Air capture – direct removal of carbon dioxide from the ambient air - is beginning to receive more attention, especially in light of recent reports that CO2 emissions are increasing much more rapidly than expected, and that certain climate changes will be "irreversible" for 1,000 years. The Center’s Roger Pielke, Jr., has an upcoming article in the journal Environmental Science and Policy on air capture (see Recent Papers and Publications below). The Economist recently ran an article titled Scrubbing the Skies that discusses the technology.
This edition of Ogmius features University of Colorado energy policy expert and Center Faculty Affiliate Paul Komor’s perspective about the possible pitfalls of pursuing air capture as a climate change response strategy. Comments welcome!
Air capture: The latest distraction? by Paul Komor
Technologies under consideration for addressing climate change fall into two categories: those commercially available, at reasonable cost, and already in use; and those higher up the R&D pipeline, not yet commercially available, and considerably more speculative. Examples of the first type (which I’ll call the A list) include some forms of renewable energy (hydro, wind, biomass), energy efficiency, and nuclear fission.
The latter (the B list) are considerably more numerous, and include for example geoengineering (such as seeding the oceans with iron), ‘enhanced geothermal’ (also called hot dry rock), various exotic renewable technologies (such as OTEC [ocean thermal energy conversion] and wave power), and nuclear fusion. All these technologies have their estimated costs, their advantages and disadvantages, and their proponents and opponents. For most of these technologies, one can find analyses arguing that, if a few technical or other barriers could be overcome, the technology could be a viable and cost-effective partial solution to climate change.
The latest technology to join the B list is air capture – direct removal of carbon dioxide (CO2) from the ambient air. This, too, has its estimated costs, its pros and cons, its proponents and opponents. The second law of thermodynamics suggests that this approach must require more energy than removing CO2 directly at the power plants. But there are of course considerations other than energy intensity.
In an ideal world, each and every proposed solution would receive significant research funds, undergo comprehensive and detailed analysis, and be the topic of widespread public and policy debate.
That is unfortunately not the world we live in, and there are several problems with the comprehensive approach. First, it’s not possible. The B list is not static: technologies are added, drop off, and in some cases even come back. Air capture, for example, is relatively new to the list. Nuclear fusion, in contrast, has long been the recipient of significant public research funds, and its proponents have used the climate issue to argue for its resurgence. And further out the exotic scale, according to a recent news article, “advocates of using satellites to beam solar power from space to Earth hope U.S. President Barack Obama's campaign promise to develop alternative energy sources will help resurrect NASA's interest in the technology.”1 Giving every technology the R&D, analytic, and policy attention its advocates desire would be a never-ending task.
Second, it would be a damaging distraction. R&D budgets are finite, policy attention is time- and attention-limited, and – most importantly – many argue that the time has come to take concrete actions to address climate change. Continued public and policy attention on the latest proposed technological solution – whether it’s air capture, concentrating solar power, or space beams – diverts attention from the need to take controversial and difficult steps to actually mitigate or adapt to climate change, rather than continuing to study the options.
So how do we move forward, given finite budgets, limited attention spans, and the need to take action? Not by ignoring air capture, certainly, but neither by letting air capture distract us from the solutions in hand. Numerous studies2 have shown the considerable carbon savings that could result from greater use of technologies already available, at costs well under $100 per ton of CO2. So why continue to pursue uncertain, expensive, and unproven technologies like air capture, when we have proven, cost-effective technologies already in hand?
Yes, air capture might prove a viable technology for addressing climate change. So might nuclear fusion, or solar power beams from space, or any of the other B list technologies. Perhaps these ideas deserve some research funds and attention. But that is a distraction from the reality: we have technologies that work; our challenge is to figure out how to make better use of them.
1. MSNBC, Becky Iannotta, "Space solar power crowd bets on Obama,” Feb. 25, 2009.
2. See e.g. McKinsey & Company, “Pathways to a Low-Carbon Economy,” 2009; Pacala, S. and R. Socolow, Stabilization Wedges: Solving the Climate Problem for the Next 50 Years with Current Technologies, Science, 13 Aug. 2004; Pachauri, R., “The IPCC Fourth Assessment Working Group Reports,” Presentation to the United Nations, 9/24/07.