In 1964, the biochemist and science fiction author Isaac Asimov predicted that at the beginning of the 21st century our nutrition would be based on precooked food, and that we would only reserve a small corner in our kitchens to prepare a dish when visitors came. He could not have been more wrong. Instead of the alienation of nature that Asimov predicted, the new century has brought the opposite trend, the return to the natural, with the consumption of organic food as one of its main banners. And although there is some controversy about whether these products are actually healthier or more nutritious than conventional ones, something that no one would deny is that they are more environmentally friendly. But are they?
Even in this case, reality seems to be more complex than appearances. Putting aside the differences due to the rules that each country can establish about what is considered an organically produced food, in general it would be said that the environmental impact of these products should be lower, due to the fact that synthetic pesticides (or chemicals in common language) are not used.
The keyword is “synthetic”; contrary to what a huge majority of consumers of these products understand, organic agriculture does in fact employ pesticides, although they must also be organic. But as some experts have warned, natural pesticides are not necessarily less toxic than synthetic pesticides. And since they often have to be used in larger quantities, their environmental impact may be higher than conventional ones, as revealed in a 2010 study by the University of Guelph (Canada) that compared the use of synthetic and organic insecticides in the cultivation of soy.
Environmental impact of organic farms
Soil pollution is not the only aspect in which organic production can fail to fulfil its promise of sustainability. In 2012, researchers from the University of Oxford (United Kingdom) analysed 71 previous studies to compare the environmental impact of organic farms and conventional farms. The results indicated that organic farms generally host 30% more biodiversity and their environmental footprint is less per unit of land, but conversely it is not always so per unit of product: while cattle and olive cultivation are more friendly with the environment in their organic versions, pigs, milk and cereals actually generate are more greenhouse gases per unit of product than their conventional equivalents.
According to the director of the study, Hanna Tuomisto, “whilst some organic farming practices do have less environmental impact than conventional ones, the published evidence suggests that others are actually worse for some aspects of the environment. The researcher points out that “people need to realise that an organic label is not a straightforward guarantee of the most environmentally-friendly product.”
One of the factors that raise the environmental cost of organic product is that more land must be used to generate the same volume of food, due to the lower use of fertilizers. This need to devote greater acreage to agricultural production leads to deforestation that reduces the storage capacity of carbon in soils. The final effect is an increase in greenhouse gas emissions responsible for climate change.
This effect is evident in a study published last December in the journal Nature. The authors analysed two specific crops in Sweden, reaching the conclusion that organic peas have a 50% higher climate impact than conventional ones, while this difference increases to almost 70% in the case of wheat.
Soils with less carbon
The principal novelty of the study is that the authors have developed a standardised methodology to measure the opportunity cost of the land in terms of carbon storage. Previous research has compared the direct emissions of greenhouse gases in organic and conventional production, but according to the authors, the indirect effect due to the alternative uses of the land if it were not devoted to agriculture is often underestimated.
The authors point out that, thanks to international trade, this effect is transmitted from one region to another. “Agriculture always uses land,” study director Timothy Searchinger of Princeton University (USA) tells OpenMind. “If there are lower yields on one hectare of land, then to produce the same food, you need to have more land producing food elsewhere, and that means this land is storing less carbon,” says Searchinger. “If you are in a country that is not deforesting land, food production still has to come from somewhere.”
In turn, this environmental cost of organic farming is transmitted to livestock. However, the authors clarify that each product is a particular case, and therefore the most ecologically responsible options consist of the choice of specific foods: “For example, eating organic beans or organic chicken is much better for the climate than eating conventionally produced beef,” says study co-author Stefan Wirsenius, from Chalmers University of Technology (Sweden). In general, chicken, pork, fish, eggs or vegetables have a lower climate impact than cattle and sheep.
Biofuels, a not so green alternative
A particularly surprising case is that of biofuels, used throughout the world as a green alternative to fossil fuels. According to the analysis of Searchinger, Wirsenius and his collaborators, this premise does not hold. From the point of view of its total impact on climate, after adding direct emissions and the opportunity cost of carbon, “it is better to use fossil fuels than biofuels,” says Searchinger. This is due to the large tracts of land occupied by the crops from which the biofuels are extracted; it does not apply to those obtained from waste.
However, says Searchinger, this does not mean that fossil fuels are the best option, but rather that, “the same money that is now being put into biofuels in the name of climate change that actually increases greenhouse gas emissions could be put into other approaches to reduce emissions.” And regarding which, Searchinger is clear about what is needed: “As rapid as possible a transition toward electric vehicles.”