To slow down climate warming and achieve sustainable development, the Paris Agreement attempts to establish cooperative approaches (Article 6.2 in the Paris Agreement) and a sustainable development mechanism (Article 6.4 in the Paris Agreement) for carbon trading. However, deficiencies in implementation exist due to a lack of systematic execution regulations and an integrated management system. To strengthen the effectiveness of the two carbon trading mechanisms for reducing carbon emission, this paper aims to propose an implementation framework of cooperative approaches and a sustainable development mechanism. Based on the international regime theory in global climate change and the nine elements of the market mechanism, the paper makes use of comparative analysis to discuss the type of mechanism, coverage of the system, operational framework, governance framework, and implementation framework of cooperative approaches and a sustainable development mechanism. The main results and conclusions are as follows: (1) Cooperative approaches are considered as project-based and quota-/credit-based carbon market mechanisms. Under cooperative approaches, trading units should be authorized at the international-regional and sub-regional levels. CO₂, CH₄, N₂O, HFCs, PFCs, SF₆, and NF₃ are the seven types of greenhouse gases that could be traded through cooperative approaches, and they shall be accounted by the unit of CO₂-eq. (2) The sustainable development mechanism is considered as an industry-based and credit-based carbon market framework. Under the sustainable development mechanism, trading units should be authorized at the international level. CO₂, CH₄, N₂O, and PFCs can work in the sustainable development mechanism as subject matters. The unit of gases shall be CO₂-eq as well. (3) The implementation framework of cooperative approaches ought to follow three stages: project preparation, project submission, and auditing, as well as internationally transferred mitigation outcomes transfer. The implementation framework of the sustainable development mechanism ought to contain three stages: project development and review, project implementation and monitoring, and project acceptance and unit transfer. The authors hope it can work as a guideline for the early implementation stage of the cooperative approaches and sustainable development mechanism to stimulate carbon reduction and further slow climate change.

The process of coal-to-methanol conversion consumes a large amount of energy, and the use of the co-production method in conjunction with carbon capture, utilization, and storage (CCUS) technology can reduce its carbon footprint. However, little research has been devoted to comprehensively assessing the carbon footprint of the coal-to-methanol (CTM) co-production system coupled with CCUS-enhanced oil recovery technology (CCUS-EOR), and this hinders the scientific evaluation of its decarbonization-related performance. In this study, we used lifecycle assessment to introduce the coefficient of distribution of methanol and constructed a model to calculate the carbon footprint of the process of CTM co-production of liquefied natural gas (LNG) as well as CTM co-production coupled with CCUS-EOR. We used the proposed model to calculate the carbon footprint of the entire lifecycle of the process by using a case study. The results show that the carbon footprints of CTM co-production and CTM co-production coupled with CCUS-EOR are 2.63 t CO₂/tCH₃OH and 1.00 t CO₂/tCH₃OH, respectively, which is lower than that of the traditional CTM process, indicating their ability to achieve environmental sustainability. We also analyzed the composition of the carbon footprint of the coal-to-methanol process to identify the root causes of carbon emissions in it and pathways for reducing them. The work described here provided a reference for decision making and a basis for promoting the development of coal-to-methanol conversion and the CCUS industry in China.

Current evaluations of carbon emission efficiency in China’s provincial power industry often neglect the impact of carbon transfers from inter-regional power transmission, leading to biased assessments that hinder the sustainable development of the energy transition. To address this, we propose an advanced efficiency evaluation model that incorporates a multi-regional input–output (MRIO) framework, refining CO₂ emission calculations and correcting parameter deviations in the slack-based measure (SBM) model. This model improves both the precision and fairness of carbon emission efficiency assessments. We apply the MRIO-SBM model to evaluate carbon emission efficiency in the power industry across 30 provinces in China for 2012, 2015, and 2017, revealing the impact of carbon transfers on efficiency. The results indicate that incorporating MRIO improves the precision of SBM evaluations. Significant regional disparities are observed: eastern coastal regions achieve higher efficiencies, while northeastern and western regions typically exhibit lower values, ranging from 0.5 to 0.7. Efficiency evaluations must account for carbon transfer dynamics, as these transfers can lead to overestimations of efficiency by up to 19% in electricity-importing regions and underestimations of approximately 10% in electricity-exporting regions. Furthermore, the findings emphasize the need to foster low-carbon cross-regional collaboration to promote sustainable development in the power industry.

The ecological threshold has not yet formed a unified definition, and there is no definition for “the threshold of the supply and demand of ecosystem services ( Tr _SD )”, leading to no limitation of the negative impact of production and life behavior on the supply and demand of ecosystem services. This study defined and set Tr _SD , and took Urumqi as an example to carry out a case study. Firstly, the concept of Tr _SD was elaborated referred to multiple definitions of the ecological threshold based on “the difference between the supply and demand of ecosystem services ( ES _r )”. Then, the geographical simulation and optimization system- future land use simulation (GeoSOS-FLUS) software was used to simulate future land use. After that, the Land Use and Land Cover (LULC) matrix model was applied to calculate ES _r . Finally, the Tr _SD was determined via the inflection point analysis of ES _r . This study concludes that the proposed Tr _SD and its systematic calculation method are innovative and rational. The results can be used for ecosystem service management and ecological valuation, which helps the sustainability progress of the global.

BackgroundTo slow down climate warming and achieve sustainable development, the Paris Agreement establishes Cooperative Approaches (CAs) and Sustainable Development Mechanism (SDM) for carbon trading. However, deficiencies in implementation exist due to a lack of systematic execution regulations and an integrated management system. The study's primary purpose is to propose a proposal of effective implementation of CAs and SDM for alleviating global warming. Based on international regime theory in global climate change and the nine elements of the market mechanism, the article analyzes the type of mechanism, coverage of the system, operational framework, and governance framework of CAs and SDM. The paper combines the operational framework with the governance framework to form an implementation framework of CAs and SDM, developing the nine elements of the market mechanism.ResultsCAs are considered as project-based and quota-/ credit-based carbon market mechanisms. Under CAs, trading units should be authorized at the international-regional/ sub-regional level. CO₂, CH₄, N₂O, HFCs, PFCs, SF_6, and NF₃ shall be covered and function as subject matters. The unit of CO₂-eq shall account for them. CAs can transfer verified ITMOs through bilateral/ multilateral cooperation agreements or ITMOs information disclosure platform. The governance of CAs shall keep up with both international and regional/ sub-regional rules and regulations.SDM is an industry-based and credit-based carbon market framework. Under SDM, trading units should be authorized at the international level. CO₂, CH₄, N₂O, and PFCs work in SDM as subject matters. The unit of gases shall be CO₂-eq. SDM is designed to transfer carbon reductions via an industry-level platform. A fully-centralized scenario is suggested as the governance model of SDM.ConclusionsThis study proposes the rules and implementation framework of CAs and SDM, which can work as a guideline for the early implementation stage of CAs and SDM. The implementation framework of CAs ought to follow three stages: project preparation, project submission & auditing, and Internationally Transferred Mitigation Outcomes (ITMOs) transfer. The implementation framework of SDM ought to contain three phases: project development & review, project implementation & monitoring, and project acceptance & unit transfer.