Iron Fertilization

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Iron Fertilization

• By Glen Romine

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Motivation

• Concerned about the sustainability of our
  environment without controls on carbon release
• Intrigued by the concept of engineering a way to
  reverse mans carbon contribution
• Personal lack of faith in predictive models of
  future CO2 concentrations (from a global warming
  perspective)

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Theory

• Iron is an essential and lacking nutrient in the
  oceans for plankton growth
• Known since the 1930s
• Heavily studied by John Martin during the 1980s
• IronEx Experiments
• 450 kg - 2500 tons of Carbon Dioxide

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Model Basics

• Model created using Stella
• Eight primary reservoirs with an emphasis on
  ocean processes
• Atmosphere
• Land Plants, Detritus and soils
• Ocean mixed layer, Marine biota, Dissolved
  organic carbon, Deep intermediate ocean, Sea
  floor sediment

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Model Basics (Cont.)

• Donor Controlled flow except
• Ocean - Atmosphere interface
• Atmosphere - Land Plant interface
• Assumes a constant rate for deforestation /
  reforestation
• Uses a market controlled fossil fuel burning
  model
• Runs from present to 2100

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The Physical Model
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Model Performance

• The model was run with 2 increments in ocean
  fertilized yielding

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Model Performance (Cont.)

• Fertilization showed a near linear response to
  final CO2 concentrations
• Maximum possible reduction in CO2 limited to 38
  PPM
• Reasonable comparison to results found in other
  studies (60 PPM)

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Shortcomings

• Model does not produce CO2 levels anticipated by
  other research
• Suspected ocean interface sensitivity problems
• Time cycles of system response vary greatly
• Linear donor-controlled flow rates inadequate
• Does not account for
• Variations in ocean temperature
• Changes in global land use
• Effects on marine biota of increased plankton

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Reality Check

• Given 1 ship can fertilize 1200 km2 per year, it
  would take 300,000 ships to fertilize 20 of the
  worlds oceans
• We would need 1.62 billion Kg of iron annually

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Conclusions

• Not a realistic means for long term carbon cycle
  control without changing fossil fuel consumption
  rates and land use patterns
• Does suggests the potential for climate
  engineering - adaptation methods
• Many unknowns in reaction of marine biota
• Numerous possible feedbacks to explore