ILUC Uncertainty

Report examines the uncertainty surrounding land use change analyses and available marginal lands.
By Kris Bevill | January 17, 2011

A report issued by the non-profit international scientific organization CABI and Hart Energy Consulting, titled “Biofuels and Land Use Change: A Science and Policy Review,” explores the various research methods used to calculate land use change (LUC) and offers recommendations for the further assessment of both direct and indirect LUC. While the long-term effects of land use for biofuels production is uncertain, the report highlights major discrepencies among the various models used to attempt to calculate LUC and said the methodological problems with lifecycle analysis only compound that uncertainty.

“There is a need to establish standard methodologies to evaluate the wide range of effects, direct and indirect, that ensue from the growing global biofuels market,” says Tammy Klein, assistant vice president of Hart Energy. “This would enable much greater confidence when comparing future studies and enable decision-makers to make more informed judgments.”

Authors of the report reviewed 67 biofuel life-cycle analyses (LCAs) and found that the studies used different methods of allocating energy used and produced and also used various start and end points. Some measure well-to-wheel, some measure well-to-tank and others calculate cradle-to-grave impacts. “The latter is the most complete and indeed is surely needed if society is to evaluate the full costs of our current freewheeling lifestyles,” the authors wrote. “But by so doing, these most comprehensive studies tend to reduce the overall differences between fuel stocks, which are often the center of interest.” Considering the wide discrepancies among analysis methods, the report’s authors found that no one LCA could be confidently credited, unless every assumption used for the analysis were to be listed and emphasis were given to remaining uncertainties.

  • Putting aside the questionable LCA methodologies, the report attempted to examine possible LUC as a result of greater biofuels demand. The authors identified several scenarios in which LUC could occur as a result of biofuels, including:
  • Bringing land into production that has not previously been used for agricultural purposes.
  • Replacing existing food crops with biofuels crops.
  • Utilizing marginal lands to produce biofuels crops.
  • Intensifying land use without reducing crop production, including improved yields, technologies and integrating crop and/or livestock activities.


With respect to marginal land use, the report’s authors found several crops with potential to thrive, including jatropha, sweet cassava, sweet potato and energy grasses. However, the authors cited a 2005 assessment that claimed nearly all of the world’s suitable land is already in use and expressed uncertainty as to how much marginal land might actually be available to satisfy biofuels expansion. “There are major doubts about official estimates of available land, including those classed as unused, abandoned, degraded and marginal,” the authors stated. “Current estimates of the land that might be pressed into service in the next 40 years vary widely, by half an order of magnitude and more. Until these discrepancies are resolved, the various attempts to calculate and model what will happen as biofuel production expands should be regarded as extremely tentative, otherwise such estimates run the risk of becoming accepted as the truth by policymakers.”

In the U.S., energy grass proponents have poured much effort into the exploitation of marginal lands for biofuel crop production. Ceres Inc., a California-based energy crop developer, recently conducted a survey of farmers in the Southeast to gauge their interest in growing energy crops and examine whether there might be enough marginal land to grow the crops. Three-quarters of the survey’s respondents said they do in fact have under-utilized land that would be suitable for grasses such as miscanthus, sorghum and switchgrass. Almost as many growers showed interest in growing those crops as a way to diversify their growing operations. Additionally, more than 70 percent of growers surveyed said they support long-term contracts and would consider putting at least half of their acreage in long-term energy crop contracts. Gary Koppenjan, communications and product marketing director for Ceres, says this is good news for end users since long-term feedstock contracts are critical for new facilities to obtain financing. “What constitutes a long-term contract will likely be an area for discussion, but it appears the suppliers and users are on the same page,” he says.