Context The urban landscape plays a crucial role in achieving sustainability goals and aspiring to a zero-emission future. Effective carbon mitigation strategies need a spatially explicit and life-cycle analysis of building emissions, detailed mapping highlights the geographical distribution and specific characteristics of buildings, enabling precise identification and targeted management of emission sources. Objectives This study aims to create a framework that reveals the spatial and temporal dimensions of building carbon emissions at each stage of their life cycle. Methods We developed a comprehensive approach for carbon accounting in buildings. This framework captures spatiotemporal carbon emission patterns across various building types, considering material, energy, and waste flows. It also identifies potential mitigation strategies within the urban building landscape. Results Applying this framework to a case study in Shenzhen, we observed a fluctuating increase in total carbon emissions, peaking at 201.5 Mt in 2016 and subsequently declining. Embodied emissions dominated before the twenty-first century, while operational emissions became significant afterward. Spatially, emissions hotspots concentrated in central urban districts, expanding outward, with residential buildings contributing the most. Scenario analysis revealed that extending building lifetimes is a key strategy for mitigating embodied carbon, while improving energy efficiency and adopting clean energy work well together to reduce operational carbon. Conclusions Mapping the spatiotemporal patterns of carbon emissions throughout a building’s lifespan can assist urban planners and policymakers in formulating targeted strategies for carbon reduction, thereby enhancing urban sustainability.

Background: White tea, despite being one of the six major types of Chinese tea, has received relatively little attention regarding its production-related environmental impacts. This study employed a cradle-to-grave life cycle assessment (LCA) to quantify the carbon footprint of Fuding white tea production. Results: An integrated cradle-to-grave assessment, informed by field surveys, literature, and background databases (including complete life-cycle data from 15 tea enterprises), revealed an average carbon emission intensity of 16.94 ± 3.41 kg CO₂ eq per kilogram of finished tea (crude). Major emission sources included electricity consumption (45–68% of total emissions), water usage (15–26%), and fertilizer application (7–22%), with major hotspots identified in the processing stage (4.10–12.73 kg CO₂ eq/kg, primarily from energy-intensive drying and refining) and consumption stage (5.17–5.67 kg CO₂ eq/kg, dominated by water heating). Analysis of 216 scenarios revealed production emissions ranged from 15.44 to 22.72 kg CO₂ eq/kg. Notably, emissions could be reduced by up to 56% through integrated measures such as organic fertilization, natural withering, and short-chain distribution. When accounting for tea garden carbon sequestration (1.17–8.45 kg CO₂ eq/kg), the production of Fuding white tea could potentially achieve net-negative emissions. Conclusions: To support decarbonization, we propose a tripartite strategy: adoption of green electricity and organic fertilizers during production, promotion of short-chain distribution systems and low-carbon consumer practices, and innovating carbon sink trading mechanisms. These findings offer a scientific foundation for reducing the carbon footprint per unit of tea and enhancing the green competitiveness of the tea industry.

【目的】 铜作为一种重要的战略性矿产资源，在电力低碳能源转型和碳中和进程中发挥着关键作用。中国是铜资源短缺的国家，科学预测电力系统未来铜资源需求量和报废量，对于保障国家铜资源安全供给、优化资源循环利用体系具有重大战略意义。【方法】 本文基于中国综合政策评估模型（Integrated Policy Assessment Model of China, IPAC）中的全球升温1.5 ℃情景和全球升温2 ℃情景，以及中国的“双碳”情景与动态物质流分析方法核算出了中国电力系统1950—2050年铜在用存量、铜需求量、理论报废量以及铜的对外依存度。【结果】 ①中国发电装机容量预计从1950年的185万kW增至2050年的540万~600万kW，其中新能源占比随政策严格度递增：到2050年1.5 ℃情景达80%，“双碳”情景73%，2 ℃情景67%；②中国电力系统铜的在用存量、需求量和理论报废量将在2050年分别达到1.4亿~1.6亿t、650万~810万t和400万~480万t，较2022年水平分别增长约3倍、1.5倍和10倍；③全球升温1.5 ℃情景下的中国电力系统铜的需求量、存量和理论报废量均最高，其次是中国的“双碳”情景；④中国铜资源对外依存度呈显著下降趋势，在全球升温1.5 ℃情景下从2023年的70%下降到2050年的48%，在“双碳”目标情景下可进一步降至40%，而在全球升温2 ℃情景下，预计将下降至38%。【结论】 中国电力低碳转型将推高铜需求，再生铜利用可降低对外依存度，但短期供应风险仍存在。建议加强资源勘探、循环利用及供需评估，保障铜资源供应安全。