This paper calculated the scale of carbon emissions embodied in the import and export of the world's major countries based on input-output principles and international trade data, as well as data on various countries...This paper calculated the scale of carbon emissions embodied in the import and export of the world's major countries based on input-output principles and international trade data, as well as data on various countries'carbon emissions in 2005 from domestic consumption and emissions embodied in trade. The results illustrate that, because of international trade, consumers in developed countries should bear the responsibility for a large portion of CO2 emissions. The researchers separated the net transfer balance of embodied emissions in international trade according to four different effects: size effect, exchange rate effect, structural effect, and pure technical effect, all of which favor the sharing of responsibilities between producers and consumers.展开更多
International trade of textiles and clothing has numerous environmental implications, such as carbon leakage. In order to estimate the CO2 emissions embodied in China's imports and exports of textiles and clothing...International trade of textiles and clothing has numerous environmental implications, such as carbon leakage. In order to estimate the CO2 emissions embodied in China's imports and exports of textiles and clothing, an empirical analysis was carried out with environmental input-output analysis (EIOA) method using the most recent data available. The results indicate that China is a net exporter of embodied CO2 emissions on account of its international trade of textiles and clothing. The amount of the net exported embodied CO2 emissions increases from 110 million metric tons(Mt) of CO2 in 2002 to 280 Mt of CO2 in 2011. In particular, United States, Japan, and European Union transfer to China 339 Mt of CO2, 291 Mt of CO2 and 396 Mt of CO2 respectively during the period of 2002 -2011.展开更多
Foreign trade drives China's growth,but as the trade scale continues to expand,the carbon emissions also increase quickly.Based on the industry panel data from 1996 to 2010,this paper calculates carbon emissions o...Foreign trade drives China's growth,but as the trade scale continues to expand,the carbon emissions also increase quickly.Based on the industry panel data from 1996 to 2010,this paper calculates carbon emissions of 27manufacturing industries.According to the intensity of carbon emissions,this paper divides the manufacturing sectors into low carbon and high carbon manufacturing industry and then analyzes the carbon emission trends.Next,the paper uses the feasible generalized least square regression to verify the existence of environmental Kuznets curve(EKC)of the manufacturing industry's carbon.In order to investigate the carbon leakage problem,the regression also includes the interaction term between trade and industrial value added.Our findings are as follows:the carbon emissions of the whole manufacturing industry and low carbon manufacturing industry accord with the EKC curve,but have a linear relationship with the high carbon manufacturing industry;trade reduces the carbon emissions of the whole manufacturing industry and low carbon manufacturing industry,but it increases those of the high carbon manufacturing industry;for the whole manufacturing industry and low carbon manufacturing industry,there is no carbon leakage,but it exists in the high carbon manufacturing industry.On the whole,pollution haven hypothesis does not hold up in China,and China does not need to limit industry foreign trade to reduce the emission of CO_2.But the manufacturing industry will still be the main engine of the economic growth,and therefore our country should make an effective low-carbon policy,introduce advanced technology,increase R&D investment into lowcarbon technologies,and upgrade and transform the original equipment to change the backward mode of production.展开更多
Due to ongoing growth in carbon emission, many governments' have taken measures to curb it. Thus, it is of great importance to measure carbon emissions in international trade and probe into the causes behind them. Th...Due to ongoing growth in carbon emission, many governments' have taken measures to curb it. Thus, it is of great importance to measure carbon emissions in international trade and probe into the causes behind them. This paper first applies inputoutput model then it estimates the carbon emissions embodied in China's international trade in 2002, 2005 and 2007. Using structural decomposition analysis, this paper measures carbon emissions in international trade by their scale effect, composition effect and intensity effect. Our results illustrate: (1) a rapidly-rising net export of carbon emissions for China, and (2) scale effect and composition effect stimulates carbon emissions embodied in exports, while intensity effect discourages it.展开更多
Constructing a model for international carbon emissions trading is an effective method to curb global warming through a market mechanism.Although the international carbon emissions market generates substantial profits...Constructing a model for international carbon emissions trading is an effective method to curb global warming through a market mechanism.Although the international carbon emissions market generates substantial profits,the relevant trading mechanism has been far from perfect.The perfect mechanism for international carbon emissions trading should be a revealing preference game.In other words,only if all players in this game truly show their information and preferences can the Nash outcome be Pareto efficient and fair.China should actively participate in the international carbon emissions trading game;promote efficiency,justice,rationality,and the quality of being manipulation-free in the carbon emissions market;and play a more important role in perfecting the international carbon emissions trading mechanism.展开更多
This study uses the global pollutant emission databases and global input-output model in 2015 to calculate the impact of international trade on global water nitrogen emission patterns,based on considering the total am...This study uses the global pollutant emission databases and global input-output model in 2015 to calculate the impact of international trade on global water nitrogen emission patterns,based on considering the total amount of pollutant transfer and pollutant emission intensity of trade flows The main conclusions are as follows:(1) There are always a large amount of water nitrogen emissions transferring from developed economies to developing economies embodied in their bilateral trade activities.Small amount of transfers are of some areas with similar endowments of agricultural resources or long distances.(2) In 2015,the net import of water nitrogen pollution embodied in China's trade was 160,000 tons,accounting for 2.72% of the global water nitrogen imports.The sharp increases in cereal imports,together with high food storage as well as high pollution intensity embedded in trade are the main reason.It is recommended that through applying alleviations such as agricultural machinery assistance and technical training to accelerate the transfer and spread of agricultural technology in Africa,Asia,and other regions,thus helping increase agricultural production productivity in underdeveloped areas and reducing the pollution intensity embodied in trade flows from underdeveloped areas to developed areas.展开更多
This study calculates the embodied carbon in imports,exports,net exports,and the processing trade of China's wood product sector between 2001 and 2016 using a non-competitive input-output(I-O)model.The results dem...This study calculates the embodied carbon in imports,exports,net exports,and the processing trade of China's wood product sector between 2001 and 2016 using a non-competitive input-output(I-O)model.The results demonstrate that embodied carbon showed a decreasing trend between 2001 and 2016.Embodied carbon was lowest in wood furniture imports and highest in paper and paperboard imports.The embodied carbon in sawnwood and veneer sheet exports was the lowest and paper and paperboard exports was the highest.The embodied carbon in the processing trade of paper and paperboard was the highest.To reduce the embodied carbon in China's wood products,the government should promote technological transformation and upgrading and encourage the implementation of green technology innovation.展开更多
China is one of the world’s major importers and exporters. On the one hand, massive exports have created enormous economic value and employment opportunities for Chinese and become one of the vital forces underpinnin...China is one of the world’s major importers and exporters. On the one hand, massive exports have created enormous economic value and employment opportunities for Chinese and become one of the vital forces underpinning the country’s economic growth. On the other hand, exports have caused a huge amount of energy resource consumption and carbon emissions and added pressure to the country for a sustainable growth. China exports a wide variety of products, each of which is attached to a different industry chain with different energy consumptions. Therefore, the evolution of the product structure has become one of the key factors affecting China’s future energy consumption and economic growth. To further promote nationwide energy conservation and emission reduction, reduce the pressure exerted by economic growth on energy consumption and the environment and win more space for sustainable economic growth, it is imperative to understand energy consumption and carbon emissions embodied in export products and provide support for China’s export policy adjustment. This study attempts to calculate, compare and analyze the embodied energy and carbon emissions in 46 major export products using the full life cycle assessment method, and concludes by offering policy recommendations.展开更多
International trade is an important impact factor to the carbon emissions of a country As the rapid development of Chinese foreign trade since its entry into the WTO in 2002, the effects of international trade on carb...International trade is an important impact factor to the carbon emissions of a country As the rapid development of Chinese foreign trade since its entry into the WTO in 2002, the effects of international trade on carbon emissions of China are more and more significant. Using the recent available input-output tables of China and energy consumption data, this study estimated the effects of Chinese foreign trade on carbon emissions and the changes of the effects by analyzing the emissions embodied in trade between 2002 and 2007. The results showed a more and more significant exporting behavior of embodied carbon emissions in Chinese international trade. From 2002 to 2007, the proportion of net exported emissions and domestic exported emissions in domestic emissions increased from 18.32% to 29.79% and from 23.97% to 34.76%, respectively. In addition, about 22.10% and 32.29% of the total imported emissions were generated in processing trade in 2002 and 2007, respectively, which were imported and later exported emissions. Although, most of the sectors showed a growth trend in imported and exported emissions, sectors of electrical machinery and communication electronic equipment, chemical industry, and textile were still the biggest emission exporters, the net exported emissions of which were also the largest. For China and other developing countries, technology improvement may be the most favorable and acceptable ways to reduce carbon emissions at present stage. In the future negotiations on emissions reduction, it would be more fair and reasonable to include the carbon emissions embodied in international trade when accounting the total emissions of an economy.展开更多
Based on the latest China-Russia input-output data sets over the period from 2007 to 2015,this study quantified the flow of embodied carbon emissions in China-Russia trade using the emission embodied in bilateral trad...Based on the latest China-Russia input-output data sets over the period from 2007 to 2015,this study quantified the flow of embodied carbon emissions in China-Russia trade using the emission embodied in bilateral trade(EEBT)approach.In addition,the structural decomposition analysis(SDA)was employed to identify the potential driving factors that affect embodied carbon in imports and exports.The results showed as follow.1)China was a net exporter of carbon emissions in bilateral trade between China and Russia during 2007–2015.Despite that the bilateral trade scale had expanded considerably,the net export volume of CO_(2)from China to Russia decreased from 13.21 Mt in 2007 to 4.45 Mt in 2015.2)From the perspective of different sectors,the metal manufacturing and the chemical sectors of China and Russia were the main sources of CO_(2)emissions.3)In terms of driving factors,it was found that the carbon emission coefficient was the main reason for contributing to embodied emission reduction.Moreover,the contribution rate of carbon emission coefficient to reduce the carbon emissions in imports reached to 95.26%,as well as 108.22%in exports.The bilateral trade scale was the main driver for the increase in embodied carbon emissions,and the contribution rate to embodied carbon emissions in imports and exports were 14.80%and 65.17%,respectively.4)This study argued that China and Russia should further optimize the energy structure and improve the energy efficiency and intermediate technology in the future.展开更多
In this paper,Embodied carbon emission competitiveness in international trade and inter-provincial trade is measured and comparative analysis is conducted.Specifi cally the non-competitive input-output model and low-c...In this paper,Embodied carbon emission competitiveness in international trade and inter-provincial trade is measured and comparative analysis is conducted.Specifi cally the non-competitive input-output model and low-carbon trade competitiveness index are constructed to study the embodied carbon emission competitiveness of 31 Chinese provinces in international trade and inter-provincial trade from the perspectives of the whole,three industries and product sectors.We find that Shanghai is the most competitive in low-carbon trade,while Qinghai is the least;carbon leakage in international trade is severe;the performance of different product sectors differ widely in embodied carbon emission competitiveness in international trade and inter-provincial trade;the primary and secondary industries are competitive in low-carbon inter-provincial trade and the tertiary industry is competitive in low-carbon international trade.The innovations of this paper is as follows:methodology in low-carbon trade competitiveness index is innovated;macro,meso and micro perspectives are taken;factors in international trade and inter-provincial trade are combined in content.In the end,development of low-carbon trade is promoted and references for policy are provided for a new round of trade competition.展开更多
With the increase in international trade, more attention has been given to quantifying the impacts of international trade on energy use and carbon emissions. Input-output analysis is a suitable tool for assessing reso...With the increase in international trade, more attention has been given to quantifying the impacts of international trade on energy use and carbon emissions. Input-output analysis is a suitable tool for assessing resources or pollutants embodied in trade and it has become a critical tool for performing such analysis. This study estimated the national and sectoral carbon emissions embodied in Chinese international trade using the latest available China input-output table of 2007. The results showed that a significant exporting behavior of embodied carbon emissions existed in China's trade. Over 1/3 of the emissions in Chinese domestic production processes were generated for exports in 2007. The net balance of emissions embodied in exports and imports accounted for nearly 30% of China's domestic emissions, which means that any policy made to increase the exports would result in a significant growth of China's domestic emissions. Since over half of China's export trade is processing trade, the re-exported emissions could not be overlooked; otherwise, it would hard to capture the actual emissions generated abroad to obtain China's domestic consumption. The enlargement of export scale is a primary driven factor to the rapid growth of China's exported emissions. It is necessary for China to adjust its economic and industrial structure to reduce the dependence of economic growth on the export trade. However, when adjusting industry structures or making policies on carbon emission reduction, it will be more reasonable to consider the relationship between production and consumption, rather than just focus on the emission values of sectors' direct production, as a large part of carbon emissions emitted by the principal direct polluters were generated to obtain the products which were required by other sectors.展开更多
文摘This paper calculated the scale of carbon emissions embodied in the import and export of the world's major countries based on input-output principles and international trade data, as well as data on various countries'carbon emissions in 2005 from domestic consumption and emissions embodied in trade. The results illustrate that, because of international trade, consumers in developed countries should bear the responsibility for a large portion of CO2 emissions. The researchers separated the net transfer balance of embodied emissions in international trade according to four different effects: size effect, exchange rate effect, structural effect, and pure technical effect, all of which favor the sharing of responsibilities between producers and consumers.
基金Special Fund for Quality Inspection Research in the Public Interest,the Ministry of Science and Technology,China(No.201010041)the Fundamental Research Funds for the Central Universities,China
文摘International trade of textiles and clothing has numerous environmental implications, such as carbon leakage. In order to estimate the CO2 emissions embodied in China's imports and exports of textiles and clothing, an empirical analysis was carried out with environmental input-output analysis (EIOA) method using the most recent data available. The results indicate that China is a net exporter of embodied CO2 emissions on account of its international trade of textiles and clothing. The amount of the net exported embodied CO2 emissions increases from 110 million metric tons(Mt) of CO2 in 2002 to 280 Mt of CO2 in 2011. In particular, United States, Japan, and European Union transfer to China 339 Mt of CO2, 291 Mt of CO2 and 396 Mt of CO2 respectively during the period of 2002 -2011.
基金supported by National Natural Science Foundation of China[grant number 71273115]
文摘Foreign trade drives China's growth,but as the trade scale continues to expand,the carbon emissions also increase quickly.Based on the industry panel data from 1996 to 2010,this paper calculates carbon emissions of 27manufacturing industries.According to the intensity of carbon emissions,this paper divides the manufacturing sectors into low carbon and high carbon manufacturing industry and then analyzes the carbon emission trends.Next,the paper uses the feasible generalized least square regression to verify the existence of environmental Kuznets curve(EKC)of the manufacturing industry's carbon.In order to investigate the carbon leakage problem,the regression also includes the interaction term between trade and industrial value added.Our findings are as follows:the carbon emissions of the whole manufacturing industry and low carbon manufacturing industry accord with the EKC curve,but have a linear relationship with the high carbon manufacturing industry;trade reduces the carbon emissions of the whole manufacturing industry and low carbon manufacturing industry,but it increases those of the high carbon manufacturing industry;for the whole manufacturing industry and low carbon manufacturing industry,there is no carbon leakage,but it exists in the high carbon manufacturing industry.On the whole,pollution haven hypothesis does not hold up in China,and China does not need to limit industry foreign trade to reduce the emission of CO_2.But the manufacturing industry will still be the main engine of the economic growth,and therefore our country should make an effective low-carbon policy,introduce advanced technology,increase R&D investment into lowcarbon technologies,and upgrade and transform the original equipment to change the backward mode of production.
文摘Due to ongoing growth in carbon emission, many governments' have taken measures to curb it. Thus, it is of great importance to measure carbon emissions in international trade and probe into the causes behind them. This paper first applies inputoutput model then it estimates the carbon emissions embodied in China's international trade in 2002, 2005 and 2007. Using structural decomposition analysis, this paper measures carbon emissions in international trade by their scale effect, composition effect and intensity effect. Our results illustrate: (1) a rapidly-rising net export of carbon emissions for China, and (2) scale effect and composition effect stimulates carbon emissions embodied in exports, while intensity effect discourages it.
基金This work was funded by Humanity and Social Science Youth foundation of Ministry of Education of China:Research on the Practices and Theoretical Innovation of Improving People's Wellbeing in the New Era[Grant number.18YJC710023]Major Projects of Social Science Fund of Jilin University:Research on China's Social Welfare System[Grant number.2019XXJD10]Major Projects of Trade Union of Jilin Province:Research on the Evaluation System of Harmonious Labor Relations[Grant number.2016LD007].
文摘Constructing a model for international carbon emissions trading is an effective method to curb global warming through a market mechanism.Although the international carbon emissions market generates substantial profits,the relevant trading mechanism has been far from perfect.The perfect mechanism for international carbon emissions trading should be a revealing preference game.In other words,only if all players in this game truly show their information and preferences can the Nash outcome be Pareto efficient and fair.China should actively participate in the international carbon emissions trading game;promote efficiency,justice,rationality,and the quality of being manipulation-free in the carbon emissions market;and play a more important role in perfecting the international carbon emissions trading mechanism.
基金Beijing Natural Science Foundation[Grant number:9154036]Special Fund for Talents of Science&Technology Innovation Engineering of Chinese Academy of Agricultural Sciences[Grant number:ASTIP-IAED-2019RC-01]The fundamental Research funds for the central research institutes(Grant number:161005201803-2).
文摘This study uses the global pollutant emission databases and global input-output model in 2015 to calculate the impact of international trade on global water nitrogen emission patterns,based on considering the total amount of pollutant transfer and pollutant emission intensity of trade flows The main conclusions are as follows:(1) There are always a large amount of water nitrogen emissions transferring from developed economies to developing economies embodied in their bilateral trade activities.Small amount of transfers are of some areas with similar endowments of agricultural resources or long distances.(2) In 2015,the net import of water nitrogen pollution embodied in China's trade was 160,000 tons,accounting for 2.72% of the global water nitrogen imports.The sharp increases in cereal imports,together with high food storage as well as high pollution intensity embedded in trade are the main reason.It is recommended that through applying alleviations such as agricultural machinery assistance and technical training to accelerate the transfer and spread of agricultural technology in Africa,Asia,and other regions,thus helping increase agricultural production productivity in underdeveloped areas and reducing the pollution intensity embodied in trade flows from underdeveloped areas to developed areas.
文摘This study calculates the embodied carbon in imports,exports,net exports,and the processing trade of China's wood product sector between 2001 and 2016 using a non-competitive input-output(I-O)model.The results demonstrate that embodied carbon showed a decreasing trend between 2001 and 2016.Embodied carbon was lowest in wood furniture imports and highest in paper and paperboard imports.The embodied carbon in sawnwood and veneer sheet exports was the lowest and paper and paperboard exports was the highest.The embodied carbon in the processing trade of paper and paperboard was the highest.To reduce the embodied carbon in China's wood products,the government should promote technological transformation and upgrading and encourage the implementation of green technology innovation.
文摘China is one of the world’s major importers and exporters. On the one hand, massive exports have created enormous economic value and employment opportunities for Chinese and become one of the vital forces underpinning the country’s economic growth. On the other hand, exports have caused a huge amount of energy resource consumption and carbon emissions and added pressure to the country for a sustainable growth. China exports a wide variety of products, each of which is attached to a different industry chain with different energy consumptions. Therefore, the evolution of the product structure has become one of the key factors affecting China’s future energy consumption and economic growth. To further promote nationwide energy conservation and emission reduction, reduce the pressure exerted by economic growth on energy consumption and the environment and win more space for sustainable economic growth, it is imperative to understand energy consumption and carbon emissions embodied in export products and provide support for China’s export policy adjustment. This study attempts to calculate, compare and analyze the embodied energy and carbon emissions in 46 major export products using the full life cycle assessment method, and concludes by offering policy recommendations.
基金National Science & Technology Pillar Programme of China,No.2007BAC03A11
文摘International trade is an important impact factor to the carbon emissions of a country As the rapid development of Chinese foreign trade since its entry into the WTO in 2002, the effects of international trade on carbon emissions of China are more and more significant. Using the recent available input-output tables of China and energy consumption data, this study estimated the effects of Chinese foreign trade on carbon emissions and the changes of the effects by analyzing the emissions embodied in trade between 2002 and 2007. The results showed a more and more significant exporting behavior of embodied carbon emissions in Chinese international trade. From 2002 to 2007, the proportion of net exported emissions and domestic exported emissions in domestic emissions increased from 18.32% to 29.79% and from 23.97% to 34.76%, respectively. In addition, about 22.10% and 32.29% of the total imported emissions were generated in processing trade in 2002 and 2007, respectively, which were imported and later exported emissions. Although, most of the sectors showed a growth trend in imported and exported emissions, sectors of electrical machinery and communication electronic equipment, chemical industry, and textile were still the biggest emission exporters, the net exported emissions of which were also the largest. For China and other developing countries, technology improvement may be the most favorable and acceptable ways to reduce carbon emissions at present stage. In the future negotiations on emissions reduction, it would be more fair and reasonable to include the carbon emissions embodied in international trade when accounting the total emissions of an economy.
基金supported by“the Funds for Firstclass Discipline Construction of Beijing University of Chemical Technology(XK1802-5)”.
文摘Based on the latest China-Russia input-output data sets over the period from 2007 to 2015,this study quantified the flow of embodied carbon emissions in China-Russia trade using the emission embodied in bilateral trade(EEBT)approach.In addition,the structural decomposition analysis(SDA)was employed to identify the potential driving factors that affect embodied carbon in imports and exports.The results showed as follow.1)China was a net exporter of carbon emissions in bilateral trade between China and Russia during 2007–2015.Despite that the bilateral trade scale had expanded considerably,the net export volume of CO_(2)from China to Russia decreased from 13.21 Mt in 2007 to 4.45 Mt in 2015.2)From the perspective of different sectors,the metal manufacturing and the chemical sectors of China and Russia were the main sources of CO_(2)emissions.3)In terms of driving factors,it was found that the carbon emission coefficient was the main reason for contributing to embodied emission reduction.Moreover,the contribution rate of carbon emission coefficient to reduce the carbon emissions in imports reached to 95.26%,as well as 108.22%in exports.The bilateral trade scale was the main driver for the increase in embodied carbon emissions,and the contribution rate to embodied carbon emissions in imports and exports were 14.80%and 65.17%,respectively.4)This study argued that China and Russia should further optimize the energy structure and improve the energy efficiency and intermediate technology in the future.
基金2018 Program of Key Research Institute of Social Sciences of Sichuan Province-Sichuan Research Center of Circular Economy:“Research on China”s Inter-Provincial Trade,International Trade and Low-Carbon Trade Competitiveness”(XHJJ-1806)Natural Sciences Research Program of Department of Education of Guizhou Province(Support Program for Science and Technology Top Talents):“Construction of Low-Carbon Trade Competitiveness Index and Empirical Study in Guizhou”(Qianjiaohe KY[2017]068).
文摘In this paper,Embodied carbon emission competitiveness in international trade and inter-provincial trade is measured and comparative analysis is conducted.Specifi cally the non-competitive input-output model and low-carbon trade competitiveness index are constructed to study the embodied carbon emission competitiveness of 31 Chinese provinces in international trade and inter-provincial trade from the perspectives of the whole,three industries and product sectors.We find that Shanghai is the most competitive in low-carbon trade,while Qinghai is the least;carbon leakage in international trade is severe;the performance of different product sectors differ widely in embodied carbon emission competitiveness in international trade and inter-provincial trade;the primary and secondary industries are competitive in low-carbon inter-provincial trade and the tertiary industry is competitive in low-carbon international trade.The innovations of this paper is as follows:methodology in low-carbon trade competitiveness index is innovated;macro,meso and micro perspectives are taken;factors in international trade and inter-provincial trade are combined in content.In the end,development of low-carbon trade is promoted and references for policy are provided for a new round of trade competition.
文摘With the increase in international trade, more attention has been given to quantifying the impacts of international trade on energy use and carbon emissions. Input-output analysis is a suitable tool for assessing resources or pollutants embodied in trade and it has become a critical tool for performing such analysis. This study estimated the national and sectoral carbon emissions embodied in Chinese international trade using the latest available China input-output table of 2007. The results showed that a significant exporting behavior of embodied carbon emissions existed in China's trade. Over 1/3 of the emissions in Chinese domestic production processes were generated for exports in 2007. The net balance of emissions embodied in exports and imports accounted for nearly 30% of China's domestic emissions, which means that any policy made to increase the exports would result in a significant growth of China's domestic emissions. Since over half of China's export trade is processing trade, the re-exported emissions could not be overlooked; otherwise, it would hard to capture the actual emissions generated abroad to obtain China's domestic consumption. The enlargement of export scale is a primary driven factor to the rapid growth of China's exported emissions. It is necessary for China to adjust its economic and industrial structure to reduce the dependence of economic growth on the export trade. However, when adjusting industry structures or making policies on carbon emission reduction, it will be more reasonable to consider the relationship between production and consumption, rather than just focus on the emission values of sectors' direct production, as a large part of carbon emissions emitted by the principal direct polluters were generated to obtain the products which were required by other sectors.