Scientists have demonstrated that genetically modified organisms have no measurable negative impacts on human health. Indeed, they may hold the key to feeding a world impacted by climate change. But does this mean GMOs are completely without risk? Nope. Here are some good reasons to be concerned.
Humans on planet earth face a serious dilemma. Our population is on the rise, expected to reach roughly 9 billion by 2050. At the same time, we are fundamentally altering the very elements of the planet we need to survive. Agriculture is a serious contributor to this alteration. Modern agriculture produces a huge amount of greenhouse gas, uses intensive chemical inputs in the form of pesticide and fertilizer, and requires a lot of water. So much water, in fact, that previously useful lands are converted to useless wastelands in a process called desertification.
Genetically modified crops can help address some of these issues. Crops can be engineered to kill harmful, costly pests, reducing the reliance on pesticides and eliminating the negative health effects these pesticides cause in farm workers. Bt corn and cotton, for example, harness the power of Bacillius thuringiensis. Genes from this bacterium are inserted into the plant genome, inducing the plant to make an endotoxin that is toxic to very specific insect pests while inducing no harm in other types of insects, or the people that consume the foods.
But agriculture doesn't happen in a vacuum. Until Rachel Carson published Silent Spring in 1962, however, the idea that agricultural practices could impact "nature" wasn't really under consideration. Agronomists studied agriculture, and ecologists studied "nature". But in the 1970s, agronomists and ecologists got together and turned a scientific eye towards agriculture as a natural system, forming the field of Agroecology.
Agroecologists now investigate agricultural systems as the complex natural systems that they are, applying ecological principals to these "agroecosystems." And these investigations illuminate the real concerns surrounding GMOs.
Biodiversity and the Agroecosystem
Biodiversity is a term for the different types of living creatures in a system. It can be measured at a number of different scales: globally (all the things!), regionally (all the Amazon rainforest things!) and locally (all the things in my research plot!). Different organisms have different genes, and different roles in the ecosystem. When one dies, especially if it's a keystone species, it can set off a chain reactions that changes a whole environment.
Maintaining biodiversity is critical in every ecosystem. Acting together, all those plants and animals and their collective genes help each other survive. They also prevent the Earth from becoming completely dominated by cockroaches and rats.
Unfortunately, agriculture has a history of decimating biodiversity. Only certain plants and animals thrive under agricultural conditions, and selective breeding has made these plants and animals dumb and defenseless. So we keep them isolated, and spoon feed them everything they need to survive and reproduce. Modern agriculture produces ecological wastelands, where a single species is the only species present, for miles and miles and miles.
Genetic modification accelerates this process in a major way. Not only are farmers planting a single crop, but also with the advent of genetic modification, they are planting a single genetic line. The GM crops grow bigger, faster, with less chemical inputs. It just makes economic sense. But over time, this practice has led to a dramatic decrease in crop biodiversity. Meaning there are fewer types of species, and fewer genes within species, to adapt to changing climate. If the wrong pathogen comes along, every population of GM soy (which, in the US, constitutes over 90% of all soy) could be destroyed in a season. Since most of that soy goes into processed food and animal feed, you can kiss your hot pockets and cheap bacon goodbye.
Biodiversity can also be altered indirectly. GM salmon grow much more rapidly than their unaltered counterparts. When these GM hulks are introduced to experimental streams with normal salmon, they use their large size to bully the other salmon for food and space. Over time, this could lead to the elimination of other species, and the loss of non-GM genetic lineages. Especially since GM salmon can produce fertile offspring with other species, and these offspring exhibit the same rapid growth and bully behavior as their GM parents. Luckily, there is some evidence that, like the muscle-bound meathead who always starts a fight and ends up in jail, being a grotesquely oversized GM salmon makes you fearless while foraging for food, increasing the chance that you'll be eaten by predators.
Mirid insect, photo by Bruce Ruston
Bt cotton has been widely adopted in China. It kills the major insect pests which destroy the crop, and requires no pesticide to do it. As a bonus, the reduction in pesticide use means that beneficial insects like spiders and ladybugs are more common where Bt cotton is grown. Slam dunk for GM technology, right? Sort of.
Because agriculture doesn't happen in a vacuum, there can be unintended and complex effects of something that, on the surface, seems like a straightforward win. While Bt cotton does kill the target pest and reduce insecticide use, it also contributes to a rise in insect pests that were never a problem before. For example, mirid bugs munch a bunch of different plants, and are unaffected by the Bt toxin. They were never really a pest historically, because they were easily controlled by applications of insecticide. With the rise in Bt cotton, however, farmers stopped spraying poison, and mirid bugs built up to plague-level populations in cotton fields.
This is bad for cotton growers, but it is also bad for every farmer nearby, as mirid bugs move to on to other crops later in the season. To deal with this problem, farmers now have to purchase Bt seeds and apply pesticide, negating any economic benefits from Bt technology.
How Do GMOs Impact the Environment?
GM technology is designed to be elegant and efficient, targeting only those traits which we want to enhance. But ecology is far more complex than pest + poison = problem solved. The things we don't understand about how nature works are myriad, and oftentimes are incredibly basic. Ecologists don't even really understand how so many species can coexist within a single environment, and it wasn't until 1969 that Robert T. Paine figured out that some keystone species are so critical to an ecosystem that removing them causes the whole place to collapse. So it is no surprise that current regulatory standards do almost nothing to address the very real concerns surrounding GM technology.
Current regulatory procedures in the United States and EU primarily focus on human-health impacts of GMOs. Obviously these are important, and should be studied. But our regulations almost entirely ignore environmental and ecological impacts, which are a very real, and mostly-unmeasured threat. The problem is that GM regulation is cumbersome, involving multiple agencies and a whole lot of time. As a result, public researchers who study things like environmental impacts are cut out of the loop, leaving GM research in the hands of private companies like Monsanto.
GM technology really does hold great promise for addressing the needs of the projected 9 billion people on this earth by 2050. Our conventional agricultural practices aren't going to sustainably feed the world. But the far-reaching impacts of this technology must be carefully assessed and managed, and we, as people on the planet that require food, should think carefully about how this technology is regulated.
While concern about human health impacts is justified, this myopic focus just underlines the hubris with which we have always treated the Earth that feeds us. We, and the GM organisms we create, are part of a larger system — and we need to be sure we don't destroy our ecosystems in the service of feeding humanity.