A target-oriented scenario of future energy demand and supply is developed in a backcasting process. The main target is to reduce global CO2 emissions to around 10 Gt/a in 2050, thus limiting global average temperature increase to 2 degrees C and preventing dangerous anthropogenic interference with the climate system. A 10-region energy system model is used for simulating global energy supply strategies. A review of sector and region-specific energy efficiency measures resulted in the specification of a global energy demand scenario incorporating strong energy efficiency measures. The corresponding supply scenario has been developed in an iterative process in close cooperation with stakeholders and regional counterparts from academia, NGOs and the renewable energy industry. The 2 degrees C scenario shows that renewable energy could provide as much as half of the world's energy needs by 2050. Developing countries can virtually stabilise their CO2 emissions, while at the same time increasing energy consumption through economic growth. OECD countries will be able to reduce their emissions by up to 80%. (C) 2007 Elsevier Ltd. All rights reserved.