Are GMOs good or bad for the environment?

The subject of Genetically Modified Organisms (GMOs) has become so controversial that it sometimes seems like we are beyond the point of rational conversation. The opposition to this way of producing crops for food has become so ingrained in the philosophy of many environmentalists and organizations that it is often a non-starter.

But regular readers of the blog and listeners to the podcast will probably know that I’m a firm believer in scientific evidence to back any claim up, whether something is good or bad for the environment. Most importantly I enjoy it when I’m proved wrong.

I’ve been asked by certain people “are ‘we’ for or against GMOs in relation to the environment” a few times now. Firstly, I’m not sure who this ‘we’ is, as if I’m forming some sort of cult. But secondly, is it that simple or is this just another one of those issues, like so many, where there is no simple answer, that perhaps there are benefits but maybe even costs that we don’t know about yet?

So I decided to write an in-depth article to try and get to the bottom of this. Where is the science at now? What evidence is there out there to back up either side of the argument?

But first a little background…

The brief timeline of GMOs

Approx. 30,000BCE – Artificial selection of dogs

You could argue that our journey towards GMOs started as far back as 32,000 years ago when our ancient ancestors first gathered wild wolves and artificially bred them to get more docile animals that could live in the tribe. We can see today that this has been taken to extremes and it is quite creepy to think a small pug is the same species as a large labrador. Although this is not GMO as many know it today, it is still an example of humans influencing genetics in other species.

Approx. 7800BCE – Artificial selection of plants

The earliest documented example of humans modifying the genetics of plants is around 7800BCE. The discovery was made during archaeological investigations in southwest Asia where domestic varieties of wheat were found which must have been artificially selected to appear how it did.

Over the next few thousand years, humans went on to do this with all sorts of other vegetables. Broccoli, cauliflower, kale, collard greens, Brussels sprouts and kohlrabi all come from the exact same original plant species (Brassica oleracea). That is technically the modification of genetics by humans through selective breeding.  

1935 – The first isolation of DNA

Jump forward to 1935 and we start on the journey towards modern genetic modification, when we started to understand what we were doing to these plants or animals. In this year, DNA was isolated for the first time by Russian scientist Andrei Nikolaevith Belozersky.

1973 – The first modern genetically modified organism

The biggest breakthrough however came in 1973 when scientists Herbert Boyer and Stanley Cohen engineered the first GMO.

They did this by taking DNA out of one organism and transferring it to another. In this early example they used bacteria to demonstrate this, taking a gene for antibiotic resistance out of one bacteria and transferring it to another which didn’t have the gene already.

1975 – Guidelines set for GMO experiments

This new technology seemed like a worrying prospect to many and so a conference was held in 1975 (The Asilomar Conference) where experts set guidelines for future experiments.

1980 – US Supreme Court allows patenting of GMOs

Perhaps one of the most significant years in the evolution of GMOs is 1980, when the US Supreme Court ruled to allow patenting of the artificially created organisms. This has since led to all sorts of ethical questions and dilemmas as large companies take ownership of a certain crop.

1987 – The first GMO food crop is approved for commercial production.

After years of experimentation, the company Calgene has the first GMO food crop approved known as the Flavr Savr tomato. The tomato had been modified to remove a certain protein, thus increasing its firmness and extending the shelf life.

1995 – The first pesticide producing plant

After years of testing the U.S Environmental Protection Agency gave the go ahead for the first pesticide-producing crop. This strain of corn, known as Bt corn, had been genetically modified to produce a small amount of herbicide, meaning that farmers do not have to apply it themselves and making it easier to cultivate.

1996 – Roundup produces first herbicide-resistant crop

The company Monsanto produced the first GMO crop, a variety of soybean, that was resistant to herbicides, specifically the herbicide glyphosate (a wide-spectrum weed killer which basically kills any other plant it touches). This meant farmers could apply glyphosate to their fields without fear that the soybean crops would also be damaged.

1996 – 2019 – Various other genetically modified organisms have been created since, for a variety of reasons. One of the more famous examples is ‘golden rice’ which was created to have high levels of vitamin A to tackle the big problem in some countries of vitamin A deficiency.

So now you know a brief history of GMOs and how/ why they came into existence, let’s move on to discuss the potential pros and cons of this technology in relation to the environment.

Potential benefits of GMOs for the environment

Less crop failure means less land required

If a disease affects a crop or a bad drought hits then it can have a big impact on food production, and with the United Nations stating that we must produce 70% more food by 2050 to feed a growing population this is an even more worrying prospect. Add to this that with climate change on the current trajectory, drought events are only going to become more frequent as time passes.

Having crops that are drought and disease resistant is good for the environment because it means greater certainty that a crop won’t fail and therefore we don’t need to produce higher amounts of food to make up for this. This means a reduction in all the energy required but it also means less land is required to produce the crops we need.

Land-use is a big environmental issue for a number of reasons. The destruction of existing habitats to make way for agricultural land leads to the release of carbon when trees and other vegetation are removed, along with removing the habitat for a variety of wildlife that depends on it. A recent report from the IPCC stated that land-use change for uses such as agriculture account for 23% of total greenhouse gas emissions, whilst at the same time the areas that haven’t been converted yet absorb almost one third of the emissions produced from fossil fuels.

It is estimated that without GM crops more than 300 million additional acres of land would be required to meet demands.

Currently, around 500 million people live in areas where drought is common, having crops that can grow reliably in these extreme conditions will be vital for feeding the world.  

Engineering crops that can grow in dry conditions reduces energy and water usage (and improves food security)

On top of land use change, benefits of being able to grow crops in drier conditions will be essential in a warming world for food security. As people need to be able to produce their own food locally without relying on imports.

But a reduced reliance on imports also has benefits for the environment, as it keeps things local and shortens the supply chain. This means less emissions from transportation (whether that is by plane, boat or truck). It also means a reduction in the need for refrigeration over those long journeys which requires a lot of energy and reduces the likelihood of food spoiling somewhere along the way.

Less water usage also has big environmental benefits. Between 1980 and 2011 GMO wheat fields saw a reduction in water usage of 12% with other crops such as potatoes being as high as 38%.

Disease resistance can mean less pesticides are required

Certain crops have been genetically engineered to be resistant to certain pests. Corn for example has been genetically modified by adding a gene from a bacteria known as bacillus thuringiensis to create ‘Bt corn’. This additional gene means that when certain pests eat the corn they die.

The advantage of this from an environmental point of view is that it reduces the need to spray fields with large amounts of pesticides, which when not applied correctly can drift on the wind and end up in nearby watercourses and in other habitats causing unwanted collateral damage to ecosystems.

Over the last 20 years the introduction of GMOs has led to a reduction in pesticide use of 8.2%.

An example in Bangladesh, where eggplants were engineered to be resistant to pests led to a significant reduction in pesticide use.

Less tillage required

By producing crops that are resistant to herbicides it reduces the need for traditional methods of weed control such as tillage.

Tillage is the process of turning the soil to dig up unwanted weeds. A method that made sense in ancient agriculture but when done on a large scale, with heavy machinery, is very detrimental to the environment. That is because when the soil is turned over it release huge amounts of carbon dioxide stored within it.

This is carbon dioxide produced by bacteria in the soil as they break down organic matter. This would usually remain trapped in the soil for long periods of time, but the turning of the soil releases it, as well as adding more oxygen to the soil which increases the microbial activity even further. 

Reduced need for tillage also leads a reduction in the amount of time tractors are required and it is estimated that no-till farming reduces fuel usage by up to 55%.

Less food waste on the farm

Disease and drought resistance leads to less spoiled food and therefore less organic waste. Organic waste from food is a big environmental issue.

Firstly, there are large amounts of energy (and therefore emissions) being put into a process to produce a product that is never even eaten. And secondly, this organic matter as it rots in landfill produces methane gas, a greenhouse gas with roughly 30 times the ability of carbon dioxide to trap heat in the atmosphere.

Reducing the number of crops that die due to pests or drought on a farm is huge if we are to reduce the amount of food that is wasted before it even leaves the farm.

Less food waste in supermarkets and homes

The problem of wasted food doesn’t just stop on the farm. There is the continued risk that food will not get eaten and simply end up in landfills throughout the supply chain, whether in the supermarkets or in our homes after purchase.

In the UK alone, around 7 million tonnes of food is thrown away by households every single year!

To try and mitigate this, crops have also been genetically modified to improve their shelf-life. For example in 2016, scientists in Israel managed to repress ripening genes in bananas. This delayed their ripening time and therefore extended the shelf-life.

GM crops that can absorb nitrogen themselves

Farmers currently add nitrogen to soils in the form of synthetic fertilisers in order to boost the growth and yields of crops. But this comes at a cost to the environment. The fertilizers can leach into the groundwater or runoff into rivers and streams.

In groundwater this can end up causing problems with drinking water. In waterways it causes plants such as algae to grow rapidly into huge algal blooms which absorb all the oxygen from the water and are very damaging to ecosystems.

On top of this, these artificial fetilizers are also responsible for the emission of ammonia and nitrogen oxide which leads to other human health issues and acid rain, along with nitrous oxide which is a greenhouse gas 300 times more potent than carbon dioxide.

The combined estimated cost of nitrogen fertilizers on human and environmental health is 70-320 billion Euros in Europe alone each year.

For this reason, scientists are looking into ways to reduce the need for nitrogen fertilizer input. One way suggested is to engineer crops that can absorb and fix nitrogen from the air, rather than needing it added to the soil.

These are just some of the environmental benefits that GMO crops could have and the possibilities are almost endless. So why are we not more excited about this? What are the possible negatives with GMO crops?

Potential cons of GMOs for the environment

Herbicide use has increased in some situations

As mentioned in the timeline above,  crops were developed in 1996 by Monsanto that are resistant to the herbicide glyphosate. This means that farmers no longer had to be cautious about spreading the product as they knew it wouldn’t damage the crop.

From 1995 to 2014 US agricultural glyphosate use rose by 9 times and globally it rose around 15 times.

But as glyphosate is a ‘broad-spectrum’ herbicide (basically it kills most things it touches), this has had many damaging affects on the environment and on biodiversity.

These impacts include damage to aquatic ecosystems, and a reduction in the number of wild plants. It also means less crop rotation and so larger areas of consistent monoculture that offers no benefit for biodiversity and damages soils much faster.

A study in 2017 found a direct link between glyphosate application and local abundance of the monarch butterfly, with a decline observed between 1994 and 2003 (the exact timeframe for the first phase of large-scale introduction of the herbicide in that region). This was not due to the direct effects of the chemicals on the butterflies, but rather the glyphosate was eliminating all the wild milkweed plants which serves as the host for the monarch’s eggs.

This is just one example and it is these unintended consequences that might occur and it is only once the impacts are large that we realise what is happening.

Genetic-mixing could occur with wild plants leading disrupting ecosystems

‘Genetic mixing’ is a term coined for when altered genes from genetically modified organisms enter the rest of the natural environment and into wild plants via cross-pollination.

This can be avoided if farmers plant crops so they flower at a different time to the native relatives, but in reality, this rule is often not followed.

This leads to potential issues if one of the herbicide-resistant or herbicide producing crops (mentioned earlier in this article) cross-pollinate with wild plants. Research is ongoing into the true impacts of this, but it is another unknown, where the true consequences for the environment may not be understood until it is too late.

One field trial in the UK found that a herbicide-resistant gene in oilseed rape had found it’s way into a wild related plant ‘charlock’, despite scientists at the time saying this would be ‘virtually impossible’.

By breeding crops that can withstand extreme conditions and are resistant to weedkillers means that from cross-pollination we could end up with plants in the wild that can easily outcompete others and this leads to a loss of diversity which will have significant effects up the food chain.

The creation of super pests or new pests

If farmers plant a monoculture of insect pest-resistant crops everything will be fine….until a pest develops a resistance. This can then lead to a complete failure of a huge amount of food, which has environmental impacts.

In this situation farmers will once again have to turn to pesticide, which as I mentioned earlier, have residual effects on wildlife and ecosystems.

Or in another scenario, perhaps the new crops are resistant to a major pest, but that leads to an increasing rise in minor pests instead. This has the potential to disrupt the entire food chain.

Common non-environmental concerns


Despite this being an environmental blog and the main focus of the article being about the environmental pros and cons of GMO technology, it wouldn’t be right to finish without briefly explaining some other reasons why people are unsure about them

A major one is that large, multi-national corporations have been able to create patents on these GMO crops, increasing farmers reliance on them. It feels odd that a company can do this and demand a ‘royalty fee’ for using their seeds but this does happen. This moves us away from the model of giving power back to local farmers and gives power and control to these large corporations as they create a reliance.

The particular concern comes when a large company owns the GMO patent and the chemical company that overlap. This leads to concerns that crops are being designed specifically to sell more pesticides.

They are dangerous to eat

People often cite GMOs as being dangerous for human consumption, but the reality is that over 2,000 studies have shown they are perfectly safe.

This is because as we mentioned already, genetic modification is simply speeding up the process that occurs naturally through natural selection. The crops have to go through rigorous amounts of testing before they get to market.

Some concerns are being monitored such as increases in allergens, but with vigorous testing this should not be a major issue.

Concluding remarks

Genetically modified organisms are a controversial topic for environmentalists, but it is a conversation that we must continue to have. Like with so many of these big issues we face as a species, there isn’t an easy solution. We have to find a way to feed over 9 billion people in increasingly more difficult climates, without chopping down rainforests to do so.

The fact is, humans have been artificially altering the DNA of plant and animal species for thousands of years, we have just found a way to do it faster.

However, I remain slightly cautious. The ability to ‘patent’ a crop or to create a crop so you can sell more of your own weedkiller is not the best way to use this technology. Farmers should have a choice and shouldn’t be controlled by huge corporations trying to increase their profits every year.

The other thing that makes me cautious (from an environmental point of view) are the unknowns. Humans have a rich history of solutions that later turned out to be even bigger problems (take asbestos for example). The gene mixing with wild plants could lead to certain species dominating and outcompeting others outside of an agricultural setting. We have seen this happen across the world in the past as species have escaped from gardens, such as Himalayan balsam and Japanese knotweed in the UK which are taking over huge areas of habitat, reducing the diversity significantly.

Perhaps it is a case that we only use it in contained environments such as vertical farms to keep things controlled?   

Like with anything, more research is needed and we need to be careful on how we apply the technology. But is it better than the alternative of constant failing crops and the requirement of more land and pesticides? This is precisely why this debate is still raging on.

Benbrook CM. Trends in glyphosate herbicide use in the United States and globally. Environ Sci Eur. 2016;28(1):1–15. doi: 10.1186/s12302-016-0070-0. 

Bawa, A S, and K R Anilakumar. “Genetically modified foods: safety, risks and public concerns-a review.” Journal of food science and technology vol. 50,6 (2013): 1035-46. doi:10.1007/s13197-012-0899-1

Raman R. The impact of Genetically Modified (GM) crops in modern agriculture: A review. GM Crops Food. 2017;8(4):195–208. doi:10.1080/21645698.2017.1413522

Rob Wreglesworth

Rob is the head writer at Innovate Eco sharing knowledge and passion cultivated over 10 years working in the Environmental Sector. He is on a mission to build a community of people that are passionate about solving environmental problems.

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