Addressing Overlaps in Non-State and Subnational Climate Action Aggregation Analyses

Abstract

Non-state and subnational climate action (NSA) has great potential for bridging the emissions gap, but aggregating its potential impacts is challenging. This Master’s thesis presents one of the aggregation challenges – addressing overlap between actions. Although overlaps lead to reinforcements in practice by, for example, technological learning and awareness raising, they lead to overestimates and double counting in ex-ante aggregation analyses when not properly accounted for. Therefore, an analytical framework for addressing overlaps between initiatives is presented in this thesis, based on seven good practices and a review of ten aggregation analyses (Figure I).

Figure I: Analytical framework for addressing overlaps between initiatives in NSA aggregation analyses.

First, overlaps need to be identified and categorised. Second, the size of overlaps needs to be determined. Third, the overlap needs to be quantified and finally, this value needs to be used to correct the sum of the potential impacts. This analytical framework was used to correct the summed greenhouse gas (GHG) emission reduction potentials (ERP) of seventeen key transnational emission reduction initiatives (TERIs) for overlaps between initiatives. Full realization of the ambitious targets was assumed which led to a global sum of ERPs of 20.4 – 27.2 GtCO2e/year in 2030, compared to a current policies scenario. After factoring in overlaps between TERIs, the global aggregate of ERPs was estimated at 17.6 – 20.7 GtCO2e/year in 2030. Hence, accounting for overlaps led to a reduction of roughly 13-23% of the summed potential impacts. Although the aggregate of ERPs is still substantial, this major difference illustrates the importance of addressing overlaps in ex-ante aggregation analyses. The thesis finds that the analytical framework is a useful and suitable method to refine overlap calculations, but several possible improvements are underlined. The presented analytical framework can therefore be seen as a first step towards more extensive overlap calculations. Moreover, the calculated aggregate of ERPs is substantial and showcases the possible level of ambition for national policies. In sum, the aggregation analysis demonstrates that exemplary NSA ambitions can bridge the emissions gap, but chickens should not be counted before they hatch.