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					   Carbon Sequestration
Methods: the State of the Art

       Daniel “J.” Leistra
     GCCS Final Presentation
        August 8, 2002
              Strategies for Addressing
              Climate Change
 For many, the debate is polarized between
  mitigation and adaptation
 Climate change policies don‟t have to be
  monolithic
 Carbon sequestration is the „third path‟
 Sequestration shouldn‟t be excluded from any
  serious discussion of policy options
    Carbon Sequestration: What It Is
 Stores CO2 removed from the atmosphere or
  captured from emissions and stores it in another
  form somewhere else (a ‘carbon sink’)
 Occurs naturally: oceans and plants are already
  absorbing much of what we emit
 We can speed the process along or deposit CO2 in
  sinks that it wouldn’t have entered before
 Possible sinks: plants and soils, carbonate minerals,
  geologic formations, ocean
                   Ocean Fertilization
   Plankton photosynthesis
    creates 45 Gt organic carbon
    per year
   Most carbon gets recycled to
    atmosphere, but some is drawn
    down into deep ocean
   Iron is the limiting factor for
    phytoplankton growth in 20%
    of the world‟s oceans (HNLC
    zones)
   Fertilization with iron could
                                      NOAA/NESDIS SeaWiFS satellite image
    enhance growth, fix more            of 1997 Bering Sea plankton bloom
    carbon                            (http://www.sfos.uaf.edu/npmr/projects)
                Studies Show…
 Geologic    record suggests phytoplankton growth
  may have substantially decreased atmospheric
  CO2 in the past
 Numerous experiments have shown huge (30-40x)
  increases in primary production, lower CO2 levels
 If it is successful, there will be virtually no limit on
  how much CO2 the oceans can hold
                   Problems
 All of these studies were short-term: unknown how
  much CO2 is being carried into the deep ocean
 Public perception, especially concerning Antarctic
  waters
 Fishing Industry???
 Fertilizing every HNLC zone would sequester
  76 Gt C by 2100, but would require 300,000
  ships and 1.6 billion kg iron annually
    Injection into Deep Saline Aquifers
 Saline aquifers are
  underground layers of
  porous sediment filled
  with brackish water
 If they are deep enough
  and hydrologically
  separated from other
  aquifers, they can safely
  hold CO2
               The Future is Now
 U.S. is already dumping 75
  million cubic meters of
  industrial waste into deep
  saline aquifers each year
 CO2 injection process is
  similar to EOR; one
  commercial venture
  already in place and running smoothly
 Preliminary geologic data available, compiled by
  Hovorka et al. (2000)
                      The Good
 Deep saline aquifers are widespread: 2/3 of U.S. power
  plants and industrial centers could inject without
  constructing pipelines
 Unlike oil and gas fields, they don‟t need special
  geometries to sequester CO2 – wide structures confined
  only by a horizontal layer of rock can hold it for thousands
  of years
 A large amount of CO2 would be incorporated into rocks
  and remain stable on a geologic time scale
 If there was a natural leak, it wouldn‟t pose any danger
The Bad
 No incentive to sequester
  without a carbon tax or a
  permit system

 Injectionwell failure =
 horrible, horrible death
              …and the Unknown

 Estimates  of worldwide sequestration potential
  range from 320 - 10,000 Gt CO2
 Environmentalists and the NIMBY effect
 More site-specific information needed before
  injection can begin
                       Conclusions
 Though no single option is perfect, carbon sequestration
  has potential for great societal benefits
 Continuing research is sure to bring about further
  breakthroughs, particularly in the field of carbon capture
 Climate change policies shouldn‟t be all or nothing: while
  carbon sequestration isn‟t the answer, it is an answer

   And they all lived happily ever after.   THE END
             Cropland Retirement
 20 – 50% of soil organic
  carbon (SOC) lost within first
  few decades of cultivation
 Worldwide estimates of loss =
  41 to 55 Gt C
 As farms face increasing
  ecological and economic
  challenges, many are being
  abandoned
      Cropland Retirement (cont.)

 Governments   or NGOs can buy back failing farms
  and attempt to reestablish natural ecosystems
 This regeneration can be active or passive
 Temporary set-asides also a possibility
                     Predictions
 Regenerating forests across eastern U.S. demonstrate that
  it can work, even without much effort
 Removing 15% of land in countries with surpluses would
  sequester 1.5 – 3 Gt C
 Conversion will increase biodiversity, provide habitat for
  endangered species, protect watersheds, reduce erosion
  and salinization
 Reestablishing grasslands more difficult than forests, but
  CRP is a well-proven alternative
                 My Analysis
 Lower  sequestration potential than other options,
  but simpler, more environmentally friendly
 Provides a good way out for struggling farmers,
  reduces need for government subsidies
 Lower food supply helps those farmers that stay in
  business, but could hurt the developing world
 Resulting ecosystems may not be „natural,‟ but a
  managed forest is better than a farm

				
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