In this work, we extend the literature by providing a time series and global-level analysis of carbon footprints of 13 occupations (Supplementary Information 1) across 45 sectors (Supplementary Information 2) in 67 economies (Supplementary Information 3) from 2000 to 2018. Based on the evaluation of occupational carbon footprints, the present study proposes a transition risk assessment framework to identify vulnerable occupations. Specifically, we evaluate the occupational exposure to climate transition risks from two perspectives: impact and likelihood. The risk impact of an occupation is measured by the ratio of its potential cost of mitigating its carbon footprint to its value added. The risk likelihood of an occupation is measured by the ratio of the volume of regulated carbon footprint to the gross volume of carbon footprint. Please refer to Supplementary Information 13 for the evaluation framework of the present study, and calculation equations are presented in the method section. Here, we first present the temporal trend and spatial pattern of occupational carbon footprints.
The gross volume of occupational carbon footprints at the global level increased from 6893.5 Mt in 2000 to 10018.2 Mt in 2018, accounting for 34.6% of global emissions (Supplementary Information 9). This indicates the significance of workforce transition to climate change mitigation. From the occupational perspective, craft workers and machine operators, a greater share of whom are mainly engaged in carbon-intensive energy and manufacturing sectors (Supplementary Information 4), rank first among the 13 occupations by the volume of occupational carbon footprints in 2018, constituting 28.7% of the total occupational carbon footprints (Fig. 1). Improving the production efficiency of craft workers and machine operators is essential for achieving the climate mitigation targets. Over the studied period, craft workers and machine operators also correspond to the greatest growth in the volume of occupational carbon footprint, with a growth of 963.7 Mt.
To provide a more detailed explanation on the changing trends in occupational carbon footprints and corresponding driving factors, we further divide the study period into three subperiods (Fig. 2). Over the first subperiod, the global occupational carbon footprints increased by 12.4%. The major driving factor to this increase was the growth in the scale of primary labour inputs (scale effect), which would cause the occupational carbon footprints to increase by 21.1% in the absence of other factors. The global carbon intensity (the amount of carbon dioxide emissions emitted per unit of GDP) decreased over the period 2000-2006, and the decrease in carbon intensity offset the global occupational carbon footprints by 12.8% (intensity effect). The change in occupation structure (structure effect, 0.04%) and industrial linkage effect (4.0%) played relatively modest roles. Although the financial crisis happened in the second subperiod, the volume of global carbon emissions increased sharply. Meanwhile, the growth rate of the volume of global occupational carbon footprints reached as high as 19.5%, which is mainly driven by the scale effect (27.6%), industrial linkage effect (3.8%) and structure effect (0.49%). The decrease in carbon intensity contributes to a decrease in global occupational carbon footprints by 12.5%. Over the third subperiod, the growth rate of global occupational carbon footprints decreased to 8.3%. Although the scale effect was still positive, the intensity effect (-10.6%) and industrial linkage effect (-3.9%) contribute to a decline in global occupational carbon footprints. The change in occupational structure still played a relatively modest role. Policymakers should implement more proactive measures to promote the green transition of workforce structure.
Figure 3 presents the volume of carbon footprints of occupations in each economy in 2018. Workers (Fig. 3a) in China correspond to the greatest volume of carbon footprints (2988.7 Mt), followed by the United States (1773.8 Mt) and the European Union (1039.7 Mt). The ranking of occupational carbon footprints (please refer to Supplementary Information 5 for the volume of occupational carbon footprints at regional and sectoral level) is mainly determined by the positions of different economies in value chains, due to the uneven distribution of occupations and emissions along the value chains. Developed countries typically occupy upstream positions in value chains, where professionals constitute a larger proportion of the occupational structure. Figure 3b shows that the carbon footprints of managers in the United States reached 337.1 Mt, a figure notably higher than that of other economies, such as the European Union (133.0 Mt) and China (123.7 Mt). Similarly (Fig. 3c), the United States (218.4 Mt) is also ranked the first by the volume of carbon footprints of engineers, followed by the European Union (176.8 Mt) and China (163.7 Mt). This is attributed to the fact that a considerable number of engineers engage in manufacturing industries, primarily concentrated in developed countries and major emerging economies (as categorized by the International Monetary Fund), such as China. China, often referred to as the “world’s factory,” is home to a vast number of producers and production supporters. Therefore, these two occupations in China correspond to the top two positions in terms of the volume of carbon footprints. The volume of carbon footprints of producers and production supporters in China reached 1633.2 Mt and 832.2 Mt in 2018, which is notably greater than that of other economies (Fig. 3d-i). Workers in other occupations generally exhibit lower carbon footprints, with the spatial distribution of carbon footprints concentrated in the world’s two largest economies, the United States and China (Fig. 3j-n).
Figure 4a shows that Australia’s workers correspond to the greatest volume of occupational carbon footprint per worker, being aligned with Australia’s high per capita carbon emissions. Workers in the other countries with a higher level of fossil fuels dependence, such as Saudi Arabia, also exhibit a greater volume of per worker carbon footprint. A territorial comparison reveals that developed countries have greater carbon footprints per worker than most emerging countries (Fig. 4b-n). However, there is a growing trend in per worker carbon footprint in emerging countries (such as China), while that of the developed countries (such as the United States) is gradually decreasing (Supplementary Information 10). In developed countries, policymakers should impose stricter regulations to control the per worker carbon footprints of occupations. Simultaneously, efforts should be made to curb the growth of per worker carbon footprints in emerging countries. The carbon intensity and the value-added intensity (the amount of occupational value added created per worker) are the primary factors that define the volume of the carbon footprint per worker. Therefore, the occupations that are primarily involved in carbon-intensive (such as drivers, Fig. 4f) and value-added-intensive (such as managers, Fig. 4b) industries are associated with a considerable level of per worker carbon footprints. Yet, it should be noted that there exist considerable occupational differences in the carbon footprint intensity, indicating that some workers may be more vulnerable to climate transition risks.
Among the 13 occupations, drivers — who make up 3.0% of the workforce — are exposed to the greatest climate transition risk, which is measured from both risk likelihood and impact perspectives. The transformation of transportation is critical in addressing climate change. Drivers are encountering escalating climate-related pressures, which increases their likelihood of experiencing risk. Climate mitigation mechanisms would raise the cost of fossil fuels use, and drivers are particularly sensitive to these changes in cost. Compared with the other 12 groups of occupations, drivers have the largest share of the protentional carbon footprint mitigation costs in relation to the economic benefit they gain (Supplementary Information 11); therefore, they correspond to the greatest nominalized impact in Fig. 5. The other occupations that are exposed to great climate transition risk are craft workers and machine operators (such as extraction and building workers, labourers in mining, construction, manufacturing, and so on), which are typically characterised by their labour-intensive nature. The craft workers and machine operators rank second in terms of the number of workers among the 13 occupations studied, constituting 17.0% of the total workforce. In addition, the corresponding workers are usually engaged in carbon-intensive production stages, and they tend to encounter notably greater challenges in switching careers due to the limited scope of technical skills or the need for a considerable capital investment. Upskilling and retraining are essential for enhancing the risk adaptability of craft workers and machine operators. There also exist occupations accounting for a greater share of the total work force, such as agriculture workers (38.1%). Agricultural workers face relatively lower carbon pricing risks, because most of current carbon pricing policies have not yet extended to the agricultural sector.
Figure 6a presents the exposure to climate transition risk of 13 occupations in different economies. The results show that most occupations in emerging countries are facing much greater carbon price rising risk than that in developed economies. Due to the greater carbon intensity in the emerging countries, occupations correspond to greater volume of carbon footprints relative to wage income; therefore, workers in the emerging countries face greater carbon footprint mitigation burdens. In addition, the emerging economies generally exhibit relatively modest climate regulations compared to those in developed economies. Therefore, workers in the emerging countries are more sensitive to the stringent regulations in the near future. Emerging countries face greater pressures to cope with the workforce transformation, particularly for drivers, craft workers and machine operators. In developed economies, there also exists territorial and occupational heterogeneity in the exposure to climate transition risks. For instance, the workers in the United States, which face a greater necessity for an enhancement of its climate regulations, are exposed to greater climate transition risk than those in the European Union. Among the studied occupations, drivers in developed countries, such as the United States and Australia, tend to be more vulnerable to climate transition risks than other occupations, and policymakers in developed countries should adopt more targeted measures to protect them. More details about climate transition risk impact can be found in Supplementary Information 12.
Figure 6b, c further illustrate the occupational and regional distribution of measures outlined in climate policies to safeguard workers against climate transition risks. Figure 6b indicates that the highest number of protection measures are associated with craft workers and machine operators, given their large workforce and considerable exposure to carbon pricing risks, as highlighted in this study. Agricultural workers are the second most supported occupation by climate policies, due to their vulnerability and large workforce. With the rapid development of renewable energy and electric vehicles, engineering professionals and drivers are also receiving considerable attention in climate policies. Figure 6c shows that the EU climate policies correspond to the largest number of occupational protection measures, followed by the UK and Canada. In comparison, climate policies in emerging countries offer less protection for occupations facing climate risks. Yet, the results of the present study show that most occupations in emerging countries are exposed to notably higher carbon price risk than those in developed economies, highlighting a regional mismatch between the climate risks faced by occupations and the protection measures in place. With the gradual increase in carbon prices in the future, we suggest that the climate policies in emerging economies should prioritize strengthening occupational protection measures, particularly for those occupations vulnerable to carbon pricing.
