China is the world’s largest emitter of CO2. As the largest sector of China’s fossil energy consumption and carbon emissions, manufacturing plays an important role in achieving emission reduction targets in China. Using the extended logarithmic mean division index (LMDI) decomposition model, this paper decomposed the factors that affect the CO2 emissions of China’s manufacturing industry into eight effects. The results show the following: (1) China’s manufacturing CO2 emissions increased from 1.91 billion tons in 1995 to 6.25 billion tons in 2015, with an average annual growth rate of 6%. Ferrous metal smelting and rolling were the largest sources of carbon dioxide emissions, followed by chemical raw materials and products and then non-metallic minerals. (2) During the research period, the industrial activity effects were the most important factor leading to increased CO2 emissions in manufacturing and energy intensity was the most important factor in promoting the reduction of CO2 emissions from manufacturing. The investment intensity was the second most influential factor leading to the increase in China’s manufacturing CO2 emissions after the industrial scale and this even exceeded the industrial activity effect in some time periods (2000–2005). R&D efficiency and R&D intensity were shown to have significant roles in reducing CO2 emissions in China’s manufacturing industry. The input of R&D innovation factors is an effective way to achieve emission reductions in China’s manufacturing industry. (3) There were differences in the driving factors of CO2 emissions in the manufacturing industry in different periods that were closely related to the international and domestic economic development environment and the relevant policies of the Chinese government regarding energy conservation and emission reduction. (4) Sub-sector research found that the factors that affect the reduction of CO2 emissions in various industries appear to be differentiated. This paper has important policy significance to allow the Chinese government to implement effective energy-saving and emission reduction measures and to reduce CO2 emissions from the manufacturing industry.

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The “Qinling-Huaihe Line” is the recognized geographical boundary between north and south China. In the context of a widening north–south gap, the large-scale population flow and the implementation of the regional coordinated development strategy, the north–south differentiation of the Chinese population requires further investigation. This study is based on national census data and uses quantitative methods, such as the centralization index, coefficient of variation, hot spot analysis and geodetector, as research methods. This study takes the Qinling-Huaihe Line as the dividing line and aims to extensively explore the spatial differentiation, evolutionary characteristics, and influential factors of the populations on both sides. The main conclusions are as follows: ① From 1982 to 2010, the population share ratio on the south and north sides of the Qinling-Huaihe Line remained at 58:42, showing a distribution pattern of “South more and North less”. ② The area within 200 km from the Qinling-Huaihe Line is a transition area with a stable distribution of the populations on both sides. ③ From 1982 to 2010, the concentration of the population distribution gradually increased on both sides, and the concentration of population on the south side was higher; the characteristics of population growth had significant spatial differences between the two sides. ④ The results calculated by the geodetector method show that socioeconomic factors are the main factors causing the spatial differentiation of the populations, while physical geographical environmental factors have a smaller influence and their influence continues to decrease.

Abstract:Modern agriculture often leads to nonpoint source pollution. From the perspective of a decoupling analysis, this research evaluates the relationship between crop production and agricultural nonpoint source pollution (via fertilizer application), using the Heilongjiang land reclamation area as a case study. As it is the largest commodity grain base and green food base in China, more than 80% of water pollution in this area comes from fertilizer application. This study adopts an export coefficient model to hindcast nitrogen loss delivered to surface water via fertilizer application and conduct a further analysis of decoupling agricultural nonpoint source pollution from crop production. The results indicated that weak decoupling frequently occurred. However, this tendency was not steady in the period 2001-2012, and weak decoupling was typical in each branch based on the average value. Regarding the example of decoupling agricultural nonpoint source pollution from rice production, weak decoupling occurred more often, but this tendency was not steady over time. In addition, expansive coupling occurred in 2006, 2010 and 2012, and there were no definite signs of it improving. All branches, except for the Suihua branch, reached the degree of weak decoupling. A basic fact is that a decoupling tendency and environmental deterioration coexist in both the past and present. The decoupling analysis will contribute to localized strategies for sustainable agricultural development.

Modern agriculture contributes significantly to greenhouse gas emissions in several ways. From the perspective of sustainability assessment, it is not enough to evaluate mitigation measures that rely only on emissions reductions. In this article, we use the method of decoupling analysis to construct a decoupling index based on carbon footprint and crop yield and evaluate the relationship between crop production and greenhouse gas emissions using the most modern grain production base in China as a case study. The results indicate that a weak but variable decoupling trend occurred from 2001 to 2015 and that each branch achieved on average a weak decoupling across the study period. In addition, rice production constituted 80% of the regional carbon footprint in a crop's life cycle. The results of our analysis of rice production show that weak decoupling was the most common outcome but was not consistent because a weak coupling occurred in 2015. Each branch on average achieved a weak decoupling except for the SH branch. Our research indicates that high agricultural material inputs with low utilization efficiency contributed to the poor relationship between crop production and greenhouse gas emissions in the study area. Fertilizer, especially N fertilizer, was an important contributor to the total greenhouse gas emissions of crop production. As a supplement to carbon footprint assessment, this decoupling analysis helps local decision-makers diagnose the level of green growth, identify key options to mitigate greenhouse gas emissions from agriculture, and adopt more targeted interventions towards sustainable agriculture.