Document Detail


The role of N2O derived from crop-based biofuels, and from agriculture in general, in Earth's climate.
MedLine Citation:
PMID:  22451102     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In earlier work, we compared the amount of newly fixed nitrogen (N, as synthetic fertilizer and biologically fixed N) entering agricultural systems globally to the total emission of nitrous oxide (N(2)O). We obtained an N(2)O emission factor (EF) of 3-5%, and applied it to biofuel production. For 'first-generation' biofuels, e.g. biodiesel from rapeseed and bioethanol from corn (maize), that require N fertilizer, N(2)O from biofuel production could cause (depending on N uptake efficiency) as much or more global warming as that avoided by replacement of fossil fuel by the biofuel. Our subsequent calculations in a follow-up paper, using published life cycle analysis (LCA) models, led to broadly similar conclusions. The N(2)O EF applies to agricultural crops in general, not just to biofuel crops, and has made possible a top-down estimate of global emissions from agriculture. Independent modelling by another group using bottom-up IPCC inventory methodology has shown good agreement at the global scale with our top-down estimate. Work by Davidson showed that the rate of accumulation of N(2)O in the atmosphere in the late nineteenth and twentieth centuries was greater than that predicted from agricultural inputs limited to fertilizer N and biologically fixed N (Davidson, E. A. 2009 Nat. Geosci. 2, 659-662.). However, by also including soil organic N mineralized following land-use change and NO(x) deposited from the atmosphere in our estimates of the reactive N entering the agricultural cycle, we have now obtained a good fit between the observed atmospheric N(2)O concentrations from 1860 to 2000 and those calculated on the basis of a 4 per cent EF for the reactive N.
Authors:
Keith A Smith; Arvin R Mosier; Paul J Crutzen; Wilfried Winiwarter
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Philosophical transactions of the Royal Society of London. Series B, Biological sciences     Volume:  367     ISSN:  1471-2970     ISO Abbreviation:  Philos. Trans. R. Soc. Lond., B, Biol. Sci.     Publication Date:  2012 May 
Date Detail:
Created Date:  2012-03-27     Completed Date:  2012-10-16     Revised Date:  2013-05-06    
Medline Journal Info:
Nlm Unique ID:  7503623     Medline TA:  Philos Trans R Soc Lond B Biol Sci     Country:  England    
Other Details:
Languages:  eng     Pagination:  1169-74     Citation Subset:  IM    
Affiliation:
Woodlands One, Pomeroy Villas, Totnes, Devon, UK. keith.smith@ed.ac.uk
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MeSH Terms
Descriptor/Qualifier:
Agriculture*
Air Pollutants / chemistry*
Biofuels*
Climate*
Denitrification
Nitrification
Nitrous Oxide / chemistry*
Soil / chemistry*
Chemical
Reg. No./Substance:
0/Air Pollutants; 0/Biofuels; 0/Soil; 10024-97-2/Nitrous Oxide

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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