Why NH3 is not a candidate reagent for ambient CO2 fixation: A response to "alternative solution to global warming arising from CO2 Emissions - Partial neutralization of tropospheric H 2CO3 with NH3"

• Published in: Environmental Progress
• Main Authors: Johnson, M.T., Vaughan, N.E., Goodwin, P., Goldblatt, C., Roudesli, S., Lenton, T.M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2008
• Subjects: 01 - Climate Change and Earth-Ocean Atmosphere Systems; Carbonic acid
• Online Access: http://eprints.esc.cam.ac.uk/2300/; http://eprints.esc.cam.ac.uk/2300/1/Goodwin_3_10298_ftp.pdf; https://doi.org/10.1002/ep.10298

It has been proposed that application of urea, or ammonium sulfate (phis lime) to nonagricultural land to evolve ammonia may provide a "solution" to increasing CO2 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) ne phenomenal energy cost associated with breaking the N≡N bond and evolving H2 for NH3 production (and associated fossil fuel CO2 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 N2O emissions, and the inhibition of the oxidation of strong green-house 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 biogeochemtetry communities is essential when putting forward ideas for potential geoengineering approaches to mitigate global climate change. © 2008 American Institute of Chemical Engineers.