ILUC is an acronym for indirect land use change and it is typically used in conjunction with the impacts of changes to global agriculture for biomass and feedstock production for biofuels. This is a controversial subject. There is little agreement on how indirect land use change can or should be measured or the degree to which changing world energy demands and other economic factors such as the impact of the rising price of oil on agriculture affect world trade in food for direct human consumption (e.g. vegetables) or for animal feed (corn as cattle feed). ''This entry requires more work and attributions of claims and arguments''.

Until 2008, several full life cycle studies had found that corn ethanol, cellulosic ethanol, and Brazilian sugarcane ethanol? reduced GHG emissions when compared to gasoline. The reduction of carbon intensity for a given biofuel was dependent on the assumptions implicit in the study. The studies did not consider the effects of indirect land-use changes. The estimation was considered too complex and more difficult to model than direct land use changes.

One argument is that an unintended consequence of indirect land use change impacts of biofuels is that there may be the unintended consequence of releasing more carbon emissions? due to land use changes around the world induced by the expansion of croplands for ethanol or biodiesel production in response to the increased global demand for biofuels. The argument proposes that as farmers worldwide respond to higher crop prices to maintain the global food supply and demand balance, land is cleared and converted to new cropland to replace the crops for feed and food that were diverted elsewhere to biofuels production. The argument continues that because rainforests? and grasslands? sequester carbon? in their soil and roots as they grow, clearance of wilderness for new farms in other regions or countries translates in a net increase in greenhouse gas emissions, and due to this change in the carbon stock of the soil and the biomass, indirect land use change has consequences in the GHG balance of a biofuel.

There are a number of difficulties with this argument, however. Here are some:

• The energy balance and equation of crops like corn being used for ethanol is inaccurately calculated in the ILUC argument presented above. Because only starch is used in first generation corn ethanol production, and the remainder DDGs is still used as an animal feed, the assumption that the entire corn crop is being diverted for fuel is erroneous.^citation?
• The rising price of food can be directly attributed to biofuels. There is evidence to suggest that agricultural commodities are far more closely tied to the price of oil than biofuels and that biofuels reduce the price of food to consumers.^citation?
• Agriculture in the first world is often subsidized by government, allowing significant quantities of food to be dumped on developing world countries, squeezing out farmers there who cannot rely on government support. This has two effects - creating a reliance on first-world agricultural products and exacerbating price fluctuations in their value and driving subsistence farmers to practices that impact their local ecology. Evidence suggests that biofuels have created high value propositions to local farmers in developing economies. Price competition for feedstocks that can be used for animal feed? or biofuels or both have assisted developing world farmers more easily make a sustainable living and reduced the reliance on dumped first-world products. As such, biofuels growth appears to have slowed land-clearing in developing countries.^citation?

Because of objections and very little verifiable science to justify indirect land use impacts, the Waxman climate bill in its current form will, if approved by the Senate and signed into law by President Obama, suspend the EPA's calculations for at least the international portion of ILUC for at least five years. This is pending a National Academy of Sciences? report and also the approval of the USDA.

Environmentalists say that it is vital that any ILUC calculation take into account both the market-mediated land impact of biofuels production in the United States as well as in other countries. They say this is because the world's remaining carbon sinks are in virgin forest in developing countries.

A paper ¹ ''Measuring Unmeasurable Land-Use Changes from Biofuels'' by Iowa State’s Bruce Babcock provides an overview of the procedures used to estimate indirect land use that are being used by the Environmental Protection Agency EPA and California Air Resources Board CARB?.

According to Paul Winters of the Biotechnology Industry Association (BIO), the indirect land use change theory bears no resemblance to reality. Babcock frames the debate over indirect land use change as “whether the models used by CARB and EPA are accurate enough to support regulations.”

Babcock points out that one criticism of the models used by CARB and EPA to estimate indirect land use is that their predictions of land-use changes aren't matched by the actual changes in land use that have been observed in the last few years in response to sharply higher biofuels volumes.

Two recent studies² of models of the impact of expanded biofuels on US and world agriculture both estimate that expansion of corn ethanol would be accompanied by a large increase in corn production?, a large decrease in soybean production?, and significant decrease in corn and soybean exports?.

History differs from these predictions. Since 2005, corn ethanol has increased by about six billion gallons. Corn acreage? has increased by about 6 percent, which is consistent with predictions. But soybean acreage? has increased by more than 7 percent, corn exports are projected to be flat in the 2009/10 marketing year, and soybean exports? are projected to increase by more than 25 percent. The model predictions completely missed the large expansion in US soybean production that has accompanied corn ethanol expansion and the ability of the United States to maintain or expand its exports of corn and soybeans.

¹ “Measuring Unmeasurable Land-Use Changes from Biofuels”

² Tokgoz et al. 2007 and Hertel et al. 2009