Regime shift in climate governance: HFCs, the UNFCCC, and the Montreal Protocol

Abstract This article explains why and how hydrofluorocarbon governance shifted from the UNFCCC to the Montreal Protocol through the Kigali Amendment. This shift of hydrofluorocarbon governance from the central climate regime to the ozone regime is surprising: while the Montreal Protocol had the institutions and expertise to regulate HFCs, it lacked a mandate over non-ozone-depleting substances. By contrast, HFCs fell squarely under the UNFCCC’s mandate and were already addressed through its institutions. Existing studies on inter-institutional interplay and climate governance offer several accounts of why states may prefer alternative venues, but do not fully explain how functional advantages can drive a durable shift in issue governance despite jurisdictional constraints. This article argues that states may initiate such a shift when the destination regime’s capability advantage is sufficient to overcome its initial jurisdictional constraints. Because such a shift is costly, proponents may first need to build and demonstrate to other parties the functional readiness of the destination regime before the legal authority can be adjusted. This article reconstructs the negotiations leading to the Kigali Amendment, focusing on the regime shift of HFC governance from the climate to the ozone regime. It examines the proponents’ motivations, strategies, and sequencing in advancing the regime shift against strong mandate-based objections from opponent states. The article shows how states can reshape institutional authority within overlapping regimes and how specialized international institutions can become venues for sectoral climate mitigation.