But doesn't the question whether CaCO3 formation is a net source or sink of atmospheric CO2 depend on where the bicarbonate comes from?
If CO2(aq, recently from atm) + H20 --> H2CO3 --> HCO3- + H+ is the source of the HCO3-, as at present in the Southern Ocean, then there is a net sink of one carbon. As the equation below requires two bicarbonate ions, 2C from atmosphere & 1C returns to atmosphere, there is a net sink of one carbon. It seems a blanket statement that CaCO3 formation emits CO2 presumes an infinite oceanic capacity to hold bicarbonate. Is that true? Doesn't increasing bicarbonate eventually degrade the ocean's H+ buffering function? Some may consider ocean acidification to be a more existential threat than greenhouse warming, in the unknown unknown category. ----- Original Message ----- From: Ken Caldeira To: [email protected] Cc: [email protected] ; [email protected] Sent: Saturday, January 05, 2013 1:49 PM Subject: Re: [geo] Geoengineering: rules needed for climate-altering science - International institute for Strategic Studies Russell has his facts right but chemical implications wrong: The net reaction for the formation of CaCO3 shells can be written: Ca2+ + 2 HCO3- ===> CaCO3 + H2O + CO2 Thus the formation of carbonate minerals from sea water acts as a carbon source to the atmosphere, not a sink. Greg Rau, among others, has proposed trying to run this reaction to the left to sequester CO2. This is sometimes known as "Accelerated Carbonate Weathering". http://crustal.usgs.gov/projects/CO2_sequestration/limestone.html _______________ Ken Caldeira Carnegie Institution for Science Dept of Global Ecology 260 Panama Street, Stanford, CA 94305 USA +1 650 704 7212 [email protected] http://dge.stanford.edu/labs/caldeiralab @kencaldeira Caldeira Lab is hiring postdoctoral researchers. http://dge.stanford.edu/labs/caldeiralab/Caldeira_employment.html Our YouTube videos The Great Climate Experiment: How far can we push the planet? Special AGU lecture: Ocean Aciditication: Adaptive Challenge or Extinction Threat? More videos On Sat, Jan 5, 2013 at 10:12 AM, Russell Seitz <[email protected]> wrote: Given the proximity of so many of ISIS proncipal to Chesapeake Bay, I am shocked they have not hit on the opportunity to combine the Beltway's lust to regulate with the best features of carbon capture and SRM. The key to this win-win-win strategem is the humble mollusc Ostrea edulis. A dozen oysters sequester a hundred grams or more of carbon in their shells, and were the daily consumption of a dozen made mandatory, their removal from the sea would make room for the sequestration of a hundred grams more. In addition, discarding the shells on land would at once take a bite out of sea level rise, and, as ouster shells are pearly white , tend to reduce the albedo footprint of those consuming them, especially if they toss them on their asphalt coated roofs, parking lots and driveways to reduce the energy toll and radiative forcing burden of the urban heat island effect . Confident that perfoming the dimensional analysis necessary to persuade themselves of the relative worth of this concept will encourage readers to do likewise to their own submissions I remain Your , etc. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To view this discussion on the web visit https://groups.google.com/d/msg/geoengineering/-/_KEqoHead7IJ. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
