The increased use of legumes is viewed as a promising option to mitigate climate change, as they are a source of proteins and provide nitrogen to the soil. In this paper, we evaluate a strategy for the increased use of legumes in Europe until 2050 by integrating a large array of food and natural system processes into a consistent modeling framework. Three contrasting scenarios are studied: a supply-side scenario entailing a change in the animal feed mix, a demand-side scenario entailing a shift in human diet, and a combination of the shift in human diet with a reforestation in Europe. We find that mitigated emissions are much higher in the two diet shift scenarios (-231 and -259 MtCO_2eq, respectively) than in the supply-side scenario (-10 MtCO_2eq). Therefore, the main environmental benefit of legumes is to provide proteins as a substitute for animal products rather than enabling a lower consumption of synthetic fertilizer through increased leguminous nitrogen fixation. Diet shift scenarios require a lower use of lands that can then be used to either reduce intensification or reforest. In the former case, the reduction in emissions concerns almost exclusively non-CO₂ emissions, mainly through enteric fermentation and manure management, and occurs largely outside Europe. In the latter case, the livestock sector still represents a substantial share of the emission reduction but is outpaced by CO₂ emissions through carbon sequestration. An increase in legume production substantially reduces greenhouse gas emissions from the AFOLU sector only when combined with a change in diet, and its combination with reforestation allows the emission reduction to be relocated to Europe through carbon sequestration. Our study concludes that an increase in legume production accompanied by appropriate measures on both the supply and demand side can be effective in reducing emissions. These results can be used to design the European Commission’s “Farm to Fork” strategy for sustainable food and to support climate-friendly farming practices of the post-2020 European common agricultural policy.

中文翻译：

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评估欧洲豆类产量增加对全球农业排放的影响

豆科植物的使用被认为是缓解气候变化的有前途的选择，因为它们是蛋白质的来源，并向土壤提供氮。在本文中，我们通过将一系列食品和自然系统过程整合到一个一致的建模框架中，评估了到2050年在欧洲更多使用豆类的策略。研究了三种截然不同的情景：供应方情景导致动物饲料结构发生变化；需求方情景导致人类饮食结构发生变化；以及人类饮食结构变化与欧洲的植树造林相结合。我们发现，在两种饮食结构转变情景（分别为-231和-259 _{MtCO 2eq）中}，_减排量要比供应方情景（-10 _{MtCO 2eq）高得多。}）。因此，豆类的主要环境效益是提供蛋白质作为动物产品的替代品，而不是通过增加豆类固氮来降低合成肥料的消耗。饮食转移的情况要求减少土地的使用，然后将其用于减少集约化或重新造林。在前一种情况下，排放量的减少几乎全部涉及非CO ₂排放，主要通过肠内发酵和粪便管理，并且主要发生在欧洲以外。在后一种情况下，畜牧业仍占减排总量的很大一部分，但被CO ₂所赶超通过碳固存的排放。只有结合饮食改变，豆类产量的增加才能大大减少AFOLU部门的温室气体排放，再加上植树造林，可以通过碳固存将减排量转移到欧洲。我们的研究得出的结论是，增加豆类产量并在供需双方采取适当措施可以有效减少排放。这些结果可用于设计欧盟委员会可持续粮食的“从农场到餐桌”战略，并支持2020年后欧洲共同农业政策的气候友好型农业实践。