Assessing the ambition of post-2020 climate targets: a comprehensive framework

摘要

One of the most fundamental questions surrounding the new Paris Agreement is whether countries' proposals to reduce GHG emissions after 2020 are equally ambitious, considering differences in circumstances between countries. We review a variety of approaches to assess the ambition of the GHG emission reduction proposals by countries. The approaches are applied illustratively to the mitigation part of the post-2020 climate proposals (nationally determined contributions, or NDCs) by China, the EU, and the US. The analysis reveals several clear trends, even though the results differ per individual assessment approach. We recommend that such a comprehensive ambition assessment framework, employing a large variety of approaches, is used in the future to capture a wide spectrum of perspectives on ambition.POLICY RELEVANCEAssessing the ambition of the national climate proposals is particularly important as the Paris Agreement asks for regular reviews of national contributions, keeping in mind that countries raise their ambition over time. Such an assessment will be an important part of the regular global stocktake that will take place every five years, starting with a light' version in 2018. However, comprehensive methods to assess the proposals are lacking. This article provides such a comprehensive assessment framework.