California Air Resources Board

Dear CARB,
Current ILUC modeling cannot be verified, and ILUC model simulation results are driven by belief and widely variable input assumptions rather than by science (see references below). More importantly, after 17 years, all the effort in modeling and ILUC simulated emission penalties have done nothing to deter deforestation and, on the margin, have likely made things worse by:
(a) distracting attention and resources away from timely responses to destructive LUC and deforestation events,
(b) undermining projects and initiatives that were trying to focus on the actual problems facing people in active deforestation frontiers through projects that used biofuel market demand to support more sustainable land use planning and enforcement; and
(c) reducing opportunities to provide clear incentives to producers to reduce their supply chain GHG emissions by adding a theoretical and unverifiable variable (ILUC) and large additional emission factors that fall outside producers' control.
It seems incredible that ILUC models are being used for policy but they cannot effectively back-cast or explain what is actually occurring, for example, the situation where the US is producing record volumes of ethanol, on less farmland than ever (Irwin 2025) – as farmland is converted under development and urban sprawl or set aside in permanent conservation easements (Land Trust Alliance-LTA; Wildlife Society), and with producer prices that are persistently so low that farmers rely on subsidies to keep operations going. ILUC models said all these indicators would go the other way with record ethanol production. It is noteworthy that the “from 2000 to 2025, land in [permanent] wetland and forest easements in the US acreage more than doubled. And total easements grew from 47 million acres in 2010 to 61 m acres in 2025” (LTA).
A more constructive path is recommended. Rather than continuing to debate ILUC, in which case nothing will change and we will still be debating it in 2040, please try doing something different. Focus on how CARB could provide incentives for more productive actions aligned with its goals and as appropriate for a performance-based low-carbon fuels program:
(1) Provide and communicate clear incentives for feedstock producers and biofuel supply chain managers to reduce their supply chain emissions based on verifiable measures.
(2) For ILUC concerns, monitor destructive LUC and hold accountable those responsible; and allocate the corresponding emissions to the actual causal factors for those emissions based on scientific causal analysis (e.g., see Efroymson et al.);
(3) Apply a risk-based approach to LUC reflecting the likelihood for a biofuel production pathway to be a causal agent for destructive LUC based on the weight of evidence approach for causality, and starting with whether or not destructive LUC is occurring I areas surrounding (or with verifiable linkages to) the biofuel feedstock production system and biorefinery supply chain.
These three things could make a positive difference in the world, catalyzed by CARB and LCFS, whereas continuing ILUC modeling and debates will not.
Thank you for your consideration of these comments. Please let me know if I can be of assistance in next steps.
Below are a few supporting references for assertions made above.
Sincerely,
Keith L. Kline
Adjunct Professor
University of Tennessee Institute for Agriculture, Knoxville
kkline@utk.edu
===================
Dale VH, KL Kline. 2013. Modeling for integrating science and management. Pages 209-240 In D.G. Brown, D. T. Robinson, N. H. F. French, and B.C. Reed (editors), Land Use and the Carbon Cycle: Advances in Integrated Science, Management, and Policy, Cambridge University Press.
Engert JE et al. 2024. Ghost roads and the destruction of Asia-Pacific tropical forests. Nature, doi:10.1038/s41586-024-07303-5
IEA 2025 report "Toward common criteria for sustainable fuels" that recommended discontinuing ILUC www.iea.org/reports/
Irwin, S. "Estimating Total Crop Acres for the U.S. over 1998-2025." farmdoc daily (15):61, Department of Agricultural and Consumer Economics, University of Illinois at Urbana-Champaign, April 2, 2025.Permalink
Kline and Dale 2020. Protecting Biodiversity through Forest Management: Lessons Learned and Strategies for Success. DOI: 10.19080/IJESNR.2020.26.556194
Kline et al. 2015. Bioenergy and biodiversity: Key lessons from the Pan America Region. Environmental Management 56:1377-1396
Kline et al. 2011. Scientific analysis is essential to assess biofuel policy effects. Biomass & Bioenergy, 35.
Land Trust Alliance (LTA) 2025 https://landtrustalliance.org/land-trusts/gaining-ground/united-states
Laurence et al. 2024. Roads of destruction; Protecting Biodiversity through Forest Management: Lessons Learned and Strategies for Success. DOI: 10.19080 (and several other papers by Lawrence and colleagues)
Oladosu et al 2021 causal analysis of historical data shows no evidence to support ILUC model assumptions: Oladosu et al.. 2021. Structural break and causal analyses of U.S. Corn use for ethanol and other corn market variables. Agriculture 11(3)
UNEP (2016) Unlocking the Sustainable Potential of Land Resources: Evaluation Systems, Strategies and Tools. Working Group on Land and Soils, International Resource Panel (IRP UNEP). Herrick, JE, O Arnalds, B Bestelmeyer, S Bringezu, G Han, MV Johnson et al. , ISBN: 978-92-807-3578-9
Warner et al. 2013. Challenges in the estimation of greenhouse gas emissions from biofuel-induced global land-use change. https://doi.org/10.1002/bbb.1434
Wildlife Society 2023 (expansion of conservation easements on former agricultural lands): https://wildlife.onlinelibrary.wiley.com/doi/10.1002/wsb.1415