Keeping Promises? Democracies' Ability to Harmonize Their International and National Climate Commitments

Since the adoption of the Paris Agreement, global emissions have put the world beyond its goals. While there are calls for increasing ambition, countries must match their current international commitments at the national level. Democracies were assumed to comply with their own international commitments, yet their ability to adopt national mitigation policies that are consistent with their nationally determined contributions (NDCs) varies. This study applies the Vertical Policy Harmonization Index to quantify the extent to which countries' mitigation commitments are vertically harmonized in their NDCs and national policies. Using qualitative comparative analysis, I investigate the role of institutions, interests, and ideas in shaping the vertical (dis)harmony of twenty-four democracies. I find that fossil fuel dependency constrains the harmonization of mitigation commitments, even in the face of high vulnerability and low abatement costs. Moreover, the results support the previous findings of an ambiguous relationship between veto points and mitigation commitment. However, the roles of an established green party and public opinion in shaping disharmony remain unclear.