Genetically modified (GM) crops have become a major topic of debate in agriculture and food systems.
They involve altering an organism’s DNA to introduce new traits not originally present.
While proponents argue GM crops can help feed the world and benefit the environment, critics have raised concerns about potential ecological and health risks.
Key Facts About GM Crops:
- Created by inserting foreign genes into a plant’s genome to give it new characteristics
- Introduced in 1996 and now grown on over 190 million hectares globally
- Main GM crops are soybean, corn, cotton and canola
- Most common traits are herbicide tolerance and insect resistance
- Top producers are USA, Brazil, Argentina, Canada and India
Source: Cureus 2020
What are Genetically Modified (GM) Crops?
GM crops are plants created through genetic engineering, a process where genes from another species are inserted into a plant’s genome giving it new characteristics.
The first GM crops were commercially introduced in 1996 and now GM varieties of soybean, corn, cotton and canola are grown on over 190 million hectares globally.
The most common traits engineered into crops are herbicide tolerance and insect resistance.
The USA, Brazil, Argentina, Canada and India are the top producers of GM crops.
GMO Foods: Pros (Advantages)
Increased Crop Productivity
GM crops have been engineered to express traits like resistance to pests, diseases and environmental stresses that can otherwise limit productivity.
For example, Bt corn contains genes from the bacterium Bacillus thuringiensis that cause it to produce proteins toxic to certain insect pests like the European corn borer.
This gives the GM corn protection against yield losses from insect damage.
Studies show Bt corn can increase yields by up to 20% compared to non-GM equivalents.
Disease resistant GM papaya has also been credited with rescuing Hawaii’s papaya industry from the papaya ringspot virus epidemic in the 1990s.
Reduced Reliance on Pesticides
GM crops that are insect resistant and herbicide tolerant enable farmers to better control weeds and insect pests while applying less chemical pesticide.
Bt crops target pests but allow beneficial insects to be spared.
A 2014 meta-analysis found that on average GM technology has reduced chemical pesticide use by 37% and increased crop yields by 22%.
This can lower costs for farmers as well as reducing occupational exposures to hazardous pesticides.
Environmental Sustainability
Higher crop yields per hectare from GM technology lessen the pressure to convert forests and other ecologically important habitats into farmland.
Herbicide resistant GM crops also facilitate no-till farming, reducing soil erosion and runoff of sediment, fertilizers and pesticides into waterways.
Bt insect resistant crops decrease the broad environmental impacts associated with heavy insecticide use.
However, sustainability benefits depend on farmers adopting integrated pest management practices with GM crops rather than solely relying on chemical approaches.
Famine Relief
Increased productivity of staple GM food crops like corn, rice and wheat in developing countries could potentially help alleviate malnutrition and reduce ongoing issues like vitamin A deficiency.
But for this to eventuate, benefits must reach smallholder farmers and malnourished communities, not just large producers and seed companies.
GMO Foods: Possible Cons (Drawbacks)
Gene Transfer to Wild Plants
There are ecological risks due to potential gene flow from GM crops to populations of wild relatives via pollen.
Transgenes that confer herbicide resistance or other traits could become incorporated into wild plants, giving them a competitive advantage and ability to displace other native vegetation, thereby disrupting habitats and ecosystems.
Creation of “Superweeds”
Just as gene transfer could create herbicide resistant wild plants, it could also enable weeds to acquire herbicide tolerance.
This can lead to weeds becoming hard to control “superweeds”.
Over-reliance on a single herbicide like glyphosate with herbicide tolerant GM crops exacerbates this problem.
Harm to Beneficial Insects
While Bt GM crops reduce damage from target pests, they may also have toxic effects on beneficial insects like honeybees, monarch butterflies and lacewings visiting Bt crop flowers for nectar and pollen.
However, Bt proteins are not equally toxic to all insect species.
The risks depend on the specific Bt proteins expressed in the GM crop and the level of exposure each insect faces.
Unknown Health Effects
Critics argue the long term effects of eating GM foods remain uncertain and so precaution should be taken.
However, major scientific bodies like the WHO state GM foods approved for the market have passed safety assessments and are not inherently more risky than conventional foods.
But some argue assessments should be broader.
Increased Herbicide Residues
Herbicide tolerant GM crops enable greater use of broad-spectrum herbicides like glyphosate.
But this can lead to higher herbicide residues on food, and research on the potential health impacts is limited.
Concerns are heightened by the greater prevalence of glyphosate-resistant weeds.
Ethical Objections
There are debates around the ethics of artificially interfering with nature through genetic modification, and “patenting life” via intellectual property over GM organisms which are often owned by large corporations.
There are also concerns that the technology may widen inequalities if benefits accrue to large multinational companies rather than smallholder farmers in developing countries.
Regulating GMOs & Genetically Modified Foods
Substantial Equivalence
Regulators assess if GM foods are “substantially equivalent” to their conventional counterparts, apart from the intended traits, before commercial release.
If deemed equivalent, GM foods are considered no less safe than existing foods. But critics argue broader safety data is needed.
Precautionary Principle
This argues new products like GM crops should not be made available until proven safe when there is scientific uncertainty about risks.
This cautious approach can restrain release of GM crops, but may also inhibit innovations with potential benefits.
Mandatory Labeling
Many advocate mandatory labels on GM foods, so consumers can choose whether to purchase/eat them.
But labeling comes with costs and logistical complexities between segregating GM and non-GM ingredients through long supply chains.
This can be challenging to fully implement.
The cultivation of GM crops and foods looks set to continue expanding globally, driven by the need to sustainably feed a growing population.
Further research on ecological impacts, human and animal health effects, and social outcomes remains vital to inform evidence-based policies and regulations around this technology.
GM crops offer significant potential benefits, but also pose risks that should be carefully assessed and managed. Finding the right balance will be an ongoing challenge.
References
- Study: Genetically modified products, perspectives and challenges
- Authors: Dimitrios T Karalis et al. (2020)
