Rewiring the Domestic U.S. Rice Trade for Reducing Irrigation ImpactsImplications for the Food–Energy–Water Nexus

Food
trade connects distant places of food production to places
of consumption. Through traded food, associated environmental impacts
are also displaced as the consumer benefits from the product without
incurring the externalities of production. Taking U.S. rice as an
example, we discuss the sustainability implications of rewiring U.S.
rice production and trade for reducing the impacts of irrigation (water
and energy) and transportation greenhouse gas (GHG) emissions. We
model a series of robust optimization scenarios that re-arrange the
origin of trade and therefore the production to target virtual water
use and GHG emission reductions. For the baseline case, virtual water
trade amounts to 35 billion m3, and embodied irrigation
and transportation GHG emissions amount to 6 billion kg CO2-equivalent and 0.7 billion kg CO2-equivalent, respectively.
Rewiring consistently achieves better results compared to the baseline
even in the presence of uncertainty. However, our findings reveal
strikingly sobering national-level savings in optimizing the water
use (2%) and GHG emissions (14%) with tradeoffs in other impacts.
To achieve these results, all rice-producing states undergo changes,
with the state of Mississippi completely stopping production. California’s
unique ability to produce medium-grain rice at a large scale makes
it indispensable for current rice production and hence a major constraint
for rewiring rice production. The findings of this work reveal the
inflexibility of our food system in balancing the food–energy–water
nexus tradeoffs through restructuring trade.