Abstract：
Agricultural systems in the 21st Century face the double challenge of achieving climate neutrality while maintaining food security. Synthetic fertilizers rich in nitrogen (N-fertilizers) boost agricultural production at the expense of increasing climate impact. Public policies, such as the Farm-to-Fork (F2F) Strategy, aim to reduce the extensive use of N-fertilizers with the ultimate goal of achieving a climate neutral European Union (EU). However, the strong link between N-fertilizers and GHG emissions (i.e., CO2, CH4 and, especially, N2O) highlights the need to better understand the climate impact of this sector. The present study conducts a climate impact analysis of Spanish N-fertilizer sector for two periods: (i) from 1960 to 2020 using real data and (ii) from 2021 to 2100 considering five forecasted scenarios. The scenarios range from business-as-usual practices to a full accomplishment of the goals pursued by the EU\'s F2F strategy. The system\'s climate stability and neutrality are analysed for the different scenarios based on radiative forcing (RF) metrics. Additionally, the study evaluates the short-term impact of the EU decarbonization goals on the climate impact of the Spanish N-fertilizer sector. The results of the study illustrate that the long-lasting climate impact of N2O and CO2 emissions compromise the capacity of N-fertilizer sector to achieve climate stability and approach climate neutrality. However, the decarbonisation of transport and N-fertilizer production activities is an important driver to substantially reduce the life cycle CH4 and CO2 emissions in the Spanish N-fertilizer sector. The results also highlight that more severe reductions on N-cycles than those suggested by the EU\'s F2F are required, especially to reduce the long-lasting N2O emissions in the N-fertilizer sector. Overall, the study concludes that using RF-based metrics increases robustness and transparency of climate assessments, which is necessary for a higher integration of climate science within public policymaking.
摘要：
21世纪的农业系统面临着双重挑战，即在保持粮食安全的同时实现气候中立。富含氮的合成肥料（氮肥）以增加气候影响为代价来促进农业生产。公共政策,例如农场到叉子(F2F)战略，旨在减少氮肥的广泛使用，最终目标是实现气候中立的欧盟（EU）。然而,氮肥和温室气体排放之间的紧密联系(即，CO2、CH4和,尤其是,N2O)强调需要更好地了解这一部门对气候的影响。本研究对西班牙氮肥行业进行了两个时期的气候影响分析：（i）从1960年到2020年使用实际数据，（ii）从2021年到2100年考虑了五种预测情景。这些方案的范围从一切照旧的做法到全面实现欧盟F2F战略所追求的目标。根据辐射强迫（RF）指标，针对不同情况分析了系统的气候稳定性和中立性。此外,该研究评估了欧盟脱碳目标对西班牙氮肥行业气候影响的短期影响。研究结果表明，N2O和CO2排放的长期气候影响损害了氮肥部门实现气候稳定和接近气候中性的能力。然而,运输和氮肥生产活动的脱碳是大幅减少西班牙氮肥行业生命周期CH4和CO2排放的重要驱动力。结果还强调，需要比欧盟F2F建议的更严重的N循环减少，特别是减少氮肥部门的持久N2O排放。总的来说,该研究得出的结论是，使用基于RF的指标增加了气候评估的稳健性和透明度，这对于气候科学在公共政策制定中的更高整合是必要的。
