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Assuming responsibility for emission reduction is an important part of participating in the global governance of climate change. Countries with a carbon neutrality target now cover about 75% of global greenhouse gas emissions. Carrying out fairness evaluations of their carbon neutrality targets provide a strong basis for the global carbon inventory. In this paper, the target years of carbon neutrality for major countries and regions under the global target of 2 °C and 1.5 °C are studied using the burden sharing model. On this basis, this paper simulates the possible pathways of carbon neutrality and evaluates the ambition of emission reduction targets in terms of annual emission reduction, per capita emission, and cumulative per capita emission. The results show that, from the perspective of equity, most of the developing countries cannot meet the global goal of 1.5 °C. The United States and the European Union nations could achieve carbon neutrality by 2050 by continuing their annual emission reductions under their existing NDC targets. However, to achieve carbon neutrality by 2060, China's annual emission reduction rate from 2030 to 2050 will be 6.7%, and the annual amount of emission reduction accounts for 51% of the global amount under the 1.5 °C target. Meanwhile, China would become the main force behind global cumulative emissions in the following decades. Thus, the emission reduction pathways China chooses will have an important impact on global climate mitigation progress. Based on the above research conclusions, this paper proposes that developed countries and developing countries should explore bilateral or multilateral cooperation in technology and finance in the field of climate change. Under the great pressure to achieve carbon neutrality, China needs to carry out research on the overall emission reduction pathways as soon as possible and clarify the paths at the scale of sectors, industries, provinces, and time stages. [ABSTRACT FROM AUTHOR]

As a complement of production-based accounting (PBA), consumption-based accounting (CBA) provides an alternative perspective to understand national emissions and responsibilities for global climate change. Existing studies assessed historical national emissions under CBA. However, how CBA might guide future mitigation under the Paris Agreement goals has not been well understood. By combining global multi-region input-output analysis and the equity principle of 'equal cumulative per capita emissions' (ECPCE), this study explores potential implications of CBA for future national emissions budgets to limit global warming to below 1.5°C. Historically, consumption-based greenhouse gas (GHG) emissions were higher than production-based emissions in most developed countries while lower in many developing countries. When CBA is used instead of PBA to allocate emissions budgets by ECPCE, future GHG mitigation burdens would become more stringent in 70% of Annex I (mostly developed) countries but slightly smaller in 55% of non-Annex I (mostly developing) countries. In particular, more than half of Annex I countries might need to achieve negative GHG budgets under 1.5°C. Our analysis emphasizes that, as net emission importers, developed countries could strive to pay equal attention to achieving consumption-based and production-based emissions reductions, and strengthen technological and financial support to developing countries that undertake production outsourcing. As net emission exporters, with international support and domestic investment, developing countries could pragmatically promote energy structure optimization and technological innovation to accelerate the decarbonization of production. To support the Paris Agreement goals, mitigation contributions initiated from the perspective of CBA could also be welcomed. Key policy insights Developed countries shift emissions to developing countries through international trade. CBA increases historical responsibilities of developed countries for climate warming from the PBA assessments. Compared to PBA, CBA has clear implications on future national emissions budgets under responsibility-based allocations, but does not change the urgency of national mitigation required to achieve the Paris Agreement goals. Allocated by ECPCE, future GHG budgets for over 50% of the world's countries would be run out before 2040 under 1.5°C at the 2015 emissions rates, using either CBA or PBA. According to different roles in global supply chains, developed countries should step up support to help developing countries improve emissions and energy intensities, which is a key to reducing emissions embodied in trade. [ABSTRACT FROM AUTHOR]

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Transportation plays an important role in achieving deep decarbonization. This paper examines how the sector might be decarbonized in China in light of three national decarbonization scenarios toward the Paris Agreement goals, using Global Change Assessment Model 4.0 (the Tsinghua University version), which includes a detailed representation of China's transportation. Results indicate that while barely affected by meeting the Nationally Determined Contribution, China's transportation sector might need significant changes beyond 2030 to decouple associated CO 2 emissions from GDP growths. Supporting national mitigation has more pronounced implications on freight than passenger transport services, and arouses a radical shift of transport fuels away from fossil-based liquids to clean alternatives. Decarbonizing China's transportation toward 1.5 °C is in many aspects similar to toward 2 °C, but lowers final energy use and ramps up clean fuels at an observably higher pace. In our 1.5 °C scenario, oil-refined liquids tend to phase out in the second half of the century, whereas clean fuels provide 62% (18–36% in 2 °C scenarios) and 98% (68–91% in 2 °C scenarios) of China's transport energy by 2050 and 2100, respectively. Fuel carbon intensity improvements are responsible for the majority of China's transport mitigation in our decarbonization scenarios, followed by energy intensity improvements and transport service reductions. [ABSTRACT FROM AUTHOR]

China's 2060 carbon neutrality requires the industrial sector to play a leading role in decarbonization. By refining China's industrial sector into 11 specific subsectors in the Global Change Analysis Model and representing industrial carbon capture and storage (CCS) and hydrogen, this study conducts a sub-sectoral analysis of China's industrial decarbonization under three carbon neutrality scenarios and explores the potential role of CCS and hydrogen. Regardless of the scenario, the results show that China's industrial CO 2 emissions peak during the 14th Five-Year Plan period, with a reduction of about 90% in 2050 compared to 2020; electricity becomes the primary energy for China's industrial sector by around 2035, with industrial electrification reaching about 64% in 2050, while coal and oil change from fuel to feedstock. Tapping the mitigation potential of cement, steel, and chemical is a fundamental requirement for China's industrial decarbonization, while further deeper mitigation requires more additional efforts in other subsectors. Cement, steel, and chemical need to reach peak CO 2 by the 14th Five-Year Plan period, and together they are responsible for 83–85% of total industrial emissions reductions from 2015 to 2050. An important way to reduce emissions from these three subsectors is to reduce energy consumption. The other industrial subsectors are expected to reach peak CO 2 by the 15th Five-Year Plan period. Increasing the electrification rate is a key way to reduce emissions in other subsectors. CCS and hydrogen can play an important role in decarbonizing China's industrial sector. In the scenarios of this study, the annual deployment of CCS in China's industrial energy use exceeds 0.3 GtCO 2 in 2035–2040, while hydrogen provides 5.2–10.4% of total industrial energy use in 2050. [Display omitted] • China's sub-sectoral industrial decarbonization is assessed under carbon neutrality. • China's 2050 industrial CO 2 reduces to about 90% below 2020 levels. • Tapping mitigation potential of cement, steel and chemical is a basic requirement. • Electricity becomes the primary industrial energy by around 2035. • Carbon capture and storage and hydrogen can play an important role. [ABSTRACT FROM AUTHOR]

Climate change present a range of equity issues for human being, but operating the equity principle within emission allocation scheme to various parties has raised multiple challenges. Although more than 40 schemes have been suggested in the literatures, there is little consistency in the way that baselines, scope, coverage and other key parameters have been compared or discussed. In this paper, we reviewed 41 schemes used in the literature so far and compared the cumulative allowances of main countries under various schemes in a consistent framework. Two cases are considered, i.e. only energy and industry related CO 2 and all Kyoto GHGs. Besides the allowances, carbon Gini coefficient in the global perspective and the reduction tradeoffs between country groups are further quantitatively discussed. It is demonstrated that the full ranges of countries’ allowances are quite large resulting from different equity considerations and implement methods behind different effort-sharing schemes. However, absolute mitigations are always required in developed countries in order to realize the 2 °C target, regardless of schemes. [ABSTRACT FROM AUTHOR]

In the long-term stabilization targets of greenhouse gases concentrations, various carbon emission rights allocation schemes have been proposed. To compare and evaluate them, the most essential is the equity-efficiency tradeoff. This paper measures the equity and the efficiency in the global rather than the narrower national perspective. Specifically, the equity of the first allocation is quantified by the carbon Gini coefficient defined by per capita cumulative emission, and the economic efficiency to accomplish obligations is described with the discounted global abatement costs. Under 20 key allocation schemes, the numerical comparison on the equity-efficiency tradeoff side is carried out through the Equitable Access to Sustainable Development model. Our studies indicate that the equity and the efficiency of future emission space allocation approximately show a three-stage relationship. [ABSTRACT FROM AUTHOR]

Highlights: [•] An allocation scheme based on equal per capita cumulative emission is presented. [•] This scheme enables the considerations of different historical responsibilities. [•] Country-specific trajectories are adjusted according to the global emission pathway. [•] Allowances and peaking years are quantitatively analyzed. [•] This new allocation scheme is compared with five others. [ABSTRACT FROM AUTHOR]

China's oil and gas consumption, which is not only significant to the industry but also related with national energy security, faces uncertainties in the future. This paper analyzes China's oil and gas consumption under five representative scenarios toward 2050 using an integrated modeling. In the Nationally Determined Contribution (NDC) scenario, China's oil consumption peaks at 705 million tons by 2035, and gas consumption ramps steadily up to reach 780 billion cubic meters by 2050. Oil provides 18% of China's primary energy by 2030 and 15% by 2050, and gas 14% by 2030 and 17% by 2050. The 2 °C and the 1.5 °C scenarios control China's 2050 oil consumption to 10% and 45% below the NDC level, respectively. Interestingly, more stringent mitigation tends to upscale China's gas consumption before 2040. Compared with the NDC scenario, the oil-price scenarios present limited influences on China's total energy consumption and end-use electrification but mainly feature a substitution between oil, gas and coal, non-fossil energy. Particularly, across our scenarios, China's oil import dependence is projected to largely fluctuate around 70% toward 2050, and gas import dependence to reach 50–60% beyond 2030, implying a continuously high risk of energy resource supply and national energy security. • China's oil and gas consumption is analyzed using an integrated modeling. • Oil consumption is estimated to peak by 2035 at 705 mtoe in the NDC scenario. • More stringent mitigation requires more gas consumption before 2040. • Oil and gas tend to still play an important role in the coming three decades. • Import dependence implies a continuously high risk of national energy security. [ABSTRACT FROM AUTHOR]

Combating global climate change calls for all countries to accelerate emissions reductions, and equity is an important guiding principle. A new indicator – the carbon Palma ratio, extended from the income Palma ratio and defined as the ratio of the total emissions of the top 10% emitters to those of the bottom 40% – is proposed, which provides a new perspective to inform the international community and the public of the distribution inequality of carbon emissions among individuals. The ratio is quantified within and across countries, by applying an elastic relationship between individual emissions and income. Results show that the carbon Palma ratios within most developing countries are overall high, suggesting them to focus more on coordinating regional and income differences and mainly guide high emitters to mitigate, so as to improve emissions and income equity simultaneously. The carbon Palma ratios within developed countries are comparatively smaller; however, the greater historical responsibilities to warming suggest them to substantially reduce emissions of all citizens, so as to enhance national mitigation contributions systematically. At a global scope, the current carbon Palma ratio is observably higher than within any country, reflecting an extremely severe inequality when looking at individual emissions beyond territorial limitations. The regional decomposition of emitters further suggests developed countries to take the lead in the post-Paris era in ratcheting up mitigation and climate finance ambition. Image 1 • Carbon Palma ratio is proposed to measure individual emissions inequality. • The ratio provides a new perspective to quantify and inform inequality. • The ratios in developed countries are overall lower than in developing countries. • The global ratio reflects an extremely severe inequality across the world. • Decomposition suggests developed countries to enhance mitigation and finance. [ABSTRACT FROM AUTHOR]

Various policies on electric vehicles (EVs) have been implemented in Beijing to promote EV diffusion, but previous research has rarely considered the indirect network effects between EVs and EV charging infrastructures (EVCIs), and has not explored the impact of EVCI-related incentives on EV diffusion. This study aims to enrich the literature by incorporating EVCI development and indirect network effects in EV diffusion. A system dynamic model is proposed to systematically analyse the interactions among consumer, EV manufacturer and EVCI operator and simulate EV diffusion and ECVI investment in Beijing. Multiple scenarios are adopted to investigate the joint effects of the policy mix on EV diffusion. The results indicate that the oil-to-electricity subsidy promoted EVs and EVCIs to a greater extent than the license plate control policy. The EVCI maintenance policy outperformed EVCI construction and production subsidies on EV diffusion. Synergistic effects exist when the oil-to-electricity subsidy is mixed with EVCI-related incentives. This study provides implications for policymakers to promote EV diffusion with innovative and efficient policy instruments. [ABSTRACT FROM AUTHOR]

Understanding the drivers of CO2 emissions changes is useful in supporting future mitigation. This study applies a log-mean divisia index decomposition to assess four drivers of CO2 emissions changes – population, income, energy intensity and carbon intensity – in 138 countries worldwide over the period 2000–2017. At the global level, income and population are the main drivers of increased emissions over time, with contributions of 116% and 60% to global CO2 emissions changes, respectively. Energy intensity is the key mitigation driver, with a contribution of −80%. Although carbon intensity increased CO2 emissions overall over the period 2000–2017 with a contribution of 4%, it has started to reduce emissions in recent years. China, the United States of America, the European Union, India and Russia are the five regions responsible for most changes in global emissions. The five regions together contribute −73% of the energy intensity effect, and China's income contribution is 83% in relation to the total of 116%. At the national level, in 2017, CO2 emissions returned to below 2000 levels in 62% of Annex I (developed) countries but increased in 88% of non-Annex I (mostly developing) countries. Among the 35 countries realizing CO2 emissions reductions, 24 were driven primarily by energy intensity, six by carbon intensity, three by economic recession, and one by population decrease. Among the 103 countries with increasing CO2 emissions, 63 were driven primarily by income, 26 by population, nine by carbon intensity increase, and five by energy intensity increase. Our analysis emphasizes the necessity of considering differences in national development stages when formulating climate change mitigation policies. Key policy insights Over the period 2000–2017, at the global and national levels, CO2 emissions increases were driven mainly by economic development and population growth, and mitigation was driven mainly by energy intensity improvement. Improving energy intensity and carbon intensity is the key to mitigating CO2 emissions. Carbon intensity is expected to play an increasing role in the future. In over one-third of Annex I countries, CO2 emissions increased from 2000 to 2017. To meet the Paris Agreement goals, Annex I countries will need to enhance mitigation ambition by further tapping the mitigation potentials of energy and carbon intensity. In accordance with national circumstances, development needs and international support, non-Annex I countries should achieve low-carbon economic and energy transitions and peak CO2 emissions as early as possible. [ABSTRACT FROM AUTHOR]

Decarbonizing road transport is important for China to achieve carbon neutrality. Road transport decarbonization requires rapid deployment of new energy vehicles, especially electric vehicles, expanding demand for critical battery minerals including lithium, cobalt, and nickel. By constructing a novel bottom-up framework that combines Low Emissions Analysis Platform and Vehicle Critical Mineral Demand model, this study assesses China's road transport decarbonization pathways and critical battery mineral demand under three illustrative scenarios. Results show China's vehicle stock peaking at 528 million in 2045 and remaining saturated through 2060. Except for diesel-fueled trucks, China's internal combustion engine vehicles are completely phased out around 2050–2055. Share of oil-derived fuels in China's road transport energy declines, while share of electricity and hydrogen increases significantly, with electricity and hydrogen together accounting for 57–88% in 2060. China's road transport CO 2 peaks at 977–1,083 Mt in 2028–2032, declining to 62–282 Mt in 2060, with private vehicles, light- and heavy-duty trucks as core mitigation areas. Cumulative demand for lithium, cobalt, and nickel from electric-vehicle batteries is estimated at 16.1–19.6 Mt LCE, 0.4–0.55 Mt and 3.3–4.3 Mt by 2060, respectively, indicating a challenge for China's local mineral supply. Recycling reduces cumulative demand for primary lithium, cobalt, and nickel resources by over 30%, 60% and 60%, respectively. [ABSTRACT FROM AUTHOR]

Developing countries usually face the twofold challenges of poverty eradication and carbon emissions reduction. How to reduce carbon emissions while achieving poverty eradication has become a headache for governments. In 2020, China announced its victory in poverty eradication. In the battle against poverty, Chinese listed companies have made meaningful contributions by actively investing in poverty reduction projects. However, the impact of their poverty reduction investments on carbon emissions in poor regions is not clear. This study empirically investigates this question using a difference-in-difference model and manually obtains data on poverty reduction investments in 592 counties in China from 2014 to 2017. Results find that Chinese listed companies' poverty reduction investments do help poor counties improve their carbon emissions efficiency, reflecting the possibility of synergy between poverty eradication and emissions reduction in developing countries. According to the mediation test, listed companies' poverty reduction investments improve the carbon emissions efficiency in China's poor counties through increasing green total factor productivity. In addition, results show that the improvement is more pronounced by strengthening government supervision, establishing economic development industries, and investing in counties with high ecological protection requirements and low per capita income. [Display omitted] • Effect of listed companies' poverty reduction investments on emissions is tested. • A DID model is used to assess effect on poor regions' carbon emissions efficiency. • We use country-level data in China and conduct a number of robustness tests. • Poverty reduction investments improve poor regions' carbon emissions efficiency. • Green productivity is an intermediary to improve carbon emissions efficiency. [ABSTRACT FROM AUTHOR]

To support the achievement of the Paris Agreement's 1.5 °C global warming threshold, China aims to peak CO 2 emissions before 2030 and achieve carbon neutrality before 2060. However, the specific carbon neutrality pathway remains to be designed. By applying a refined Chinese version of Global Change Analysis Model, this study examines implications of four illustrative carbon neutrality scenarios for aligning China's energy system with below 1.5 °C by 2100. The results feature a trade-off between China's ambition to transform its energy system toward mid-century and its reliance on carbon dioxide removal (CDR) after carbon neutrality. From a full time perspective until 2100, accelerating carbon neutrality could help China's energy system align with below 1.5 °C. Compared to a 2060 carbon neutrality scenario, a 2050 carbon neutrality scenario reduces China's total mitigation costs between 2021 and 2100 by 1.04% of GDP, reduces reliance on CDR by 36%, and provides some additional co-benefits, such as reduced air pollutants. However, special attention needs to be paid to the fact that accelerating carbon neutrality poses greater challenges and costs to China in overcoming development inertia and restructuring its energy system over the next 30–40 years. Compared to a 2060 carbon neutrality scenario, a 2050 scenario increases China's mitigation costs by a factor of 1.13 between 2021 and 2050. This study suggests through quantitative evidence that China could accelerate emissions reductions and energy system transformation to achieve carbon neutrality, based on its national circumstances and capabilities and international support. • Implication of carbon neutrality for China's energy system under 1.5 °C is explored. • Four illustrative carbon neutrality scenarios are assessed by integrated modelling. • Trade-off between energy transition to mid-century and reliance on CDR is shown. • AcCelerating carbon neutrality reduces China's mitigation costs to align with 1.5 °C. • China could consider accelerating transition and pursuing early carbon neutrality. [ABSTRACT FROM AUTHOR]

The successful market penetration of electric vehicles (EVs) is subject to the capacity of charging infrastructure, and the development of charging infrastructure is mainly driven by economic incentives. This study analyzes the advantages of crowdfunding financing for promoting the construction of electric vehicle charging piles compared with other incentive methods. A three-level Stackelberg game is proposed to model the interactions between the electricity supplier, the charging infrastructure operator and crowdfunders. The results indicate that crowdfunding is an effective and efficient way to promote the penetration of charging piles, since it has the same effect as supplying a 20% subsidy with regards to the promotion of charging pile installation. Theoretical analysis finds that crowdfunding’s performance is affected by crowdfunders’ risk attitude, and less risk-averse crowdfunders have stronger incentives for charging piles investment. Sensitivity analysis is conducted on crowdfunding’s performance in terms of repayment rate, unit construction cost, charging volume and risk tolerance. The results show that the effect of crowdfunding is most sensitive to construction cost, and when unit construction cost decreases from 0.03 to 0.01 USD/(watt · year), the total annual construction quantity under crowdfunding model increases from 18.8 MW to 56.6 MW, which provides managerial insights for the government to promote charging infrastructure related technologies. [ABSTRACT FROM AUTHOR]

To reduce traffic congestion and protect the environment, license plate control (LPC) policy has been implemented in Beijing since 2011. In 2019, 100,000 vehicle license plates were distributed, including 60,000 for electric vehicles (EVs) and 40,000 for gasoline vehicle (GVs). However, whether the current license plate allocation is optimal from a social welfare maximization perspective remains unclear. This paper proposes a two-level Stackelberg game, which portrays the interaction between vehicle applicants and the government to quantify the optimal number of EV license plates under the LPC policy in Beijing. The equilibrium number of EV license plates derived from the Stackelberg model is 58,800, which could increase the social welfare by 0.38%. Sensitivity analysis is conducted to illustrate the impact of important influential factors — total license plate quota, vehicle rental fee, and energy price — on EV adoption. The LPC policy under COVID-19 is also studied through a scenario analysis. If the government additionally increases the total quota by 20,000, 24% could be allocated to GV and 76% to EV. One third reduction of the current vehicle rental fee could increase EV license plates by 10.5%. In terms of energy prices, when gasoline price is low, reducing electricity prices could contribute to EV adoption significantly, while that effect tapers off as gasoline prices increase. • The optimal license plate allocation between EVs and GVs in Beijing is analyzed. • A Stackelberg game is proposed to model stakeholders' interaction under LPC policy. • The optimal license plate allocation policy under COVID-19 is also studied. • One third reduction of vehicle rental fee could increase EV adoption by 10.5%. [ABSTRACT FROM AUTHOR]

As a major technical route to utilize biomass energy, biomass combustion power generation (BCPG) has been shown to be of environmental and economic significance. According to the operating experience, the installed capacity has a decisive impact on the operation and economic return of BCPG projects. In China, an installed capacity of either 30 MW or 12 MW is often chosen for constructing a BCPG project. To explore which one is more suitable for China, this paper uses actual operating data to compare the operation performance and techno-economics of two representative BCPG projects with an installed capacity of 30 MW and 12 MW. The results show that the operation situation and electricity production of the 30 MW project are better than those of the 12 MW project. The 30 MW project has a lower biomass consumption than the 12 MW project to produce per unit of electricity. The Internal Rate of Return (IRR) of the 30 MW project is greater than the industry benchmark in China and is almost three times the IRR of the 12 MW project. Therefore, it is recommended to construct BCPG projects with installed capacity of 30 MW in China. [ABSTRACT FROM AUTHOR]

With the increasing competition for limited metal ore resources, nexus between economics society and mineral resource utilization has been studied broadly. However, the driving forces and pathways of metal footprint change still haven't been fully understood. Therefore, in the present study, the additive structural decomposition analysis based on an environmental input-output model is adopted to decompose the world metal footprint from 1995 to 2013 into five major driving factors: metal consumption intensity effect, production structure effect, category effect, consumption patterns effect and consumption volume effect. The obtained results indicate that: i) the modern production structure has been becoming increasingly dependent upon metal resources; ii)the production structure effect and consumption volume effect are dominant factors driving the metal footprint increase, yet the metal consumption intensity effect is the main force offsetting this inclining trend; iii) distinct patterns can be observed among different kinds of metals due to the production structure effect; iv) all the driving factors in developing countries tend to be more divergent comparing with developed countries consistent with their economic growth characteristics. The findings of this study are significant for policy makers to understand the deep causes for domestic metal footprint change and propose proper relevant polices. [ABSTRACT FROM AUTHOR]

• The Stackelberg game theoretical models of recycling retired EV batteries are established. • The social-economic-environmental impacts of three recycling mechanism are analyzed. • The reward-penalty mechanism presents greater effects on recycling rate. • The minimum recycling rate is the key factor for social-economic-environmental impacts. With the increasing popularity of Electric Vehicles (EVs), a large number of EV batteries are intensively reaching their end-of-life, which has posed substantial challenges in ecological protection and sustainable development. However, the traditional subsidy mechanism is not effective in the current recycling market. Moreover, it is not conducive for guiding the EV industry to reduce dependence on the governmental financial support. As the reward-penalty mechanism has been successfully applied in similar fields, such as the recycling of waste portable batteries, it is expected to become a feasible alternative policy to promote the recycling of retired EV batteries. Therefore, this study aims to investigate the social-economic-environmental impacts of recycling retired EV batteries under reward-penalty mechanisms by developing a Stackelberg game theoretical model. Three scenarios are proposed and compared: S1 no policy intervention, S2 subsidy mechanism, and S3 reward-penalty mechanism. The obtained results show that:(i) Compared with the subsidy mechanism, the reward-penalty mechanism presents greater effects on recycling rate and the social welfare; (2) Under the subsidy mechanism, consumer surplus and the profit of EV manufacturer are two main driving factors of the social welfare. Under the reward-penalty mechanism, the reduced environmental burden tends to be another key contribution; (3) A relatively low minimum recycling rate favors the environmental benefit, consumer surplus and profit of EV manufacturer, while a relatively high minimum recycling rate is beneficial to reduce both the policy implementation cost and environmental burden caused by untreated EV batteries. [ABSTRACT FROM AUTHOR]