Wallace E. Tyner, Purdue University, West Lafayette, IN, USA, and colleagues used a well-known Computable General Equilibrium (CGE) model, GTAP-BIO, to estimate the economic and environmental value of genetically modified (GM) crops.

The team found that replacing GM corn, soybeans, and cotton with conventionally bred varieties worldwide would lead to an increase in food costs of 0.27–2.2 %, depending on the region, with poorer countries hit the hardest. In addition, a ban on GM crops would lead to a conversion of pastures and forests to cropland to compensate for lower productivity of conventional crops. This would lead to substantial amounts of stored carbon to be released into the atmosphere.

The researchers state that if countries planting GM crops matched the rate of GM crop plantings in the United States, global greenhouse gas emissions would fall by an equivalent 0.2 billion tons of carbon dioxide, and would allow 0.8 million hectares of cropland (about 2 million acres) to return to forests and pastures.

• Evaluating the Economic and Environmental Impacts of a Global GMO Ban,
  Harry Mahaffey, Farzad Taheripour, Wallace E. Tyner,
  J. Environm. Protec. 2016, 7, 1522–1546.
  DOI: 10.4236/jep.2016.711127