Reducing US biofuels requirements mitigates short-term impacts of global population and income growth on agricultural environmental outcomes

Biobased energy, particularly corn starch-based ethanol and other liquid renewable fuels, is a major element of federal and state energy policies in the United States. These policies are motivated by energy security and climate change mitigation objectives, but corn ethanol does not substantially reduce greenhouse gas emissions when compared to petroleum-based fuels in all production scenarios. Corn production also imposes substantial negative externalities (e.g., nitrogen leaching, higher food prices, water scarcity, and indirect land use change). In this paper, we utilize a partial equilibrium model of corn-soy production and trade to analyze the potential of reduced US demand for corn as a biobased energy feedstock to mitigate increases in nitrogen leaching, crop production and land use associated with growing global populations and income from 2020 to 2050. We estimate that a 24% demand reduction would sustain land use and nitrogen leaching below 2020 levels through the year 2025, and a 41% reduction would do so through 2030. Outcomes are similar across major watersheds where corn and soy are intensively farmed.

Automated summary

Biobased energy, particularly corn-based ethanol and other renewable fuels, is an important component of energy policies in the US. However, corn ethanol fails to significantly reduce greenhouse gas emissions compared to petroleum fuels and has various negative impacts such as nitrogen leaching, higher food prices, water scarcity, and indirect land use change. Using a partial equilibrium model, this paper analyzes the potential of reducing US demand for corn as a biobased energy feedstock to mitigate negative effects on land use, nitrogen leaching, and crop production from 2020 to 2050. The study suggests that a reduction of 24% in demand can maintain the levels of land use and nitrogen leaching below those of 2020 until 2025, and a reduction of 41% can do so until 2030. The results are similar across major watersheds with intensive corn and soy farming.