extract on geoengineering from minutes from a DOE LERDWG meeting, Nov 8, 2006
Ken Caldeira
Folks,
The following is an extract of minutes from a DOE meeting, known as the LERDWG meeting, held on Nov 8, 2006, held at the Joint DOE Lab. Offices, Suite 900 Aerospace Center Bldg., 901 D Street SW, Washington, DC 20024. These minutes were prepared, I believe, by Bill Fulkerson.
Enjoy,
Ken
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... a perfect introduction to Ken Caldeira's talk that he called "Geoengineering the Arctic Climate. Ken is with the Carnegie Institution Department of Global Ecology, and his paper had collaborators Lowell Wood of Hoover Institution and Mike McCracken of the Climate Institute. Mike McCracken attended the meeting. All three were formerly of LLNL. Ken asked the question: would it be possible to geoengineer the Arctic to avoid catastrophic loss of biodiversity, Greenland Ice, etc.? He showed that if one believes the models he used that this is indeed possible by putting particulates in the stratosphere. It doesn't really matter where one injects the particles because they tend to migrate to the poles. By reducing the solar radiance by 0.37% Arctic sea ice is preserved assuming a doubling of CO2 concentrations to 560 ppm(v) compared to preindustrial levels. Temperature is reduced to preindustrial levels in the Arctic but precipitation rises as for the case of doubling of CO2 without geoengineering. There is one other impact that is not reduced and that is ocean acidification. The tendency to dissolve carbonate materials is greater in the Arctic than anywhere else on the planet. Other concerns that Ken mentioned about such geoengineering are that it might negatively impact the stratospheric chemistry, and although Paul Crutzen believes this is not an issue, his conclusion should be independently tested. Second, the perception of geoengineering as an inexpensive technological fix could divert attention from the controlling GHG emissions. Finally, Ken wonders if there may be some unanticipated negative environmental impacts.
Is research on geoengineering technology important, and if so, should it be undertaken by DOE? These are two questions that Bill Fulkerson tried to answer. He answered in the affirmative to both. Fulkerson made this presentation in the place of Ehsan Khan who was scheduled to talk about a potential geoengineering R&D plan, but his paper was not cleared by the Office of Science. Hopefully it can be cleared in time for Ehsan to present his paper on February 7, the next LERDWG meeting. Fulkerson argued that offset technologies are a sort of insurance policy that is cashed in only if mitigation of emissions of GHG cannot be accomplished adequately to meet the UNFCCC objective of preventing dangerous anthropogenic interference with the climate system. He then made a crude estimate of the cost of offset based on Paul Crutzen's recent paper in Climate Change 2006 that suggested that 5 Tg of sulfur could offset a carbon doubling and that the cost per Tg injected in the Stratosphere was $25B. Fulkerson assumed 5Tg injections every other year for 100 years giving $6.25T and if this cost is discounted at 5% the number is 2.5T. Ehsan Khan believes this number is on the high end of the range of costs of offset. This can be compared to the range of costs for mitigating GHG emissions so that two degrees are not exceeded calculated by Jae Edmonds and Steve Smith in their paper Technologies of Two Degrees published earlier this year in the Proceedings of the Exeter Conference. For a range of advanced technologies the cost discounted at 5% may be as low as $2-3T over 105 years, but it may be as high ad $18T using existing technologies. Hence the conclusion that offset is on the lower end of GHG mitigation costs. An injection of particles in the stratosphere is reversible in two to three years as demonstrated by the eruption of Mt. Pinatubo. One definite negative is that by allowing carbon emissions to raise the pH of oceans will decrease endangering some aquatic life. So Tom Wigley in the Oct 20, 2006 edition of Science Magazine argues that both mitigation of emissions and offset to counteract overshoot may be good strategy. Another possible negative is that offset may detract from efforts to mitigate emissions if it is viewed as an inexpensive technology fix. Finally, there may be unforeseen consequences that are negative. Clearly, a dedicated R&D program is needed. It might consist of scoping, understanding relevant phenomena, laboratory tests of various particles, and injection of small quantities into the Stratosphere to measure persistence and transport, and development of verifiable models for predicting outcomes. It should determine engineering costs and explore options for bring the cost down. Ehsan Khan estimates that an adequate program might cost $100 M over 5 years.
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Ken Caldeira
Department of Global Ecology
Carnegie Institution
260 Panama Street
Stanford, CA 94305 USA
+1 650 704 7212; fax: +1 650 462 5968
kcal...@globalecology.stanford.edu