It is the objective of the ⁠UN⁠ Framework Convention on Climate Change to stabilise the concentration of greenhouse gases on such a level that ”would prevent dangerous anthropogenic interference with the climate system” (article 2 of the Framework Convention on Climate Change). This objective is an essential basis for the international negotiation process to further develop the climate regime (Kyoto Protocol and follow-up agreements). Based on the EU target to avoid a warming of the Earth’s atmosphere by more than 2±C compared to the pre-industrial level, it has been the mission of the research project to identify the magnitude of costs to attain such a climate protection target under different designs of the post-2012 climate regime.