School of Environmental and Chemical Engineering, Shanghai University, 200444 Shanghai, China.
Center of Air Quality Simulation and System Analysis, Chinese Academy of Environmental Planning, 100012 Beijing, China.
Environ Int. 2024 Sep;191:108958. doi: 10.1016/j.envint.2024.108958. Epub 2024 Aug 14.
Regional budget assessments of methane (CH) are critical for future climate and environmental management. CH emissions from rice cultivation (CH) constitute one of the most significant sources. However, previous studies mainly focus on historical emission estimates and lack consideration of future changes in CH under climate change or anthropogenic policy intervention, which hampers our understanding of long-term trends and the implementation of targeted emission reduction efforts. This study investigates the spatiotemporal variations of CH over the past two decades, using an integrated method to identify the major drivers and predict future emissions under climate change scenarios and policy perspectives. Results indicate that the CH emissions in China ranged between 6.21 and 6.57 Tg yr over the past two decades, with a spatial distribution characterized by decreases in the south and increases in the north, associated with economic development, dietary shifts, technological advancements, and climate change. Factors such as the rate of straw added (RSA), fertilization, soil texture, temperature, and precipitation significantly influence CH emissions per unit rice production (CH), with RSA identified as the most significant tillage management factor, explaining 32 % of the variance. Lowering RSA to 8 % is beneficial for reducing CH. Scenario analysis indicates that under policies focusing on production or demand, CH is expected to increase by 0.3 % to 5.6 %, while adjusting RSA can reduce CH by 9.4 % to 10.0 %. Structural adjustments and regional cooperation serve as beneficial starting points for controlling and reducing CH in China, while optimizing industrial layouts contributes to regional development and CH control. Implementing policies related to maintaining field and crop yields can achieve a balance between rice supply and demand ahead of schedule. Dynamic adjustment of rice cultivation based on supply-demand balance can effectively reduce CH from excess rice production. By 2060, the reduction effect could reach 8.95 %-12.01 %. Introducing policy-driven tillage management measures as reference indicators facilitates the reduction of CH.
区域预算评估对于未来的气候和环境管理至关重要。水稻种植产生的甲烷（CH）排放是最重要的来源之一。然而，以前的研究主要集中在历史排放量估计上，缺乏对气候变化或人为政策干预下 CH 未来变化的考虑，这阻碍了我们对长期趋势的理解以及实施有针对性的减排工作。本研究使用综合方法调查了过去二十年 CH 的时空变化，以确定主要驱动因素，并预测在气候变化情景和政策视角下未来的排放量。结果表明，过去二十年中国 CH 排放量在 6.21 到 6.57 Tg yr 之间，空间分布特征是南部减少，北部增加，这与经济发展、饮食结构变化、技术进步和气候变化有关。因素如稻草添加率（RSA）、施肥、土壤质地、温度和降水对每单位水稻产量的 CH 排放量有显著影响，其中 RSA 是最重要的耕作管理因素，解释了 32%的方差。将 RSA 降低到 8%有利于减少 CH。情景分析表明，在以生产或需求为重点的政策下，CH 预计将增加 0.3%到 5.6%，而调整 RSA 可以减少 9.4%到 10.0%。结构调整和区域合作是中国控制和减少 CH 的有益起点，而优化产业布局有助于区域发展和 CH 控制。实施与保持田间和作物产量相关的政策可以提前实现水稻供需平衡。基于供需平衡的水稻种植动态调整可以有效地减少因过量水稻生产而产生的 CH。到 2060 年，减排效果可达 8.95%到 12.01%。引入以政策为导向的耕作管理措施作为参考指标有助于减少 CH。
