In implementing the European Green Deal to align with the Paris Agreement, the EU has raised its climate ambition and in 2022 is negotiating the distribution of increased mitigation effort among Member States. Such partitioning of targets among subsidiary entities is becoming a major challenge for implementation of climate policies around the globe. We contrast the 2021 European Commission proposal - an allocation based on a singular country attribute - with transparent and reproducible methods based on three ethical principles. We go beyond traditional effort-sharing literature and explore allocations representing an aggregated least regret compromise between different EU country perspectives on a fair allocation. While the 2021 proposal represents a nuanced compromise for many countries, for others a further redistribution could be considered equitable. Whereas we apply our approach within the setting of the EU negotiations, the framework can easily be adapted to inform debates worldwide on sharing mitigation effort among subsidiary entities.

After having agreed in the European Council of December 2019 on transforming the European Union to climate neutrality by 2050, the next step requires adjusting the 2030 targets on climate and energy accordingly. This Research Brief focuses on the effort sharing (ES) sector, which covers all greenhouse gas (GHG) emissions that are neither included in the EU Emissions Trading Scheme (EU ETS) nor covered under “land use and land use change”1. Starting from the Effort Sharing Decision of 2018, this Brief frames the issue in the broader context of global emission budgets that are compatible with the Paris Agreement climate targets and considers criteria for allocating the respective EU budget among the EU-27. The Research Brief (full version) is available upon request: wegcenter@uni-graz.at