Easter Island
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Transcript of Easter Island
Natural Resource Economics
The Simple Economics of Easter Island:
A Ricardo-Malthus Model of Renewable Resource
Use
Brander, J.A. & Taylor, M.S.
Objectives
1.Study a pattern of:
Economic andPopulation Growth
ResourceDegradation
Economic Decline
2. Construct a model linking population dynamics and renewable resource dynamics
3. Apply the model to the case of Easter Island
Components of the Model
1. Malthusian population dynamics: increase in productivity leads to pop growth. Pop growth might overshoot productivity gains, resulting in readjustment (boom-and-bust).
2. Open-access renewable resource: no property rights established, anyone can use the resource stock freely.
3. Ricardian production structure: production function where labour and the renewable natural resource are inputs.
A Short Chronology of Easter Island
● 400 AD: first settlements, between 20 and 100 people● 900 AD: evident deforestation● 1100-1400: most forest gone, soil erosion. Maoi carving.
Population peaked at around 10,000 people.● 1400-1500: falling food consumption. Maoi carving
stopped. Weaponry, conflict, cannibalism.● 1722: about 3,000 human inhabitants. Moai worshipping.● 1774: About 2,000 inhabitants. Maoi worshipping
stopped, statues pushed down (usually facedown)
The Model (parameters)● Production function: labour (L) and renewable
resources (S) – ecological system of soil and forest:DS/dt = G(S) – H
● Society harvests (H) the renewable resources. Society as hunters, resources as prey.
HP = αSLH
● Due to open-access, there is no rent to depletion of S.
● Biological growth follows a logistic function.
The Model (static equilibrium)
The Model (dynamics equilibrium)
● As consumption increases, net fertility increases. Positive feedback effect;
● Population growth dissipates resource productivity improvements;
● Resource depletion decreases carrying capacity.
Transition Dynamics
The Model (results)
What's different about Easter Island?● Other Polynesian island societies in the area
did not suffer such overshooting and collapse.● However, Easter Island has distinct
disadvantages:- slow growth rate of local resources- short lifespan of individuals- climate too cold- no property rights- isolation
Easter Island: a “closed” system
Source: Diamond, J. (2005) Collapse: How Societies Choose to Fail or Succeed (in Portuguese). Rio de Janeiro: Editora Record.
~2100 mi
Institutional Adaptation● Various institutional decisions could help
diminish the risk of such collapses:- Correct and agreed-upon understanding of the problem- Relevant policies affect relevant parties in a similar way (cfr. Pareto)- Low discount rates- Low enforcement costs- Trust and cohesion in the community
Collapse:How Societies Choose to Fail or Succeed
Causes of societal collapse
1. Human impact over surrounding environment
2. Climate change (natural)
3. Increasing pressure by hostile neighbours
4. Diminished support by friendly neighbours
5. Societal response to ongoing problems
Deforestation and habitat destruction
Soil problems (erosion, salinization, and soil fertility losses)
Water management problems
Overhunting
Overfishing
Effects of introduced species on native species
Population growth
Increased per-capita impact of people
Thank you all.