New Report Challenges Searchinger et al, ILUC Study (re biofuels)

[JohnWxy]

http://blog.25x25.org/?p=404

A report published this week severely criticizes a study published by Science magazine last year that opened the ongoing debate over indirect land use changes (ILUC) resulting from biofuels production. John A. Mathews and Hao Tan, of Macquarie University in Sydney, Australia, take issue with the methodology and assumptions used by Tim Searchinger and others in the study, Use of U.S. Croplands for Biofuels Increases Greenhouse Gases through Emissions from Land Use Change, which was published in February, 2008.
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The final concluding paragraph is most damning, not only of the Searchinger "study" but also of the journal Science for even publishing it:

"Indeed if you wished to put US ethanol production in the worst possible light, assuming the worst possible set of production conditions guaranteed to give the worst possible ILUC effects, then the assumptions chosen would not be far from those actually presented (without argument or discussion of alternatives) in the Searchinger et al. paper. This, together with the fact that the paper is not replicable, since the models and parameters used are not accessible, places a question mark over the refereeing procedures used for this paper by the journal Science. A paper that seeks to place a procedure in the worst possible light, and refrains from allowing others to check its results, is perhaps better described as ideology than as science."


Actually, I think the better term here is not "ideology" but religion. This product was certainly not science it was just a relentless repitition of dogma.__JW


Link to complete report

Excerpts: (all emphases my own_JW)


Searchinger et al. do not discuss alternative approaches, but actually several have been discussed in the literature and
have resulted in published results remarkably at variance with those published by Searchinger et al. For example,
one approach would be to take actual plantings of biofuel crops around the world, as reported by FAO, to calculate
the impact of a ‘spike’ in consumption in the USA or elsewhere. This was the approach adopted by Gurgel et al.10
and others such as Ahammad and Mi11 and Golub et al.12 Two versions of the model are employed in Gurgel et al.,10
one allowing unrestricted conversion of natural forest and grass land to cropland and another based on observed land
supply response. Both models are simulated for two alternative future scenarios, i.e., the scenario of business-as-usual
(BAU) and the policy scenario where a global effort would be mounted to limit global cumulative emissions to about
1490 billion metric tons (bmt) from 2012 to 2050 (and 2834 bmt from 2012 to 2100). Gurgel et al.10 estimate that in the
first scenario the global biofuel production will be below 16 Exajoules (i.e., about 68 billion liters of ethanol) ‡‡‡ until
2040 and in the second scenario the global biofuel production will be around 70 Exajoules (about 300 billion liters of
ethanol) in 2040 – both exceeding the ‘peak’ considered by Searchinger et al.
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Other economic modeling works also produce results at variance from those in Searchinger et al. For example, using Five different variants of the Global Trade Analysis Project (GTAP) model at Purdue University, Golub et al.12 project ‘a strong move towards aforestation in response to increased demand for forest products worldwide, including ASEAN, South Asia and the Rest of the World – three regions which have experienced extensive deforestation in the past few decades’. It is projected by all Five models that land use in China, for example, moves from agricultural crops to pasture (for ruminants) and forestry in the next 15 years, a conclusion sharply at odds with that of Searchinger et al. ...


Actually there are available alternative views as to the carbon released by changes in land use by bodies as reputable as the IPCC (above) and the OECD. These make much more reasonable assumptions than employed in Searchinger et al. The OECD, for example, estimates that the US EISA program and the new EU Directive on Renewable Energy (DRE) together are expected to increase use of ethanol by some 17% by 2013–2017, i.e., 19.4 billion liters.22 However, the impact on total crop area in the world is much more modest compared with the calculation of Searchinger et al., rising by less than 1% from the baseline of about 6.8 million ha, as shown in Fig. 3.


For its part, the EU is also developing alternative estimates of ILUC e# ects that will no doubt be very different from
those offered by Searchinger et al. In countries directly influenced by these considerations, such as Brazil, stringent efforts have been made to accurately assess the real land use change effects that have occurred as a result of expansion of biofuel crops. In Brazil, around 22 billion liters of bioethanol were produced on 3.6 million ha of area in 2007/2008, accounting for a very small proportion of the cultivated area and the total rural properties, as shown in Fig. 4.
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In fact, the kind of ILUC effects that form the basis of the calculations offered by Searchinger et al. (calculations that
are not in fact replicable by other scientific laboratories since key models and relationships and parameters are not speci-
fied) simply open up the prospect of endless scientific debate and controversy. There can never be a ‘definitive’ calculation of ILUC effects since such effects depend, as we have shown in this perspective, crucially on the kinds of assumptions made, which in turn make all kinds of assumptions as to regulatory impositions and world trade developments.


Concluding remarks

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Indeed if you wished to put US ethanol production in the worst possible light, assuming the worst possible set of production conditions guaranteed to give the worst possible ILUC effects, then the assumptions chosen would not be far from those actually presented (without argument or discussion of alternatives) in the Searchinger et al. paper. This, together with the fact that the paper is not replicable, since the models and parameters used are not accessible, places a question mark over the refereeing procedures used for this paper by the journal Science. A paper that seeks to place a procedure in the worst possible light, and refrains from allowing others to check its results, is perhaps better described as ideology than as science.