Expanding climate policy adoption improves national mitigation efforts

Abstract

To identify means to improve mitigation efforts, we investigated whether the number of climate policies is associated with emission projections up to 2030 and compared policies' prevalence across country groups. We find that larger and more comprehensive policy portfolios are conducive to emission reductions, regardless of whether absolute emissions increase or already decline. However, country groups have distinct entry points to expand climate policy. Countries with fast-increasing emissions have significantly fewer policies overall but policies are especially missing in energy-demand sectors, such as buildings and transport. Countries with stalling emissions lack climate strategies and other cross-sectoral policies. This suggests the need for better coordination of mitigation efforts across sectors. In all country groups that fail to reduce emissions, policies to reduce energy and material demand are also substantially fewer. Despite the collective increase of policies in force, countries can still expand climate policy to use the full breadth of mitigation options available.

Keywords: Climate-change mitigation; Projection and prediction.

Fig. 1. Clustering analysis results.

Mind the log scale in all charts. The three letters represent the country’s ISO-3 code and the two digits the year of the data (historical GDP/capita, historical emissions/capita and projected average change rate developed in the respective year).

Fig. 2. Relationship between average annual projected emission change rates and a number of policies.

Countries with more climate policies have lower projected emission change rates (a). This result is valid across clusters although to a different degree (b). Results are statistically significant despite variance.

Fig. 3. Comparing policy density to moderate decline cluster.

Results from Mann–Whitney U one-tailed test comparing policy density across sectors (a), policy instrument types (b) and mitigation areas (c). Colours indicate whether policy density is significantly lower when compared to the ‘moderate decline’ cluster. Labels present the percentage difference of the medians. For example, the median number of climate strategies in the ‘high growth’ and ‘moderate growth’ clusters are respectively, 30% and 50% lower compared to the ‘moderate decline’ cluster.