Sustainability What does it mean? What does it have to do with the Tragedy of the Commons? See “Weighing the Issues,” p. 6

Easter Island (Rapa Nui) When ``discovered’’ by Europeans in 1722, had small population, no trees. Statues evidence of a sophisticated culture. Polynesians settled between 500 and 1200.

What happened? Polynesians settled Easter Island between 500 and 1200 AD (still controversial) Used the palm trees, hunted birds. Gradually (or quickly) deforested the island Wiped out bird species (only 1 native species still nests there)

Island once had trees Pollen analysis to reconstruct vegetation history This is obviously NOT Easter Island

Natural resources What natural resources did Easter Islanders exploit? Renewable vs. non-renewable

Conventional view of Easter Island’s collapse Islanders overexploited a renewable resource What do you think the Easter Islander who cut the last tree said? Results of deforestation: –Faster runoff of rainwater –Increased soil erosion  lower agricultural productivity –Less infiltration  less drinking water

Natural resources

Impact of population on natural resources

Thinkers on population Through most of human history: Lots of children a benefit Thomas Malthus: late 1700s –Essay on the Principle of Population –Without limits on births, deaths will increase Paul Ehrlich: Population Bomb (malthusian)

Thinkers on population Julian Simon (died, 1998) –Anti-malthusian –Humans are ``the ultimate resource’’ –``His keystone work was "The Ultimate Resource," published in 1981 and updated in 1996 as "The Ultimate Resource 2" (Princeton University Press). Its central point is clear: Supplies of natural resources are not finite in any serious way; they are created by the intellect of man, an always renewable resource. Coal, oil and uranium were not resources at all until mixed well with human intellect.’’ Ben Wattenberg, obituary essay

Tragedy of the commons Commons: a resource that belongs to none (or belongs to everyone) OR that is used as if it belongs to all. Examples?

Tragedy of the commons A commons can be destroyed by uncontrolled use –Intent is not required. –Nor is ownership.