Modeling the circular economy in environmentally extended input–output: A web application

Global environmental and resource problems ask for new ways of managing the production and consumption of resources. The implementation of new paradigms, such as the circular economy, requires decision‐makers at multiple levels to make complex decisions. For this, clear analyses and modeling of scenarios are of utmost importance. Meanwhile, as the sophistication of databases and models increases so does the need for user‐friendly tools to use them. The RaMa‐Scene web platform reduces these barriers by allowing users to visualize easily diverse impacts of implementing circular‐economy interventions. This online web platform makes use of the multi‐regional environmentally extended input–output database EXIOBASE version 3 in monetary units, which has been modified to show explicit transactions of raw materials from recycling activities.     

Urban development and sustainability challenges chronicled by a century of construction material flows and stocks in Tiexi,China

Construction materials are considerable forces of global environmental impacts, but their dynamics vis‐à‐vis urban development are poorly documented, in part because their long lifespans require elusive and sometimes nonexistent decade‐long high‐resolution data. This study analyzes the construction material flow and stock trends that shaped and were shaped by the development, decline, and renewal of the Tiexi district of Shenyang, a microcosm of China's urban transformations since the early 20th century. Chronicling building‐by‐building the material flows and stock accumulations involved in the buildup of this area, we shed light on the physical resource context of its socioeconomic history. We find that 42 million tonnes of construction materials were needed to develop the Tiexi district from 1910 to 2018, and 18 million tonnes of material outflows were generated by end‐of‐life building demolition. However, over 55% of inflows and 93% of outflows occurred since 2002 during a complete redevelopment of the district. Only small portions of end‐of‐life materials could have been reused or recycled because of temporal and typological mismatches of supply and demand and technical limitations. Our analysis reveals a dramatic decrease in median building lifetimes to as low as 6 years in the early 21st century. These findings contribute to the discussion of long‐term environmental efficiency and sustainability of societal development through construction and reflect on the challenges of urban renewal processes not only in China but also in other developing and developed countries that lost (or may lose) their traditional economic base and restructure their urban forms. This article met the requirements for a Silver/Silver JIE data openness badge described at http://jie.click/badges .     

Economic Integration in Tanzania (1970–2011): A Biophysical Assessment

This article assesses the impact of economic integration on Tanzania's sociometabolic profile for the years 1970–2011, which witnessed an opening and further integration of Tanzania's economy through increased trade and foreign investment, through a time‐series economy‐wide material flows analysis (EW‐MFA). The EW‐MFA results show that contrary to the trade patterns of many developing countries, increased economic integration has resulted in Tanzania becoming a net importer of resources across all material categories when measured by the physical trade balance indicator. Additionally, the article discusses the conceptual and empirical challenges of measuring ecologically unequal exchange with EW‐MFAs for developing countries whose export profiles are dominated by lightweight, high‐value precious stones and metals. It also assesses the degree to which the Tanzanian economy has undergone dematerialization over the past 40 years of economic integration.     

Greenhouse gas emissions and global warming potential of traditional and diversified tropical rice rotation systems

Global rice agriculture will be increasingly challenged by water scarcity, while at the same time changes in demand (e.g. changes in diets or increasing demand for biofuels) will feed back on agricultural practices. These factors are changing traditional cropping patterns from double‐rice cropping to the introduction of upland crops in the dry season. For a comprehensive assessment of greenhouse gas (GHG) balances, we measured methane (CH₄)/nitrous oxide (N₂O) emissions and agronomic parameters over 2.5 years in double‐rice cropping (R‐R) and paddy rice rotations diversified with either maize (R‐M) or aerobic rice (R‐A) in upland cultivation. Introduction of upland crops in the dry season reduced irrigation water use and CH₄ emissions by 66–81% and 95–99%, respectively. Moreover, for practices including upland crops, CH₄ emissions in the subsequent wet season with paddy rice were reduced by 54–60%. Although annual N₂O emissions increased two‐ to threefold in the diversified systems, the strong reduction in CH₄ led to a significantly lower (P < 0.05) annual GWP (CH₄ + N₂O) as compared to the traditional double‐rice cropping system. Measurements of soil organic carbon (SOC) contents before and 3 years after the introduction of upland crop rotations indicated a SOC loss for the R‐M system, while for the other systems SOC stocks were unaffected. This trend for R‐M systems needs to be followed as it has significant consequences not only for the GWP balance but also with regard to soil fertility. Economic assessment showed a similar gross profit span for R‐M and R‐R, while gross profits for R‐A were reduced as a consequence of lower productivity. Nevertheless, regarding a future increase in water scarcity, it can be expected that mixed lowland–upland systems will expand in SE Asia as water requirements were cut by more than half in both rotation systems with upland crops.     

中美减排二氧化碳的GDP溢出模拟

基于气候保护模型(State-contingent模型与Demeter模型)和GDP溢出模型(Mundell-Fleming模型),对中美两国在实施控制性气候保护措施之后所导致的GDP溢出影响的变化进行了模拟分析。结果表明,美国实行控制性减排政策对于中国的GDP溢出影响与不实施任何减排的情况相比,两者的差别并不明显,但是这种影响经历一个从负向到正向逐步上升的发展趋势,虽然中国实行控制性减排政策对于美国GDP溢出的影响,相比美国对于中国的影响,所导致的GDP溢出影响更小,但是也同样表现出了一个从负溢出到正溢出的过程。这一结果表明一国的控制性气候保护政策从长远来看会对另一国的经济发展产生正向的溢出。同时,针对两种情况,即不考虑他国GDP溢出影响和考虑他国GDP溢出影响,分别模拟计算了中美两国的GDP,进而对两种情况下的差额结果进行对比,分析了中美相互之间GDP溢出量的大小。结果发现,美国对中国GDP溢出影响要大于中国对美国的GDP溢出。     

Resource Consumption of New Urban Construction in China

The volume of China's recent additions to its urban-built environment is unprecedented. China now accounts for half of all new building area in the world. Increases in building stocks of all types have occurred during an extended period of accelerated growth of the national economy. This expansion promises to continue through 2030. As a result, the rapid conversion of land from low-density agricultural and light manufacturing to new urban zones of high density and material-intensive commercial and residential buildings has consumed enormous quantities of domestic and imported resources and has irreversibly altered the Chinese landscape. This article examines the consumption of material resources dedicated to Chinese building construction through a survey and analysis of the material intensity of three major building types. This provides a basis for outlining the emerging life-cycle issues of recent additions to the built environment and of continued construction. With this as the starting point, the field of industrial ecology can work toward formulating strategies for a circular economy that include a resource-efficient urban China.     

福建外来物种入侵现状及对经济社会和生态的影响

福建已成为中国遭受外来物种入侵最严重的省份之一。本文概述了福建主要入侵物种的数量、种类、地理起源、分布、引入途径和入侵特点,系统分析了福建外来物种入侵严重的原因和外来物种入侵对福建生态安全、经济及社会的影响,在此基础上提出了针对外来物种入侵的防控对策。     

Two explanations for the compliant running paradox: reduced work of bouncing viscera and increased stability in uneven terrain

Economy is a central principle for understanding animal locomotion. Yet, compared with theoretical predictions concerning economy, animals run with compliant legs that are energetically costly. Here, we address this apparent paradox, highlighting two factors that predict benefits for compliant gaits: (i) minimizing cost of work associated with bouncing viscera; and (ii) leg control for robust stability in uneven terrain. We show that consideration of the effects of bouncing viscera predicts an energetic optimum for relatively compliant legs. To compare stability in uneven terrain, we introduce the normalized maximum drop (NMD), a measure based on simple kinematics, which predicts that compliant legs allow negotiation of relatively larger terrain perturbations without failure. Our model also suggests an inherent trade-off in control of leg retraction velocity (ω) for stability: low ω allows higher NMD, reducing fall risk, whereas high ω minimizes peak forces with terrain drops, reducing injury risk. Optimization for one of these factors explicitly limits the other; however, compliant legs relax this trade-off, allowing greater stability by both measures. Our models suggest compromises in leg control for economy and stability that might explain why animals run with compliant legs.     

重工业城市(抚顺)实施清洁生产发展循环经济实例研究

论证了清洁生产与循环经济之间的关系 ,全面论述了发展循环经济的重要性、必要性及现实意义 ,提出了发展循环经济的切实可行的对策方案 ,为开创资源型城市可持续发展道路打下了扎实的理论基础。同时 ,以抚顺为研究对象 ,通过对其工业布局、产业结构、经济发展规模的分析 ,探索找出了重工业城市实施清洁生产的最佳途径。