Comparison of city-level carbon footprint evaluation by applying single- and multi-regional input-output tables

Differences in carbon emissions between the digital economy sectors in China and the USA

In an era of rapid development of digital technologies and dramatic global climate change, digital economy is crucial to achieving the 'carbon peak' and 'carbon neutral' goals. However, less research has been done in the area of indirect carbon emissions in the digital economy sector. Therefore, this study uses an input-output model to calculate the embodied carbon emissions of the ICT (information and communication technology) industry in China and the USA in 2005, 2010 and 2016 from the production and consumption sides. Moreover, a comparative analysis is conducted in terms of the driving factors of carbon emissions and the relationship between emissions and economic benefits in the two countries. The results reveal that emissions are larger on the production side in the USA and on the consumption side in China. For both countries, electricity is the largest upstream sector in terms of emissions. ICT in the USA causes sectoral emissions mainly in manufacturing and services. While China mainly causes sectoral emissions in manufacturing. The US ICT sector is more economically efficient for the same emissions. Regarding drivers, the primary driver of the fall in emissions is a reduction in emission intensity. The increase in emissions driven by final demand is greater in China than in the USA. Finally, the results of the two countries are extended to other developed countries and emerging economies, providing recommendations for reducing carbon emissions in the ICT sector.

Extension and update of multiscale monthly household carbon footprint in Japan from 2011 to 2022

Household consumption significantly contributes to greenhouse gas emissions as it is the largest component of final demand in the national accounting system. Nevertheless, there is an apparent lack of comprehensive and consistent datasets detailing emissions from household consumption. Here, we expand and update Japan's multiscale monthly household carbon footprint from January 2011 to September 2022, combining data from government statistics and surveys. We constructed a dataset comprising 37,692 direct and 4,852,845 indirect emission records, covering households at the national, regional, and prefectural city levels. The dataset provides critical spatiotemporal information that allows for revealing carbon emission patterns, pinpointing primary sources of emissions, and discerning regional variances. Moreover, the inclusion of micro-scale carbon footprint data enables the identification of specific consumption habits, thereby regulating individual consumption behavior to achieve a low-carbon society.

Characteristics and transfer paths of CO2 emissions embodied in trade and China's carbon reduction strategies

This study focused on CO₂ emissions embodied in trade (CEET) to better promote carbon emission reduction given that foreign trade occupied an increasing proportion of the global economy. Based on technical adjustment, CEET balance worldwide during 2006-2016 was calculated and compared to avoid false transfer. This study also explored the influencing factors of CEET balance and identified the transfer pathway of China. Results indicate that developing countries are the major exporters of CEET, and developed countries are CEET importers in general. China is the largest net exporter of CEET and bears a large amount of it for developed countries. Trade balance and trade specialization are important factors of the imbalance of CEET in China. The transfer of CEET between China and the USA, Japan, India, Germany, South Korea, and other countries is relatively active. Agriculture, mining, manufacturing, electricity, heat, gas, water production and supply, and transportation, storage, and postal services are the major sectors, where the transfer occurs in China. Reducing CO₂ emissions requires global cooperation in the context of globalization. Strategies are proposed to deal with imbalances and transfer of CEET issues in China.

How can Chinese metropolises drive global carbon emissions? Based on a nested multi-regional input-output model for China

Given metropolises' participation in complex regional and global trade networks, they have huge demands for vast carbon-embodied intermediate and final goods. To clarify embodied carbon transfers of metropolises in regional and international trade, a metropolis-centered model was constructed by nesting the World's multi-regional input-output table and China's multi-regional input-output (CMRIO) table. Based on this model, we analyzed the multi-scale impact of two typical Chinese metropolises, namely Beijing and Shanghai, on global carbon emissions. Structural decomposition analysis and social network analysis (SNA) were used to explore the driving factors of consumption-based carbon (CBC) and the roles of metropolises in the carbon networks. Results showed that both Beijing and Shanghai are net embodied carbon consumers, which respectively drove 231.19 and 219.52 Mt global carbon emissions in 2017. These figures were underestimated by 12.54 % and 15.41 % when using the CMRIO. After China's economy entered a new normal, instead of technological progress, structural adjustment became the prominent factor driving the CBC reduction of metropolises. During 2012-2017, the consumption structure optimization reduced 18.87 and 32.48 Mt CBC in Beijing and Shanghai, respectively. Compared with other domestic regions, the CBC of Beijing has continued to increase, whereas that of Shanghai has declined. At the international scale, the combined net carbon emission imported by the two metropolises was 88.43 Mt in 2017, equivalent to 18.09 % of China's total carbon deficit. This indicates that metropolises have become pioneering regions for China to alleviate the carbon deficit in international trade. By using SNA, we further found that both metropolises are crucial carbon consumers in the global carbon network, with strong stability and obvious hub roles. Furthermore, various urban functions and geographical locations form the heterogeneous structural characteristics of CBC in the two metropolises, highlighting the need for different strategies for embodied carbon mitigation in these metropolises.

Water footprint of nations amplified by scarcity in the Belt and Road Initiative

The growing water scarcity due to international trade poses a serious threat to global sustainability. Given the intensified international trade throughout the Belt and Road Initiative (BRI), this paper tracks the virtual water trade and water footprint of BRI countries in 2005-2015. By conducting a multi-model assessment, we observe a substantial increase in BRI's water footprint after taking water scarcity into account. Globally the BRI acts as a net exporter of virtual water, while the export volume experiences a decreasing trend. Noticeable transitions in nations' role (net exporters vs. net importers) are found between the BRI and global scales, but also between with and without considering water scarcity. Overall economic and population growth is major drivers of scarcity-weighted water footprint for BRI nations, as opposed to the promotion of water-use efficiency and production structure that can reduce water scarcity. Improving international trade and strengthening cooperation on water resources management deserve priority in alleviating the water scarcity of BRI.

Horizontal CO2 Compensation in the Yangtze River Delta Based on CO2 Footprints and CO2 Emissions Efficiency

PURPOSE

In this study, we attempted to reduce the negative economic externalities related to Carbon Dioxide (CO2) emissions in the Yangtze River Delta region (YRD) and designed a cross-municipality responsibility-sharing mechanism.

METHODS

We estimated the municipal CO2 footprints in the YRD from 2000 to 2019 based on nighttime light data and measured CO2 emissions efficiency using a super slack-based measurement (super-SBM) model. Based on this, we designed a scenario of horizontal CO2 compensation among the YRD's municipalities from the perspectives of both CO2 footprints and CO2 trading (CO2 unit prices in trading were determined based on CO2 emissions efficiency).

RESULTS

The results showed the following: (1) The CO2 footprints evolution of the YRD municipalities could be divided into four categories, among which, eleven municipalities showed a decreasing trend. Thirteen municipalities stabilized their CO2 footprints. Thirteen municipalities exhibited strong growth in their CO2 footprints, whereas four municipalities maintained a low level of slow growth. (2) Spatially, CO2 emissions efficiency evolved from a broad distribution of low values to a mosaic distribution of multi-type zones. (3) After 2011, the ratio of CO2 footprint compensation amounts to local Gross Domestic Product (GDP) in most municipalities was less than 0.01%, with its center of gravity shifting cyclically. It was appropriate to start charging the CO2 footprint compensation amounts after 2011, with a dynamic adjustment of 3 years. (4) After 2007, the supply-demand relationship of CO2 trading continued to deteriorate, and it eased in 2016. However, its operational mechanism was still very fragile and highly dependent on a few pioneering municipalities.

INNOVATIONS

In this study, we designed a horizontal CO2 compensation mechanism from the binary perspective of CO2 footprints and CO2 trading. In this mechanism, the former determines the CO2 footprint compensation amounts paid by each municipality based on whether the CO2 footprint exceeds its CO2 allowance. The latter determines the CO2 trading compensation amounts paid by the purchasing municipalities based on their CO2 emissions efficiency. This system balances equity and efficiency and provides new ideas for horizontal CO2 compensation.

Towards low-carbon domestic circulation: Insights from the spatiotemporal variations and socioeconomic determinants of emissions embedded within cross-province trade in China

For a country like China with unbalanced development pattern among provinces, domestic circulation (i.e., cross-province trade) is important for the long-term stability and prosperous development of economic market. However, with the rapid advance of integration of domestic regional economy, while expanding the internal market scale and deepening the provincial division of labor network for promoting the economic growth, the carbon emissions embedded within the cross-province traded products and services cannot be underestimated. Under the background of climate-trade dilemma, it is necessary to exploring the spatiotemporal variations and socioeconomic determinants of provincial "invisible" carbon emissions for a better understanding of trade-induced eco-environmental effects. To that end, this study developed an environmental-economic system model through integrating the environmentally extended multiregional input-output method and weighted average structural decomposition analysis technique to explore the trade-related emissions at the provincial level and generate the mitigation-management strategies for decisionmakers. Overall, more than half the emissions were embedded within cross-province goods and services trade over the whole study period. Furthermore, the distribution of traded emissions showed obvious spatial heterogeneity and great unbalance was existed between provincial imports and exports. Among all provinces, carbon surplus provinces were always more than deficit ones and the trading patterns of approximately 65% regions remained unchanged during 2007-2017. Remarkably, the emissions trading pattern undergone transition from carbon deficit to carbon surplus in provinces like Henan, Hubei, Guizhou, and so on. Conversely, provinces like Jilin, Shanghai, and Xinjiang showed opposite change. With the prevalence of online payment and electronic commerce in the future, the central and sub-national government could consider launching a pilot project for the design and creation of personal carbon consumption account in the carbon surplus provinces such as Guangdong, Henan, and Jiangsu. Meanwhile, for the provinces with larger carbon exports, it is necessary to establish the horizontal high technical transfer channels and vertical compensation mechanisms such as financial subsidies for improving the low-carbon production level. Our findings provided a holistic depict of national traded emissions at the provincial level, highlighting the importance of cross-province emission effect in exploring ways to promote the low-carbon transition of domestic circulation and fulfill the high-quality development of 'dual circulation' new pattern and successful achievement of 'double carbon' solemn commitment.

Carbon Footprint Research Based on Input-Output Model-A Global Scientometric Visualization Analysis

Reducing the effect of mankind's activities on the climate and improving adaptability to global warming have become urgent matters. The carbon footprint (CF), derived from the concept of ecological footprint, has been used to assess the threat of climate change in recent years. As a "top to bottom" method, input-output analysis (IOA) has become a universally applicable CF assessment tool for tracing the carbon footprint embodied in economic activities. A wide range of CF studies from the perspective of the IOA model have been presented and have made great progress. It is crucial to have a better understanding of what the relevant research focuses on in this field, yet so far a systematic synopsis of the literature is missing. The purpose of this paper is to explore the knowledge structure and frontier trends in respect of the IOA model applied to CF research using scientometric visualization analysis. The main findings of this paper are as follows. (1) Published articles show a two-stage increase in the period 2008 to 2021, and present a complex academic network of countries, authors, and institutions in this important domain. (2) The classic studies are mainly divided into three categories: literature reviews, database application introduction, and CF accounting in different scales. (3) The research hotspots and trends show that the research scales tend to be more microscopic and applications of models tend to be more detailed. In addition, supply-chain analysis and driver-factor analysis will probably become the main research directions in the future.

Comparative Study in Software and Healthcare Industries between South Korea and US Based on Economic Input–Output Analysis

In the modern era, software technology is being used not only as a core technology for manufacturing but also in various industries, such as telemedicine services, and the importance of the healthcare industry is being emphasized due to the demand for improved quality of life from the increase in the general level of earnings. However, if the industry emits a lot of carbon dioxide (CO2), it is questionable whether it is a sustainable industry. This study aimed to analyze the economic linkage effect of software and healthcare industries in South Korea and the United States by applying input–output analysis and examine whether these industries are sustainable in terms of CO2 emissions. The input–output tables and CO2 emissions from 2005 to 2015 were used for analysis from OECD. As a result of the analysis, CO2 emissions from the software and healthcare industries were less than 1% in both South Korea and the United States, suggesting that these industries are well-suited for low-carbon development in these countries. The forward and backward linkage effects of the software industry are different between South Korea and the United States. Specifically, the backward linkage effect of the software industry is large in South Korea, and the forward linkage effect is large in the United States. The forward linkage effect of the healthcare industry is different in the two countries, but the backward linkage effect is not. It means that there are differences in the industrial structure of the two countries. The software and healthcare industries need to devise strategies to drive production in other industries while maintaining current low carbon emission levels.

Pollution Haven Hypothesis of Global CO2, SO2, NOx-Evidence from 43 Economies and 56 Sectors

With the development of trade liberalization, the pollutants emissions embodied in global trade are increasing. The pollution haven hypothesis caused by trade has aroused wide attention. The fragmentation of international production has reshaped trade patterns. The proportion of intermediate product trade in global trade is increasing. However, little has been done to study the pollution haven of different pollutants under different trade patterns. In this paper, major environmental pollutants CO₂ (carbon dioxide), SO₂ (sulfur dioxide), and NO_x (nitrogen oxides) are selected as the research objects. This study investigated the global pollution haven phenomenon in 43 countries and 56 major industries from 2000 to 2014. Based on the MRIO model, the trade mode is divided into three specific patterns: final product trade, intermediate product trade in the last stage of production, and the trade related to the global value chain. The results show that trade liberalization could reduce global CO₂, SO₂, and NOx emissions, and intermediate product trade has a more significant emission reduction effect than final product trade. Trade’s impacts on each country are various, and the main drivers are also different. For example, the European Union avoids becoming a pollution haven mainly through the trade related to the global value chain. The suppressed emissions under this trade pattern are 71.8 Mt CO₂, 2.2 Mt SO₂, 2.2 Mt NO_x. India avoids most pollutants emissions through intermediate product trade. China has become the most serious pollution haven through final product trade. The trade pattern could increase China 829.4 Mt CO₂, 4.5 Mt SO₂, 2.6 Mt NO_x emissions in 2014.