According to the Oil Price Information Service (OPIS) and other media organizations, 14 scientists and researchers submitted a letter to the California Air Resources Board (CARB) on March 6 urging the agency to meaningfully reduce its indirect land use change (iLUC) penalties for corn ethanol under the Low Carbon Fuel Standard (LCFS). The letter couldn�t have been more timely, as CARB staff is hosting a workshop March 11 to discuss potential changes to the program�s existing iLUC penalties. The bottom line from the letter is this: �In general, our recent work�and analyses conducted by other experts in the field�indicates that CARB�s existing [carbon intensity] factors significantly overestimate the GHG emissions associated with potential ILUCs resulting from corn ethanol expansion. Analyses conducted since CARB adopted the LCFS in 2009 show that potential ILUC emissions associated with corn ethanol are more likely in the range of 6-15 grams per megajoule of CO2 equivalent (g/MJ), compared to CARB�s estimate of 30 g/MJ.� We�ll discuss the letter in more depth in a moment. But first, a little history and background on the LCFS and the iLUC controversy. The LCFS requires California fuel producers and suppliers to annually reduce the carbon intensity (CI) of the fuel they provide to the market, culminating in a 10% reduction from 2010 levels by 2020. CARB expects fuel suppliers will accomplish these CI reductions by entirely replacing high-carbon fuels with low-carbon fuels, or by blending low-carbon fuels with high-carbon fuels to reduce the CI of the finished fuel. Every fuel is assigned a CI score�measured in grams of CO2-equivalent/mega joule (g/mj)�based on CARB�s estimate of the total lifecycle emissions associated with producing and marketing the fuel. For reference, gasoline has a CI score of 99.2 g/mj. In a highly controversial decision almost five years ago, CARB adopted a punitive iLUC penalty of 30 g/mj against corn ethanol when it finalized the LCFS regulation. The effect of this penalty (which was based on the hotly debated and highly uncertain results of hypothetical scenario modeling) was to render most Midwest corn ethanol unfit for mid- or long-term compliance under the LCFS program. The assessment of ILUC penalties meant that rather than reducing GHG emissions by 30-40% compared to gasoline, most corn ethanol would be treated as only slightly better�or slightly worse�than gasoline in terms of lifecycle CI impacts. That is, without the iLUC penalty, most corn ethanol would fall in the 60-70 g/mj range (according to CARB). But when the 30 g/mj penalty is applied, the CI scores for corn ethanol jump to 90-100 g/mj; that means blending 10% corn ethanol with gasoline generally isn�t viewed by fuel providers as an effective mid- or long-term compliance strategy. The scientific community, biofuels industry, and some lawmakers warned CARB in 2009 that the iLUC concept was not ready for regulatory primetime. They cautioned that iLUC modeling results were unverifiable, too uncertain, and too dependent on crude assumptions. They also voiced the concern that crop-based biofuels were being unfairly singled out, and underscored that all fuels have uncertain and immeasurable indirect effects. But alas, CARB voted to adopt the 30 g/mj iLUC penalty despite these warnings. That penalty remains in effect today. That brings us back to the letter. Just because CARB stopped studying the land use impacts of biofuels in 2009 doesn�t mean the scientific community stopped caring. In fact, just the opposite is true. Over the past five years, scientists, economists, and lifecycle analysis experts from around the world have continued to rigorously examine the land use impacts of biofuels expansion. They have refined and improved existing modeling frameworks, collected better data, created entirely new methodologies, and tested the original iLUC hypothesis by examining real-world trends. The result of all their hard work is a much better understanding of the impacts of biofuels expansion on land use. Still, important uncertainties remain. Incidentally, the research community also has a better understanding today of the carbon impacts associated with petroleum fuels [see study]. Not surprisingly, as more is learned, ethanol�s carbon footprint continues to shrink, while the footprint for crude oil continues to grow. Some of the published research conducted over the past few years is referenced in the letter from the scientists, five of whom served on a CARB-appointed iLUC working group in 2010. They cite 15 recent studies and suggest that the research shows it is much more likely that potential iLUC emissions are in the range of just 6-15 g/mj�or 50-80% lower than CARB�s current penalty. It�s important to point out here that the scientists aren�t stating that the 6-15 g/mj range represents the definitive or �right� estimate in terms of actual iLUC impacts�rather, they seem to be saying the 6-15 g/mj range is the right place to move for now within the LCFS regulatory construct. Here�s what they say: �Many of us continue to believe the use of point-estimate ILUC factors is inappropriate for the purposes of regulation. However, to the extent that CARB continues to rely upon the use of ILUC factors in calculating CI scores for the LCFS, we believe the Board should be familiar with the most recent independent modeling results.� In other words, attempting to asses iLUC penalties against biofuels in 1 g/mj increments is a fool�s errand, given the associated uncertainty in the estimates, the total lack of validation, and the absence of real-world data to support the concept. But we�re stuck with an arcane policy framework built on the g/mj scoring metric, so the policy ought to at least be informed by the latest science. Let�s hope CARB does the right thing and follows the advice of these scientists.