Top-down approaches for sharing GHG emission reductions: uncertainties and sensitivities in the 27 European Union Member States

To reduce GHG emissions, the 27 European Union Member States committed themselves in 2007 to reduce emissions from 1990 levels by 20% by 2020. In January 2008, the EU Commission gave the first country-specific proposals to reduce emissions in sectors outside the EU emission trading system (non-ETS). In this study, we looked at several ways of sharing emission reductions in the non-ETS sector. We considered population and economic growth as significant drivers of the development of emissions. In particular, we analyzed development in GHG intensity of economies. Reduction requirements vary greatly among countries depending on the principle of effort sharing. The results of our calculations can be perceived as examples of how effort sharing between the EU Member States could look like when certain assumptions are made. Generally they illustrate the sensitivity of the results to data used, assumptions made, and method applied. The main strength of simple top-down approaches is transparency. A major weakness is a very limited ability to consider national circumstances. Political negotiations are ultimately crucial; an analysis like this provides material for negotiations and makes a contribution to solving the effort-sharing problem. As future development is partly unpredictable, implementation of some kind of subsequent adjustment could be considered during the process.