Future mobile telecommunication systems have to contribute to reductions in energy consumption and greenhouse gas emissions of ICT and to enable massive increase of utilization and data rates. Quite some progress has already been achieved in the last decade, but there is a big need for a holistic approach and research on system level innovations. EARTH is a European research project that has set to improve 3G and 4G systems and to provide metrics and design rules for energy efficient deployments. On the component level, strategies will be developed to dynamically adapt the energy consumption to the actual system needs.. The ambitious goal of EARTH is to provide within 30 months solutions that cut the energy consumption of mobile broadband networks by 50%.