Yupeng Liu, Jiajia Li, Wei-Qiang Chen*, Lulu Song, Shaoqing Dai

Journal of Industrial Ecology  2022，1–10

https://doi.org/10.1111/jiec.13252

Abstract

Rapid urbanization generates substantial demand, use, and demolition waste of construction materials. However, the existing top-down or bottom-up frameworks combining material flow analysis (MFA) and geographic information system (GIS) tend to underestimate both input and output of construction material flows due to insufficient descriptions of key processes in building construction and demolition. To address this limitation, this study identifies four important and complementary processes—construction, demolition, replacement, and maintenance, and integrates them into an improved framework to capture all material flows. We take Xiamen, a rapidly urbanizing city, as a case study to verify this framework. The results show that ∼40% of material inputs and ∼65% of outputs are underestimated by previous frameworks because they fail to capture material inputs in building maintenance and outputs in construction. These findings indicate a better estimation of such key flows in the modeling framework helps to accurately characterize building material metabolism. Based on systematic counting of material stocks and flows, the improved framework can help design effective policies for urban resource management by explicitly recognizing the spatiotemporal patterns and processes of material metabolism.

Keywords

geographic information systems (GIS)；high-resolution urban grids (HUGs)；industrial ecology；material flow analysis；urbanization

Wang, Peng, Shen Zhao, Tao Dai*, Kun Peng, Qi Zhang*, Jiashuo Li,Wei-Qiang Chen*

Renewable and Sustainable Energy Reviews. 2022,161 112367

https://doi.org/10.1016/j.fmre.2022.02.003

Abstract

Steel production is one of few “difficult-to-decarbonize” sectors that requires strong decarbonization actions. However, the present focus is mainly limited to technical efforts, while regional disparities in steel production and its impacts on energy and carbon efficiency are rarely explored. By integrating environmental extended input-output analysis and material flow analysis, this study, as one of the first attempts, provides an analytical perspective to explore the regional emission performance of steel production across 44 countries and the rest 5 regions from 2000 to 2015, in which the physical indicators such as CO₂ emission, energy use, and carbon intensity are compared. The results show that the CO₂ emission associated with global steel production has increased by 2.5-fold from 2000 to 2015, and the global steel production has only increased by 1.9-fold, indicating a worsening environmental performance with emission intensity increasing from 2.1 tCO₂/t in 2000 to 2.8 tCO₂/t in 2015. This is closely linked to the historical changes in the geographical distribution of steel production as well as the faster increase of steel production in less efficient regions compared to that of more efficient regions. Despite the efficiency improvement in several nations, the carbon intensity of both developed (OECD, from 1.6 t CO₂/t to 2.3 t CO2/t) and developing nations (non-OECD: 2.7 t CO₂/t to 3.0 t CO₂/t) were increasing during the past decade. Thus, there is a need to incorporate regional disparities and inequalities in the designingglobal decarbonization strategies of steel and other heavy industrial sectors.

Keywords

Steel production; Carbon neutrality; Energy efficiency; Carbon-intensive; Diffcult to decarbonize sector; Regional disparity

卢浩洁; 刘宇鹏*; 宋璐璐; 陈伟强

北京师范大学学报(自然科学版), 2021, 43(3): 501-512

DOI: 10.18402/resci.2021.03.07

摘要：

建筑在城市中的积累和废弃能够对城市环境产生显著影响。本文以同处于闽三角地区、但处于城市化不同阶段的福州市、厦门市和泉州市为例，通过物质流分析预测了三座城市至本世纪末在高速发展、历史轨迹和可持续发展三种情景下住宅新建量、保有量和拆除量的动态变化规律和趋势。研究结果表明:（1）未来福厦泉城市群的人均居住条件有望达到甚至超过欧美现有水平。（2）相较于沿历史轨迹继续发展，盲目追求过高的居住条件（高速发展情景）将带来严重的资源环境问题；而倡导可持续的发展模式能够在不影响居民居住水平的前提下，大幅节约资源并减少其环境影响．（3）对于城镇化率较高的厦门，通过旧楼改造、建筑延寿等手段可显著减少建筑垃圾产生量，而对于处于城市化进程中的福州和泉州则需通过发展紧凑型城市避免“过量”的建筑垃圾产生。

关键词：

住宅建筑 ，住宅保有量 ，建筑垃圾产生量 ，多情景预测

Lulu Song, Ji Han, Nan Li*, Yuanyi Huang, Min Hao, Min Dai and Wei-Qiang Chen

Scientific Data  2021, 8 , 303

https://doi.org/10.1016/j.wasman.2021.10.039

Abstract:

As the world’s top material consumer, China has created intense pressure on national or global demand for natural resources. Building an accurate material stocks and flows account of China is a prerequisite for promoting sustainable resource management. However, there is no annually, officially published material stocks and flows data in China. Existing material stocks and flows estimates conducted by scholars exhibit great discrepancies. In this study, we create the Provincial Material Stocks and Flows Database (PMSFD) for China and its 31 provinces. This dataset describes 13 materials’ stocks, demand, and scrap supply in five end-use sectors in each province during 1978–2018. PMSFD is the first version of material stocks and flows inventories in China, and its uniform estimation structure and formatted inventories offer a comprehensive foundation for future accumulation, modification, and enhancement. PMSFD contributes insight into the material metabolism, which is an important database for sustainable development as well as circular economy policy-making in China. This dataset will be updated annually.

Yupeng Liu* , Lulu Song , Wanjun Wang , Xiaomei Jian, Wei-Qiang Chen

Waste Management   137 (2022) 150–157

https://doi.org/10.1016/j.wasman.2021.10.039

Abstract:

The growing amount of electronic waste (e-waste) poses considerable risks to the environment and human health, especially when treated inadequately. However, it is difficult to assess the significance of these issues without quantitative understanding of spatiotemporal patterns of e-waste generation. This paper proposes a new model to estimate in-use stock of electric household appliances (HAs) and e-waste generation at the level of 1 km × 1 km grids by coupling geographic information system (GIS) and material flow analysis (MFA). We took Xiamen, a rapidly urbanized city in China, as a case and the results showed that demands for HAs increased from 1980, peaked in 2016, and then declined. In-use HAs exhibited a logistic growth and significantly increased in both spatial extent and intensity. E-waste generation kept rising until 2019, and its spatial center expanded outward from downtown to suburban areas. Our study highlights that a dynamic and spatial model is useful for designing effective policies for e-waste management by providing spatiotemporal details of e-waste types and generation magnitudes and explicitly recognizing generation hotspots in cities.
Keywords: Urbanization; Material flow analysis; Spatial analysis; WEEE; Industrial ecology; High-resolution urban grids (HUGs)

Keywords

Urbanization; Material flow analysis; Spatial analysis; WEEE; Industrial ecology; High-resolution urban grids (HUGs)

Linlin Duan, Yupeng Liu*, Yi Yang, Lulu Song, Min Hao, Jiajia Li, Min Dai, Wei-Qiang Chen

Resources, Conservation and Recycling,2021,175,105848

https://doi.org/10.1016/j.resconrec.2021.105848

Abstract:

Copper is ubiquitously used in buildings, infrastructure, transportation, machinery, and other products because of its high conductivity. Massive amounts of copper have accumulated in cities with rapid urbanization. However, the lack of detailed spatiotemporal information on copper stocks presents a challenge for waste management and resource recycling. Here, we took the Jing-Jin-Ji urban agglomeration in China, which has experienced rapid urbanization over the past few decades, as a case study to characterize the spatiotemporal patterns of in-use copper stock. The results showed that in-use copper stocks per capita had reached 61 kg in 2016, about 3.8 times the level it was in 1990. Buildings, electric power transmission and distribution systems, small passenger cars, industrial machinery, and air conditioners dominated the in-use stocks and thus, they were the main reservoirs of secondary resources. Significant economic and population growth stimulated a rapid increase in copper stocks, especially in the megacities (e.g., Beijing, Tianjin, Shijiazhuang, Tangshan, and Handan). Based on the scenarios of urbanization, we estimated that in-use stocks of copper per capita would continue to grow in the Jing-Jin-Ji urban agglomeration until saturation, and that the saturation level might be lower than that of developed countries. High population density was key to promoting copper resource utilization efficiency, particularly in the infrastructure sector. This critical information highlights the urgent need for developing compact cities to reduce the pressure caused by copper resource consumption in China.

Keywords:

Copper; In-use stocks; Jing-Jin-Ji urban agglomeration; Urban mining; Material flow analysis; Industrial ecology

Wang, Peng,  Morten Ryberg*,  Yi Yang,  Kuishuang Feng,  Sami Kara*,  Michael Hauschild, Wei-Qiang Chen*

Nature Communications. 2021, 12, 2066

DOI：https://doi.org/10.1038/s41467-021-22245-6

Abstract

Steel production is a difficult-to-mitigate sector that challenges climate mitigation commitments. Efforts for future decarbonization can benefit from understanding its progress to date. Here we report on greenhouse gas emissions from global steel production over the past century (1900-2015) by combining material flow analysis and life cycle assessment. We find that ~45 Gt steel was produced in this period leading to emissions of ~147 Gt CO₂-eq. Significant improvement in process efficiency (~67%) was achieved, but was offset by a 44-fold increase in annual steel production, resulting in a 17-fold net increase in annual emissions. Despite some regional technical improvements, the industry’s decarbonization progress at the global scale has largely stagnated since 1995 mainly due to expanded production in emerging countries with high carbon intensity. Our analysis of future scenarios indicates that the expected demand expansion in these countries may jeopardize steel industry’s prospects for following 1.5 °C emission reduction pathways. To achieve the Paris climate goals, there is an urgent need for rapid implementation of joint supply- and demand-side mitigation measures around the world in consideration of regional conditions.

宋璐璐, 曹植, 代敏

资源科学, 2021, 43(3): 501-512

DOI: 10.18402/resci.2021.03.07

摘要：

中国是全球最大的汽车制造和消费国，汽车行业带来的资源消耗和温室气体排放受到了学者的广泛关注。辨析汽车行业的物质资源代谢特征和碳减排潜力可为落实循环经济政策和实现可持续发展提供科学依据。本文基于动态物质流模型，预测了中国乘用车中21 种物质材料的代谢特征，评估了乘用车使用过程中的碳减排潜力。研究结果表明：①1949—2019 年中国乘用车中的物质存量呈现指数型增长趋势，由2.3 万t 增加至3.7 亿t。2030 年后物质存量逐渐饱和，并于2050 年达到5.6 亿~11.1 亿t；②2050 年乘用车中物质材料报废量将超过需求量并达到37.4 百万~73.8 百万t/年；其中，钢铁（包括高强钢、普通钢和铁）报废量将达到21.2 百万~42.4 百万t/年；其他战略金属和稀贵金属报废量将达到36.8 万~59.8 万t/年；延长乘用车使用寿命以及较低的乘用车保有量可有效减少产废量；③提高汽油车的燃料效率是最有效的碳减排策略，其碳减排潜力高达3.3 亿t，可降低40%的碳排放量。本文的研究结果可为汽车行业物质资源的有效管理以及碳减排策略的制定提供科学支撑。

关键词：

物质资源代谢；存量；流量；乘用车；资源管理；碳减排；物质流分析；中国

汪鹏，王翘楚，韩茹茹，汤林彬，刘昱，蔡闻佳，陈伟强

资源科学, 2021, 43(4): 669-681.

DOI: 10.18402/resci.2021.04.03

摘要：

在“碳中和”背景下，学术界日益清晰地认识到“关键金属”与低碳能源技术之间存在着紧密的相互依赖关系。为提升国际社会对“关键金属-低碳能源”关联研究的认识，本文整理了该领域2000—2020 年发表的200多篇文献资料，综述了该领域研究的发展历程与最新进展，阐述了主要的科学发现：①能源低碳转型将驱动多种关键金属的开采量和贸易量持续快速增长，加剧关键金属供应国的生态环境污染，加深世界各国对关键金属资源的依赖和争夺；②部分关键金属存在储量不足、贸易供应链脆弱、地理分布不均、环境污染严重等风险，并将对全球低碳转型产生约束，进而重塑全球能源地缘政治格局；③中国作为多种关键金属的生产、消费和贸易大国，为推动全球能源低碳转型付出了巨大的资源和环境代价，且自身同样面临关键金属供应短缺的风险。建议在“碳达峰”与“碳中和”目标的背景下，中国应深化金属-能源关联研究，开展金属-能源协同管理，研判关键金属对中国发展低碳技术的支撑和限制作用，警惕能源系统低碳转型带来的新型地缘政治风险。

关键词：

低碳能源；关键矿产；金属-能源关联；环境影响；资源安全供应

Zijie Ma, Yi Yang, Wei-Qiang Chen*, Peng Wang, Chao Wang, Chao Zhang, and Jianbang Gan

Environmental Science & Technology,  2021 55 (13), 8492-8501

DOI: 10.1021/acs.est.1c00642

Abstract：

Waste paper, an essential substitute for wood and other plant-based fibers in paper making, is an indispensable part of the circular economy; yet, the impacts of China’s ban on global waste paper cycles have not been well understood. We modeled the evolution of the global waste paper trade network during 1995–2019. We found that the cumulative trade volume of global waste paper reached 1010 million tons in the last 25 years and showed a downward trend since 2015. The global import center of waste paper experienced a transfer from Europe to East Asia and then to Southeast Asia. The ban has stimulated some developed countries to reduce the exports of unsorted waste paper since 2017, but for many major importers their changes in waste paper trade patterns were related to waste paperboard, which was not banned by China, suggesting that this import change trend may be inevitable and irrespective of China’s ban. Besides, India has replaced China to become a new import hub of unsorted waste paper. Our results lay a foundation for exploring the evolution of the future global solid waste cycle under the background of zero import of solid waste increasingly implemented by China and many other developing countries.

Key words：

Waste paper trade；Solid waste；Waste import ban；Industrial ecology；Circular economy

Wanjun Wang, Wei-Qiang Chen*, Zhou-Wei Diao, Luca Ciacci, Leila Pourzahedi, Matthew J. Eckelman, Yi Yang, and Lei Shi*

Environmental Science & Technology , 2021 55 (10), 7102-7112

DOI: 10.1021/acs.est.0c08836

Abstract：

Disputes around trade inequality have been growing over the last 2 decades, with different countries claiming inequality in different terms including monetary deficits, resource appropriation and degradation, and environmental emission transfer. Despite prior input–output-based studies analyzing multidimensionaltrade consequences at the sector level, there is a lack of bottom-up studies that uncover the complexity of trade imbalances at the product level. This paper quantifies four types of flows, monetary, resource, embodied energy use, and embodied greenhouse gas (GHG) emissions, resulting from aluminumtrade for the four economies with the highest aluminumtrade, that is, the United States, China, Japan, and Australia. Results show that the United States has a negative balance in monetary flows but a positive balance in resource flows, embodied energy use, and GHG emissions. China has a positive balance in monetary and resource flows but a negative balance in embodied energy use and GHG emissions. Japan has a positive balance in all flows, while Australia has a negative balance in all flows. These heterogeneous gains and losses along the globalleaders of aluminumtrade arise largely from their different trade structures and the heterogeneities of price, energy use, and GHG emission intensities of aluminum products; for example, Japan mainly imports unwrought aluminum, and its quantity is 3 times that of the exported semis and finished aluminum-containing products that have similar energy and GHG emission intensities but 20 times higher prices, while Australia mainly exports bauxite and alumina that have the lowest prices, the quantity of which is 25 times that of imported semis and finished products. This study suggests that resource-related trade inequalities are not uniform across economic and environmental impacts and that trade policies must be carefully considered from various dimensions.

Key words：

aluminum, trade inequality, embodied energy, embodied GHG emissions, material flow analysis, industrial ecology

Lulu Song; Shaoqing Dai; Zhi Cao; Yupeng Liu; Wei-Qiang Chen^*

Journal of Cleaner Production, 2021,297：126482

https://doi.org/10.1016/j.jclepro.2021.126482

Abstract：

High-resolution mapping of steel resources accumulated above ground (referred to as steel stocks) is critical for exploring urban mining and circular economy opportunities. Prior studies have attempted to approximate steel stocks using nighttime light (NTL). Although proven to be a fast estimation technique, the accuracy of the NTL-based approach may be subject to several limitations, and it has not been used for projecting future steel stocks. To fill these gaps, we developed an aggregative downscaling model that fuses multiple large-scale spatial datasets, including gridded population, gross domestic product (GDP), and built-up area. We demonstrated the utility of this model by using it to map steel stocks in mainland China at 1 × 1 km resolution. Our results found the steel stocks increased from 12,873 t/km² to 33,027 t/km² during 1995–2015, and four steel stocks clusters (i.e., Beijing-Tianjin-Hebei agglomeration, Yangtze River Delta, Guangdong-Hong Kong-Macao Greater Bay Area, and Chengdu-Chongqing metropolitan) possessed over 40% of the national total in 2015, revealing an unbalanced distribution of steel stocks across China. Moving forward, with the assumed population growth, GDP growth, and built-up area expansion, steel accumulation is expected to climb up to 64,636 t/km² and cencentrate in larger cities in 2030, such as Beijing, Shanghai, Shenzhen, and Guangzhou. Our analysis highlights the magnitude and pace at which steel resources have been and are expected to be accumulated above ground. Our estimates capture the spatiotemporal dynamics of steel stocks, potentially allowing better policy-making and business decision-making on resource efficiency, waste management, and environmental sustainability on regional or urban scales.

Key words：

In-use stocks; Steel; Spatiotemporal pattern; Stocks prediction; Mainland China