Reducing US Biofuels Requirements Mitigates Short-term Impacts of Global Population and Income Growth on Agricultural Environmental Outcomes

TL;DR

Reducing US biofuel mandates can significantly lessen the environmental impacts of global population and income growth on land use and nitrogen leaching, with substantial benefits observed within a decade.

Contribution

This study quantifies how lowering US biofuel demand can mitigate environmental externalities linked to agricultural expansion amid global growth.

Findings

A 23% demand reduction sustains land use and nitrogen leaching below 2020 levels through 2025.

A 41% reduction maintains these environmental metrics below 2020 levels through 2030.

Outcomes are consistent across major agricultural watersheds.

Abstract

Biobased energy, particularly corn starch-based ethanol and other liquid renewable fuels, are 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. 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 23% 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.