Abstract
Shifting towards healthy, plant-based diets is widely recognized as a strategy to reduce greenhouse gas emissions (GHG) from food systems, primarily through reduced methane emissions from livestock. However, the implications of this transition for soil-based GHG emissions, a major contributor to climate change, remain uncertain. We used the MAGNET economic model and the DayCent biogeochemical model to assess the impacts of dietary shifts aligned with the EAT-Lancet guidelines on soil organic carbon (SOC), nitrous oxide (N(2)O) emissions, and the soil GHG balance across the European Union and the United Kingdom. Adopting the EAT-Lancet diet reduced livestock production, organic carbon (C) and organic nitrogen (N) inputs from manure, and permanent grassland areas for agricultural use. This results in potential SOC losses of an EU average of 14 Mg CO(2)e ha(-1) and reaching up to 50 Mg CO(2)e ha(-1) in livestock-intensive regions by 2100. However, afforestation of land released from production could offset approximately half of the diet-induced soil C losses by 2100. When above-ground biomass from afforestation is factored in, this could yield an additional 65 Mg C ha(-1) in afforested areas, resulting in net CO(2) removal at the European scale. N(2)O emissions exhibited more moderate and heterogeneous changes by 2100, ranging from 10 to -13 Mg CO(2)e ha(-1) across the continent, and dependent on land use change (LUC) and increased synthetic N inputs. The changes in SOC were driven by LUC, lower organic inputs, soil types and, to a lesser degree, climatic zones. This study's findings underscore the importance of dietary changes in tackling climate change. However, practitioners and policymakers should carefully consider potential soil-related trade-offs by supporting and implementing appropriate soil conservation practices, such as no-tilling or afforestation, to realize the full co-benefits of more sustainable diets.