The Free and Hanseatic city of Hamburg has implemented a climate action plan in the year 2007. The climate action plan shall help to lower Hamburg's carbon dioxide emissions until 2012 by 2 million tons compared to 2007. This target shall be achieved by municipal actions, federal and European Union policies, efforts of the industrial sector to reduce its carbon dioxide emissions, raising awareness and technological progress. This study is based on the evaluation and monitoring concept for the calculation of emission and energy consumption reductions achieved by the single measures and measure packages of the climate action plan. The evaluation and monitoring concept was developed by the Wuppertal Institute in 2009. Within the current project a balance sheet of the overall reductions of carbon dioxide emissions and energy consumption shall be compiled. To this end the effects of individual municipal measures and federal policies are calculated or estimated. The study is prepared by the Wuppertal Institute in cooperation with its subcontractor Öko-Institute.