Another likely victim of climate change? Our food system. According to a recent United Nations panel, food shortage could be one of the most serious side-effects of a warming planet. If the global temperature were to rise by even two degrees Celsius—a very real possibility considering the trajectory we're on now—extreme weather could throw off crops' growing seasons, make land inhospitable to farming, and make crops vulnerable to disease. Complicating matters even more, there will be approximately 10 billion people on earth by 2050—today, the global population is around 7.7 billion—which means we will need to produce about 56 percent more food over the next 30 years.
Some experts claim that technology has already given us a powerful tool to address some of these issues: genetically engineered (GE) crops, more commonly known as GMOs. Of course, the pros and cons of GMOs have been hotly debated. Studies show that GMO foods are safe for human consumption, but many experts believe more research needs to be done before we can be sure that they're risk-free in the long term. Yet, if food shortages were to occur as a result of extreme weather, some experts argue that crops genetically engineered to survive changing weather conditions could potentially feed millions of people who might otherwise go hungry. "A genetically engineered crop that can withstand environmental stresses would certainly be useful as climate change takes hold," says Fred Gould, PhD, chair of the National Academies of Sciences, Engineering, and Medicine committee that authored Genetically Engineered Crops: Experiences and Prospects.
Companies have started to develop genetically engineered crops specifically with the future of our environment in mind. But is this truly the best way forward—or are there equally effective ways of protecting our food supply from climate change through conventional methods?
The pros of GMOs in a changing climate
With an eye on the world's growing population, scientists are already engineering crops like soybeans, rice, and potatoes for increased yield. "[That means] more food is produced using similar chemical, water, and land inputs," says Jennifer Kuzma, PhD, co-director of the Genetic Engineering and Society program at North Carolina State University. This would have an extra benefit for the environment, as fewer precious resources would be needed to create a larger amount of food. Critics of genetic engineering claim that crop yield can also be increased using organic farming techniques, but research shows that organic crops wouldn't be able to create the same yield as GE crops without clearing more land for farming via deforestation or simultaneously ensuring a massive reduction in food waste and meat consumption. Despite the increased interest in plant-based eating, demand for animal-based foods is still predicted to rise by 70 percent by 2050, making this option potentially less feasible.
Other crops are being genetically modified to withstand extreme weather conditions such as drought or flooding. "One example of a crop meant to resist...increased flooding is a salinity-tolerant variety of rice," says Dr. Kuzma. (Translation: A type of rice that is able to grow in soil with a higher saltwater content than normal.) "A drought- and salinity-tolerant soybean has been developed by gene editing in the U.S. as another example of a crop that is meant to withstand conditions that may result from climate change," she says. A type of corn engineered to thrive in drought conditions is currently available commercially in the U.S. But Dr. Gould says it may not be all that necessary to go the GMO route to produce these types of crops. "Conventional breeding for drought stress has very similar outcomes to engineering for drought stress," he says. "There is no major advantage to engineered drought tolerance."
There are also several types of GMO crops in development that may help reduce the negative environmental impacts of farming. For example, Dr. Kuzma says cereal crops are now being engineered to pull nitrogen (essential to plant growth) directly from the air instead of just from the soil, in the hopes of reducing farmers' reliance on nitrogen fertilizers. (In 2014, nitrogen fertilizers were responsible for releasing 195 million metric tons of CO2 equivalent into the air, which is comparable to the emissions from 41 million passenger vehicles.) She notes that other scientists are engineering crops that can be used as alternatives to fossil fuels—although in some cases, it takes more fuel to grow the crop than what can be extracted in return. Genetic engineering is also being used to create stronger "cover crops" that are planted on fields to regenerate the ecosystem and restore the soil, she adds.
"In the future, we may be able to engineer commercial varieties of crops for heat stress, better nutrient use, better photosynthesis, and salinity tolerance," says Dr. Gould. But whether they'll take off in the market, he says, remains to be seen.
Not every environmental impact of genetic engineering is positive
Clearly, genetic engineering shows some promise from an environmental perspective. But it's also been proven to have some major downsides—specifically when it comes to the widespread planting of crops that can withstand high doses of weed-killing chemicals.
In some cases, says Dr. Gould, genetic engineering has allowed farmers to use safer herbicides than in years past. But that's not always what happens. "Most of our corn, soybeans, and cotton are now [engineered] to resist glyphosate," says Dr. Kuzma. "We are now seeing [glyphosate-] resistant weeds, which are causing a huge problem for farmers." Glyphosate resistance forces farmers to increase their herbicide use in order to keep their fields weed-free—those who grow GE crops report using 28 percent more herbicide than non-GMO farmers—as well as resort to stronger, potentially more destructive chemicals.
This is critical, because herbicides and pesticides aren't used in a vacuum—they can impact the immediate environment as well. "If a genetically engineered crop enables use of chemicals that are harmful to beneficial species, then they are enabling environmental harm," says Dr. Gould. Additionally, certain herbicides can drift to neighboring farms and lands, affecting their crops and local ecosystems, too. Dr. Gould also warns that if crops are engineered to grow in a wider range of conditions, naturally vegetated land that can't currently tolerate farming could be cleared for agriculture. "This would decrease biodiversity," he says.
The Center for Biological Diversity recently spoke out about this troubling reality following a decision by the Trump administration to allow the use of genetically modified seeds on wildlife refuges. "Glyphosate use on genetically altered crops has significantly contributed to the monarch butterfly’s 80 percent decline over the past two decades because the pesticide kills milkweed, the monarch caterpillar’s only food," the Center wrote in a statement.
Perhaps the greatest concern of all, says Dr. Kuzma, is that many genetically engineered crops aren't regulated in the U.S. "What can happen with even small genetic changes is a shift in the level of nutrients, toxicants, or allergens that may affect human health," she says, although she notes that the same can be said of conventional plant breeding practices. "Glyphosate was thought to be 'safe' back during the approval of GE crops meant to resist it. Risks of weed resistance were dismissed back then, too. We need better foresight and anticipation of risk prior to the market entry of GE crops—whether gene-edited or engineered—and arguably, even conventionally bred crops. In my opinion, all modified crops should undergo some screening studies prior to environmental growth and certainly product marketing."
So do the pros of GMOs for climate change outweigh the cons?
Based on our current knowledge about genetic engineering, Dr. Kuzma believes the sustainability rewards of GE crops might justify the risks, although she stresses that the benefits and downfalls would need to be assessed on a product-by-product basis. Either way, she's not sure how enthusiastic farmers will be about embracing such crops if they aren't able to turn a major profit from them.
"[Pest-resistant and herbicide-tolerant] crops were a market success because farmers benefitted from less intensive agronomic practices and thus wanted to pay a premium for them," she says. These types of crops have allowed farmers to reduce costs associated with chemical sprays and labor while increasing their productivity, and as a result they've earned an additional $150 billion since 1996. "With sustainability, however, who is going to ensure a market exists? They are primarily meant to benefit the environment."
Dr. Gould adds that even if farmers do buy into crops that have been engineered to benefit the planet, there's no guarantee that those benefits will actually materialize. "An interesting article in the journal Science showed that when midwest farmers were offered drought-tolerant corn, instead of using the seeds to decrease losses from drought stress, they planted the seeds closer to get higher yield than in normal years," he says. "This led to more sensitivity to drought in those fields. It is both the trait and how the trait is used that determines what it will do in a farming system."
This is why, from his perspective, it's impossible to talk about the pros and cons of GMOs in all-or-nothing terms. "Yes, some engineered traits could be used in ways that would harm the environment and would favor corporate farms over family farms. And yet, some may alleviate hunger," Dr. Gould says. "Why not conclude that it's society's responsibility to enable the positive uses for engineered crops while constraining uses of products that would potentially have negative effects?"
That is, if we're lucky enough to even have a choice in the future. If we continue down our current path, GMOs may be our only option for feeding the world. As Dr. Kuzma puts it: "With harsher weather conditions, farmers may eventually demand them."
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