This came to my attention via Adam Cherson. More from our esteemed colleagues at the PNAS: http://www.pnas.org/content/108/51/20277 Unfortunately, subscription required. Can anyone out there facilitate distribution of the whole story (link or pdf) to the masses? Thanks, happy holidays, and wishing the globe a lower carbon footprint in '12. Greg
Geoengineering: The good, the MAD, and the sensible Hans Joachim Schellnhuber1 + Author Affiliations Potsdam Institute for Climate Impact Research, Telegraphenberg A31, 14412 Potsdam, Germany After the collapse of international climate policy in Copenhagen in December 2009, the tale of geoengineering, promising end-of-the-chimney fixes for anthropogenic global warming, has become increasingly popular (1). This is essentially a tale of two fairies (2): the rather wicked one conjures up solar radiation management (SRM), and the tolerably good one delivers CO2 removal through schemes like industrial “air capture” (IAC). Unfortunately, a study by House et al. (3) pours lots of cold water on the hot IAC stuff. Most notably, the authors maintain that the total systems costs of IAC (factoring in all pertinent processes, materials, and structures) might well be on the order of $1,000 (US$) per ton CO2 extracted from the atmosphere. This is tantamount to forecasting a financial tsunami: for making a tangible contribution to global warming [and ocean acidification (4)] reduction, several Gt CO2 should be “scrubbed” every year in the last third of the 21st century (see below), thus generating a multitrillion-dollar IAC bill. House et al. arrive at their important cost estimate by blending existing bits of scientific and technical information into a convincing common-sense analysis. The take-home message is that the energetic and economic challenges of IAC systems design and implementation have probably been underestimated by previous studies promoting that climate-fix option (5–7). The House et al. argument rests on five cognitive pillars, namely (i) an evaluation of the pertinent Sherwood-plot approach to dilute streams (8); (ii) a realistic thermodynamic efficiency assessment of the processes involved in IAC; (iii) a rough quantification of the power costs for IAC, which can achieve significant carbon negativity only by tapping nonfossil energy sources; (iv) an analogy assessment of the work required for chemical removal of trace gases from mixed streams, exploiting rich empirical data available for SO2 and … -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to geoengineering@googlegroups.com. To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
