Why NH 3 is not a candidate reagent for ambient CO 2 fixation: A response to “Alternative solution to global warming arising from CO 2 emissions—Partial neutralization of tropospheric H 2 CO 3 with NH 3 ”

• Published in: Environmental Progress
• Main Authors: Johnson, Martin T., Vaughan, Naomi E., Goodwin, Philip, Goldblatt, Colin, Roudesli, Sonia, Lenton, Timothy M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2008
• Subjects: Carbonic acid
• Online Access: http://dx.doi.org/10.1002/ep.10298; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fep.10298; https://onlinelibrary.wiley.com/doi/pdf/10.1002/ep.10298

Abstract It has been proposed that application of urea, or ammonium sulfate (plus lime) to nonagricultural land to evolve ammonia may provide a “solution” to increasing CO 2 concentrations by neutralizing atmospheric carbonic acid to ammonium bicarbonate at ambient concentrations and subsequent storage in the surface ocean (Apak [2007]: Environmental Progress 26, 355–359). We identify a series of major flaws in this hypothesis, which indicate that the approach is unfeasible and would not succeed if attempted at any scale: (i) The phenomenal energy cost associated with breaking the NN bond and evolving H 2 for NH 3 production (and associated fossil fuel CO 2 emissions under the current energy generation market); (ii) the radiative forcing associated with substantially increasing the concentration of ammonia in the atmosphere, and (iii) a number of unwanted indirect effects, including eutrophication, enhanced N 2 O emissions, and the inhibition of the oxidation of strong greenhouse gases such as methane in the atmosphere. We strongly urge future efforts to be directed away from this approach and suggest that engagement with the climate, earth‐system, and biogeochemistry communities is essential when putting forward ideas for potential geoengineering approaches to mitigate global climate change. © 2008 American Institute of Chemical Engineers Environ Prog, 2008