The most commonly used method for analysing the environmental impacts of agricultural systems tends to overlook major factors such as biodiversity, soil quality, pesticide impacts and societal shifts, reports France’s National Research Institute for Agriculture, Food and the Environment (INRAE).
An INRAE researcher, working with two colleagues from Sweden and Denmark, has produced a paper featured in Nature Sustainability. It reports that these oversights can lead to wrong conclusions when comparing high-input intensive agricultural systems and less intensive agroecological systems such as organic agriculture.
INRAE explains that Life Cycle Assessment (LCA) is the most common method used for assessing the environmental impacts of agriculture and food. Studies using this method, it reports, sometimes claim that agroecological systems such as organic agriculture are worse for the climate than conventional agriculture because of lower yields and therefore more extensive use of land to make up for this.
Taking into account many LCA studies, the three researchers say this implementation of LCA is too simplistic, missing some of the major benefits of approaches such as organic farming.
INRAE says: “Firstly, their analysis shows that current LCA studies rarely account for biodiversity, which is of crucial importance for ecosystem health and resilience. However, it is declining worldwide, and intensive, conventional agriculture has been shown to be one of the main drivers of negative trends such as insect and bird decline.
“Agriculture occupies more than one-third of global land area. Therefore, any links between biodiversity losses and agriculture are extremely important. Earlier studies have already shown that organically managed fields support biodiversity levels approximately 30% higher than conventionally managed fields.
“Furthermore, between 1990 and 2015, pesticide use worldwide has increased by 73% and pesticide residues in soils and in water and food can be harmful to human health, terrestrial and aquatic ecosystems, and cause biodiversity losses. Organic farming precludes the use of synthetic pesticides. But few LCA studies account for these effects.”
It adds that land degradation and reduced soil quality due to unsustainable management of agroecosystems is also an issue which is seldom considered in LCA studies.
“Crucially, LCA generally assesses environmental impacts per kilogram of product,” says INRAE. “This favours intensive, conventional systems that may have lower impacts per kilogram of product, while having higher impacts per hectare of land. LCA also needs a more fine-grained approach, considering ecological processes, adapted to local soil, climate and ecosystem characteristics.
“Current LCA methodology and practice is simply not good enough to assess agroecological systems such as organic agriculture. It therefore needs to be improved and integrated with other environmental assessment methods to get a more balanced picture and to better support political decision-making.”
Reference: Van der Werf, H.M.G., Trydeman Knudsen, M., Cederberg, C. Towards better representation of organic agriculture in life cycle assessment. Nature Sustainability (2020) doi: 10.1038/s41893-020-0489-6
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