I have never been a supporter of Brexit, except for one thing: it has allowed the UK to break free from the damaging straitjacket of European Union agricultural policy, including its prohibition on genetically modified crops. I have always believed this was based more on sentiment than science. In post-Brexit Britain, science has won.
Last year, the came into force, allowing the development of gene-edited crops and animals in England. This isn鈥檛 quite GM, which allows for the insertion of genes from other species, rather than gene editing鈥檚 approach of only changing an organism鈥檚 existing DNA, but its potential is very similar (from this point on, we鈥檒l just use the term GM). Done right, this could usher in a new era of genetic engineering that unlocks the ability of this tech to undo some of agriculture鈥檚 environmental damage.
Nearly 30 years on from the controversial introduction of GM crops, they have become a fixture in agriculture. They now cover around of the world鈥檚 arable land, mostly in Brazil, the US, Argentina, Canada and India.
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In those fraught early days, advocates of GM often claimed modified crops were a win-win: they would help to feed a growing population without increasing the environmental impact of agriculture. That was largely because higher yields would reduce the need to expand into natural habitats, and their engineered traits would nullify the need for further intensification.
You might think we would know if this is true by now. But this year a team led by environmental economist on the of GM crops and found that there are still gaping holes in our knowledge.
That isn鈥檛 for lack of trying. GM crops have been tested in many field trials. These are in terms of the impact on producers, showing, for example, increased yields from GM crops compared with non-GM versions, though their impacts on the wider environment are mixed.
GM crops also have complex indirect effects that aren鈥檛 captured by these trials, which usually have only one variable 鈥� GM versus non-GM. Everything else, such as the application of agrochemicals, is held equal. But out in the real world, the adoption of GM often has ripple effects on agriculture, such as changes in agrochemical use, with what Noack describes as 鈥減rofound environmental implications鈥�.
Increased drought resistance and improved nitrogen efficiency could make farming much greener
First, the good news. More realistic experiments have shown benefits along the lines claimed by early GM advocates. One in found that shifting to pest-resistant aubergine increased yields by 50 per cent and reduced use of pesticides by 40 per cent.
But, again, these trials don鈥檛 capture the full picture. Consider greenhouse gas emissions. Food production for about a quarter of the world鈥檚 emissions, around a third of which is directly attributable to arable farming.
In principle, adoption of GM crops could decrease this carbon footprint. One analysis found that if Europe were to embrace GM more widely, its emissions from agriculture would fall by due to gains in yield. GM crops can also reduce the need for tilling of soil as well as agrochemicals, both of which rely on fossil fuels. But there are large uncertainties about the actual size of these reductions, according to Noack.
On the destruction of habitat, the evidence is mixed. In theory GM crops should reduce the pressure to expand production because yield increases lead to price reductions. But in practice, GM can have the opposite effect. In Brazil, better yields increased farmers鈥� profit margins and them to encroach into forests. It is a similar story with biodiversity. Some studies show wildlife doing better with GM, others the opposite.
All told, says Noack, 鈥渢he broader effects [of GM] remain poorly understood鈥�. But what the evidence does show, he says, is that GM crops could have 鈥渦nambiguous positive environmental consequences鈥�. The reason they don鈥檛 is largely because today鈥檚 GM landscape is dominated by two technologies 鈥� herbicide tolerance and resistance to pests 鈥� in just four crops: soya bean, maize (corn), cotton and rapeseed (canola). These were developed with profits in mind, not sustainability. Newer and greener tech, applied to a broader range of species, has been held back by steep regulatory costs.
But those advances 鈥� things like increased drought resistance and improved nitrogen efficiency 鈥� could make farming much more environmentally friendly. What is needed, says Noack, is a regulatory regime that both embraces new tech such as gene editing and emphasises sustainability, not just profitability. Rather, I am hoping, like the new regime in the UK. Bring on the sunlit uplands.
Graham鈥檚 week
What I鈥檓 reading
I recently moved back to my hometown, York, so I鈥檓 reading up on the city鈥檚 rich history.
What I鈥檓 watching
Season 2 of Sherwood on the BBC.
What I鈥檓 working on
Trying to secure an interview with a really big name. Can鈥檛 say who.
Graham Lawton is a staff writer at New Scientist and author of Mustn鈥檛 Grumble: The surprising science of everyday ailments. You can follow him @grahamlawton
