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Researchers: Lark’s Attack on RFS ‘More Problematic’ Than Initially Thought

May 25, 2022

Research, RFS


A recent, highly publicized report led by Tyler Lark of the University of Wisconsin attacking the Renewable Fuel Standard is “more problematic than what we initially evaluated to be the case,” according to a new review of the work by researchers from the Department of Energy’s Argonne National Laboratory, Purdue University, the University of Illinois, and elsewhere. The scientists note specifically that Lark and his colleagues grossly misinterpreted land-use change and attributed far too much hypothesized land conversion to the RFS policy while overlooking other factors.


“We welcome this thorough and thoughtful rebuttal to the biased hit piece produced by Lark and his colleagues, which was funded in large part by the National Wildlife Federation,” said Renewable Fuels Association President and CEO Geoff Cooper. “Now, we call on policymakers, regulators, and especially the media to carefully consider this refutation, as well as previous critiques, of the Lark study. It’s time to bring balance, objectivity, and scientific integrity back into discussions and media coverage focused on the RFS and ethanol’s environmental impacts.”


The new review is the latest volley over the environmental benefits of the RFS between Lark et al. and the researchers from Purdue, the University of Illinois, Argonne, Informed Sustainability Consulting, and CropGrower LLC. Lark and his team published a report in the Proceedings of the National Academy of Sciences in February, which was followed on March 22 by the first technical review from Purdue University’s Farzad Taheripour and his colleagues.


“After a detailed technical review of the modeling practices and data used by Lark et al., we conclude that the results and conclusions provided by the authors are based on several questionable assumptions and a simple modeling approach that has resulted in overestimation of the GHG emissions of corn ethanol,” the group wrote. Lark et al. then unconvincingly responded on April 7, prompting today’s follow-up rebuttal.


RFA itself issued two reviews of the Lark attack. In its preliminary rebuttal, published on the same day the Lark study was released, the association pointed out  how “the authors of this new paper precariously string together a series of worst-case assumptions, cherry-picked data, and disparate results from previously debunked studies to create a completely fictional and erroneous account of the environmental impacts of the Renewable Fuel Standard.” A more in-depth final rebuttal was published by RFA on April 1.


Yesterday, RFA called on EPA to remove Lark and others from consideration as peer-review candidates for its upcoming Third Triennial Report to Congress on the RFS, noting Lark’s bias and that he should not be allowed to peer-review a report that will likely be based on his own discredited work.