Synergies evaluation and influencing factors analysis of the water-energy-food nexus from symbiosis perspective: A case study in the Beijing-Tianjin-Hebei region

Competitive and synergic evolution of the water-food-ecology system: A case study of the Beijing-Tianjin-Hebei region, China

A vital approach to attaining sustainable development lies in the in-depth examination of both competition and synergy between these subsystems from a water-food-ecology (WFE) system perspective, while previous or existing studies have limitations in to quantitative characterize and evaluation the cooperative and competitive relationships between different systems. In this study, an evaluation indicator system is constructed from the two dimensions of resources and efficiency, and the WFE synergic development capacity (WFE-SDC) is proposed by integrating the order degree of the coupled system, enables a multidimensional and comprehensive quantitative assessment of the sustainable development of the WFE system. Then a synergic evolution model is constructed to explore the competitive and synergic evolution of the WFE system in the Beijing-Tianjin-Hebei region. The following key insights were obtained: (1) The WFE-SDC (range of 0-1) shows a fluctuating increase, indicating a shift from mild dysfunctional recession to intermediate synergic development (0.24 to 0.72). (2) Principal factors impeding WFE-SDC encompass diversion water, ecology water consumption, grain demand, reclaimed water consumption, and outbound water, both come from resource dimension, with a combined impediment degree of over 46 %, and the improvement of efficiency dimension may improve the WFE-SDC. (3) The water subsystem acts as a driving force for synergic development, fostering cooperation within the food and ecology subsystems, although they mainly operate in a competitive state. (4) Within the WFE system, Beijing, Tianjin, and Hebei exhibited mutual cooperation and significantly contributed to one another's development. Beijing has played a pivotal role in the progress of both Tianjin and Hebei. This study offers valuable insights for the formulation of policies and the application of technical approaches for the sustainable development of the WFE system in relevant regions.

Comparing the EU and Chinese carbon trading market operations and their spillover effects

A carbon trading market (CTM) policy for trading carbon dioxide emission rights as a commodity was created to reduce greenhouse gas emissions. CTMs operate differently in different countries and regions, and their interactions deserve an in-depth study. This study focused on the world's largest CTM, the European Union (EU), and the CTM of China, largest carbon-emitting country. First, we evaluate the liquidity and volatility of the two CTMs. Subsequently, the VAR model is used to explore the mean spillover effect between the two markets and the BEKK-GARCH model is used to explore the volatility spillover effect between the two markets. The study concludes that: (1) The liquidity of China's CTM is better than that of the EU's CTM. (2) Both the EU and Chinese CTMs are unstable, but the volatility of the Chinese CTM is lower than that of the EU CTM. (3) Price changes in the EU and Hubei CTMs have a mutual influence. (4) There are interactions between the market fluctuations of the EU CTM and the Shanghai CTM and those of the EU CTM and the Hubei CTM. The results of this study have implications for the construction and development of CTMs in the EU and China.

Quantifying the energy-material-pollution nexus in a typical fine chemical industry: A sustainable development-oriented support for collaborative emission reduction

The fine chemical industry is currently facing challenges in energy saving, material conservation, and pollution reduction due to the dual policy pressure of precise system management and collaborative pollution and carbon reduction. However, the interweaving of materials and energy input-output was not well understood due to the incomplete coverage and the lack of a generic framework. Therefore, a methodology based on the energy-material-pollution (E-M-P) coupling nexus was proposed to quantitatively assess multi-level coupling. According to the selected generic 32 coupling units, two representative glyphosate (PMG) production processes were taken as case studies. Quantification results showed that the solvent element and the material system had a higher priority. Moreover, Process 2 owned a greater optimization potential as the coupling relationship pairs were 2.55 compared to 2.32 for Process 1, and the correlation proportions of material systems reached 69.26 % and 56.92 %, respectively. In addition, assessment results indicated that Process 2 was more environmentally friendly because of the lower ecological indexes (9.7 GPt vs. 15.8 GPt) and weaker carbon footprint (CF) (1.16E+08 vs. 2.32E+08). Combined coupling nexus and environmental assessment organically, methanol had the most optimization potential and was beneficial for the measures such as solvent substitution. This work offered theory and practice guidance with demonstrative value to support the sustainable development of precise system management.

Elements of the water - food - environment nexus for integrated sustainability analysis

Water and food security are constantly on the sustainable development agenda since they are interrelated with anthropogenic and ecosystemic issues present in the economic, environmental, and social spheres. The non-integrative management of these issues points to unsustainable futures. In this context, nexus approaches deserve considerable attention in the search for integrative management solutions capable of contributing to leveraging synergies that increase agricultural productivity, while simultaneously reducing environmental impacts, including water resources. This systematic literature review article aims to analyze the integration factors from the perspective of the water - food - environment nexus in the context of water and agricultural sustainability. The systematic methodology, including a content analysis, allowed the identification of analytical categories composed of the most present integrating factors and discussed in the scientific scope and how they are correlated from the perspective of the nexus. Among the extensive number of factors, the systemic management inserted in the integrated management of watersheds, the sustainable intensification from the perspective of food security and the demand for water resources, categorized in water security, presented higher frequency of occurrence when compared with the other factors. It is proposed that these factors can be considered as indicators of sustainability in the context of integrated water resources management and agricultural food production, since their synergistic effects have consequences in the water, agricultural and environmental management sectors. Thus, this study stands out for identifying trends and gaps in the water - food - environment nexus that can contribute to the development of innovative decision-making tools, in order to assist in the management of the watershed, where agriculture plays a key role in socio-environmental issues.

Can digital economy development contribute to carbon emission reduction? Evidence from China

With the rapid growth of the digital economy, it is essential to understand its impact on carbon emissions reduction. This study uses provincial panel data from China during 2011-2019 to construct a moderating mediating effect model and a spatial panel Durbin model to examine the relationship between the digital economy and carbon emissions reduction. This study analyzes the mediating effect of the energy structure on the digital economy's impact on carbon emission reduction, and the spatial effect and regional heterogeneity of the digital economy's impact on carbon emission reduction. The findings indicate that the development of the digital economy can effectively promote regional carbon emission reductions, both directly and indirectly, with a significant spatial spillover effect. Second, the energy structure plays a significant mediating role in promoting carbon emission reduction in the digital economy, and the industrial structure has a positive moderating effect. Third, the impact of the digital economy on carbon emissions reduction has significant regional heterogeneity, and the inhibitory effect of the digital economy is more effective in the central and western provinces. This study provides a theoretical reference for achieving high-quality development of the digital economy while promoting carbon emissions reduction.

Natural gas spot price prediction research under the background of Russia-Ukraine conflict - based on FS-GA-SVR hybrid model

The ongoing Russia-Ukraine conflict has led to significant upheaval in the worldwide natural gas sector. Accurate natural gas price forecasting, as an essential tool for mitigating market uncertainty, plays a crucial role in commodity trading and regulatory decision-making. This study aims to develop a hybrid forecasting model, the FS-GA-SVR model, which integrates feature selection (FS), genetic algorithm (GA), and support vector regression (SVR) to investigate Henry Hub natural gas price prediction amidst the Russia-Ukraine conflict. The results show that: (1) The feature selection automates model input variable selection, decreasing the time required while improving the model's accuracy. (2) The use of genetic algorithm for selecting support vector regression hyperparameters significantly improves the accuracy of natural gas price predictions. The algorithm leads to a decrease of approximately 70% in measurement indicators. (3) During the Russia-Ukraine conflict, the FS-GA-SVR hybrid model demonstrates more consistent and accurate predictions for natural gas spot prices than the base SVR model. This study serves as a valuable theoretical reference for energy policymakers and natural gas market investors worldwide, supporting their ability to anticipate fluctuations in natural gas prices.

Assessment of sustainable agricultural development based on the water-energy-food nexus framework in the middle and upper reaches of the Yellow River, China

Water, energy and food are inextricably linked in agricultural system. Social and environmental issues arising from socio-economic development pose new challenges for sustainable agricultural development. Achieving sustainable agriculture from the perspective of water, energy and food resource conservation is of critical importance to the national strategy for high-quality development of the Yellow River Basin in China. In this study, the mass productivity and economic productivity of water and energy in agricultural system were considered, and an integrated assessment index system for agricultural system based on the Water-Energy-Food Nexus (WEFN) was proposed in three dimensions: reliability, coordination and resilience. Based on these indicators, the agricultural water-energy-food nexus index (AWEFNI) and integrated risk index (IRI) were performed to assess the current status of agricultural development in the middle and upper reaches of the Yellow River. Results indicate that the AWEFNI in the middle and upper reaches of the Yellow River is increasing year by year, and the level of sustainable agricultural development is improving, but the overall level is lower. The AWEFNI values vary widely among provinces. The reliability of single subsystem in the study area accounts for more than 1/3 of the AWEFNI, with poor water endowment， rich food and energy resource endowments, the coordination of the AWEFN is weakening. The resilience of the third subsystem is gradually declining. The contradiction in water and energy supply and demand in Ningxia is the most prominent among the five provinces, and the level of AWEFN development is the lowest, so the regulation policies should be implemented as soon as possible to promote the synergistic development of AWEFN around the region.

Evaluation of the symbiosis level of the water-energy-food complex system based on the improved cloud model: a case study in Heilongjiang Province

As the conflict between the supply and demand of resources intensifies, it is critical to deeply study the important relationships and symbiotic evolution mechanisms among water resource development and utilization, energy production, agriculture, and the socioeconomic system to promote multiresource synergy management. This study introduced symbiosis theory to build a regional water-energy-food complex system in which the water-energy-food nexus was the main body and the social-economic-natural system was the external environment. Then, a symbiosis evaluation index system was established from three dimensions, including the symbiotic unit, symbiotic relationship, and symbiotic environment. Using the improved cloud model, we judged the symbiosis level of the water-energy-food complex system in Heilongjiang Province from 2010 to 2019. The results indicated that (1) the symbiosis level of the provincial water-energy-food complex system, symbiotic unit, and symbiotic environment was on the rise from level II in 2010 to level IV in 2019, and the symbiosis level of the symbiotic unit fluctuated between level III and level IV. The system exhibited an overall strong symbiosis state. (2) The weights of the three criteria were ranked as symbiotic environment > symbiotic unit > symbiotic relationship. The state of the social-economic-natural system could be considered a "monitor" of the symbiosis level, the symbiotic unit was an important basis for the evolution of the complex system, and the symbiotic relationship was the shortcoming of the system symbiosis enhancement. (3) The trade-offs between food production and water savings constrained socioeconomic development in the province. The resource demands of the economic and social systems and the emissions to the natural system that occurred during the resource exploitation and utilization processes were important factors affecting the coordinated development of the studied system. Overall, the experimental results were consistent with the research subjects' actual situations, and the government should promote the regional three-way flow of social, natural, and economic resources to allow the targeted management of multiresource security.

A copula-based security risk evaluation and probability calculation for water-energy-food nexus

Water-energy-food (WEF) are essential for human survival and development and they interact complexly. The research on Water-energy-food-coupling security risk (WEF-CSR) is crucial to promoting multi resource collaborative management. In this study, a comprehensive index system was constructed using three dimensions: reliability (Ra), coordination (C), and resilience (Rs). We selected the middle and upper reaches of the Yellow River Basin in China to study WEF-CSR conflicts, coupled with the Copula method of risk probability calculation. The results showed that: 1) from 2005 to 2021, the WEF-CSR index in the study area showed a progressively increasing trend, with a mean value of 0.49 in a critical safety state and lower values in the upper reaches of Ningxia and Gansu provinces. 2) The Ra-indexes in the criterion layer is not clearly affected by resource endowment conditions between annual periods; C-indexes are growing rapidly, with their annual growth rate four times as fast as the Ra-indexes, and Rs-indexes growing at about 2.7 times faster. 3) "Energy consumption per capita, carbon emissions, and water-related indicators" are the six main limiting factors, with a combined impediment degree of over 35 %, water resources are major constraint. 4) The Ra-C, C-Rs, and Ra-C-Rs indexes are well fitted by Clayton copula, and the C-Rs indexes are well fitted by Frank copula. The three-dimensional joint distribution risk probability, Ra-C-Rs (Ra ≤ 0.4, C ≤ 0.4, Rs ≤ 0.4) is 0.29. When the Ra or C indexes increases, the probability of unsafe Rs rises to 40 %-50 %, meaning future development must emphasize synergy, especially in Rs. In future, the five provinces in the middle and upper reaches of the Yellow River should focus on reducing energy pressure, improving water shortage conditions, and enhancing the overall resilience to avoid single-factor adverse conditions affecting WEF's coordinated and sustainable development.

Influencing Factors and Symbiotic Mechanism of the Integration of Medical Care and Disease Prevention during the COVID-19 Pandemic: A Cross-Sectional Survey of Public Hospital Employees

Background: The COVID-19 outbreak has accelerated the huge difference between medical care and disease prevention in Chinese medical institutions. This study aimed to investigate the relationship between the symbiotic units, environments, models, and effects of the integration of medical care and disease prevention. Methods: This cross-sectional study involved 762 employees of public hospitals in 11 cities in Zhejiang Province by random stratified sampling. We analyzed the influence paths of elements in the mechanism of integration of medical care and disease prevention and the mediating effect of symbiotic models among symbiotic units, symbiotic environments, and effects on this integration. Results: The path coefficient of the symbiotic unit on the symbiosis model was 0.46 (p < 0.001), the path coefficient of the symbiotic environment on the symbiosis model was 0.52 (p < 0.001). The path coefficient of the symbiotic unit and the environment was 0.91 (p < 0.001). The symbiotic models exhibited a partial mediation effect between symbiotic units and the effect of this integration. Sobel test = 3.27, β = 0.152, and the mediating effect accounted for 34.6%. Conclusions: It is suggested that health policymakers and public hospital managers should provide sufficient symbiotic units, establish collaborative symbiotic models, and improve the effects of integration of medical care and disease prevention in public hospitals.

Interaction between Urbanization and Eco-Environment in Hebei Province, China

Understanding the complex interaction between urbanization and the eco-environment is necessary for rapid and quality urbanization, eco-environmental protection, and the harmonious coexistence of humans and nature within a region. Based on panel data from Hebei Province between 1985 and 2019, we suggested a symbiosis hypothesis of urbanization and the eco-environment (SHUE) and used the distance coordination coupling model, the Tapio decoupling model, and the symbiosis model to quantitatively determine the interaction relationship between urbanization and the eco-environment. We found that (1) the improved ‘Northam curve’ of urbanization in Hebei Province met the logistic equation. (2) During the study period, the coordinated coupling degree (CCD) of urbanization and eco-environment exhibited an overall upward trend, while the coupling type gradually changed from the endangered imbalance recession type to the coordinated development type. (3) The decoupling types showed strong and weak decoupling fluctuations, with a high frequency of strong decoupling; the growth rate of the urbanization index was higher than that of the eco-environment index; and there was a positive effect between urbanization and eco-environment indicating positive urbanization. (4) The research results verified SHUE. The symbiosis mode of urbanization and eco-environment was mainly asymmetric mutualism, with the two demonstrating mutual promotion and mutualism. However, in 2016–2019, the symbiosis mode became parasitic, urbanization development enforced upon the eco-environment. The study constructed a set of quantitative method to systematically discuss the interaction relationship from two dimensions: coupling and decoupling. The results provide reference for the coordinated development of urbanization and eco-environment in Hebei Province and consequentially enrich this research field.

Hubs for Circularity: Geo-Based Industrial Clustering towards Urban Symbiosis in Europe

Since the Green Deal, ambitious climate and resource neutrality goals have been set in Europe. Here, process industries hold a unique position due to their energy and material transformation capabilities. They are encouraged to develop cross-sectorial hubs for achieving not only climate ambition, but also joining a circular economy through urban–industrial symbiosis with both business and community stakeholders. This research proposes a data-based approach to identify potential hub locations by means of cluster analysis. A total of three different algorithms are compared on a set of location and pollution data of European industrial facilities: K-means, hierarchical agglomerative and density-based spatial clustering. The DBSCAN algorithm gave the best indication of potential locations for hubs because of its capacity to tune the main parameters. It evidenced that predominately west European countries have a high potential for identifying hubs for circularity (H4Cs) due to their industrial density. In Eastern Europe, the industrial landscape is more scattered, suggesting that additional incentives might be needed to develop H4Cs. Furthermore, industrial activities such as the production of aluminium, cement, lime, plaster, or electricity are observed to have a relatively lower tendency to cluster compared with the petrochemical sector. Finally, further lines of research to identify and develop industrial H4Cs are suggested.