Significant multicropping and low land‐use risk classifications in international aviation and maritime fuel standards

Abstract Multicropping occurs when two or more crops are harvested on the same land in the same year. Multicropped soybean‐corn production has expanded substantially in Brazil in recent years, with some of the second‐crop corn used as a biofuel feedstock. Adding a second crop to single‐cropped land is a form of intensification that increases productivity. In regions with high levels of land speculation, like Brazil, systematic and large‐scale productivity gains incentivize land conversion by increasing the economic returns to cropland. There can also be high induced land‐use change (ILUC) greenhouse gas (GHG) emissions from the conversion of land into agriculture because the climatic conditions conducive for multicropping occur in regions that would otherwise have carbon‐dense vegetation. Despite these linkages, the production of second‐crop corn at a large scale in Brazil has been classified as having low ILUC risk without consideration of its potential market‐mediated responses and indirect emissions in international carbon intensity fuel protocols. In this paper, I provide an overview of how ILUC GHG emissions are estimated in clean transportation fuel programs. I review the literature on the ILUC GHG emissions and the Brazilian second‐crop corn specifically, which has become a prominent biofuel feedstock. I then describe land‐use risk classifications in international aviation and maritime fuel carbon intensity standards and the implications of classifying globally traded feedstocks that are harvested as second crops as ‘low‐risk’ for land‐use change. I conclude by discussing the importance of re‐evaluating land‐use risk classifications in clean transportation fuel programs while research on the topic remains ongoing.