Implementing New GWP Values in the EU: A Quantitative Analysis
Oeko-Institut Working Paper 3/2019
The quantitative analysis for the EU-28 and all member states indicates that a change of GWP values from AR4 to AR5 would have very small effects. Based on the emission reductions achieved so far as well as projections by member states for 2030, the EU-28 would have to conduct slightly smaller emission reductions to achieve its NDC (about 0.1 percentage points considering current progress). The same holds true for the achievement of the ESR targets. Even at member state level, the differences in emission reductions with AR4 and AR5 values are small for national totals (between +/-0.5 percentage points) but somewhat larger for the effort sharing sector. This is mainly because the increase in the GWP value of methane partially levels out with the decrease in the GWP value of nitrous oxide. If the EU internally adopted an approach where ESR target levels are determined using AR4 values but emissions are reported using AR5 values, there is a larger, and opposite, effect: in this case, the EU-28 would need to implement more emission reductions to achieve the ESR targets (in aggregate about 1 percentage point). Under this approach the impact on member states also differs more strongly as compared the situation that AR5 values were used for both ESR target levels and reporting of emissions.