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Carbon Sequestration Methods: the State of the Art

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

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Carbon Sequestration Methods: the State of the Art

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  1. Carbon Sequestration Methods: the State of the Art Daniel “J.” Leistra GCCS Final Presentation August 8, 2002

  2. 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

  3. 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

  4. 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 enhance growth, fix more carbon NOAA/NESDIS SeaWiFS satellite image of 1997 Bering Sea plankton bloom (http://www.sfos.uaf.edu/npmr/projects)

  5. 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

  6. 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

  7. 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

  8. 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)

  9. 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

  10. The Bad • No incentive to sequester without a carbon tax or a permit system • Injection well failure = horrible, horrible death

  11. …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

  12. 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

  13. 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

  14. 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

  15. 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

  16. 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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