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 enhance growth, fix more carbon NOAA/NESDIS SeaWiFS satellite image of 1997 Bering Sea plankton bloom (

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

 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 The Future is Now 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  Injection well failure = horrible, horrible death

…and the Unknown  Estimates of worldwide sequestration potential range from ,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