Corn field marked with genetically modified sign
In the United States, corn yields would decline by 11.2% if elimination of bioengineered organisms occurred.

WEST LAFAYETTE, IND. — Researchers at Purdue University have completed a study that assesses the benefits of bioengineered organisms in farming and the food supply. The study’s conclusions note the extreme measure of eliminating bioengineered organisms would lead to higher food prices, a boost in greenhouse gas emissions and a major loss of forest and pastureland.

Wally Tyner, Purdue University, agriculture
Wally Tyner, James and Lois Ackerman professor of agricultural economics at Purdue University

“This is not an argument to keep or lose G.M.O.s,” said Wally Tyner, the James and Lois Ackerman professor of agricultural economics at Purdue University. “It’s just a simple question: What happens if they go away?”

Mr. Tyner and Farzad Taheripour, a research associate professor of agricultural economics; and Harry Mahaffey, an agricultural economics graduate student, wanted to know the significance of crop yield loss if bioengineered crops were banned from U.S. farm fields, as well as how that decision would trickle down to other parts of the economy. They presented their findings at the International Consortium on Applied Bioeconomy Research in Ravello, Italy, last year. The findings of the study, funded by the California Grain & Feed Association, will be published in the journal AgBioForum this spring.

The economists gathered data and found that 18 million farmers in 28 countries planted about 181 million hectares of bioengineered crops in 2014, with about 40% of that in the United States.

Farzad Taheripour, Purdue University, agriculture
Farzad Taheripour, research associate professor of agricultural economics at Purdue

They fed the data into the Purdue­ developed GTAP­BIO model, which has been used to examine economic consequences of changes to agricultural, energy, trade and environmental policies. Eliminating all bioengineered organisms in the United States, the model shows corn yield declines of 11.2% on average. Soybeans lose 5.2% of their yields and cotton 18.6%. To make up for that loss, about 102,000 hectares of U.S. forest and pasture would have to be converted to cropland and 1.1 million hectares globally for the average case.

Greenhouse gas emissions would increase significantly because with lower crop yields, more land is needed for agricultural production, and it must be converted from pasture and forest.

“In general, the land­use change, the pasture and forest you need to convert to cropland to produce the amount of food that you need is greater than all of the land­use change that we have previously estimated for the U.S. ethanol program,” Mr. Tyner said.

Greenhouse gas emissions
Greenhouse gas emissions would increase significantly because of lower crop yields caused by elimination of bioengineered organisms.

With lower crop yields without bioengineered traits, commodity prices would rise, according to the study. Corn prices, for example, would increase as much as 28% and soybeans as much as 22%. Consumers could expect food prices to rise 1% to 2%, or $14 billion to $24 billion per year.

“Some of the same groups that oppose G.M.O.s want to reduce greenhouse gas emissions to reduce the potential for global warming,” Mr. Tyner said. “The result we get is that you can’t have it both ways. If you want to reduce greenhouse gas emissions in agriculture, an important tool to do that is with G.M.O. traits.”

In the United States, bioengineered organisms make up almost all the corn (89%), soybeans (94%) and cotton (91%) planted each year. Some countries have already banned bioengineered organisms, have not adopted them as widely or are considering bans. Mr. Tyner and Mr. Taheripour said they will continue their research to understand how expansion of and reductions of bioengineered crops worldwide could affect economies and the environment.