Defined by uneven responsibilities, burdens, and resource distribution in the pursuit of carbon neutrality, carbon emission inequality is simultaneously embedded in global structures of production, consumption, and trade that produce pronounced disparities across regions, sectors, and populations. Despite growing attention, existing studies often rely on national-level data or single accounting perspectives, limiting understanding of regional dynamics and long-term structural drivers. This study addresses these gaps by integrating both production-based and consumption-based emission measures within a regional analytical framework. Employing the Theil index and Index Decomposition Analysis (IDA) from 1995 to 2020, the research decomposed emission inequality into emission intensity, economic structure, and per capita value-added effects, enabling a comprehensive assessment of underlying drivers across five major regions: Asia, Europe, North America, Africa, and South America. Findings reveal a marked decline in global emission inequality, with production-based and consumption-based indices decreasing by 64% and 59%, respectively. Consumption-based inequality remained higher due to the carbon embedded in traded goods, highlighting the role of global supply chains in transferring environmental burdens from developed to developing regions. Emission intensity emerged as the most recurrent driver of inequality in Asia, Africa, North America, and globally, while structural factors dominated in Europe, and per capita value-added was most influential in South America. Regional convergence was observed, particularly driven by industrial growth and efficiency improvements in Asia, though disparities persisted in less industrialized regions.

Abstract Climate change is an emerging global crisis, largely due to the runaway emissions of carbon dioxide (CO₂) through the burning of fossil fuels. The inclusion of carbon capture and sequestration (CCS) into deep saline aquifers has become a promising mitigation strategy; however, the accurate simulation of CO₂ migration and dissolution continues to remain a challenge, owing to the complicated characteristics of subsurface reservoirs. This study expands existing modelling of CO₂ sequestration by integrating with fractional derivatives (involving power-law and exponential kernels) to encompass non-local and anomalous diffusion effects. In contrast to traditional methods, our model incorporates the factors of porous media heterogeneity, spatial variation of permeability, and complex CO₂-brine interaction into the simulation process, thus making it more physics-based in describing subsurface flow. This power-law behaviour is not captured in classical, exponential kernels, highlighting the importance of more sophisticated mathematical approaches when dealing with these types of processes, as demonstrated by numerical simulations. Our findings provide important insights into CO₂ plume dynamics, velocity fields, pressure distribution, injection behaviour, and the security of storage. Here, by evaluating flow stability and leakage risks, we show that permeability fluctuations modulate the efficiency of CO₂ dissolution and long-term containment. The approaches outlined in this paper enhance the confidence in CCS’s efficacy, whilst highlighting the importance of sound site selection, risk assessment, and regulatory regimes to support large volume deployment. This study combines theoretical modelling with practical implementation to provide a more predictable and flexible framework for CO₂ sequestration in heterogeneous geological formations. Ongoing research and innovative modelling will remain critical for delivering a viable pathway for large-scale climate mitigation amidst persisting economic and policy challenges.

This paper introduces TIMES-Europe, a novel integrated multi-sectoral energy system optimization model for Europe based on the TIMES generator. We describe its main specifications and assumptions as well as its underlying methodology, and summarize the type of policy questions that it can help answering. TIMES-Europe can be used to analyze policy instruments designed for implementing the EU Green Deal and Fit-for-55 program, and to create strategic energy decarbonization and climate change mitigation insights for Europe against the backdrop of its interactions and relations with neighboring countries. Thanks to its technology richness across all main sectors—including power production, transport, industry and the commercial, agricultural and residential sectors—it allows for performing in-depth studies on the role of a large range of low-carbon options in the energy transition of all European countries, both jointly and individually. Three characteristics render TIMES-Europe particularly valuable: (1) it covers the entire European energy system and its main greenhouse gas emissions, (2) it includes all EU member states individually as well as a large set of countries in the EU’s vicinity, and (3) it can be used to generate high-level strategic insights as well as detailed recommendations for both national and EU policies. TIMES-Europe is especially suitable for analyzing system integration, which makes it an ideal tool for assessing the implementation of the energy transition and the establishment of a low-carbon economy. We present several research and scenario examples, and characterize opportunities for future energy and climate policy analysis.