中国城市生活垃圾处理碳排放时空分布特征及减排潜力

Spatio⁃temporal distribution characteristics and reduction potentials of China's MSW⁃related GHG emissions

传统垃圾处理方式(填埋、焚烧等)是温室气体尤其是CH4排放的重要来源。基于此,该研究采用IPCC碳排放计算方法,分析了2006—2021年中国297个地级及以上城市的城市生活垃圾处理结构和温室气体排放时空分布特征,并结合灰色预测模型,对2030年和2060年的排放情况进行预测。结果表明:①在处理方式层面,绝大多数城市不再以填埋为唯一垃圾处理方式,垃圾焚烧逐步替代填埋成为主流。②在排放量层面,中国城市生活垃圾处理的碳排放总量快速增长,在2019年到达7940.66万t后趋于稳定,北京、上海、广东深圳等超大城市的总碳排放量最高;中国城市生活垃圾处理净碳排放量经历先升后降的过程,且净碳排放量较高地区向三四线城市转移;城市生活垃圾处理碳排放呈现随城市人口规模扩大和经济发展水平提升而显著增加的变化规律。③预测结果表明,中国城市生活垃圾处理总碳排放量将于2030年达到6575万~9942万t;在直辖市和省会城市中,仅甘肃兰州可以实现垃圾处理碳排放达峰;垃圾分类对净零排放存在较大影响,如采取垃圾分类措施,大部分城市未来可实现碳中和。最后,作者提出城市生活垃圾“三步走”分级管理策略:对于仍采用填埋为主要处理方式的城市,应推动从填埋到焚烧的转型;对于已实现垃圾零填埋的城市,应加快推进垃圾分类工作;对于已实施垃圾分类政策的城市,应进一步减少垃圾产生并落实源头减量措施。

Landfilling,incineration,and other waste disposal methods,are major contributors to greenhouse gas emissions,particularly methane.Using the IPCC method,this study examined MSW treatment structures and GHG emissions in 297 prefecture-level cities in China from 2006 to 2021.Additionally,the study predicted MSW-related GHG emissions for 2030 and 2060 by employing a grey fore⁃casting model.The findings revealed that:①Most cities were transitioning from landfilling to incineration as the predominant waste dis⁃posal method.②Total MSW-related carbon emissions in China showed rapid growth,stabilizing after reaching 79.41 million tons in 2019,with mega-cities such as Beijing,Shanghai,and Shenzhen exhibiting the highest emissions.Meanwhile,net carbon emissions from MSW treatment experienced an initial increase followed by a decline,with higher-emission regions shifting towards third-and fourth-tier cities.Carbon emissions from MSW treatment would increase with the expansion of urban population and the improvement of economic development level.③The forecast results indicated that China's total MSW-related GHG emissions would range from 65.75 to 99.42 million tons by 2030.Among 31 cities,only Lanzhou was projected to achieve peak carbon emissions in waste treatment.Waste classification would significantly impact achieving carbon neutrality,and most cities could attain it with effective waste sorting measures.Finally,this study proposes a‘three-step’hierarchical strategy for MSW management.For cities still relying on landfilling,efforts should be made to transition from landfilling to incineration.For cities that have achieved zero landfilling,waste classification is necessary.For cities that have already implemented waste classification policies,the implementation of source reduction measures is es⁃sential.