This article examines why the International Maritime Organization (IMO) has persistently resisted operationalising the climate-law principle of common but differentiated responsibilities and respective capabilities (CBDR-RC) in regulating greenhouse gas emissions from international shipping. Existing scholarship often explains this impasse as a matter of political disagreement or doctrinal incompatibility between maritime and climate law. This article argues instead that the resistance is deeper and institutional, rooted in the IMO's historical ‘institutional DNA’. The organisation's legal culture and regulatory architecture were built around uniformity, non-discrimination and depoliticised technical standard-setting, forged in a mid-twentieth-century order dominated by major shipowning powers and designed to exclude commercial and distributive questions from its mandate. By contrast, international climate law emerged from a post-colonial multilateral order and embeds a distributive logic of responsibility grounded in equity, historical contribution and differentiated capacity. Decarbonisation measures inevitably raise questions of burden-sharing that the IMO was historically structured to keep at arm's length. This tension is compounded by a regulatory mismatch: maritime law regulates ships as the primary unit of obligation, whereas climate law allocates responsibility at the level of states. Integrating CBDR-RC into maritime decarbonisation thus requires rethinking the inherited boundary between technical regulation and distributive justice.
Huiwen Yang (Mon,) studied this question.