Measuring ecosystem services supply and demand in rural areas: cases from China's key counties to receive assistance in pursuing rural revitalization.

There is a considerable challenge to meeting the Sustainable Development Goals (SDGs) of ending poverty and maintaining ecosystems' function in rural areas, largely due to that the rural people's livelihood relied heavily on fragile ecosystems. China is ambitious to solve this issue by enacting economic stimulus policies such as ecological protection compensation and payment for ecosystem services (ESs). However, these interventions are generally based on stockholders' willingness and lack of scientific basis. Here, we firstly combined InVEST model and social-economic data to evaluate the ecosystem services supply and demand (ESSD), by taking 25 key counties to receive assistance in pursuing rural revitalization in Sichuan province as the study cases. The coupling coordination degree model was then employed to measure the coordination relationship of ESSD. Finally, the driving factors were analyzed based on correlation analysis and stepwise regression method. The results showed that all ESs, except carbon sequestration, were oversupplied with significant spatial heterogeneity. From 2000 to 2020, the supply of all ESs increased, in which the food production had the most notable increase ratio amounting to 48.20%, while the demand of water retention and air purification decreased substantially. Due to the inconsistency between cultivated land area and population changes, significant spatial heterogeneity existed in the coordination relationship of food production. The counties with the highest and the lowest annual average coordination index were Yanyuan (0.9950) and Rangtang (0.1208), respectively. The rural employees and the agricultural gross output value were the key positive factors influencing the quantity and coordination of ESSD, while ecological compensation and financial expenditure had no significant impact, further indicating that these policies were not linked to the performance of ecosystems' function. Finally, policy implications were raised. This study provides a scientific framework for enacting the interventions towards ecological sustainability and poverty ending from ESSD perspective.

The anthropogenic cycles of palladium in China during 2001-2020.

Palladium (Pd) is a strategic metal and can help reduce environmental pollution, especially from vehicle exhausts. China is the world's largest Pd consumer, but with very limited reserves. However, Pd anthropogenic cycles remain unclear in China. This study aims to uncover the dynamic Pd flows and stocks in China for the period of 2001-2020 by conducting dynamic material flow analysis. The results show that the demand for Pd had increased by 10 folds during the study period due to stricter vehicle emissions policies. Also, China mainly imported such resource from the United States, Western Europe, and East Asia, with a share of 88.8 %. However, due to insufficient end-of-life vehicle (ELV) recycling system, the total recycled Pd was only 12.3 tons although the end-of-life Pd flow increased from 3.7 tons in 2001 to 30.8 tons in 2020. This implies a great Pd recycling potential. Therefore, it is urgent to promote Pd recycling by establishing an effective Pd recycling system. In addition, other policy recommendations, such as diversifying Pd import partners, increasing Pd emergency reserves, and economic instruments, are raised by considering the Chinese realities so that the overall Pd resource efficiency can be improved.

Exergy analysis of natural resources embodied in China's interregional trade and its implication for regional imbalance.

Large-scaled interregional trade is based upon massive exchanges of natural resources, leading to more environmental emissions and economic imbalance. China is the largest trade country in the world and has to face such challenges since different Chinese provinces are in different development stages with different resource endowments. By using the latest multi-regional input-output (MRIO) tables and exergy accounting, this study aims to investigate natural resources and added values embodied in interregional trade in China for years of 2012, 2015, and 2017. Regional environmental inequality (REI) index and logarithmic mean Divisia index (LMDI) were applied to measure the imbalance states and uncover corresponding driving factors. Results show that the total trade volumes in the middle Yellow River and eastern coastal regions were generally higher than those in other regions, together accounting for 41.50 ~ 41.78% of the total trade volume during the study period. The major flows of embodied natural resources shifted from the middle Yellow River region to western coastal, eastern coastal, and southern coastal regions. The northern coastal and eastern coastal regions were the major exporters of embodied added value. Less developed regions had higher REI values, indicating more environmental and economic losses than developed regions. Natural resources intensity was the major impact factor on the trade imbalances in most provinces. This study provides valuable insights for alleviating trade imbalance and promoting sustainable natural resources management based on cross-regional collaboration.

Measuring the anthropogenic cycles of light rare earths in China: Implications for the imbalance problem.

Light rare earth elements (LREEs) are of strategic importance for low carbon transition and decarbonization. However, the imbalance between LREEs exists and a systematic understanding of their flows and stocks is lacking, which impedes the attainment of resources efficiency and exacerbates the environmental burdens. This study examines the anthropogenic cycles and the imbalance problem of three representative LREEs in China, the largest LREEs producer in the world, including cerium (the most abundant), neodymium and praseodymium (the fastest demand-growing). We find that 1) from 2011 to 2020, the total consumption of Nd and Pr increased by 228 % and 223 %, respectively, mainly attributed to the increasing demand of NdFeB, whereas that of Ce increased by 157 %; 2) the supply insufficiency of Nd and Pr under the current quota system accumulated to 138,086 tons and 35,549 tons, respectively, while the oversupply of Ce reached 63,523 tons; and 3) China has become a net importer of LREEs concentrates, and a net exporter of LREEs in the form of intermediate and final products, imposing further burdens to the domestic environment. It is clear that the imbalance of LREEs occurred during the study period, raising urgent needs to adjust the LREEs production quotas, seek other Ce applications, and eliminate illegal mining.

Mapping the Global Anthropogenic Chromium Cycle: Implications for Resource Efficiency and Potential Supply Risk.

Chromium (Cr) is a critical metal due to its non-substitutable application in the metallurgy industry and highly uneven distribution of global reserve. However, there is a lack of in-depth analysis of global Cr flow patterns and its trade networks among individual cycles, which leaves the potential barriers and opportunities unexplored for improving chromium resource efficiency. Here, we employ a trade-linked multilevel material flow analysis (MFA) to map the global anthropogenic Cr cycle for year 2019. Social network analysis is also used to identify the key countries involved in the global Cr trade network. The results highlight that the global Cr cycle depends substantially on international trade in different forms, of which stainless steel is the leading application. Although South Africa, Kazakhstan, and Turkey are the major Cr primary resource suppliers, China and India play substantial roles in manufacturing Cr-containing products. Regional disparities exist in the scrap contents of individual country cycles, varying from 7% (uncertainty ranges from 4 to 11%) in China to 88% (uncertainty ranges from 87 to 89%) in India. Additionally, several countries are essential in the global Cr redistribution and in the connectivity of the Cr trade network, which may lead to their strong import dependence and even supply disruption.

Uncovering the Key Features of Dysprosium Flows and Stocks in China.

Dysprosium (Dy) is a critical rare earth element and plays an indispensable role in clean energy technologies, such as wind turbines and electric vehicles. However, its flows and stocks in the whole life cycle and potential barriers to sustainable supply remain unclear, although the demand for Dy is increasing and its reserves are limited. This study aims to track China's Dy cycle for the period of 2000 to 2019 by employing dynamic material flow analysis. The results show that (1) demand for Dy had increased by 117-fold, with an accumulative use of 37,317 tons, of which 50% was obtained from illegal mining; (2) 33% of the overall Dy resource was used in wind turbines in 2019, followed by air conditioners and electric vehicles (22 and 17%, respectively); (3) China's net Dy export had increased by 10-fold from 2000 to 2019, with Dy concentrates and final products being the dominant import and export products, respectively. Illegal mining, inadequate recycling policies, and limited Dy supply sources are potential barriers influencing sustainable Dy supply.

Environmental damage cost assessment from municipal solid waste treatment based on LIME3 model.

Environmental damage cost can measure the impact of pollution caused by human activity on final safeguard subjects from endpoint perspective. Application of environmental damage cost to municipal solid waste (MSW) management is still rare. To fill such a research gap, this study established a MSW environmental damage cost assessment method using Life Cycle Impact Assessment Method based on Endpoint (LIME) model. Four types of environmental damage cost, namely, primary productivity, social assets, biodiversity and human health for waste treatment were investigated in the city of Shanghai. Results show that the environmental damage cost was 113.7, 116.9, 140.0, 144.0 and 170.8 million dollars in Shanghai from 2014 to 2018, respectively. Damage cost of social assets was the dominant component, accounting for about 55%. Landfill mainly caused social assets damage cost, while incineration mainly caused human health damage cost. Scenarios analysis further revealed that after implementing MSW separation, the total environmental damage cost could be reduced by about 1/3. The best MSW treatment method is fermentation, followed by compost, incineration and landfill, with unit environmental damage cost being 0.22, 4.51, 16.04 and 23.47 USD/ton, respectively.

Greenhouse gas emission mitigation potential from municipal solid waste treatment: A combined SD-LMDI model.

Fast urbanization and economic prosperity generate huge amount of municipal solid waste (MSW). It is therefore critical to identify the determinants of greenhouse gas (GHG) emissions from MSW treatment and prepare potential GHG mitigation measures. A combined System Dynamics - Logarithmic Mean Divisia Index model is developed to identify the driving forces of GHG emission generated from MSW treatment and explore the mitigation potentials. Shanghai, a typical megacity in China is selected as a case study. Results showed that economic development, population scale and emission intensity were driving forces to induce GHG emissions from MSW treatment, while generation intensity and treatment structure were the factors to mitigate GHG emissions from MSW during 2000-2017. Scenario analysis further revealed that landfill gas utilization and MSW separation improvement were the most effective measures in reducing GHG emissions from MSW treatment, leading to about 88.07% and 85.48% of reduction compared with the business-as-usual scenario in 2050. Scenarios of improving incineration rate, reducing per capita MSW generation and restricting population growth will reduce GHG emissions by 72.29%, 30.06% and 0.30%, respectively. Utilizing landfill gas, improving MSW separation and promoting green behaviors are suggested to mitigate GHG emissions from MSW treatment.

An overview of the municipal solid waste management modes and innovations in Shanghai, China.

Municipal solid waste (MSW) management and recycling has become an emerging issue in developing countries. Shanghai, the largest megacity in China, is well-known nationwide due to leading China's MSW separation and recycling. Therefore, this paper introduces the Shanghai mode for MSW management and its current situation to enrich existing MSW management studies. Results show that the total generation volume of MSW and amount of MSW generation per capita were 9.00 million tons and 372.16 kg in 2017, increased approximately eight-fold and four-fold compared with the data in 1978, respectively. The MSW treatment rate reached 100% since 2014, with incineration rate increased to 48.56% in 2017. The cost of MSW management after implementing MSW sorting regulation is increased to 985 CNY/ton, including 390 CNY/ton of MSW sorting cost. Then three key features and innovative MSW management modes, namely, mandatory MSW sorting legislation, Green Account program, and the Combined Network program are introduced. Meanwhile, two main challenges are urgent to be responded, including inadequate collecting vehicles and limited wet waste treatment capacity. Finally, policy recommendations on strengthening MSW recycling process, constructing complete terminal treatment industry, and making systematic policies were provided to respond existing challenges.