  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.
