Genetically engineered crops can slow climate change. Here’s how.

Man picking papayas (© Cornell Alliance for Science)
Michael Kamiya harvests genetically engineered papayas on his family's farm in Hawaii. (© Cornell Alliance for Science)

This is the first in a two-part series on climate smart agriculture. Next will be a story on farming that adapts to the effects of climate change.

Many agricultural activities — driving tractors, tilling soil, applying fertilizer or pesticides — emit greenhouse gases into the environment. But experts are finding that genetically engineered crops can reduce these emissions.

Genetic engineering is when scientists use recombinant DNA technology to alter an organism’s genetic makeup. In 2019, it was the fastest-adopted crop technology in the history of modern agriculture. During that year, the most recent for which data is available, farmers in 29 countries planted 190 million hectares of genetically engineered crops, according to the International Service for the Acquisition of Agri-biotech Applications (ISAAA).

Common genetically modified crops are varieties of corn, soybeans, cotton and canola. Their traits can address agricultural challenges and, while doing so, help to slow climate change. The two most notable traits are herbicide tolerance and insect resistance.

These traits allowed farmers to reduce pesticide spraying by 8.6% between 1996 and 2018, according to the Cornell Alliance for Science.

Fewer weeds, less tilling

Herbicide-tolerant crops do not die or wilt when they’re treated with herbicides that kill unwanted vegetation.

Planting herbicide-tolerant crops “allows optimal production — the ability to manage crops for other variables, knowing that they’re not going to be overwhelmed by weeds,” said David Baltensperger, head of the department of soil and crop sciences at Texas A&M University.

What’s more, these tolerant crops result in fewer herbicide applications and less tilling.

Tilling breaks up weeds’ destructive root systems. But it also releases greenhouse gases from the turned soil into the atmosphere, as do the tractors used for tilling. Herbicide-tolerant crops require less tilling, so there’s less greenhouse gas. And farmers can reduce soil erosion and get better harvests.

Scientists introduced herbicide-tolerant crops to the United States in 1996. By 2020, 90% of the domestic corn area used these kinds of seeds, according to ISAAA. Other examples of herbicide-tolerant crops in the U.S. are cotton, canola and soybeans.

Less pesticide, emissions and waste

Meanwhile, crops can be genetically engineered to resist harmful insects by incorporating a protein from insect-killing bacteria. These are commonly referred to as “Bt crops,” because proteins from Bacillus thuringiensis (Bt), a soil bacterium, have been added to them. About 405 million hectares of farmland around the world grow crops that incorporate Bt, according to the Cornell Alliance for Science.

Farmers who plant insect-resistant crops control pests without spraying harmful chemicals. This in turn reduces greenhouse gas emissions from the machines that deliver insecticides.

Eggplant crops (© Cornell Alliance for Science)
Bt brinjal, a genetically engineered eggplant that is resistant to insects, grows in Bangladesh. (© Cornell Alliance for Science)

Bt genes have been available for U.S. corn and cotton production since 1996. In 2020, 82% of America’s corn fields and 88% of U.S. cotton fields were planted with these tolerant crops, resulting in fewer herbicide applications and less tilling, according to the U.S. Department of Agriculture.

The insect-resistant crops are planted across the world and are in widespread use in Argentina, Australia, Brazil, Canada and the United States.

Bt crops provide farmers with greater certainty of a high-quality, nutritious harvest. (When crops are not insect resistant, “you have a lot of food waste from insects, because they damage the crop and it is lost to human consumption,” Baltensperger said.) Bt cotton, increasingly grown on small farms in places like India and Australia, can halve the use of insecticide sprays while significantly boosting farmer incomes, according to a report by ISAAA.

In Bangladesh, Bt brinjal (eggplant) has transformed food systems for farmers, allowing them to earn more and feed more people.

“With traditional varieties, I would lose 40% of my crop due to pest damage,” farmer Md. Milon Mia told Alliance for Science. “With Bt brinjal, I don’t need to use pesticide, and the crop doesn’t get any pest damage. All my neighbors are excited, and they say, ‘What is this? Please give us a brinjal, we want to try it!'”

Climate smart agriculture is clearly catching on.