1. Introduction
Global warming is a major challenge for contemporary humanity [
1]. Extreme phenomena, such as the accelerated melting of global glaciers, rise in the sea level, and polarization of droughts and floods, caused by the continuous increase in CO
2-based greenhouse gases have become more frequent in recent years [
2,
3], which have caused serious impacts on agricultural production, human life, and socioeconomic activities, and ultimately hindered the process to achieve sustainable development on a global scale. In this context, the promotion of low-carbon development has become an international consensus [
4]. The Chinese government has conducted many attempts to undertake the responsibility of reducing carbon emissions, making emission-reduction commitments at the United Nations General Assembly, in which strategic goals were proposed that China would realize carbon peaking by 2030 and carbon neutrality by 2060. However, for a long time, China’s extensive development model characterized by factor-driven factors has led to a significant amount of energy consumption and carbon emissions, along with the rising energy consumption caused by industrialization and urbanization [
5], which also leads to the long-term pressure on China to reduce carbon emissions [
6]. According to the statistical data of World Energy Statistics Yearbook 2021, China’s carbon emissions increased from 8.83 billion tons to 9.90 billion tons from 2011 to 2020, indicating how severe the situation of the country’s emission reduction is. The issue of carbon emissions has become an important topic in current academic and social circles.
Meanwhile, with the continuous development of human society, the phenomenon of aging has attracted particular attention from China and even the whole world. As a populous country, China has been aging at an astonishing rate since entering aging society in 2000 [
7]. By 2025, the proportion of older adults or people aged 65+ or similar is expected to increase to 14% of the total population, which means that China has gone through the aging period that has taken decades or even centuries in developed Western countries in just 25 years, and will be confronted with the dual challenges of “getting old before getting rich” and “getting old without preparation”. Population aging has become a major demographic characteristic in many countries, which brings changes in social production and consumption. And carbon emissions are mainly achieved through economic and social production and consumption, which implies that there may be a correlation between population aging and carbon emissions. Thus, clarifying the impact of population aging on CO
2 emissions is of great significance for the high-quality development of China’s economy and society. Therefore, this study will focus on China, which has the biggest carbon emissions as well as a serious aging issue. However, in view of the differences in the development of various regions in China, the provincial areas of China are divided into three regions—east, west, and center—and the effects of the relationship between aging and carbon emissions are thoroughly examined. This can serve as an important theoretical guide for regions to understand and cope with the relationship between population aging and regional carbon emissions.
There have been many insightful discussions on the relationship between population aging and carbon emissions. However, the previous research has not yet achieved a consensus conclusion, and three different kinds of viewpoints have been formed. The first kind of view confirms that population aging can increase carbon emissions. From the perspective of the national level, Tonn and Eisenberg [
8] showed that population aging would lead to an increase in the use of conventional fossil fuels, which could increase carbon emissions for the entire society. Li et al. [
9] established a three-sector equilibrium analysis framework based on the PET model for production, consumption, and government. On this basis, the population, economy, and carbon emissions data from 1995–2016 in China are adopted, and the empirical results showed that the relationship between population and consumption factors, especially population aging and carbon emissions, is increasingly positively correlated. In addition, from the perspective of the regional level, Zhang et al. [
10] investigated the impact of population aging on national and regional carbon emissions and discovered a positive correlation between population aging and carbon emissions in China, based on the STIRPAT model and Chinese provincial panel data. From the perspective of the household level, Fan et al. [
11] investigated the impacts of population aging on household carbon emissions in both rural and urban China and discovered that both urban and rural aging have a significant positive impact on household carbon emissions. The second kind of view shows us that population aging will inhibit carbon emissions. Hu et al. [
12] and Kim et al. [
13] pointed out that households with several generations or with a high percentage of middle-aged and older members were conducive to reducing household energy consumption. However, the third type of view argues that the importance of population aging for carbon emissions is uncertain in different circumstances. Yang and Wang [
14] and Li [
15] pointed out that population aging has a threshold effect on reducing carbon emissions. And Liu and Zhang [
16] investigated the carbon footprint and inequality of household consumption in 25 Chinese provinces and found that there are significant variances in per capita of carbon emissions among different household groups, with older adults tending to produce fewer emissions.
Overall, the existing literature has conducted many beneficial explorations on the relationship between population aging and carbon emissions. However, these research conclusions remain controversial. And they are mainly focused on either the promotion effect or inhibition effect, separating the comprehensive impact of the two effects on carbon emissions. Moreover, there is no proper answer to whether there is heterogeneity of these various effects and the mechanisms behind it. According to the above analysis, the marginal contributions of this study might be as follows. Firstly, based on the dual attributes of population aging, this article proposes the analysis framework of the bilateral effects of population aging on regional carbon emissions, which theoretically enriches the research on the relationship between population aging and carbon emissions. Secondly, a bilateral stochastic frontier model is adopted while considering the bilateral effects of population aging; this paper specifically measures the promotion, inhibition, and net effects of population aging on carbon emissions. It also further analyzes the spatial-temporal distribution characteristics and variation patterns of the bilateral effects, which provides literature references for understanding the intrinsic mechanism of population aging on regional carbon emissions. Thirdly, this paper investigates the heterogeneous characteristics of the net effect of population aging on carbon emissions under various aging, human capital, and urbanization levels, which is conducive to objectively and comprehensively understanding the general principles of population aging on carbon emissions, and policy recommendations on how to achieve carbon neutrality in the context of population aging are, finally, provided.
The remainder of this paper is organized as follows:
Section 2 describes the theoretical mechanism of the relationship between population aging and reginal carbon emission;
Section 3 introduces the models, variables, and data sources adopted in this paper;
Section 4 presents the empirical results and the relevant analysis;
Section 5 summarizes the conclusions and proposes policy recommendations.
5. Conclusions and Policy Implications
5.1. Conclusions
To clarify the relationship between population aging and carbon emissions in regions, this study applies a bilateral stochastic frontier model to measure and analyze the inhibition, promotion, and net effects of population aging on regional carbon emissions, using panel data from 30 Chinese provinces from 2011 to 2020. And the following conclusions are obtained: (1) The promotion effect of population aging increases carbon emissions over the frontier level by 10.63%, while the inhibition effect reduces carbon emissions by 15.77%. And the net effect of population aging on carbon emissions is −5.14%, indicating that regional carbon emissions are greatly decreased by population aging. (2) In terms of regional distribution characteristics, population aging in eastern, western, and central regions significantly reduces the regional carbon emission level, and the inhibition effect of population aging on carbon emissions in the eastern region is stronger than that in the central and western regions. (3) In terms of temporal distribution characteristics, the inhibition effect of population aging on carbon emissions increases continuously, and gradually holds the dominant position during the study period. (4) With the growth of population aging, human capital, and urbanization, the inhibition effect of population aging on regional carbon emissions can be strengthened.
5.2. Policy Implications
Based on the above analysis, the policy recommendations are proposed as follows.
Firstly, the problem of reducing carbon emissions should be considered in terms of population. The human production and consumption behaviors have the determinant function on economic development, the industrial structure, and technological innovation; thus, it makes more sense to focus on the population while reducing carbon emissions. As aging has gradually become a trend in the development of the world’s population in recent years, it is necessary to pay attention to the important role of demographic changes on regional carbon emissions. Appropriate policies should be created to fully exploit the impact of population aging on carbon reduction. To alleviate the pressure brought about by population aging as much as possible, policies can be focused on the features of the arrangements and adjustments of social structures and socioeconomic institutions for older adults. Moreover, promoting cooperation between the young and older adults is a good alternative.
Secondly, heterogeneous governance strategies based on regional development differences should be implemented. Nowadays, there still exists the relative backwardness condition of older adults’ social security coverage in the central and western regions of China. Moreover, older adults usually have much lower income levels, pension insurance coverage rates, and basic medical insurance participation rates. Therefore, governments should strengthen their support for older adults in the central and western regions and give appropriate policy welfare to them in these districts. For instance, establish the minimum income guarantee system and purchase a certain amount of community services to improve the income level and life quality of old adults, thus achieving the goal of reducing carbon emissions.
Thirdly, it is necessary to increase investments in human capital through the way of improving the quality and quantity of labor resources of older adults. In order to increase older adults’ options for education and training, a flexible retirement age can be chosen to realize the growth of life expectancy. And some relevant regulations on the employment of them can be developed to encourage enterprises to eliminate age discrimination and intergenerational conflicts in the employment of older adults, thus reducing the crowding-out effect of population aging on human capital investment.
Moreover, low-carbon consumption concepts and behaviors should be encouraged in the whole society. Therefore, governments should give correct guidance to citizens about the consumption patterns of social groups, including how to lessen their need for high-energy-consuming products and unnecessary daily expenses. At the same time, governments must put forward their efforts to promote energy conservation and environmental protection, encourage more environmentally friendly and low-carbon modes of transportation, and accelerate the formation of green and low-carbon lifestyles and consumption patterns for all the regions in China.
5.3. Research Limitation and Future Work
This study concentrates upon the bilateral effects of population aging, providing a theoretical reference to facilitate regional green and sustainable development. Nevertheless, there still exist certain limitations which demand to be enhanced further. For one thing, on account of data availability, the indicators we chose cannot accurately cover the various aspects of regional population aging, such as aging size, aging structure, and aging quality. Therefore, a more complicated evaluation system is preferred to enhance the practical significance of relative research. For another thing, this study focuses on the different dimensions of the effects and fails to capture various and specific paths to maintain the positive function of population aging, which will be the expanded orientation of the follow-up work.