Going completely organic could increase greenhouse emissions, new study finds
Conventional farming is known to contribute around nine percent of overall greenhouse gas emissions both in the UK and US
For all its health and environmental benefits, organic food production could be counterproductive, according to a new study. It could increase overall greenhouse emissions if countries go completely organic.
The analysis by scientists from Cranfield University and University of Reading was done for England and Wales.
Organic farming on its own does not cause the rise. In fact, it brings the emissions down, the study predicts. But they add that its impact on the greenhouse effect will be more indirect. By significantly reducing food production, it could increase imports. As a result, more grasslands from other countries will be converted into arable lands, leading to more emissions.
Normally, conventional farming is known to contribute around nine percent of overall greenhouse gas emissions both in the UK and the US. This led people to turn to organic farming. Earlier studies showed that converting land from conventional agriculture to organic production could reduce greenhouse gas emissions.
In the current analysis, the scientists used modeling to predict the scenario of England and Wales switching to a 100% organic way of producing food. Their study revealed a drop in emissions of about 20% for crops and around four percent for livestock could occur. Simultaneously, they could predict a dip in food production, by around 40% compared to conventional farming.
This decline, the authors say, can be attributed to smaller crop yields and the use of nitrogen-fixing legumes in crop rotations, which reduces the amount of land available for food production.
Low-food production will drive England and Wales to import food from other countries. To meet the demands, it could push these countries to convert grasslands into arable lands. The overall emissions would go up by 21 percent, if half the grasslands are turned into farmlands.
The team estimates that for organic farming to be adopted wholesale without any change in diet, they would need nearly six million more hectares of land. "Much of which would need to come from Europe. This has an associated impact on the environment, adding potentially unnecessary food miles and greenhouse gas emissions to our food systems," said one of the authors, Philip Jones, from the University of Reading.
However, there is one flaw in the study. The authors did not factor in a change in people's diet, according to Rob Percival of the Soil Association, also a proponent of organic farming. "The study assumes no change in diet, which is clearly untenable given the global dietary health crisis, and that we would keep diverting most of our cropland to over-production of the wrong things - livestock feed, commodity crops for processed food and biofuels," he told BBC.
In response, co-author Dr Adrian Williams from Cranfield University said, "The assumption about diets is crucial: today's organic consumers are a self-selecting group and not typical of the nation. Whether a different national diet could be provided by the same land area under all organic production is a different study. This was aimed at understanding limits to production. The study was based on rigorous modelling that had its foundations in establishing the biophysical limits of crop production without manufactured nitrogen."
The study is published in Nature Communications.