Unequal transitions: Social progress and decarbonization contradictions across 160 countries

Efforts to mitigate climate change through CO₂ emissions reduction must be balanced with achieving social progress sustainably and equitably. Yet, their interlinkages remain insufficiently understood across global contexts. This study uses a multi-method diagnostic to find structural inconsistencies between emissions and social progress across income levels, extending beyond correlation analyses. This study examines the associations between total CO₂ emissions and 55 Social Progress Indicators (SPIs) across 160 countries from 2011 to 2023. Unlike traditional Environmental Kuznets Curve interpretations, this study disaggregates SPI categories to reveal uneven relationships often concealed in aggregate models. Using Spearman correlation, Theil-Sen bootstrapping, and hierarchical clustering, this study identifies trajectory patterns where high-income countries show a larger share of positive correlations (29 %), reflecting alignment between decarbonization and social improvements, particularly in health, education, and environmental quality. Nevertheless, contradictions persist in areas such as equal access to quality healthcare, intimate partner violence, freedom of peaceful assembly, equality before the law and individual liberty, world press freedom, equal access to quality education, academic freedom, political rights, equal protection, housing affordability, and vulnerable employment. Lower-middle and low-income countries exhibit a larger share of negative correlations (46 % and 38 %, respectively), suggesting that SPIs' improvement frequently coincides with rising emissions, with many emitting more annually for each unit of social improvement. Moreover, the prevalence of weak correlations in high-income (53 %) and upper-middle-income (61 %) nations suggests that additional policy-driven mechanisms and economic transitions mediate SPI-emission relationships. Correlation results do not imply causation; rather, they reflect statistical associations based on temporal co-movement, appropriate for a diagnostic study to identify patterns of alignment and contradiction. These findings highlight the need for differentiated, justice-oriented climate policies that reduce emissions without deepening inequality, particularly in lower-income contexts, and support the joint pursuit of environmental and social objectives at national and global levels.