Ocean Carbon Sequestration

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Ocean Carbon Sequestration

• John Nowoslawski
• Spring Update 2004

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Today

• Quick Review of CO2 in the atmosphere and what
  rising CO2 levels has done to the ocean.
• How the ocean can safely remove CO2 from the
  atmosphere while reversing the negative effects
  on ocean chemistry from increased atmospheric CO2
• Experiments and updates.
• Where it could go.

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Follow the Carbon
Ocean soaks up about 1/3 of the Carbon we emit
into the atmosphere each year!!!
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Carbon in the Ocean
The entire system is in equilibrium
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Anthropogenic Effects

• As the atmospheric CO2 concentration increases
  more CO2 dissolves into the ocean as carbonic
  acid
• The Buffer system of the ocean converts the
  limited number of CO3- ions into HCO3- ions.
• Bottom Line the pH of the ocean is slowly
  decreasing and will continue to decrease. The
  concentration of carbonate ions (CO3--) is
  decreasing.

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Solution?

• Increase the CO3-- concentration. But how?
• Add CO3-- ions by throwing rocks into the ocean.
• What will this do?

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Throwing Rocks into the Ocean

• Dissolving Alkaline Rocks (Calcite, for example,
  is CaCO3) into the ocean will increase the CO3--
  concentration
• Reverses the acidification of the ocean.
• It will also cause the ocean to suck up more CO2
  from the atmosphere
• But in a good way.
• Ocean is trying to fix the disequilibrium we
  caused by dissolving alkaline rocks.

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Experiments

• Made Artificial Seawater in the laboratory
• Figuring out which minerals dissolve into
  seawater and what problems arise
• Ocean chemistry is very unstable because the
  upper 100m of the ocean is supersaturated with
  respect to Calcite (CaCO3)
• Built a dissolution rate calculator
• Whatever mineral added to the water must dissolve
  in the upper 100m of the ocean, or it is too far
  from the atmosphere to pull out CO2

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Dissolution Rate Calculator
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Final Project Goals

• Finish the lab work this week
• What size rock of Ca(OH)2 will finish dissolving
  at 100m?
• Put a price tag on the process
• In dollars per ton of CO2 sequestered
• Must be cost competitive with geologic
  sequestration if it will ever be used

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What Could This Thing mean?

• Carbon Trading is has been happening around the
  world for several years
• Companies have to pay fines or pay to have Carbon
  dioxide taken out of the atmosphere if they are
  above whatever limit their country has given
  them.
• Carbon Sequestration has saved companies that are
  emitting more CO2 than their country allows them
  has saved the companies millions of dollars
  annually
• This could be another method

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Conclusion

• It is possible that the addition of alkaline
  minerals will decrease atmospheric CO2
  concentration and safely sequester it while
  having other positive effects on ocean chemistry.
• Experiments are being performed to determine if
  the dissolution will happen and if the effects
  are beneficial.