, statue building came to an end…

21. All statue carving had stopped. Someone had cut down the last standing tree. Only shrubs and grasses were left.

22. 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

23. With no more wood… They could no longer build replacement boats. Porpoise hunting, their main source of meat, came to an end. They couldn’t 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.

24. Starvation was rampant Fighting broke out over the diminishing food supply Desperate, they even resorted to cannibalism Winter temperatures were as low as 45°F. Without firewood, everyone suffered. Social order was in shambles. Vandals toppled rival clans’ statues There was a massive die-off

25. Then came the Europeans: It was on Easter Sunday of 1722 Dutch Admiral Jacob Roggeveen arrived He found 3000 people living in destitute conditions

26. Then 52 years later, Captain Cook visited the island The only animals to be seen were chickens. The warring clans were in constant battle

27. Over the next century : Mostly due to contact with Europeans, the population plunged to a low of 111

28. Wow! How could that happen when the island had so much to offer its people at the start?

29. It’s simply that the Rapa Nui population exceeded the island’s 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 is how many organisms a territory can support indefinitely without degradation of the life support systems of that territory.

30. 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 9 lbs of grain to produce one lbs 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.

31. Lifestyle has an influence on CARRYING CAPACITY All of these… …influence these PER CAPITA Square feet of living space Cars, RV’s, boats Miles driven Airplane, cruise ship and pleasure trips Tools, electronics, Cookware, etc., etc. PER CAPITA Square feet of living space Cars, RV’s, boats Miles driven Airplane, cruise ship and pleasure trips Tools, electronics, Cookware, etc., etc. Depletion of natural resources Destruction of biodiversity Future cropland compromised Earlier Peak Oil All of these effects reduce carrying capacity All of these effects reduce carrying capacity

32. 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 promotes its reproduction.

33. After a population overshoots, a massive die-off of the species follows.

34. 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.

35. 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.

36. Like the Easter Island peoples and the St. Matthew Island reindeer, industrial age humans have encountered a rich and previously unexploited stock of resources that promoted their reproduction –

37. PETROLEUM!

38. The exploitation of oil is 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 Earth’s ability to provide us with food.

39. In other words, oil artificially tripled the Earth’s carrying capacity.

40. How did oil do this?

41. …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

42. : All of these factors artificially increased food production – temporarily.

46. Population Density--# of people per square mile

47. But when oil becomes rare, food production will plummet – just at a time when population is at its largest! :

48. If we can’t convince our government to take action, we may not be able to bring renewables on line fast enough…

49. …And if we have to resort to 19th century technology, will we be able to feed our growing population?

50. And if ever we had to resort to using draw animals instead of tractors… …then we’d need to develop 25 to 30% more cropland just to grow the feedstuffs to nourish the animals.

51. The Easter Islanders no longer had seaworthy vessels that would enable them to escape to another island. They had no place to go.

52. …and neither do we.