The document outlines Hamburg's plan to become a more sustainable and green city through reducing CO2 emissions, improving energy efficiency in buildings, advancing sustainable transportation, rethinking building design, developing the city sustainably, and greening information and communication technology (ICT). The plan includes reducing CO2 emissions 20% by 2012 and 40% by 2020 compared to 1990 levels through over 170 climate protection measures. Hamburg aims to reinvent itself as an energy efficient city through retrofitting buildings, decentralized renewable energy, and efficient district heating networks.