Using data from the National Agricultural Statistics Services (NASS) on GMO and non-GMO acreages, agricultural economists Wally Tyner, Farzad Taheripour, and Harry Mahaffey found that there would be adverse effects on the environment if GMO crops were eliminated.
Using the GTAPBIO model, developed at Purdue, they found that “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,” a Purdue press release on the study said.
Releasing more greenhouse gasses
The study also estimated that “greenhouse gas emissions [will] increase significantly because with lower crop yields, more land is needed for agricultural production.
"Some of the same groups that oppose GMOs want to reduce greenhouse gas emissions to reduce the potential for global warming," Tyner said in a press release. "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 GMO traits."
A critical reception
Some entities saw Purdue’s findings consistent with others. The Biotechnology Innovation Organization (BIO) saw similar results in two different studies: One by the International Service for the Acquisition of Agri-Biotech Applications that concluded that biotech crops can help preclude deforestation, and another by PG Economics that saw how GMOs can contribute to “significantly reducing" greenhouse gas emissions.
“The environmental and economic benefits of biotech crops are well documented. More than 18 million farmers around the world choose to plant crops improved by biotechnology because they produce higher yields on less land and with fewer inputs such as fertilizers and insecticides,” Karen Batra, director of food and agriculture communications at BIO, told FoodNavigator-USA.
“Biotech crops have also contributed mightily to the adoption of low-till and no-till farming practices, which helps reduce greenhouse gas emissions while protecting air and soil quality,” she added.
“Eliminating access to the technology would deny farmers the ability to farm sustainably and to provide for a growing global population.”
EWG: Study relies on 'seriously biased data'
However, anti-GMO organizations such as the Environmental Working Group (EWG) dismissed the study. In a blog piece, EWG research analyst Emily Cassidy wrote that Purdue’s claims “rely on seriously biased data – a fact the government paper that the authors drew from warned against.
“All this study really does is compare yields from the type of farms that grow GMOs to the type of farms that don’t. By themselves, the GMOs may not be improving yields at all,” she added.
“The flaw – comparing different farms and assuming that GMO seeds were the reason for larger yields – lies in what researchers call self-selection.”
The Non-GMO Project concurs. “We feel that the fundamental premise of the study [is] flawed. Studies on yield are highly dependent on the crop in question and how you define yield,” a spokesperson from The Non-GMO Project said. The organization then referred to a plant yield scientist, from whom a comment is still pending.