Table of Contents Sections

Chapter 4

Our growing pains

Could GMOs feed more people?

  • Jackie Grimm

    Molecular Biology

    Princeton University

There is some evidence that planting GM crops increases yield. But more crucially, as the climate changes, we will need to fight plant diseases quickly to maintain agricultural yield, and GM offers a toolkit to do this. One meta-analysis found that adopting GM technology increased crop yields by 22 percent globally, with the biggest gains occurring in developing countries.

One of the biggest challenges currently facing humanity is how to feed the world's growing population, which is expected to surpass 9 billion people in just 30 years (there are about 7.5 billion people now).

Hunger is a complex problem with a lot of variables, but producing more food is certainly an important part of the solution. The UN's Food and Agriculture Organization predicts that we will have to increase agricultural productivity by at least 60 percent by 2050 if we want to keep up with population growth. And we'll have to do that against the backdrop of climate change, which presents a whole range of new obstacles. A potential solution is to improve our crops using genetic engineering.

In the 1960s, best-selling books like The Population Bomb and Famine 1975! made similarly dire predictions of looming mass starvation. In response, a series of initiatives, now known as the Green Revolution, aimed to increase global food productivity in part by breeding new, higher-yield varieties of crops. Thanks to these efforts, between 1960 and 2000, the yield of wheat in developing countries increased by 208 percent. The yield of rice rose by 109 percent, maize by 157 percent, and potatoes by 78 percent. In 1970, Norman Borlaug, the father of the Green Revolution, was awarded the Nobel Peace Prize in recognition of his efforts to end global hunger.

But after the astounding successes of the Green Revolution, agricultural productivity has begun to stagnate. That may be because we have reached the upper limit of how much food we can produce using current methods, which has led some to suggest that GM technology may be the key to boosting agricultural productivity in the 21st century.

Increasing yield

There is already some evidence that planting GM crops increases yield. One meta-analysis found that adopting GM technology increased crop yields by 22 percent globally, with the biggest gains occurring in developing countries. These crops were not engineered specifically to increase yield, but rather to be resistant to insects and herbicide.

More recently, genetic engineers have improved yield by tinkering with the process of photosynthesis. In 2016, scientists with the RIPE (Realizing Increased Photosynthetic Efficiency) project showed that they could increase the yield of tobacco plants by 15 percent by speeding up how quickly the plants adapted to changes between light and shade. They accomplished this by taking three genes that are involved in that process and adding an extra copy of each one, which increased the levels of each protein.

Scientists have also created plants that require 25 percent less water by increasing the amount of just one protein. This result comes with some major caveats: the researchers did not measure drought tolerance directly, and the sample size was small. But if successful, engineering plants to need less water would be very useful in the context of climate change. This is because rising temperatures affect the planet's water cycle: in some areas causing more rainfall and flooding, and in others, causing drought.

Decreasing disease

Another crucial part of feeding the world is fighting disease. Perhaps the most famous plant pathogen is late blight, which caused the deaths of over a million people in Ireland's Great Famine in the 1840s. Late blight is still around, and most types of potato are still susceptible to it. But by taking a gene from a wild South American potato plant that is naturally resistant to blight, scientists were able to modify commercial varieties of potato to resist infection. These potatoes were recently cleared by the US Food and Drug Administration and the Environmental Protection Agency, which means that Americans may soon see them on their dinner tables. But in Europe, where anti-GMO sentiment is more widespread, the idea of blight-resistant GM potatoes has faced more pushback.

Beyond North America, publicly funded scientists in Uganda successfully created bananas resistant to a devastating bacterial disease. Starch-rich bananas (or matoke) are a staple food in much of East Africa and are cultivated by small-holder farmers who suffer great losses from the disease, called BXW (Banana xanthomonas wilt). BXW ravages the crop, rotting the banana fruit and causing estimated annual losses of $200-800 million. In 2010, scientists working at the International Institute of Tropical Agriculture in Kampala, Uganda transferred a gene from sweet pepper into a banana variety and found that it made the bananas completely resistant to BXW. These results were then confirmed in field trials of the GM bananas. However, because a 2012 biosafety and biotechnology bill there recently failed to pass into law, these disease resistant bananas remain unavailable to Ugandan farmers.

Much of the public’s distrust of GMOs is rooted in anti-corporate sentiment, particularly the idea that large biotechnology companies care more about their bottom line than they do about consumer safety. But many of the scientists conducting this research are not motivated by profit, but by a genuine desire to fight hunger and malnutrition, particularly in the developing world. While these incredibly daunting problems cannot be solved by technology alone, there are certain things that are possible using genetic engineering, such as optimizing photosynthesis, or improving the vitamin content of crops, that would be nearly impossible to achieve using conventional techniques. As we prepare to face the significant challenges ahead of us, we should think twice before setting aside these powerful tools.

Could GMOs affect biodiversity?

  • Gabriela Serrato Marks

    Marine Geology

    Massachusetts Institute of Technology

They theoretically could, but there isn’t much solid evidence that they have. GMOs don't have a negative impact on biodiversity because some are unlikely to outcompete wild organisms and others are highly unlikely to make it out into the wild in the first place. There is no evidence that hybridization of GM and non-GM plants is harmful.

Biodiversity is important for the health of an ecosystem, so it certainly makes sense to value it. But do GMOs actually harm biodiversity? So far, it looks like the answer is no.

A popular, but untrue, example of GMOs "taking over the world" is GM salmon. A Canadian company has developed transgenic salmon that grow significantly faster than wild or farmed salmon. It took more than 20 years for the US Food and Drug Administration to approve the GM salmon, making them probably the most regulated fish you could ever eat. As wild salmon populations are declining across the world, farm-raised salmon production will need to increase to meet demand. Raising more salmon, both conventional and GM varieties, would allow people to still consume the fish without continuing to decimate wild populations.

But there are fears that rogue escapee salmon would outcompete all the non-modified (wild) salmon or breed and create a franken-salmon - think "Jurassic World," but underwater. In fact, it is impossible for GM salmon to escape” to the wild: they are only raised in land-based facilities (not in ocean nets) and are carefully enclosed by metal screens, jump fences, and drain covers. There are even chlorine pucks in the drains and pipes around the facility to kill any eggs or fish that get out. If the GM salmon did manage to get around all those barriers, they wouldn’t last long in the wild because all the salmon grown for food are female – and sterile.

That's not to say that all GMOs are inherently sterile, or that they could never hybridize with their wild cousins. In one case, herbicide-resistant grass did pass the herbicide resistance gene on to wild grass nearby. Researchers went to the fields where the GM grass is cultivated and planted non-modified grasses up to 21 km away. Then, they sprayed the area with herbicide to see how many plants would survive and checked the genetic composition of the surviving grasses. They found that up to 20 percent of plants were positive for the herbicide-resistance gene.

That may sound worrisome, but there is no evidence that hybridization is harmful, or that GM plants and animals can outcompete the wild versions. That's because transgenic organisms are specifically designed to grow in a farm environment, where food is plentiful, predators are nonexistent, and herbicide is everywhere. It isn't very helpful to be an extremely herbicide-resistant grass in the wild, when no one is spraying herbicide on you. Likewise, if GM salmon could survive in the wild, they would be easy prey for predators because they would be slower, easier to see, and probably highly appealing because they are so big.

In short: no, GMOs do not have a negative impact on biodiversity, some because they are unlikely to outcompete wild organisms and others because they have are highly unlikely to make it out into the wild in the first place. Genetically modified animals are more heavily regulated than conventional species and have to pass rigorous testing before they can be marketed.

In contrast, there are more than 240 species of invasive grasses in North America alone, which do have the ability to outcompete native species. Invasive plants are easy to buy and plant in your garden, potentially causing a massive loss in biodiversity. GMOs interact with their environment, but so do non-modified organisms - often on a much more destructive level. That shouldn’t be an automatic reason to not grow, raise, or consume modified organisms.

How can GMOs help us adapt to climate change?

  • Gabriela Serrato Marks

    Marine Geology

    Massachusetts Institute of Technology

GMOs (in agriculture and beyond) could potentially help us to reduce climate change's impact on humans and our natural environment. There is a lot more research to be done here.

Climate change is already affecting millions of people, and its effects will become only more apparent in the next few decades. The good news is that GMOs may be able to help on at least two fronts: insect-borne illnesses and carbon reduction.

Insect-borne illnesses

Consider a tick that latches onto a migratory bird and then falls off its host in northern Canada. Fifty years ago, that tick would have died quickly, too cold and hungry to survive - good news for Canadians in the neighborhood. But today the tick is much more likely to survive long enough to transmit Lyme disease; both mosquito- and tick-borne illnesses are increasingly common because of higher global temperatures. Insects and arachnids that carry diseases simply don't die as easily as they used to – the Centers for Disease Control and Prevention announced in early May that the number of Americans getting diseases from tick, flea, and mosquito bites has more than tripled, in part because of rising temperatures.

Genetic modification offers one potential solution in the form of transgenic mosquitoes that can’t compete as well for mates or produce viable offspring. Though it might sound counterintuitive to release more mosquitoes or ticks into the wild, GM bugs could actually help keep populations down. When modified mosquitoes successfully mate with wild mosquitoes, they transmit a gene that makes all the offspring die. That will cause a decrease in the overall mosquito population. Another, more controversial, approach is to engineer mosquitoes to pass on malaria resistance. Keeping mosquito and tick populations down controls the spread of viruses, such as Dengue or West Nile, and tick-borne pathogens with huge public health impacts. To put it bluntly, the world would be better off without mosquitoes.

Carbon reduction

In contrast to a swarm of malaria-laden mosquitoes, carbon emissions are a largely invisible problem, but they have major consequences for the global climate. As policy-driven efforts move slowly to decrease greenhouse gas production, many scientists and engineers are looking for other potential tools and strategies.

One carbon removal tool might be lurking in the ocean. Some varieties of coastal seagrass have a lot of potential to capture and store carbon. Using genetic engineering to add that ability to other seagrasses would make this a more viable way to capture atmospheric carbon dioxide. Growing transgenic seagrass will not stop climate change, but it does help us move in the right direction by decreasing carbon dioxide in our atmosphere.

No single person can stop the expanding range of ticks or remove all the excess carbon dioxide from the atmosphere, but we can advocate for evidence-based policies surrounding GMOs. Just like other climate adaptation tools, such as levees and seawalls, GMOs could potentially help us to reduce climate change's impact on humans and our natural environment.

Do GMOs use resources more or less efficiently than conventional crops?

  • Gabriela Serrato Marks

    Marine Geology

    Massachusetts Institute of Technology

They can, especially around water and pesticides. However, the impact of drought-resistant GM crops on agriculture's use of water is still unclear. Humans extract water from the environment at an astounding rate, and a huge portion of that water goes into crops. Agriculture uses 75 to 90 percent of global water, depending on what estimates you look at.

Climate change adaptation and natural resource management are tightly linked, as increasing temperatures and changing environmental parameters put more stress on our planet's water, plants, and animals. Because of the upcoming changes, we need to develop more efficient ways to use natural resources, such as water.

Humans extract water from the environment at an astounding rate, and a huge portion of it goes into crops. Agriculture uses 75 to 90 percent of global water, depending on which estimates you look at. Though that use is spread out across the globe, there have already been irreversible changes in many bodies of water. In Central Asia, the Aral Sea was long one of the largest inland seas; it is now half its previous size due to agricultural irrigation. It has lost an area larger than Lake Michigan in just 50 years. As climate change progresses and fresh water becomes even more valuable, it is important to find ways to decrease water usage so that we do not repeat this crisis.

Crops will also need to be drought tolerant, as droughts will grow much worse as climate change progresses. The good news is that GM, drought-resistant plants could solve both problems at once. If farmers and companies cultivate more efficient plants that can withstand weather extremes, there will more water available for other uses while still providing sufficient food for everyone. One example of a drought-tolerant plant is DroughtGuard, a USDA-approved corn variety developed by Monsanto in 2012. Farmers in the US have had mixed results with the DroughtGuard corn, but it seems to have potential.

Water use isn't the only relevant environmental issue in agriculture: overusing fertilizer can harm both people and the natural environment. When fertilizer runs off of farmland and ends up in a body of water, which happens constantly in places like the American midwest, microorganisms"bloom" and rapidly consume all the oxygen in the water. These leave behind dead zones that drive away fish, which struggle to breathe there. Commercial fertilizers also contribute to N2O emission, a greenhouse gas. Across the globe, nitrogen use has increased eight times and phosphorous fertilizer has tripled since 1961. Between the gas release and toxic conditions in waterways, agriculture companies and farmers need to find innovative ways to use less fertilizer. GM crops provide one potential solution.

Scientists are predicting that the increasing temperatures projected for the next 80 years will decrease global crop production, including a 20-40 percent corn yield decrease in the US. This diminishing yield is likely to cause rippling consequences. Decreased crop yields have already caused mental health crises in the US and internationally. In fact, farmers have the highest suicide rate of any profession in the US. Inconsistent crop yields also hurt children in the region: survival rates are lower for kids born in years with low yield. GM soybeans, corn, and cotton have increased farmer profits by 68 percent in some regions.

Taking shorter showers and carrying a reusable shopping bag are easy, popular ways for consumers to reduce their personal impact on the environment. But perhaps supporting GMOs should be another way.