Mitigating climate change through soil carbon sequestration: a literature synthesis on agricultural LCAs

Mitigating climate change and ensuring food security are among the greatest challenges for modern agricultural systems. Indeed, while the latter largely contribute to the total global greenhouse gas emissions, they also have the potential to mitigate the related climate change, mainly through carbon sequestration. Especially improved soil management practices, such as zero tillage, crop residue recycling, and application of organic matter, can increase soil organic carbon (SOC) stocks, thus leading to a sequestration of carbon dioxide emissions from the atmosphere into the soil. Additionally, those beneficial practices can enhance soil fertility and agroecosystems’ productivity. All those practices will contribute to making agricultural systems more sustainable, thereby favouring the green transformation of all those sectors that depend upon agricultural products and activities, such as the tourist one. Within the LCA community, no consensus has been reached thus far on considering and quantifying SOC sequestration in agricultural systems. However, accounting for soil carbon sequestration could be particularly relevant for comparative LCAs between conventional and organic farming systems to determine their environmental profiles and the room for improvements. In line with this, the present study aimed at comprehensively reviewing agricultural LCAs adopting specific methods to measure SOC changes due to the application of organic and conservative soil management practices. This allowed the authors to stress the importance of carbon sequestration benefits from agroecological practices and to identify and discuss both the advantagesand limitations of the most adopted methods and approaches for including SOC sequestration accounting into LCA.