If climate change continues at its current pace, in 40 years a hotter planet will lower corn production by 7 percent while requiring a 9 percent increase in irrigation water, putting US biofuel goals out of reach, says a study by University of California, Davis and Rice University researchers.
The study, published in the American Chemical Society’s journal, Environmental Science and Technology, says climate change will hinder US goals of producing 15 billion gallons of ethanol by 2022 to blend with fossil fuel, as per the Energy Independence and Security Act (EISA) of 2007.
Pedro Alvarez, the head of Rice’s civil and environmental engineering department and lead author of the study, says the cost of water will spiral and outweigh concerns about emissions from fossil fuels, creating a trade-off.
For the study, Alvarez’s team built computer simulations based on crop data from the nation’s top 10 corn-producing states: Iowa, Illinois, Nebraska, Minnesota, Indiana, Ohio, South Dakota, Wisconsin, Missouri and Kansas. They used estimates of carbon dioxide and other elements from a number of models, including the government’s Environmental Policy Integrated Climate (EPIC) model. The simulations predict crop outcomes over the next 40 years in relation to expectations of climate change.
The study found that the Corn Belt states and the Great Lakes region rely primarily on rainfall that would change its patterns, necessitating a 5 percent to 25 percent increase in irrigation, which would in turn require water catchment infrastructure. In the Great Plains region including South Dakota, Nebraska and Kansas, which rely heavily on irrigation, drought has already begun affecting farmland. This will lead to a decline in crop yields, even with continued irrigation.
The Rice study calculates that the production of 1 liter of gasoline requires 3 liters of water, whereas the production of 1 liter of corn ethanol requires between 350 and 1,400 liters of water from irrigation, depending on the location.
This is not the first time Alvarez has raised the red flag — he has been questioning US support of biofuel as a means to cut vehicle emissions since 2010, when he raised the issue in a white paper published by Rice’s Baker Institute of Public Policy.
In 2009, Alvarez estimated that it would take 50 gallons of water to grow enough corn in Nebraska to produce the ethanol needed to drive one mile, in an Environmental Science and Technology report.