Climate change is one of the greatest challenges currently facing society. Despite acknowledged uncertainties, the overwhelming majority of scientists view it as highly probable that climate change results from anthropogenic greenhouse gases (GHG), and that a significant reduction in GHG emissions is imperative if dangerous climatic shifts are to be prevented (cf. IPCC 2007a, 2007c). According to the Intergovernmental Panel on Climate Change (IPCC), which was established to review scientific information on the various components of climate change comprehensively, global GHG emissions must be halved by 2050 in order to head off potentially severe climatic threats resulting from increasing GHG concentrations in the atmosphere, including a rising global mean temperature (IPCC 2007c). For this goal to be achieved, industrialized countries must collectively reduce their GHG emissions by 80 to 95 per cent from the current level by 2050, even if developing countries substantially reduce their emissions by approximately 15 to 30 per cent (den Elzen and Höhne 2008) from business-as-usual levels (IPCC 2007c: 776).