| In the context of responding to global climate change,China has proposed to achieve the goal of reaching the peak of CO2 emissions by 2030,which will strongly promote the arrival of the peak of global CO2 emissions,and will further lay the foundation for the realization of the carbon neutral goal.In recent years,there has been a turning point in the CO2 emissions of some international countries and domestic provinces.However,due to the fluctuating and rising characteristics of emission trends,in the absence of relevant reference standards,it is still difficult to judge whether the turning point is the peak value based on the change trend alone.Therefore,based on the current dilemma in the judgment of CO2 emissions peak,this study starts from the perspective of the dynamic evolution of the socioeconomic system of countries that have peaked CO2 emissions,and reveals the peaking law and mechanism of CO2 emissions by constructing a socioeconomic system framework.On this basis,this paper has constructed a quantitative peak comprehensive judgment system.Under the premise of determining the corresponding judgment standards,it judges the peak status of countries with different levels of development in the world and different provinces and cities in China,and the system is revised according to China’s national conditions,and corresponding policy recommendations are put forward.This paper mainly includes the following four aspects:1.Based on the constructed society-economy-technology-energy system framework,using principal component analysis(PCA)and panel threshold regression(PTR)model to analyze the influence effects of each subsystem on CO2 emissions in different development stages of 16 OECD countries from 1960 to 2016,and then reveal the peaking mechanism of CO2 emissions under the evolution of the socio-economic system.The results show that the social and energy subsystems promote CO2 emissions,the technology subsystem suppress emissions,and the economic subsystem have a nonlinear dual-threshold effect,which manifests as the impact on CO2 emissions from promotion to suppression,and then the suppression effect is further enhanced.At the peak,the indicators of the four subsystems show strong regularity: GDP growth rate is1.20-4.94%,per capita GDP is US$18,519-44,597,tertiary industry accounts for 51-65%,and population growth rate is less than 1%,the urbanization rate is 68%-78%,the energy intensity is 0.10-0.18 kgoe/USD,the carbon dioxide emission efficiency is 2.17-3.01 kg/kgoe,the energy consumption growth rate is-1.11-8.05%,per capita Energy consumption is 2590-4710 kgoe,and fossil energy accounts for 75%-89% of total final energy consumption.The peak of CO2 emissions is the result of the long-term stable optimization of structural and technological effects and the rapid short-term changes in scale effects.After reaching the social and economic foundation required for peaking CO2 emissions,in order to achieve the true peak,the evolution of the socioeconomic system in the pre-peak stage mainly focuses on economic and social adjustments,while the post-peak stage focuses on the optimization of technology and energy.2.Taking 19 OECD countries that have peaked CO2 emissions as examples,the Fuzzy Comprehensive Evaluation Method(FCEM)is used to construct a peak comprehensive judgment system by determining the index evaluation levels,singleindex evaluation results,index weights,comprehensive evaluation indexes and peak standards.The Monte Carlo method is used to carry out systematic uncertainty analysis.The results show that the criterion for peak judgment is that the comprehensive evaluation index must remain above 0.9 at the turning point and the following years,and the indexes of the economic,social,technological and energy subsystems reach an average level of 0.30,0.10,0.22 and 0.30.The sensitivity of the 10 indicators in descending order are: energy intensity,carbon emission efficiency,energy consumption per capita,growth rate of energy consumption,proportion of fossil energy consumption,GDP growth rate,population growth rate,proportion of tertiary industry,urbanization rate,GDP per capita.Among them,energy intensity and carbon emission efficiency have a greater potential impact on the setting of comprehensive evaluation index standards.3.The peak comprehensive judgment system is used to judge the peak status of134 countries around the world in 2017,and cross-validate the judgment result through logistic regression in the machine learning binary classification algorithm.Based on the vector autoregressive model(VAR),through the use of impulse response analysis(IRA)and variance decomposition analysis(VDA),34 typical countries at different development stages are explored on the changes in CO2 emissions from structural adjustments and technological changes from 1990 to 2016.The results show that in2017,27 countries out of 134 countries have a comprehensive evaluation index above0.90.Among them,23 countries have reached their CO2 emissions peak.The countries below 0.90 have basically no peak except the former Soviet Union and Yugoslavia countries.Compared with the evaluation criteria,its shortcomings show different characteristics according to the socioeconomic development level.Logistic regression results show that the regression model is stable.For countries in various stages of industrialization development,the proportion of renewable energy consumption has always played a negative driving role in the changes in CO2 emissions,and the industrialization rate only shows a significant negative impact on changes in CO2 emissions in the post-industrialization stage.Carbon emission intensity and energy intensity only showed a significant negative driving effect in the post-industrialization stage and the initial stage of industrialization.Changes in CO2 emissions in postindustrialized countries are dominated by industrial structure and energy structure,while industrialized countries are dominated by energy intensity and carbon emission intensity.In the early stage of industrialization,the early-mid-stage of industrialization,the middle-late stage of industrialization,and the late-stage of industrialization,the country’s average driving degrees of changes in CO2 emissions reach 24.38%,27.56%,21.11%,and 27.87%,respectively.Meanwhile,the structural effect factors reach14.71%,10.87%,11.27%,and 14.00% respectively.4.Based on the constructed comprehensive judgment system for peaking CO2 emissions,the peak status of major provinces in my country and cities in the Northeast and Yangtze River Delta regions have been judged.Through the positioning of the socioeconomic foundations required for China to achieve peak carbon emissions in the future,from Starting from the actual situation,analyze the applicability of the peak comprehensive judgment system in China,so as to modify and improve the comprehensive judgment system suitable for Chinese localization.The results show that as of 2018,except for Beijing,the comprehensive evaluation index of all provinces and cities in China is below 0.9.Among them,the changes in the comprehensive evaluation index of Beijing,Tianjin,Shanghai and other places are dominated by the economic subsystem,while the changes in most other regions are dominated by the energy subsystem.The standard of the peak comprehensive judgment system is revised from the original comprehensive evaluation index of 0.9 to 0.85,and the comprehensive evaluation index of the economic,social,technological and energy subsystems are revised to 0.25,0.10,0.20 and 0.30 respectively.Specifically,the per capita GDP evaluation standard has been adjusted from the original 20,000 U.S.dollars to about14,000 U.S.dollars,the GDP growth rate has been adjusted from 2.8% to about 5.0%,and the energy intensity has been adjusted from 0.12 kgoe/USD to 0.20 kgoe/USD,the judging criteria for other indicators remain unchanged.Through research results and analysis,specific policy recommendations are put forward for areas of different development levels characterized by comprehensive evaluation indexes in China. |
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