The Environmental Case for Genetically Engineered Crops

Genetically engineered crops have well recognized environmental benefits, allowing farmers to reduce pesticide use and herbicide toxicity. But genetically engineered crops also have climate benefits, and those are often ignored. By reducing loss to pests and weeds, genetically engineered crops raise yields, which can reduce cropland expansion and, in turn, GHG emissions. In our research, we find that the climate mitigation potential is even greater than previously shown.

Unfortunately, policies in the European Union (EU) prevent most cultivation of genetically engineered crops, thereby foregoing the potential environmental benefits. And those are substantial. In the European Union alone, growing more genetically engineered crops could avoid a yearly 33 million tonnes CO2 equivalents (Mt CO2e/yr) in emissions, largely by increasing yields and reducing cropland expansion. That’s equivalent to 7.5% of total EU agricultural emissions from 2017.

Yet Europe’s progress on genetically engineered crops has stalled. The EU had a de-facto moratorium on genetically engineered crops from 1999-2004 and, since then, has only marginally cultivated genetically engineered crops, and mainly restricts those imported to animal feed. While the EU is currently undergoing another reassessment of genetically engineered crop regulation and may soften its opposition, we find that its policy has left environmental benefits — including climate mitigation — on the table.

To get precise about those benefits, in 2020, we conducted our own analysis based on the Carbon Benefits Calculator from Searchinger et al. (2018). In using this method, we assume that increased crop production in one location leads to a proportional decrease in production and related land-use change elsewhere. Because the EU typically has higher crop yields and lower agricultural emissions (per unit of crop produced) than the global average, increasing EU production by growing genetically engineered crops with higher yields would result in a net reduction of global agricultural land area and emissions.

We rely on a meta-analysis that shows an average yield increase from genetically engineered traits for insect resistance and herbicide tolerance of 9.7% and 6.5%, respectively, in industrialized countries. We apply this yield increase to five crops with genetically engineered traits that have been widely adopted in the US, Brazil, Canada, and Argentina: maize, soybean, cotton, canola (also called rapeseed), and sugarbeet. We assumed that the EU grew similar proportions of these crops with insect resistance and herbicide tolerance traits (the most common traits) as the US did in 2017.

Out of the total 33 Mt CO2e/yr reduction that would have come from growing genetically engineered crops, maize and canola contributed the most — 21 and 9 Mt CO2e/yr respectively — as shown in the graph above. This is the result of a number of factors. Maize and canola are the most widely grown crops. Maize also has a larger yield gain than soybean, canola, and sugarbeet, as it is commonly grown with both insect resistance and herbicide tolerance traits. And finally, globally, canola is grown on land with high carbon stocks.

We make two main assumptions in our analysis that create uncertainty but could balance one another out to some extent.

First, we assume a 1:1 relationship between increased crop production in the EU and decreased crop production elsewhere, which likely leads to an overestimate of benefits. Although raising yields in one place does generally reduce the need to convert new cropland elsewhere — because global crop demand and production is rising — it is nonetheless difficult to predict how land use will respond to crop yield increases in a particular situation because outcomes vary.

Second, we assume that the EU could widely adopt genetically engineered crops without affecting adoption in other countries, which likely skews our figures towards an underestimation of the benefits—one that more than compensates for the overestimation created by the first assumption. The EU policy on genetically engineered crops has undoubtedly discouraged their use by other countries, which may fear the loss of development funding or trade relationships. Widespread genetically engineered crop cultivation in the EU could therefore increase adoption elsewhere and amplify the climate mitigation impact of this change.

In comparison, Europe’s Farm to Fork Strategy in the European Green Deal would have the opposite effect. Since organic farming has lower average crop yields than conventional farming, its goal to increase organic farming to 25% of agricultural land by 2030 would result in global farmland expansion.

While we show that the EU could save 33 Mt CO2e/yr in emissions by adopting genetically engineered crops, a 100% conversion to organic production in just England and Wales could increase GHG emissions by 46 Mt CO2e/yr, mainly due to induced land-use change abroad (compared in the graph below).

There is a global need to increase crop production to feed a growing population. High-income industrialized countries already have the tools to increase crop yields; in contrast, farmers in lower-income countries often struggle to access inputs like fertilizer. By prioritizing organic production over yields, the EU is promoting deforestation and biodiversity loss in lower-income countries — all while continuing to import the non-organic genetically engineered crops that EU countries refuse to grow domestically.

In response to the EU’s anti-GMO stance, European scientists are becoming increasingly vocal and critical, particularly since 2018 when this rejection grew to include new gene-editing technologies. As new genetically engineered crops are developed — and those recently commercialized are more widely adopted — the EU’s forgone benefits will continue to grow. In terms of forgone benefits, carbon and otherwise, 33 Mt CO2e/yr — about the emissions from the EU’s most polluting power plant — is just the beginning.

This article reports on an analysis published by Emma Kovak, Dan Blaustein-Rejto, and Matin Qaim in "Trends in Plant Science": https://doi.org/10.1016/j.tplants.2022.01.004