Search

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]

Global climate change mitigation needs all countries’ efforts under the United Nations Framework Convention on Climate Change’s guideline of equity and common but differentiated responsibilities and respective capabilities. The medium-to-long term regional emissions pathways simulated by integrated assessment models with global mitigation costs minimized to achieve the 2 °C goal might be very different from the regional emissions allowances allocated based on effort-sharing principles. Global carbon trading is a cost-effective mechanism to bridge the gap. Insight of previous papers has mainly focused on the impact of a single effort-sharing scheme on global carbon market, while this study attempts to explore the scale and benefit of global carbon market under different effort-sharing principles to achieve the 2 °C goal, with the application of a consistent modeling framework, consisting of an integrated assessment model and an effort-sharing platform. The results indicate that scale of global carbon market would be highly related with the effort-sharing principles. The global trading volumes would change from 1.8 Gigatons (Gt) carbon dioxide (CO2) to over 12 GtCO2 per year and largely peak between 2030 and 2040 under different kinds of effort-sharing principles. Correspondingly, annual global finance flows in the carbon market would increase gradually and reach the scale of hundreds of billions United States (US) dollars since 2020. Global carbon market would lower the abatement costs of developed countries, and the overall global abatement costs would drop by 0.4-2.6% during 2011-2050. The developing countries would not only acquire revenues from global carbon trading but also be provided with an opportunity to accelerate their domestic low-carbon energy transformation, local environmental improvement, job creation, and economic development. Linking national and regional carbon markets to develop global carbon market will be critical to maximize the utility of the market mechanism. [ABSTRACT FROM AUTHOR]

In order to achieve the Paris Agreement goals of keeping the temperature rise well below 2 °C or even 1.5 °C, all countries would need to make fair and ambitious contributions to reducing emissions. A vast majority of countries have adopted reduction targets by 2030 in their Nationally Determined Contributions (NDCs). There are many alternative ways to analyze the fairness of national mitigation contributions. This article uses a model framework based on six equity principles of effort-sharing, to allocate countries’ reduction targets under global emissions scenarios consistent with meeting the Paris climate goals. It further compares these allocations with the NDCs. The analysis shows that most countries need to adopt more ambitious reduction targets by 2030 to meet 2 °C, and even more for 1.5 °C. In the context of 2 °C, the NDCs of the United States of America and the European Union lack ambition with respect to the approaches that emphasize responsibility; China’s NDC projection falls short of satisfying any approach in 2030. In the context of 1.5 °C, only India, by implementing its most ambitious efforts by 2030, could be in line with most equity principles. For most countries, the NDCs would use most of their allowed emissions space for the entire 21 st century by 2030, posing a major challenge to transform to a pathway consistent with their fair contributions in the long-term. [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]

The Kyoto Protocol inspires the idea of establishing emissions trading scheme, regarding economic-effectiveness as a significant factor to achieve reduction targets and meet obligation. With this trend, marginal abatement cost curves (MACCs) have been used in climate policy analysis under general equilibrium framework, and have been proved a valid device to highlight the superiority of ETS. This paper focuses on the comparison of MACCs at industry level in China, derived by us from CGE, GCAM and TIMES respectively. It's clear that there is no dynamic adjustment process in these models, so we use linear interpolation method to introduce carbon tax to simulate actual situation. Meanwhile, we also take data from potential and cost study into account. To make our work more targeted, we pay close attention to energy-intensive industries with high carbon emissions level such as electricity, cement and steel, which are most likely to be covered in carbon market. The results indicate how MACCs change and illustrate why they change, depending on applied methodology and underlying assumptions. As we ignore the indirect effects, for instance, tax distortions and non-financial costs during above simulation, the emissions abatement cost we achieve by using integral calculus won’t be equivalent to real cost. Therefore, it's a wise decision for government department and research institute to be cautious when using MACCs as basis of policy making and academic studies. [ABSTRACT FROM AUTHOR]

Towards a low carbon world, the global emission space in the future will be very restricted, which will have a significant impact on the deployment of energy infrastructure system. A low carbon energy system will be the key to achieve 2 degrees trajectory. This paper addresses this issue by combining the Equitable Access to Sustainable Development model (EASD) and the Global Change Assessment model (GCAM) to analyze the development of regional energy consumption and power generation in the process of combating climate change. GCAM, a dynamic-recursive integrated model, has divided the world into 14 regions. Under the long term targets resulting in harmonized radiative forcing levels, the carbon constraints of all regions are quantified in EASD through the allocation based on the per capita, the convergence and the status-quo basis, respectively. These constraints are then set as the policy scenarios in GCAM simulations. The findings underline the substantial reductions in coal consumption and huge growth in renewable energy and nuclear in all regions. The fossil fuel consumption of developed regions has to plummet at once on the per capita basis and peak before 2020 on both the convergence and the status-quo basis. In developing regions, the nuclear and the coal/gas with carbon capture and storage (CCS) gradually dominate the power supply. CCS and nuclear are the two main technology choices for electricity generation in developed regions. [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]

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]