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999			_c62829 _d62821
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003			MX-TxCIM
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008			201030s2012||||xxk|||p|op||||00||0|eng|d
022			_a0962-8436
022			_a1471-2970 (Online)
024	8		_ahttps://doi.org/10.1098/rstb.2011.0313
040			_aMX-TxCIM
041			_aeng
100	1		_aSmith, K.A. _912844
245	1	4	_aThe role of N2O derived from crop-based biofuels, and from agriculture in general, in Earth's climate
260			_aLondon (United Kingdom) : _bThe Royal Society, _c2012.
500			_aPeer review
520			_aIn 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 (N2O). We obtained an N2O 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, N2O 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 N2O 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 N2O 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 NOx 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 N2O concentrations from 1860 to 2000 and those calculated on the basis of a 4 per cent EF for the reactive N.
546			_aText in English
650		7	_aNitrous oxide _2AGROVOC _94669
650		7	_aBiofuels _2AGROVOC _97324
650		7	_aAgriculture _gAGROVOC _2 _91007
650		7	_aEmission _2AGROVOC _911417
650		7	_aLife Cycle Analysis _2AGROVOC _98633
700	1		_aMosier, A.R. _916847
700	1		_aCrutzen, P.J. _912847
700	1		_aWiniwarter, W. _916848
773	0		_dLondon (United Kingdom) : The Royal Society, 2012. _x0962-8436 _gv. 367, no. 1593, p. 1169-1174 _tPhilosophical Transactions of the Royal Society of London. Series B, Biological Sciences _wu444862
942			_cJA _n0 _2ddc