China's climate and energy policy: at a turning point?

Drying characteristics of sewage sludge pre-conditioned by CaO and sawdust under low-temperature drying conditions

Heat pump drying is a low-carbon method of sludge drying. The operating temperature of a heat pump is generally not more than 70℃. To improve the drying efficiency of heat pump dryers, the effects of air parameters and additives on sludge drying characteristics at low temperatures were studied. The sludge drying experiments were conducted at an air temperature 50-70℃ and an air velocity of 0.5-1.7 m/s. The experimental results showed that the increase of air temperature, velocity and the addition ratio of additives can accelerate the sludge drying process. The average and maximum drying rates of sludge pre-conditioned by CaO and sawdust increased by 14.23% and 25.71%, respectively, compared with those of pure sludge. The two-way analysis of variance (ANOVA) revealed that the influence of air temperature on the sludge drying was higher than that of air velocity. Five reference models were fitted by the drying experiment data. The Page model has the highest R2, so it is the most suitable model to predict the drying time of sludge at low temperatures.

Machine learning analysis of socioeconomic drivers in urban ozone pollution in Chinese cities

The escalation of ground-level ozone (O3) pollution presents a significant challenge to the sustainable growth of Chinese cities. This study utilizes advanced machine learning algorithms to investigate the intricate interplay between urban socioeconomic growth and O3 levels. Surpassing traditional environmental chemistry, it assesses the effectiveness of these algorithms in interpreting socioeconomic and environmental data, while elucidating urban development's environmental impacts from a novel socioeconomic perspective. Key findings indicate that factors such as urban infrastructure, industrial activities, and demographic dynamics significantly influence O3 pollution. The study highlights the particular sensitivity of urban public transportation and population density, each exerting a unique and substantial effect on O3 levels. Additionally, the research identifies nuanced interactions among these factors, indicating a complex web of influences on urban O3 pollution. These interactions suggest that the impact of individual socioeconomic elements on O3 pollution is interdependent, being either amplified or mitigated by other factors. The study emphasizes the crucial need to integrate socioeconomic variables into urban O3 pollution strategies, advocating for policies tailored to each city's distinct characteristics, informed by the detailed analysis provided by machine learning. This approach is essential for developing effective and nuanced urban pollution management strategies.

A review contribution to emission trading schemes and low carbon growth

In this study, the researchers focus on policy instruments that employ a market-based strategy to promote emission reduction, find the key spots and recent changing aspects in the field of Eemission Trading Systems (ETS) and Low Carbon Growth, and make suggestions for future studies. Making use of the bibliometric analysis, the researchers examine a sample of 1,390 research from the ISI Web of Science database to find research activity on ETS and low carbon growth between 2005 and 2022. Also, the researchers visualized the knowledge domains in this field using software like CiteSpace and R-Biblioshiny. The research unravels the most influential published articles and authors on their citations and publications and their location and significance within the network. The researchers further examined the recent themes, identified the barriers to developing literature in this field, and made recommendations for future research. Research on ETS and low carbon growth globally lack cross-border collaborations between emerging and developed economies. The researchers concluded the study by recommending three future research directions.

Climate change: Comparing "green" and "polluting" nation-states

Some nation-states, i.e., Norway, Sweden, and Denmark, repeatedly score the highest in environmental indicators such as the Environmental Performance Index (EPI) and the Climate Change Performance Index (CCPI). Their cities win environmental awards; they have well-developed recycling systems; they perform well with biodegradable waste; and their citizens show awareness of environmental problems, protesting publicly and even sueing their governing bodies if they don't do the same. For these and other reasons, recent scholarship defined these countries as "exemplary" green nation-states. The question is, which factors pushed them toward the green transition faster than others? And overall, what stops top polluting countries such as China, the United States and Russia from walking the same path? This article attempts to answer these questions by looking at climate change through a theoretical framework based on theories of nationalism and case studies of green nation-states. It compares three of said top polluting countries, China, the United States, and Russia, with "exemplary" green nation-states, and argues that the pace of greener nation-states rests on (1) a tradition of ecologism and environmentalism rooted in the long run, (2) the lock in of "green nationalism," a form of nationalism grounded on sustainability, (3) free and effective environmental movements, (4) inclusivity and welfare, and (5) a sense of national pride in environmental achievements. The available evidence seems to suggest that top polluting nation-states lack one or more of these factors.

The economic impact of climate change: a bibliometric analysis of research hotspots and trends

Climate change has been a widely concerned issue for decades. As the key policy target, the economic impact caused by climate change has received general attention from scholars and governments around the world. For the number of literatures is huge and the relationships among the literatures are not clear, we aim to clarify the research hotpots and the research trends of current literatures and provide inspiration for the development directions of future research in this paper. Using the bibliometric method, this paper characterizes the literatures on the economic impact of climate change based on the Web of Science (WoS) Core Collection. The results reveal that the USA occupies the leading position of the studies, which publishes most documents, and contains the most productive institutes and well-known scholars. From 2009, the number of documents published by a Chinese scholar started to increase rapidly, which makes China the second most productive country in recent years. The journals both belong to the WoS Categories of economics and environmental sciences and tend to publish more literatures than others. Adaptation, vulnerability, uncertainty, economic growth, climate policy, ecosystem service, energy consumption, renewable energy, food security, and land use are the representative keywords that have both high frequency and high centrality. Potential benefits, fat-tailed risk, social cost, international migration, and sustainable intensification are the top five main research hotspots. Based on the citation network of the top 50 documents with the highest local citation score, four research trends are sorted out: (i) the methodological innovation to monetized estimate the economic impact of climate change, (ii) the effect of current and future adaptive measures on agriculture, (iii) the interactional relationship between induced technological change and carbon tax, and (iv) the effect on labor market caused by climate change.

Methods, mechanisms, models and tail gas emissions of convective drying in sludge: A review

In tandem with the population and economic growth worldwide, the scale of wastewater treatment has been increasing each year. Thus, a large amount of sludge is being produced. If the problem of sludge treatment and disposal cannot be effectively solved, it will cause serious environmental pollution. The premise of sludge drying is that sludge is "harmless" and can be "recycled." Currently, the studies on convective drying focus on the direction of thin-layer drying, fluidized bed drying, spray drying and pneumatic drying. This paper systematically reviews the convective drying technology of sludge. First, the effects of air velocity temperature, relative humidity and particle size on the drying effect are precisely described, as well as the four different drying stages in the drying process, including preheating, constant rate drying, first falling rate drying, and second falling rate drying stages. Second, the research progress of different convective drying treatment technologies and the application of eight mathematical models of thin-layer drying in this field are elaborated. The effects of sludge shrinkage formation mechanisms and sludge viscous resistance generation during the drying process are also discussed in detail. The formation mechanism of sludge shrinkage and the effect of sludge viscosity resistance during drying are also elaborated. Finally, the main dry tail gases and restraining methods are elaborated during the drying process. This paper will provide a structured reference for the related research of sludge convective drying in the future.

Reflexive Green Nationalism (RGN): A sociological antidote to the climate crisis?

What can theories of nationalism and the nation-state tell us about climate change? Much of the available literature, including works by prominent thinkers Ulrich Beck and Bruno Latour, identify it as a collective global challenge rather than a local and national one. But is it really so? This article develops an original theoretical framework integrating the theory of "reflexive modernity", theories of nationalism, and case studies of green nation-states. The goal is to change the observation point and search for original solutions to the climate crisis. Building on this theoretical framework, this study puts forward the following claims: (1) climate change is undeniably a global phenomenon, but its causes are national. It can be traced back to a small number of top polluting nation-states (the US, China, Russia, India, Japan and EU28) whose historical share of carbon dioxide and other greenhouse gases, the main cause for global warming, surpasses 74%; (2) Most of these nation-states are entrenched in Resource Nationalism (RN), a form of nationalism that sees the environment as a resource to exploit; (3) there exist forms of sustainable nationalism, which this study conceptualizes as Reflexive Green Nationalism (RGN); (4) the solution to climate change is local rather than global. It depends on top polluters' capacity to re-modernize and develop RGN; and (5) according to the Intergovernmental Panel on Climate Change, if emissions are not reduced by 43% by 2030, the world is likely to cross the tipping point into a global climate catastrophe. Therefore, updating these nation-states and their ideology to more sustainable forms is humanity's best shot at halting the climate crisis.

Possible Scenarios for Reduction of Carbon Dioxide Emissions in Serbia by Generating Electricity from Natural Gas

The main purpose of this paper is to develop possible scenarios for reducing carbon dioxide (CO2) emissions in Serbia by switching from coal-fired to natural gas-fired electricity generation by the end of 2050. Accordingly, the challenges are to establish scenarios and identify measures that are best suited to all Western Balkan countries. In particular, this paper proposes a number of energy mix scenarios that offer some options for reducing CO2 emissions while maintaining an economic way of consumption. Projections of these reduction scenarios are obtained by combining the Kaya identity with the emission factor method. A simplified methodology based on sensitivity analysis is used as a source of data to estimate the nonstatistical uncertainty limits for the projections of the reduction scenarios. The sensitivity analysis is carried out using historical data from Serbia for the period from 1990 to 2019. In addition, a direct verification of the proposed methodology is performed based on historical data for 2020. The developed scenarios 1 and 2 show that CO2 emissions could be reduced by 10.94% and up to 74.44% from baseline in 1990, respectively. The obtained results are also contrasted with the data available for some other countries with similar experiences. Finally, it is found that the developed scenarios are achievable only at significantly decreased levels of coal-fired electricity generation.

Evaluation of TPGU using entropy - improved TOPSIS - GRA method in China

China is still one of the countries dominated by thermal power generation. In order to generate more efficient, stable and clean power, it is necessary to evaluate thermal power generation units (TPGU). Firstly, a comprehensive evaluation index system for TPGU with 20 secondary indicators was established from four aspects: reliability indicators, economic indicators, technical supervision indicators, and major operating indicators. Secondly, the entropy weight method can be used to calculate the weight of each second-level index. Mahalanobis Distance improved Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) method is coupled with the Grey Relational Analysis (GRA), and the comprehensive evaluation values of 5 units (600MW) are respectively 0.4516, 0.5247, 0.3551, 0.5589 and 0.6168 from both vertical and horizontal dimensions. Finally, by comparing and analyzing this method with the above research methods, it is found that the results obtained by this method which re-establishes the coordinate system based on the data set are more accurate. In addition, this method can effectively evaluate the operation of TPGU, which is of great significance for cleaner production while generating electricity. In conclusion, some suggestions on clean production of TPGU are put forward, and the innovation points and limitations of this paper are pointed out.

Understanding China's changing engagement in global climate governance: a struggle for identity

This article offers a novel understanding of China's changing engagement in global climate governance over the past decade. This article argues that China has embedded the construction of its international identity, which has been transforming towards what this article conceptualizes to be a 'Yinling leading power', in promoting and leading global climate governance. China's transforming identity construction has contributed to changing its construction of climate justice and led China to proactively undertake more responsibilities, provide international public goods and promote international climate cooperation. Global climate governance has become one of China's prototypical discursive frames in constructing its new international identity, an important platform where China seeks to share leadership with other major powers and the climate leadership in turn constitutes China's new identity. However, China's inadequate response to international expectations and lack of self-reflection in its climate policy have influenced international recognition on its climate leadership and new identity. In general, China's transforming identity construction and its reconstruction of climate justice have far-reaching implications for China and Europe to cooperate and coordinate in strengthening global climate justice and promoting global climate governance.

Multifunctional, Robust, and Porous PHBV-GO/MXene Composite Membranes with Good Hydrophilicity, Antibacterial Activity, and Platelet Adsorption Performance

The limitations of hydrophilicity, strength, antibacterial activity adsorption performance of the biobased and biocompatible polymer materials, such as polyhydroxyalkanoates (PHAs), significantly restrict their wider applications especially in medical areas. In this paper, a novel composite membrane with high antibacterial activity and platelet adsorption performance was prepared based on graphene oxide (GO), MXene and 3-hydroxybutyrate-co-hydroxyvalerate (PHBV), which are medium-chain-length-copolymers of PHA. The GO/MXene nanosheets can uniformly inset on the surface of PHBV fibre and give the PHBV—GO/MXene composite membranes superior hydrophilicity due to the presence of hydroxyl groups and terminal oxygen on the surface of nanosheets, which further provides the functional site for the free radical polymerization of ester bonds between GO/MXene and PHBV. As a result, the tensile strength, platelet adsorption, and blood coagulation time of the PHBV—GO/MXene composite membranes were remarkably increased compared with those of the pure PHBV membranes. The antibacterial rate of the PHBV—GO/MXene composite membranes against gram-positive and gram-negative bacteria can reach 97% due to the antibacterial nature of MXene. The improved strength, hydrophilicity, antibacterial activity and platelet adsorption performance suggest that PHBV—GO/MXene composite membranes might be ideal candidates for multifunctional materials for haemostatic applications.

Environmental Challenges, Opportunities, and Policy Implications to Materialize China’s Green Belt and Road Initiative

China’s Belt and Road Initiative (BRI), announced in 2013, is an unprecedented mega-project that aims to improve connectivity between China and over 70 countries through infrastructure investment and regional cooperation. It has unparalleled potential to bring about positive economic development across vast regions of the world but, at the same time, may inevitably come with considerable environmental challenges. Even so, opportunities exist to prevent or mitigate environmental risks and realize China’s promise of a green BRI. China has proposed to construct a green BRI. The existing environmental law framework of host states, green development practices by China and BRI participating countries, and the role of bilateral investment treaties (BITs) as well as multilateral environmental agreements (MEAs) all increase the odds of a green BRI. This article contributes to existing BRI-related literature by examining the environmental challenges and opportunities of the BRI and providing suggestions on building a comprehensive environmental protection mechanism. It is suggested to stringently implement environmental norms and green BRI policies, make greater use of BITs and MEAs, bring together various actors, mobilize all available resources, and establish an efficient environmental dispute settlement and environmental remediation system.