People are keener than ever to make ethical, environmentally friendly food purchases. But a spate of bad press about the environmental impact of organic produce may leave some people scratching their heads. The debate about this is contentious. Critics say organic farming is less efficient than conventional farming, and so uses more land, leading to greater deforestation, which causes higher carbon dioxide emissions and biodiversity loss. A recent paper followed this logic to find that going 100 per cent organic in England and Wales would raise these emissions by up to 56 per cent. The claim made headlines. But the findings from this study and similar ones are too simplistic and ignore important positive aspects of organic farming. We have analysed such studies and found that the method they often use doesnt give the full picture. Known as a life cycle assessment (LCA), this approach simply relates environmental impacts to the amount of product harvested from a given area of land. Looked at this way, intensive farming is often more efficient, since its yields are higher. But this doesnt properly address all environmental aspects. Such assessments fail to fully account for the role of land degradation, biodiversity decline and pesticide impacts of intensive agriculture. Consider biodiversity, for example. The variety of life on Earth is an incredibly important factor in the health and resilience of ecosystems. But worldwide, it is in decline insect and bird populations are being decimated, something that has been repeatedly linked to the damaging practices of intensive farming. Organically managed land, however, has been shown to support biodiversity levels around 30 per cent higher than conventionally farmed fields. It might be argued that the land saved through conventional farming could be reserved for biodiversity and CO? absorption. But the relationship between agricultural intensification and reduced deforestation is unclear. In Brazil, for example, agricultural intensification has coincided with more deforestation. Widespread use of pesticides is also a concern between 1990 and 2015, global pesticide use has increased more than 70 per cent. Pesticide residues can be harmful to land and aquatic ecosystems, as well as our health. The avoidance of synthetic pesticides in organic farming, and the overall much lower levels of pesticide use in general, is a factor that is often overlooked in LCAs. In the 34 studies comparing organic with conventional agriculture that we reviewed, only nine looked at pesticide-related impacts. The debate around the environmental impact of organic farming has become too simplistic and narrow. Our review, published in Nature Sustainability, shows that organic farmings strengths and environmental benefits are often overlooked by the current research, and simply claiming that organic farming is worse for the environment is misleading. The current use of LCAs needs to be improved and integrated with other environmental assessment tools. Only then will consumers get a more balanced picture.
newscientist.com, 16 March 2020