Comparing emissions mitigation efforts across countries

A natural outcome of the emerging pledge and review approach to international climate change policy is the interest in comparing mitigation effort among countries. Domestic publics and stakeholders will have an interest in knowing if peer countries are undertaking (or planning to undertake) comparable efforts in mitigating their GHG emissions. Moreover, if the aggregate effort is considered inadequate in addressing the risks posed by climate change, then this will likely prompt a broader interest in identifying those countries where greater effort is arguably warranted based on comparison with their peers. Both assessments require metrics of effort and comparisons among countries. We propose a framework for such an exercise, drawing from a set of principles for designing and implementing informative metrics. We present a template for organizing metrics on mitigation effort, for both ex ante and ex post review. We also provide preliminary assessments of effort along emissions, price, and cost metrics for post-2020 climate policy contributions by China, the European Union, Russia, and the United States. We close with a discussion of the role of academics and civil society in promoting transparency and facilitating the evaluation and comparison of effort.Policy relevanceStatement: Our article presents a framework for the review of intended nationally determined contributions and the ex post review of contributions under the UNFCCC negotiations. We provide an illustration of this framework with an energy-economic model. Our work focuses on how countries may use the review to compare mitigation effort – planned under INDCs and delivered by implementation of the pledged contributions – to address concerns about equity, efficiency, competitiveness, and the stability of any agreement that arise in international negotiations.