Navigating the maize

The report by Cerulogy critiques an ICF International assessment that claimed corn ethanol's GHG intensity in 2014 was 30% lower than the U.S. EPA's 2022 projections. Cerulogy identifies systemic errors, including the use of preliminary rather than final EPA data, the double-counting of co-product credits, and an over-reliance on a single non-peer-reviewed study (Babcock and Iqbal, 2014) to justify lower international land use change emissions. The review concludes that the ICF report's results are 'meaningless' or 'inaccurate' in several key areas, including rice methane and nitrogen emissions, and recommends that the ICF's revised lifecycle intensity be disregarded.

• The ICF report contains significant data errors, such as using preliminary rather than final RFS2 analysis data for rice area and methane emissions, which led to an inappropriate multiplication of the rice methane reduction credit by a factor of 20.
• ICF's reassessment of domestic and international rice methane is considered essentially meaningless because it incorrectly compared the 'corn only' scenario to the 'reference case' instead of the 'control case' required by the RFS RIA methodology.
• The review identifies a major methodological error where ICF double-counted emissions benefits from ethanol co-products (distillers' grains), as these credits were already implicitly included in the land use and farming emissions data used from the RFS RIA.
• ICF's claims regarding the rapid adoption of precision agriculture and reducing nitrogen fertilization rates are not supported by USDA statistics; the review notes that N-fertilization rates per bushel dropped by only 0.1% from 2005 to 2010.
• The ICF report's preference for the GTAP-CCLUB modeling framework over the EPA's FAPRI-FASOM framework is inadequately justified and ignores known limitations of GTAP, such as its inability to bring 'unmanaged land' into productive use.
• The use of the CCLUB model for land use change emissions factors is criticized for relying on unsupported assumptions that converting cropland or cropland pasture to corn increases soil carbon stocks.
• The review argues that ICF's international land use change (ILUC) results are based on a systematic over-reliance on a single non-peer-reviewed staff report by Babcock and Iqbal (2014), while ignoring caveats in that source and misinterpreting data for Brazil, China, Indonesia, and Sub-Saharan Africa.
• In Brazil, the B&I data used by ICF contained labeling errors and incorrect values; a correct analysis of the full 2003-2015 period shows that 65% of harvested area change was extensive, contradicting the 24% extensive rate assumed by ICF.
• The ICF report's 'building blocks' scenario, which suggests a 76% potential GHG reduction, is characterized as 'aspirational' and 'perhaps unachievable' because it assumes unrealistic 100% adoption of nitrogen inhibition by 2020.
• The review concludes that the ICF report exhibits a systematic imbalance, favoring data and studies that suggest lower carbon intensity for corn ethanol while ignoring evidence of higher emissions, such as the link between ethanol refineries and the loss of carbon-rich grasslands and wetlands in the U.S.

APA

Malins, C. (2017). Navigating the maize. Clean Air Task Force. https://cdn.catf.us/wp-content/uploads/2018/10/21094507/CATF_Pub_NavigatingTheMaize.pdf

Chicago

Malins, Chris. Navigating the maize. Clean Air Task Force, 2017. https://cdn.catf.us/wp-content/uploads/2018/10/21094507/CATF_Pub_NavigatingTheMaize.pdf.

Wikipedia

{{cite report |last1=Malins |first1=Chris |title=Navigating the maize |publisher=Clean Air Task Force |date=July 2017 |url=https://cdn.catf.us/wp-content/uploads/2018/10/21094507/CATF_Pub_NavigatingTheMaize.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{malins2017navigating, author = {Malins, Chris}, title = {{Navigating the maize}}, institution = {Clean Air Task Force}, year = {2017}, month = jul, url = {https://cdn.catf.us/wp-content/uploads/2018/10/21094507/CATF_Pub_NavigatingTheMaize.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }