Who should bear the costs of the green transition? Inferential gaps, burden-sharing principles, and the epistemology of global climate justice

The definitive regime of the European Union’s Carbon Border Adjustment Mechanism (CBAM), in force since January 2026, and the establishment in September 2026 of a World Trade Organization panel to examine it (DS639) have turned the question of who should bear the costs of the green transition into a live institutional dispute. This conceptual article argues that the question is composite: it bundles questions about environmental effectiveness, aggregate welfare, incidence, normative allocation, and decision authority. Drawing on a Scopus AI–assisted evidence map of 74 records, supplemented by canonical work in climate ethics, welfare economics, and incidence theory, the article identifies seven inferential gaps through which evidence about one object is routinely taken to settle another: from effectiveness to legitimacy, statutory liability to economic incidence, proportional to absolute burden, entitlement to receipt, aggregate to individual outcomes, operational to life-cycle impacts, and present to future generations. Each gap is bridged by normative premises, such as welfare weights, baselines, units of analysis, and discount rates, that economic models embed but seldom disclose. Burden-sharing principles are then reconstructed as evidential programs; public data show that they rank economies differently and that accounting boundaries reorder responsibility. Islamic legal maxims are shown to encode parallel distinctions and to carry the same evidential burden. Applied to CBAM from the standpoint of exporting middle-income economies such as Indonesia, the framework yields a disclosure standard for normatively transparent policy evaluation and an agenda for firm- and household-level research.