4.1. The Analysis of China’s IPPU CO2 Emissions from 1991 to 2012
Five major IPPU industrial departments’ CO
2 emissions and gross value of industrial output are shown in
Table 3. In addition, due to the consideration of the impact of industrial employed population scale on IPPU CO
2 emissions and economy,
Table 3 also illustrates the employed population scale of each industrial department. It is important to note that the line chart in
Figure 1 represents the gross value of industrial output at a constant price in 1990 (blue line) and industrial employed population (red line), the units are one hundred million yuan and ten thousand people.
Some conclusions can be drawn from
Table 3 and
Figure 1. In terms of the overall scale, the proportion of gross industrial output value and industrial employed population of the five major IPPU CO
2 emissions departments is about 20% of the total, and remained stable for a generous portion of the time period. It is also determined by each IPPU CO
2 emission department’s characteristic: they represent favorable industrial bases and facilities overall, both in basic manufacturing and mining departments, as far as ensuring stable development of the national economy and livelihood, and more stable product supply and marketing demand; thus, the proportion remains around 20% steadily.
From the overall view, CO2 emissions are determined by the product yield, so with the increase of product output, CO2 emissions rose and reached their maximum in 2012, 2142.3957 million tons, while the industrial department employed population and gross industrial output value firstly began to decline from 1996 to 2002 steadily and then increased after 2002. This is because, since 1998, China’s accumulation of deep-seated economic issues became problematic, and layoffs and unemployment became common social phenomena in China’s state-owned enterprises. In the middle of the 1990s, China experienced an economic recession characterized by lack of external or internal demand. The stagnation of the whole industry chain made all related enterprises face a very embarrassing situation. Large- and medium-sized, state-owned enterprises going bankrupt reduced the GIOV during this period; both reached their nadir in 2002, at 8.22 million (the total employed population in 2002 is 37.29 million) and 863.006 billion (the total China’s GIOV in 2002 is 4675.18 billion yuan), respectively. After 2002, with China’s accession to the WTO (World Trade Organization), a massive boom in domestic and foreign demand strengthened the economy and saved many state-owned enterprises from bankruptcy. Particularly, large state-owned enterprises like iron and steel producers began to make the transition from the planned economy to the market economy, ultimately rising to meet renewed external and internal demand. The industrial worker population and GIOV rose again; worker population peaked in 2010 at 21.0441 million (compared to the total population of China, 95.4471 million) and GIOV in 2011 at 1355.766 billion yuan (compared to the total gross value of China, 6,394.32 billion yuan), but, in 2011 and 2012, both values leveled off as the growth of the global economy slowed; this weakened external demand considerably, causing declining domestic infrastructure investment and weakening China’s real estate market regulations. These reasons sharply slowed down the speed of China’s economic growth, especially in manufacturing. Manufacturing’s employed demand growth slowed markedly while the construction, resident service and other services employed demand grew rapidly. As a result, the employment pressure will be more and more aggravated. In the next few years, China’s labor supply and structure will continue to change, the overall workforce will usher in a new turning point in a few years, and the new labor force and employed population will continue to decline among young adults. In the next few years, China’s labor supply and structure will certainly continue to change. New turning points in the country’s overall workforce are inevitable, including reducing the number of young adults employed in the industrial field. As the economy slows down and reaches stagnation, the employed population size will be stable.
From the view of the five major IPPU CO2 emission industrial departments, steel and iron alloy manufacturing, and non-metallic manufacturing accounted for more than 80% of total emissions, and reached 82.2% in 2012. With the increasing production of steel and cement, glass, CO2 emissions will continue to increase steadily over these years, while the rest of the industry growth rates are slower than A1 and A2. Taking the five major IPPU CO2 emission industrial departments as a whole, the steel and iron alloy manufacturing and chemical industry occupy nearly 60% of gross industrial output value, and non-metal and metal manufacturing industry occupies 20%. Non-metallic mining comprises the smallest portion at only about 2%. The non-metallic manufacturing industry, interestingly, shows the greatest proportion of the worker population at nearly 30%, while steel and iron alloy manufacturing and the metal industry comprises 19% and 11% of the worker population, respectively. The non-metallic mining worker population also presents a rising trend, from 7.7% in 1991 to 17.3% in 2012, while the chemical industry fell about 5% in 2012 in comparison to that of the 1990s. Due to the relative stability of China’s industrial development in recent years, the employed population structure also tends to be stable, both as a reflection of domestic and foreign demand characteristics. Due to the relative stability of China’s industrial development in recent years, the employed population structure also tends to be stable, both as a reflection of domestic and foreign demand characteristics. As China’s cement, glass, and iron alloy manufacturing industries are national leaders in production (and accordingly are top-priority infrastructure investment targets, demand-creators, and policy-drivers), the corresponding GIOV and employed population stayed at high levels toward the end of the time period we examined. The chemical industry and metal industry are pillars of China’s industrial infrastructure and effectively serve as the foundational livelihood of a massive employed population and of China’s economic and social stability—in short, no changes to this infrastructure can be expected in the short term. Non-metallic mining can be considered as a bottleneck industry, conversely. Due to its high dependence on natural resources, this industry tends to be more exploitative (i.e., its GIOV, in effect, inextricably corresponds to the exploitation and industrial pretreatment of its products.). Obviously, making any substantial increase in industrial output of this kind of resource-intensive industry is impossible in terms of environmental sustainability.
4.2. The Verification of IPPU CO2 Kuznets Curve
Upon testing, the time sequence series are consistent with cointegration test precondition. The result of the unit root test shows that the IPPU CO2 emissions of per employed person time series and the GIOV per employed person time series are both non-reposeful time series and integrated series of the first order. Then, taking the variable cointegration with the Johanse–Juselius test. The examination shows that the corresponding variable co-integration relationship exists as well. Therefore, scatter plot description and regression analysis can proceed.
Figure 2,
Figure 3,
Figure 4,
Figure 5,
Figure 6 and
Figure 7 shows the scatterplots of five major IPPU CO
2 emissions departments as well as their summation. It can reflect the relationship between IPPU CO
2 emissions per employed person and
GIOV per employed person, as well as the change trend in both. The abscissa represents
GIOV per employed person and the unit is ten thousand yuan. The ordinate represents the IPPU CO
2 emissions per employed person, and the unit is tons. Natural logarithm processing has been done to all data.
Unlike those drawn in previous studies, the scatter do not present any classic inverted U-shaped, N-shaped and other Kuznets curve types. Except non-metallic mining’s scatterplot presenting a function type growth curve, the rest of the IPPU department data are divisible into two parts marked with red and black splashes, respectively. The black scattered data represents 1991–2002 values which presented a function type growth curve and the red scattered data represents 2002–2012 values, which created a gathering type phenomenon, and all red scattered data are upper left of the black curve, namely GIOV per employed person value declined after 2002.
We consider non-metallic mining as a regression example in
Table 4 because
β3 is not significant in cubic form, while
β2 is significant, so quadratic regression is adopted. Then, we checked the D.W. value to judge whether the regression residuals show series autocorrelation.
According to the result, D.W. = 0.498941 < D
L = 0.9711, which indeed demonstrates autocorrelation between CO
2 emissions and
GIOV. Then, we added AR (AR(1) means the random disturbance is the first-order autoregressive form of serial correlation) to the estimating equations to eliminate autocorrelation sequence via the generalized least square method and obtain the results list in
Table 5.
The final result (in which we took four decimal places, the same as the following regression analysis results):
The following regression analysis results can be obtained in
Table 6 with the Generalized Least Squares. According to the results, estimate equation and the analysis of the results are shown as follows:
After obtaining the coefficient and the related parameters in the equation, due to the uncertainty of initial definition, diagnostic tests (tests on residuals, specification and stability tests and so on) of regression equations should be checked. In this paper, White heteroscedasticity testing, Chow breakpoint test, and Granger causality test are adopted from different perspectives. Consider the chemical industry as a regression example, and the results are as follows:
From the result in
Table 7,
F-statistic and the corresponding probability indicate that there is no heteroscedasticity in the residual and regression coefficient keeping stable at different times,
PCA4 does not Granger Cause
PGIOVA4 and
PGIOVA4 does not Granger Cause
PCA4.
Similarly, other industry departments and the total industrial department also carry out the diagnostic test and get the same conclusion. Because of the limitation of length, there is no more tautology here. Finally, the estimate equations are obtained in
Section 4.2.1 to
Section 4.2.6.
4.2.1. Steel and Iron Alloy Manufacturing
1991–2002
In 2002, PGIOVA1, PCA1 reached maximum, lnPGIOVA1 = 2.686, lnPCA1 = 4.629.
2003–2012
lnPGIOVA1 stays within the interval (2.398, 2.599). lnPCA1 began to rise resiliently in recent years after a slight decline, and reached the maximum, 5.581, in 2012.
4.2.2. Non-Metallic Manufacturing
1991–2002
In 2002, PGIOVA2, PCA2 reached maximum, lnPGIOVA2 = 2.071, lnPCA2 = 4.828.
2003–2012
lnPGIOVA2 stays within the interval (1.331, 1.469). lnPCA2 began to rise resiliently in recent years after a slight decline, and reached its maximum, 4.837, in 2011. The value was 4.832 in 2012.
4.2.3. Non-Metallic Mining
1991–2012
In 2002, PGIOVA3, PCA3 reached the maximum of the whole time series from 1991 to 2012, lnPGIOVA3 = 1.066, lnPCA3 = 5.066. In fact, compared to the value in 2002, lnPGIOVA3 and lnPCA3 in 2003–2012 both showed a greater degree of decline and did not follow the increasing trend pre-2002, though the data do fall onto the overall fitting curve coincidentally.
4.2.4. Chemical Industry
1991–2002
In 2002, PGIOVA4, PCA4 reached maximum, lnPGIOVA4 = 2.292, lnPCA4 = 3.373.
2003–2012
lnPGIOVA4 stays within the interval (1.806, 2.045). lnPCA4 began to rise resiliently in recent years after a slight decline, and reached its maximum, 3.293, in 2012.
4.2.5. Metal Industry
1991–2002
In 2002, PGIOVA5, PCA5 reached maximum, lnPGIOVA5 = 2.612, lnPCA5 = 2.474.
2003–2012
lnPGIOVA5 stays within the interval (2.255, 2.467). lnPCA5 began to rise resiliently in recent years after a slight decline, and reached its maximum, 2.977, in 2012.
4.2.6. The Sum of the Five Major IPPU CO2 Emission Departments
1991–2002
In 2002, PGIOVA, PCA reached its maximum, lnPGIOVA = 2.351, lnPCA = 4.405.
2003–2012
lnPGIOVA stays within the interval (1.771, 1.988). lnPCA began to rise resiliently in recent years after a slight decline, and reached its maximum, 4.673, in 2012.
Compared with the previous studies on industry EKC, the source of basic data and curve shape are not the same for several situations, but the vast majority of the carbon emission data are from the energy consumption [
11,
12,
15,
16], there is almost no carbon emissions EKC analysis caused by industrial production process. On the other hand, from the point of curve shape, although the curve shapes exist in a variety of forms [
3,
4,
5,
6,
7,
8,
9,
10,
14,
15,
16], the two obvious parts of the scatters have never appeared before. This paper focused on the relationship between industry CO
2 emissions and economic activity, and CO
2 emissions are accounted for in terms of IPPU rather than energy consumption. Though the surface result is similar with the research [
10,
16] that an inverted-U EKC does not exist, due to the IPPU CO
2 data the first time, our novel use of IPPU CO
2 data made our scatter and regression analysis quite different from those of previous researchers. Because of the data result accounting and the curve fitting situation, a new relationship between IPPU CO
2 emission and
GIOV is put forward for the first time in this paper. The reasons and discussions are as follows.
Prior to 2002, reduction in domestic and foreign demand caused either stagnation or decline in China’s manufacturing sector overall (including the steel, cement, glass, and chemical industries) as well as a decline in the GIOV as prices remained constant and employed population declined, while the decreasing amount is far from the range of laid-off and unemployed workers. Several of China’s state-owned enterprises reduced surplus staff during this time in effort to prevent bankruptcy, maintain (low) production levels, and avoid collapse exponentially of the employed population. This caused the ascendant trend in the GIOV per employed curve.
After 2002, with China’s accession to the WTO, the increasing domestic and foreign demand and widespread new construction of domestic infrastructures required a larger workforce; accordingly, the population of employed persons increased yearly from this point forward. The economic growth rate also tended to be stable in those years, though it grew at a slower rate than that of the worker population. To this effect, the GIOV per worker data moved to the left of the black curve after 2002. After 2010, China’s labor force structure was fairly stable, and the number of workers was around 90 million. As-affected by a sluggish global economy, weakened external demand, slowed domestic infrastructure investment, new real estate market regulations, and other factors, China’s economic growth then slowed down (especially in terms of manufacturing growth rate). The GIOV stalled once again while the GIOV per worker remained unchanged, dropping below the maximum in 2002.
The production increase is related to domestic and foreign demand directly working on increasing CO2 emissions; likewise, emissions decline when production declines. After 2002, IPPU CO2 emissions per employed person in all departments presented a slight decline in 2003, followed by an overall increase until reaching maxima in 2011 and 2012. Among the separate curves for individual department, steel and iron alloy manufacturing and metal industry IPPU CO2 emissions per employed person reached its maximum in 1991–2012, while the remaining departments’ extremum values were slightly smaller than that of the 2002 maximum.
GIOV is affected by the apparent output consumption data accounted in this paper by IPPU CO2 emission, and there was a greater distance between data points in 2003 to 2012 and the fitting curve in 1991–2012 that reflects the greater difference between product output and consumption. Take the iron and steel industry for example, before 2003, China’s steel industry was in short supply and domestic production did not meet the needs of economic development, but, after 2003, with the capacity of expanding and enterprise’s production enthusiasm, the iron and steel industry appeared in the steel stocks. As the economy gradually stabilized over these years, the overcapacity problem got worse noticeably. In 2012, the difference between demand and supply reached its maximum, nearly 300 million tons, and its reflective phenomenon reflects the scatter performance.
In fact, the calcium carbide and lime mining also complies with the principle of the above. In 2002, lnPCA3 and lnPGIOVA3 reached the maximum, then it dipped to a low level.
The scatter we created for the summation of all five major IPPU CO2 emission departments was similar to that of individual manufacturing sectors (apart from that of non-metallic mining, which was quite a bit smaller and had fewer effects on the whole). In 2002, the GIOV per employed person value reached its maximum and then began to decline, as discussed above. The IPPU CO2 emissions per employed person rose slightly after a slight decline in 2002, then reached its maximum in 2012.
According to the classic Kuznets curve theory, carbon emissions and economic growth present the inverted U-shaped curve. However, in this paper, the results show a weaker relationship between IPPU CO2 emissions per worker and GIOV per worker (i.e., two different curve shapes) in terms of IPPU CO2 emissions. These scatterplots may provide a valuable reference for future policy adjustments made to the industrial sector as well.
Especially the data since 2003, which moved to the left above the curve in 1991-2002, the per capita CO2 emissions presents an increasing trend in recent years and reached the maximum in 2011 or 2012. This reflects a serious circumstance: due to small changes in GIOV and the employed population, China’s iron and steel, cement and other industries demand have tended to become saturated and even reduced. While the production is still increasing, the problem of excess production capacity has appeared in China in recent years, and a worsening overcapacity situation has been alarming the government.