查看更多>>摘要：Cobalt is widely recognized as a strategic mineral especially for current energy and low carbon revolution. Nonetheless, the geographically concentrated supply makes reliable access to cobalt more of a strategic concern. Understanding the systemic impacts of epicenter economies, and how crises propagate if these economies were hit by negative shocks, are thus important for policy makers. To explore this issue, we construct a global cobalt trade network using the data of 2019, upon which a cascading failure model is established. Accordingly, we simulate the avalanche process, and an avalanche network is derived to analyze the structural features of crisis propagation dynamics. Results show that (1) When the ratio r >= 8, avalanche sizes of major epicenter economies increase rapidly from 22 to 36; (2) Democratic Republic of Congo, Mainland of China, Germany, and United Kingdom have systemic impacts in the global cobalt trade network; (3) Out-degree, in-strength, out-strength, and betweenness show influences on the dynamics of supply crisis propagation, while in-degree and eigencentrality do not show clear influences on the propagation dynamics; (4) Indirect cascades account for a significant fraction of the avalanche sizes. These findings contribute to more efficient supply management of the strategic raw material for policy makers.
查看更多>>摘要：Plastics are used in a wide range of applications generating significant waste streams. This is driving policy interventions to increase circularity, reduce waste and improve resource efficiency. However, information on plastic waste flows is not widely available across regions and nations. With an overarching aim to make rec-ommendations for supporting the transition to a circular plastics economy in Northern Ireland, this study used quantitative uncertainties to conduct regional material flow analysis and geospatial mapping to identify local hotspots. It was observed that 149 & PLUSMN; 11 kilo tonnes of plastic waste were produced in Northern Ireland (79.2 kg/ capita) in 2018. Reuse and recovery for recycling reached up to 35%, while 62% of plastic waste was landfilled with the remainder (3%) incinerated. This study found that there are increasing amounts of plastic waste locked in sectors with long product lifetimes, such as the construction sector with 21.3 kilo tonnes for 2018. It is therefore important to consider the processing capacities and environmental impacts of plastic waste manage-ment, not only for current plastic waste flows but also for tackling possible future growth of these flows. The results indicate that there is a need for a holistic all-island approach for effective plastic waste management in both Northern Ireland and the neighbouring Republic of Ireland. Furthermore, stricter enforcement of existing waste management rules and regulations could prevent need for additional policies to support a circular econ-omy. This research provides robust scientific data to aid the transition to a circular economy for plastics in the region.
查看更多>>摘要：Reverse osmosis membrane is widely applied in advanced wastewater treatment. Along with the production of clean water, 30%-50% reverse osmosis concentrated water (W-ROC), containing massive nitrogen and phosphorus, is also produced. W-ROC would bring ecological risk if discharged into the natural water body. Hence, attached microalgae cultivation based on W-ROC was proposed to recovery the nutrients from water in this study. The results showed that the initial concentrations of nitrogen and phosphorus in W-ROC(TNR-.150 mg/L, TPR-.110 mg/L) were not too high to inhibit attached microalgae growth. Among the complex chemicals in W-ROC, non oxidizing bacteriostatic agent had the worst impact on the growth of microalgae with an 8-day inhibition ratio of 25%. Compared with the microalgae cultured by nutrient medium, the lipid and protein contents in attached microalgae cultured by WROC were relatively high and stable during the whole cultivation period. Seen from the micro level, there was no obvious resistance to the transfer of TN and TP in the microalgae biofilm. However, the photosynthetic rate of microalgae in the biofilm decreases along with the depth. In conclusion, uneven light distribution in biofilm and the non-oxidizing bacteriostatic agent in WROC were the main resistance to the growth of attached cultured microalgae, which should be optimized or per-treated.
查看更多>>摘要：Limiting temperature rise below 2 degrees C requires large deployment of Negative Emission Technologies (NET) to capture and store atmospheric CO2. Compared to other types of NETs, biochar has emerged as a mature option to store carbon in soils while providing several co-benefits and limited trade-offs. Existing life-cycle assessment studies of biochar systems mostly focus on climate impacts from greenhouse gasses (GHGs), while other forcing agents, effects on soil emissions, other impact categories, and the implications of a large-scale national deployment are rarely jointly considered. Here, we consider all these aspects and quantify the environmental impacts of application to agricultural soils of biochar from forest residues available in Norway considering different scenarios (including mixing of biochar with synthetic fertilizers and bio-oil sequestration for long-term storage). All the biochar scenarios deliver negative emissions under a life-cycle perspective, ranging from-1.72 +/- 0.45 tonnes CO2-eq. ha(-1) yr(-1) to-7.18 +/- 0.67 tonnes CO2-eq. ha(-1) yr(-1) (when bio-oil is sequestered). Esti-mated negative emissions are robust to multiple climate metrics and a large range of uncertainties tested with a Monte-Carlo analysis. Co-benefits exist with crop yields, stratospheric ozone depletion and marine eutrophica-tion, but potential trade-offs occur with tropospheric ozone formation, fine particulate formation, terrestrial acidification and ecotoxicity. At a national level, biochar has the potential to offset between 13% and 40% of the GHG emissions from the Norwegian agricultural sector. Overall, our study shows the importance of integrating emissions from the supply chain with those from agricultural soils to estimate mitigation potentials of biochar in specific regional contexts.
查看更多>>摘要：Plastic pollution is one of the most urgent worldwide environmental issues that humans need to address. Despite the awareness of the harm that plastic pollution brings to our planet, environmental impact is the least important consideration for consumers when making their daily choices regarding plastic packaging. It is less known how to motivate consumers, especially those of generation Z, who are considered to be more concerned with the environment than previous generations, to engage in plastic pollution reduction and increase their intention to recycle in China. Drawing upon Protection Motivation Theory, we investigate the impacts of individual motivators (self-esteem, self-actualization, and self-expression) and collective motivators (social optimism, social pessimism, and Confucianism) on consumers' environmental concern (threat appraisal) and how these drivers eventually influence consumers' engagement and recycling intention (coping appraisal). Our findings reveal that engagement and recycling intentions are driven primarily by self-expression and social pessimism, respectively. Environmental concerns play a significant role in mediating these relationships. We offer important theoretical and practical implications for policymakers.
查看更多>>摘要：One of the most significant negative environmental impacts of biofuels is GHG emissions caused by land use change (LUC). In Brazil, the National Biofuels Policy (RenovaBio) has the main objective to encourage the incorporation of biofuels into the energy matrix to promote the country's energy transition. This policy, however, does not cover the impacts of LUC through its Life Cycle Assessment (LCA) for calculating GHG emissions from biofuel, moving in the opposite direction of international policies such as the European Union (EU) Directive 2018/2001 (REDII). Therefore, this paper analyses the importance of considering LUC for a more realistic GHG emissions assessment. We applied the methodologies of REDII and Decision 2010/335 to calculate GHG emissions from LUC for the Brazilian territory using first-generation sugarcane ethanol (E1G) as a reference for the current and 2030 scenarios. We identified areas where LUC emissions could reduce the carbon intensity of E1G by 5 g CO2e/MJ, while others have the potential to increase by up to 316 g CO2e/MJ. We found that only 10% of the Brazilian territory, if replaced by sugarcane crop, would probably produce sugarcane that contributes to the production of an E1G that mitigates GHG emissions when compared to gasoline. A biome and state analysis were also conducted and the results are concerning, particularly in the case of the expansion into the Amazon biome and Mato Grosso state. We concluded that Brazil must include LUC emissions to align its biofuels with REDII criteria and position the country as a major supplier of EU.
查看更多>>摘要：Securing the supply of platinum-group metals (PGMs) is crucial for the development of fuel cell vehicles (FCV), which are among the most promising low-carbon vehicle technologies in the future. Existing research has evaluated the worldwide demand and supply of platinum-group metals in this century with bottom-up models on the competing battery technologies for electric vehicles. However, it is important to evaluate the material efficiency for emission reduction if an aggressive transition towards net-zero carbon emissions is pursued at the global scale due to the geochemical scarcity of platinum-group metals on earth. This research aims to bridge this gap by linking the material flow analysis (MFA) and a bottom-up integrated assessment model, namely, the Integrated Model of Energy, Environment and Economy for Sustainable Development (IMED|TEC). Through this cutting-edge integrated approach and taking passenger cars as a case study, we attempt to evaluate the nexus between platinum and the emission reduction in CO2 in the use phase of cars under the progressive electrification scenarios towards carbon neutrality within half a century. The results show that the uneven market penetration of battery electric vehicles and fuel cell vehicles can lead to geographical disparity in supply and demands for platinum, which will reshape the world material flows. The material efficiency for emission reduction in the use stage of cars during the progressive adoption of carbon-neutral automotive technologies highly relies on the alignment of the recycling sector with the global automobile production network. Global coordination is needed to enhance the material efficiency for rare metals in the transition towards a carbon-neutral future.
查看更多>>摘要：The power sector needs to take the lead in decarbonizing to support China's carbon neutrality goal. It is urgent to explore the potential and pathways of decarbonization of China's power sector. The United Kingdom (UK) has achieved significant greenhouse gas reductions in the power sector through a series of long-term initiatives. Firstly, this paper applies the multi-level perspective approach to investigate the historical transition pathways of the UK power sector into three stages. Then it analyzes the interactions among technological niche, sociotechnological regime and landscape, and summarizes the replicable experience of decarbonization in the process. Extending the UK experience to China, this paper explores the initiatives for accelerating China's power sector decarbonization from the multi-level perspective and proposes possible future transition pathways.
查看更多>>摘要：The aluminum extrusion industry is growing rapidly; however, there has been little work on quantifying or reducing extrusion's environmental impacts. This article first derives cradle-to-gate cumulative energy demand, greenhouse gas emission, and cost models for direct aluminum extrusion using data collected from extrusion companies, life cycle inventory measurements (e.g., electricity demand) from our own case studies, and physics-based extrapolations. These models show there is significant scope for increasing both the process energy and material efficiency; however, only increasing the material efficiency will lead to significant environmental benefits and cost savings. Subsequently, an alloy-shape-application material flow analysis of the 2018 North American extrusion industry is conducted to highlight opportunities for improved material utilization throughout the supply chain. Material flow data were collated from existing academic and gray literature in addition to semi-structured interviews with North American extrusion experts. The material flow analysis reveals that around 40% of all aluminum cast into extrusion billets is scrapped before completion in a fabricated product, which increases the cost of the fabricated profile by approximately 16% and the greenhouse gas emissions and cumulative energy demand by approximately 40%. Most of this scrap is created by removing structural and surface finish extrusion defects that are inherent to the current process. Process adaptations that might reduce the material scrapped due to these defects are identified and discussed. Even a 10% reduction in extrusion process forming scrap could save the North American (U.S. and Canada) extrusion industry 270-311 million USD per year and prevent the release of 0.5-2.3 Mt.CO2eq annually.
NSTL
Elsevier