Approaches to redistribute the costs of climate policy (effort sharing) have been central to European Union (EU) climate change policy since its inception in the early 1990s. This is both due to the nature of the problem, which inherently involves (re)distributing costs between sectors, jurisdictions and generations, and the nature of the EU. This paper seeks to survey the effort sharing approaches taken over the course of EU climate policy, since its early efforts to agree to the distribution of a common EU Kyoto target among Member States to the 2008 Climate and Energy Package. In so doing, the paper aims to draw lessons learned for other jurisdictions and the EU itself as they develop and implement climate change policies. The
paper comes to several central conclusions. Firstly, climate policy negotiation in the EU takes place within an enormously complex web of other policies and interests, allowing space for (implicit) bargaining that is unlikely to exist in other international settings. Secondly, a central difficulty over the history of EU effort sharing has been the harmonization of climate policy across multiple, overlapping climate regimes, including the Kyoto Protocol; the Burden Sharing Agreement between the EU15; and the European ETS. This overlap led to linkages and disharmonies that proved difficult to reconcile. Thirdly, the EUs climate policy has moved gradually towards more centralized modes of governance; this has facilitated the harmonization and effectiveness of ambitious climate policies, but at the cost of derogations, which have potentially weakened harmonized instruments such as the ETS. Overall, the balance appears positive, however, as EU effort sharing approaches have allowed Member States to go further than they would in a purely domestic context. Ultimately, the EUs effort sharing policies need to be seen in the difficult context of shared competences between the EU and Member States in the energy sector, and conflicting EU principles of the internal market and solidarity, which implies a differentiated approach to fundamental economic reform.