The Unexpected Impact of Genetically Modified Crops on Global Carbon Emissions

Genetically modified (GM) crops are expected to reduce agricultural carbon emissions, which account for approximately 30\% of global carbon emissions, by reducing the use of high-emission production inputs. However, upon examining the gradual roll-out of GM crops across countries, we find that GM crops have increased total agricultural carbon emissions by 7.4% and increased the carbon-emission intensity of crops by 9.4%. A key reason is that GM crops have expanded cultivation into marginal lands, which require more fertilizer and energy inputs. While exporting GM crops to non-GM countries could reduce the global carbon-emission impact of GM crops, a large portion of GM crops is used for domestic livestock production, which further increases carbon emissions. Policies that restrict GM crops to the lands most suitable for them and encourage the export of GM crops could help mitigate the impact of GM crops on global carbon emissions.