How Bad Are GMOs for the Environment?

Genetically modified organisms (GMOs) are organisms that have modified DNA, such as the insertion of a gene that does not occur naturally. People have used selective breeding and cross-breeding, among other practices, to produce plants and animals with specific characteristics for thousands of years. In the 1970s, genetic engineering took these practices a step further, and in the 1990s, policies were created around genetically modified foods.  

Scientific breakthroughs in manipulating plant genetics are largely responsible for the commercial success of crops in the United States, especially corn and soy. But are genetically modified crops considered sustainable? How has this technology impacted the environment over the years?

The Growth of the GMO Industry

Shortly after the initial breakthrough in modern-day genetic engineering, when scientists Herbert Boyer and Stanley Cohen successfully transferred a gene from one organism to another, concerns about the future of this technology arose. At the Asilomar Conference of 1975, guidelines were developed to ensure the safe and ethical usage of and research on GMOs. Once these guidelines were in place, the field exploded—beginning with genetically modified bacteria, then moving on to medications, food crops, and animals.

Supporters of genetic engineering argue that GM crops have higher yields and more nutrients while using less fertilizer and fewer pesticides. These are some of the top reasons GM foods are so prevalent today. In fact, the vast majority of soybeans and corn produced in the United States are genetically modified—94% of soybeans and 92% of corn planted in 2018, the U.S. Department of Agriculture reported. Other GM crops include canola, papaya, alfalfa, potato, and apple.

GM crops are herbicide-resistant, meaning farmers often can apply herbicide rather than till soil. Less soil tilling equals less carbon dioxide released into the atmosphere. It also means the work is less labor-intensive, and the farmers do not need to use their equipment as much.

Environmental Impacts of GMOs

GMOs are not without their downsides. The expansion of GM crops has led to a rise in herbicide usage—as well as a rise in types of herbicide-resistant weeds—new pests, and decreased biodiversity in areas where chemicals are used.

According to Earthjustice, within the span of 16 years, about 527 million pounds of herbicides were applied to crops in the U.S. The most widely used herbicide, glyphosate, has been labeled a probable carcinogen by the World Health Organization, which cited strong evidence of cancer occurring in animals. While glyphosate is considered safe to use by some, studies show its long-term use can have damaging effects on agroecosystems and crop nutrition.

Moreover, identifying herbicide-resistant weeds has led farmers to use different, potentially more damaging herbicides to control their plots of land.

The Unpredictability of Genetic Engineering

Another concern is that genetically modified plants or animals could interbreed with wild populations. This could create problems such as population explosions or crashes, or offspring with dangerous traits that would go further into harming the delicate ecosystem.

Some fear that GMOs will cause a decline in mixed cropping and an increase in monoculture. This would be dangerous because monocropping threatens the biological diversity of our food supply.

Moreover, GMOs are transferring genes in a much more unpredictable way than natural breeding allows. One of the built-in safeguards of natural breeding is that a member of one species will not produce fertile offspring with a member of another species. With transgenic technology, scientists are transferring genes not just across species but across kingdoms—inserting animal genes into microbes or plants. The resulting genotypes could never exist in nature–and the process is far more unpredictable than crossing a Macintosh apple with a Red Delicious apple.