Shifting Traction : Differential Treatment and Substantive and Procedural Regard in the International Climate Change Regime

Whilst the meaning of the principle of common but differentiated responsibilities (CBDR) in the international climate change regime was relatively clear-cut under the United Nations Framework Convention on Climate Change (UNFCCC) and its Kyoto Protocol, its significance under the Paris Agreement to the UNFCCC is more nuanced, flexible and inchoate. According to the CBDR principle, all states have common environmental responsibilities, but the manner in which each state meets its responsibilities should vary according to country-specific economic, historical, social and ecological variables. Whereas the UNFCCC and its Kyoto Protocol codified this principle in the form of differential treatment in their central treaty obligations, including those pertaining to mitigation, the Paris Agreement replaces top-down differentiation with respect to mitigation obligations with a new paradigm of bottom-up ‘self-differentiation', as parties select their own mitigation targets. Despite the diminished role for the CBDR principle in relation to prescriptive, substantive mitigation commitments under the Paris Agreement, this article posits that there is increasing scope for the CBDR principle to shape procedurally-oriented implementation and support mechanisms under the Paris Agreement. In particular, CBDR will continue to play a pivotal role in the context of adaptation, finance and technology transfer, capacity building and compliance. However, the increasingly salient avenues for procedural differentiation will need to be buttressed by robust accountability mechanisms, including consequences for deficient performance, to be effective. Currently, such accountability mechanisms are underdeveloped in this nascent phase of the Paris Agreement