HR: 1340h
AN: GC33A-0938    [Abstracts]
TI: Does Aerosol Geoengineering the Earth's Climate Pass a Cost-Benefit Test?
AU: * Keller, K
EM: kkeller@geosc.psu.edu
AF: Department of Geosciences, Penn State, 208 Deike Building, University Park, PA 16802, United States
AU: Urban, N
EM: nurban@psu.edu
AF: Department of Geosciences, Penn State, 208 Deike Building, University Park, PA 16802, United States
AU: Tuana, N
EM: ntuana@la.psu.edu
AF: Department of Philosophy, Penn State, Rock Ethics Institute, University Park, PA 16802, United States
AB: Anthropogenic carbon dioxide (CO₂) emissions are changing the Earth's climate with potentially dangerous consequences. Ratified international agreements call for a reduction of CO₂ emissions to avoid dangerous anthropogenic interference with the climate system. Recent studies have, however, proposed an alternative strategy: to geoengineer Earth's climate by injecting aerosol precursors into the stratosphere. It is often claimed that aerosol geoengineering would provide net economic benefits because geoengineering requires far lower near-term investments compared to deep cuts in CO₂ emissions. However, aerosol geoengineering projects can also cause nontrivial economic costs. This is because aerosol geoengineering hinges on successfully counterbalancing the forcing effects of CO₂ emissions (which decay over centuries) with the forcing effects of aerosol emissions (which decay within years). A failure to maintain this delicate balance can lead to abrupt climatic changes, with potentially substantial economic damages. Deferring cuts in CO₂ emissions in favor of aerosol geoengineering is hence a deeply uncertain gamble, as it requires so far unknown institutions to reliably control aerosol forcings over centuries. Here we use a simple economic model to evaluate potential costs and benefits of aerosol geoengineering for a wide range of the deeply uncertain parameters. We show that aerosol geoengineering projects may cause economic damages that can far exceed the benefits and may hence fail a cost-benefit test.
DE: 1605 Abrupt/rapid climate change (4901, 8408)
DE: 1622 Earth system modeling (1225)
DE: 6304 Benefit-cost analysis
DE: 6309 Decision making under uncertainty
DE: 6329 Project evaluation
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting