Disproof of the ACP biofuel paper - N2O release from agro-biofuel production negates global warming reduction by replacing fossil fuels

May 2008

The fundamental approach of the Atmospheric Chemistry and Physics (ACP) biofuel paper is that the N content of a crop or crop part determines the amount of N2O emissions ascribable to its production, and the paper compares the warming effect Meq of the N2O emissions related to liquid biofuels to the cooling effect M of the CO2 savings resulting from their replacing fossil fuels, expressed in the ratio Meq/M. Although this N contents approach is sound, a set of assumptions and simplifications far from reality, including an overestimation of the N2O emissions from agriculture as a whole, result in completely misleading values of Meq/M, so the sensational unconditional conclusion, that liquid biofuels cause warming rather than cooling, is simply a fallacy.
As demonstrated in this disproof with its available sources and comprehensive calculations based upon the conditions in the real world outside the cities, liquid biofuels produced as part of responsible and competent agriculture cause no or only small N2O emissions in themselves, which leads to Meq/M values that are either 0 or rather low, in other words no, or only a limited, warming effect to counteract the cooling effect of using liquid biofuels; even for an agriculture as incredibly wasteful as assumed in ACP biofuel paper, unthinkable in responsible and competent agriculture, the real Meq/M values are far below the paper values. Apart from reducing GHG emissions, the production of liquid biofuels may contribute to significant environmental improvements in agriculture as a whole, especially if it is regulated by simple and reasonable environmental requirements on a worldwide scale.

By: P. J. Crutzen, A. R. Mosier, K. A. Smith, W. Winiwarter

 
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