Carbon dioxide emissions peaks depend on changes in economic scale and industrial structure

Reaching carbon dioxide (CO₂) emissions peak is a prerequisite for achieving carbon neutrality. Most developing countries are puzzled about how to achieve CO₂ emissions peak, whereas other countries are uncertain whether the recent inflection points in CO₂ emissions represent genuine peaks. In this study, we identified the decisive factors and numerical ranges for peaking CO₂ emissions from a socioeconomic development perspective, and we further established the criteria for distinguishing between genuine and spurious CO₂ emissions peaks. By employing principal component analysis and the panel threshold regression model, in this study, we investigated the nonlinear dynamic impacts of socioeconomic factors on CO₂ emissions in 16 developed countries with peak emissions during the period from 1960 to 2016. The results demonstrate that a nonlinear threshold effect is exerted by the economic subsystem, characterized by economic scale and industrial structure, on CO₂ emissions, thus playing a predominant role in the peaking process of CO₂ emissions by shaping both the total amount and the timing of reaching the peak, and emerging as the key factor in distinguishing between genuine and spurious CO₂ emissions peaks. The identified criteria for this distinction are as follows: a gross domestic product (GDP) growth rate of between 1.20 % and 4.94 %, a GDP per capita ranging from USD 18,519 to USD 44,597, and the ratio of tertiary industry output value to the total GDP falling within 51–65 %. All three key indicators must be simultaneously satisfied to fulfill the criteria to achieve a genuine CO₂ emissions peak. The findings of this study not only facilitate the scientific and precise identification of the CO₂ emissions peak but also provide invaluable references for countries or regions that have not yet reached their peaks in formulating and refining economic development strategies to achieve CO₂ emissions peak.