RFA disputes study on climate change impacts on corn production

By Erin Voegele | June 05, 2013

The Renewable Fuels Association has spoken out to criticize a study published by Rice University and the University of California-Davis that claims climate change will increase irrigation costs for corn while reducing yields. In a statement, Bob Dinneen, RFA president and CEO, said that “it appears the authors have chosen to highlight a doomsday scenario, rather than giving equal consideration to a broad array of possible future outcomes.

According to the study’s principal investigator Pedro Alvarez, the George R. Brown Professor and chair of Rice’s Civil and Environmental Engineering Department, temperatures increases over the next 40 years could reduce corn yields by 7 percent while increasing the amount of irrigation needed by 9 percent. Information published on the study by Rice University also specifies that the authors of the new study “have long questioned the United States’ support of biofuels as a means to cut vehicle emissions.” Rosa Dominguez-Faus, lead author of the paper, Rice University alumna and postdoctoral researcher at UC-Davis, also authored a 2010 white paper with Alvarez on biofuels policy that detailed what the authors saw as economic, environmental and logistical shortcomings of the renewable fuel standard (RFS).

To complete the research, the team built computer simulations based on crop data from Iowa, Illinois, Nebraska, Minnesota, Indiana, Ohio, South Dakota, Wisconsin, Missouri and Kansas. They also used estimates of carbon dioxide and other elements from several models, including the government’s Environmental Policy Integrated Climate model. The simulation was used to predict crop outcomes over the next 40 years in relations to climate change expectations.

According to information published by Rice University, the simulations determined that while corn growth in Iowa, Illinois, Indiana, Ohio, Missouri, Minnesota and Wisconsin is currently fed primary by rainfall, climate change would results in more intense, less frequent precipitation in the summer. As a result, the researchers projected that these states would require a 5 to 25 percent increase in irrigation.

Corn already depends on irrigation in South Dakota, Nebraska and Kansas. According to the study, crop yields in these states would decline even if irrigation continues to be applied as needed.

In his response to the study, Dinneen questioned why anyone should believe the study can accurately depict weather conditions 40 years from now when weathermen and climatologists are often wrong about next week’s forecast. “The effects of climate change on future precipitation and crop yields is a highly unsettled and uncertain area of analysis. Some studies have actually shown crop yields in the north-central U.S. will increase due to climate changes in the long term. It appears the authors have chosen to highlight a doomsday scenario, rather than giving equal consideration to a broad array of possible future outcomes,” he said. “It also appears that the authors have ignored the future commercialization of crop technologies under development today that will better withstand drought and heat stress.”