Ecological Sustainability: what can models tell us?

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Ecological Sustainabilitywhat can models tell
us?

• CSCI 1210
• Fall 2003
• Note please dont forget the online student
  evaluations!

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What is sustainability?

• Humans living in a way that does not diminish
  Earths capacity to sustain life
• Alternatively living within Earths ecological
  carrying capacity
• Are we going through a global ecological crisis?

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Overshoot and collapse

• Previous model assumes carrying capacity is
  constant
• What if a severe overshoot degrades the
  environment?
• Carrying capacity might be permanently reduced
• Imagehttp//www.dieoff.com/page80.htm

4
Humans are different

• Human carrying capacity is hard to define,
  because
• Technological changes affect food production
• Complex social factors affect population

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UN world population projections

• World population may have passed its inflection
  point in 1970.
• Herman Kahn called this time The Year Zero

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World3The Nightmare Scenario

• World3 model created by MIT systems group for the
  Club of Rome
• Model updated, 1990
• Graphic www.dieoff.com

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Malthus in, Malthus out!

• Nonrenewable resources run out
• Capital is diverted to resource extraction
• Less capital for agriculture
• Yields fall, leading to famine and death
• Is this realistic??

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The Cornucopians

• Economist Julian Simon bet ecologist Paul Ehrlich
  that prices of nonrenewable resources would fall
• Ehrlich lost and had to pay Simon 1000
• Cornucopians argue that human ingenuity will
  surmount all limits to growth.
• http//www.cato.org/pubs/policy_report/cpr-20n2-1.
  html

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Are there limits?

• Simon and climatologist Steven Schneider offered
  to bet Simon 1000 on each of 15 ecological
  indicators getting worse over time.
• Simon declined this bet.
• The limits to growth are not industrial
  resources, but ecological resources
• The real limit may be the ability of Earth to
  absorb pollution

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World3 model and pollution

• Here is what happens when you increase the
  initial stock of natural resources by 1000 times.

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World3 model and pollution

• This time there is no shortage of agricultural
  inputs, but land fertility suffers because of
  pollution.

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The IPAT formula I PAT

• Proposed by Paul Ehrlich
• I environmental Impact
• P population size
• A Affluence
• T Technology factor
• http//www.stanford.edu/group/CCB/Staff/paul.htm

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IPAT a conceptual model

• Population is not the only factor
• An American has more environmental impact than a
  Bangladeshi or Chinese
• To reduce environmental impact we must control P,
  A, T or all three
• Problem with IPAT no defined measure of total
  impact I

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Ecological Footprint model

• Definition of total impact
• Ecological fooprint is the total land area that
  would be needed to support a city, country, or
  other population unit.
• http//www.ire.ubc.ca/ecoresearch/ecoftpr.html

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Results of Ecological footprint

• Were everyone on Earth to live as an average
  North American
• It would require three Earths to sustain this
  lifestyle.

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World3 Persistent Pollution
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World3 pollution model

• In World3, the world reacts to pollution problems
  after the pollution has already become a problem
• Inevitable delays in inventing and deploying
  technology cause overshoot.
• Pollution technology is modeled as a stock. You
  can add more technology but cannot make
  qualitative changes.

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Real-world pollution response

• In order to avoid overshoot, societies try to
  deal with pollution problems before they become
  severe
• In the long term, qualitative changes
  (redesigning technology) is more powerful than
  adding filters to the back end of the smokestack

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Ecological safety factor?

• Many scientists believe that humans should use at
  most 50 of Earths ecological capacity
• This gives us a safety margin in case our
  calculations are off
• It also leaves some room for other living things
  to share our planet

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The Big Question

• How much do humans have to change in order to
  live within Earths carrying capacity?

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And the answer is

• Ecological overload factor if every Earthling
  comes up to US lifestyle 3
• Additional population increase from
• 6 to 9 billion
  1.5
• Further improvement needed to
• leave 50 of Earth alone 2
• TOTAL IMPROVEMENT NEEDED 9

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What does this mean?

• We need at least a 9-fold reduction in the amount
  of pollution caused by each dollar of economic
  activity
• Design school Factor Ten
• Another design school Zero Waste

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Is Zero Waste possible?

• Nature does it!
• Bill McDonough divide materials into industrial
  nutrients and ecological nutrients
• Recycle industrial nutrients
• Compost biological nutrients
• Voila! Future technology!

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A Democracy Deficit?

• Those most vulnerable are far away
• And have little power to promote change
• Needed effective planetary democracy
• Struggle over the global trade system the front
  line of the battle to save the Earth?

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Acknowledgements

• DOE vs EIA Hubbert curves http//www.dieoff.org/p
  age177.htm
• Hubbert curves from http//www.hubbertpeak.com