For instructors who include a geoengineering module in their courses, an excellent new article on one of the leading carbon dioxide removal (CDR) schemes, air capture, was published this week in Scientific American, Klaus L. Lackner, Washington Carbon out of the Air, Scientific American 66-71 (June 2010) (subscription required). Lackner, a professor of geophysics, at Columbia University is also co-founder of a company that is seeking to develop air capture technology. This article is appropriate for undergraduate, graduate and law students and provides a passionate, “birds eye” view of efforts to develop geoengineering technologies. It also focuses on a form of geoengineering that could pose far fewer risks of side effects than many of the others that have been discussed in this blog to date. It should be noted at the outset that Lackner himself argues that air capture doesn’t constitute “geoengineering” because “the process doesn’t change the natural dynamics of the earth or create a potential environmental risk.” However, I subscribe to the National Academy of Science’s definition, which is “options that would involve large-scale engineering of our environment in order to combat or counteract the effects of changes in atmospheric chemistry.” One would be hard-pressed to argue that air capture would not fit under the rubric of this definition” given its potential for removing huge amounts of carbon dioxide from the atmosphere and the potential impacts on warming.
Among the take-aways from the article:
- Air capture machines, or “synthetic trees,” as the Lackner often terms them, could trap carbon dioxide from a ton to several hundred tons per day. The system being developed by Lackner’s company uses thin fibers of sorbent material that are arranged in large, flat panels. As Lackner explains the process, capture is effectuated when air passes through fibers covered by negative charged carbonate ions, which attract the hydrogen ions from residual water molecules, resulting in the formation of bicarbonate. The remaining hydroxide ions capture carbon dioxide molecules, also forming bicarbonate. Once the panels were saturated with carbon dioxide they would be moved down a track into a regeneration chamber inside a container. The trapped gas would then we freed from the sorbent and compressed into a liquid;
- Lackner suggests that collected carbon dioxide could be piped underground for storage, as is contemplated in carbon capture and sequestration systems. However, he also suggests several potential alternative uses, including sales to industries that use carbon dioxide, e.g. purveyors of carbonated beverages and dry ice. Ultimately, Lackner argues that ultimately companies could claim carbon credits for gas sequestered underground, and could contribute to enhanced oil recovery efforts. Additionally, captured carbon dioxide could be utilized to produce synthetic gases;
- Ten million units could collect 3.6 gigatons of carbon dioxide per year, which could reduce atmospheric levels by 0.5ppm per year, perhaps escalating to 5ppm annually, more than the rate of global increase at this point. In a future scenario in which atmospheric concentrations of carbon dioxide are stabilized, carbon capture technologies could reduce atmospheric concentrations;
- The initial cost of capturing carbon dioxide could be high, about $200 per ton; however, if the technology followed standard learning and manufacturing curves, capture costs could ultimately drop to around $30 per ton.
Among the discussion questions that might be relevant:
1. Could air capture technologies result in a moral hazard problem, i.e. divert efforts to reduce carbon dioxide emissions by mitigation approaches.If the technology proved to be effect, would that be problematic?
2. What are the opportunity costs, if any, in pursuing this technological approach vis-a-vis mitigation and adaptation responses?;
3. Is there a possibility that some countries would object to reducing atmospheric levels of carbon dioxide? If yes, what would the implications be for governance?
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