Science of GM crops reviewed

News Date: 2 Jun 2016

Two renowned science academies – the US National Academies of Science, Engineering and Medicine and the UK’s Royal Society – have released reports on the science behind genetically modified (GM) (also known as genetically engineered, GE) crops.

GM crops were first commercialised in 1996. Since then, they have been planted across a cumulative total of 2 billion hectares in 28 countries, providing benefits to farmers of more than US$150 billion. Indeed, nearly 18 million farmers now grow GM crops each year, 90% of whom are small, resource-poor farmers in developing countries (ISAAA). However, doubts and controversy about their safety and efficacy still rumble on.

In efforts to address the arguments brought up by those against the use of GM crops, the US National Academies commissioned a committee of 20 eminent scientists with expertise in biochemistry, plant biology, food science, crop science and soil science to review the evidence. The team’s two-year analysis took into account some 900 journal articles published during the past 30 years, as well as expert testimony and public submissions.

To summarise, the report confirms that that there is no scientific evidence that GM crops are unsafe to eat or harm the environment.

According to a press release from the National Academies: "The committee carefully searched all available research studies for persuasive evidence of adverse health effects directly attributable to consumption of foods derived from GE crops but found none."

In fact, the committee found evidence that GM crops had benefitted human health, for example by reducing insecticide poisonings.

Concerning the effects on the environment, the committee concluded that: “The use of insect-resistant or herbicide-resistant crops did not reduce the overall diversity of plant and insect life on farms, and sometimes insect-resistant crops resulted in increased insect diversity.”

Finally, with regard to yields and farmers’ profits, the verdict is more equivocal: “Evidence indicates that GE soybean, cotton, and maize have generally had favorable economic outcomes for producers who have adopted these crops, but outcomes have varied depending on pest abundance, farming practices, and agricultural infrastructure.”

On the down-side, the report notes that evolved resistance to some GM crops is a major agricultural problem – for example, there are records of bollworms developing resistance to lines of Bt-cotton.

While the report from the US National Academies runs to 400 pages, the Royal Society’s report comes in at 40 and is designed to be more user-friendly, offering up a series of regularly-asked questions and answering them in accessible language.

The questions themselves – 18 in all – were derived from a survey of the public and address such issues as: What is genetic modification (GM) of crops and how is it done?; How does GM differ from conventional plant breeding?; and What GM crops are currently being grown and where?

"The answers draw on a wide range of evidence and give some specific examples. In general, it is important to recognise that when the GM method is used, the crops produced should be assessed on a case by case basis. GM is a method, not a product in itself. Different GM crops have different characteristics and it is impossible, from a scientific point of view, to make a blanket statement that all GM is good or bad," said Venki Ramakrishnan, president of the Royal Society.


The two reports are avaiable from the academies' respective websites:

US National Academies - Genetically Engineered Crops: Experiences and Prospects

Royal Society - Genetically Modified (GM) Plants: Questions and Answers