Many countries’ current national climate change mitigation (hereafter: mitigation) policies fall short of the pledges outlined in their Nationally Determined Contributions (NDC), limiting the likelihood of reaching the goals of the Paris Agreement. This project combines insights from various (sub)disciplines and engages with multiple research methods to investigate to what extent and under what conditions countries deviate from their international pledges at the national level.

To this end, we developed two novel indices that measure countries’ level of vertical policy harmonization along three key dimensions of mitigation policymaking (see Task 1). The Target Index compares the level and scope of the greenhouse gas (GHG) reduction targets (hereafter: targets) of 82 countries’ NDCs and national policies – i.e., we measure whether these targets are harmonized or to what extent they deviate. The Policy Effort Index incorporates countries’ climate policy mix to assess the credibility of 36 countries’ targets. We find that despite a quarter of the countries covered having national targets that are either in line with or more ambitious than their NDC target, most countries (accounting for 70% of global emissions) fall short of their targets given countries’ relatively insufficient policy mixes. Additionally, we show that different macro-level factors (e.g., democracy and fossil fuel dependency) are associated with greater deviations between countries’ NDCs and national policies.

In Task 2, we collaborated with computer scientists to create two datasets related to participation in international climate negotiations. In the first dataset, we count how often each country makes a statement in the negotiations, and how often and in what manner it interacts with other countries or country groups. In the second dataset, we systematize information on countries’ negotiation delegations, including their size, composition, experience, and affiliation of their members. We use this data to assess the extent to which countries with a stronger engagement in the UN climate negotiations, in the broader ecosystem of international climate-related organizations, and in transnational climate governance initiatives have more ambitious NDCs and stronger domestic mitigation policies; we find substantive differences between developing and developed countries. Additionally, we examine the presence and participation of small states in the UN climate negotiations to discuss the ways by which small states can compensate for their limited personnel capacities in order to meaningfully engage in the negotiations.

In Task 3, we turn our focus to the national decision-making processes with the aim to examine which factors in a climate policy subsystem drive the harmonization of NDCs and national policies. At the domestic level, actors’ preferences and power resources can influence the political feasibility of policies, and thus countries’ ability to keep their promises. Following this, we expect certain attributes of a policy subsystem (e.g., the level of actor involvement, the presence of “two-level connectors”) to precondition the likelihood of policy adoption, in turn driving harmonization. In addressing these expectations, we draw on the Policy Effort Index. So far, we have run six policy elite surveys to collect data on the relevant factors of a policy subsystem. Ourpreliminary results indicate that the existence of “two-level connectors” are relevant in explaining the gap between countries’ NDCs and national mitigation policies.

In Task 4, we used the Predictioneer’s Game to forecast the ability or willingness of the German and Swiss governments to close the gap between their NDCs and national policies. To this end, we focused on relevant, country-specific factors that may facilitate the harmonization of NDCs and national policies.

The project makes important contributions to the study of countries’ policy responses to climate change. The Vertical Policy Harmonization Indices and subsequent analysis shed further light on countries’ ability to keep commitments and provide the basis for future research on the multilevel governance of climate change and other policy problems.