In the framework of the « Grenelle de l'Environnement », the Programmes for the Climate and the Energy at the Territory scale (PCET) should be a way to introduce the issues of energy savings and climate change to those of urban systems, buildings and transportation. The objective of the project is to propose a method that helps planning the PCETs through a systemic approach focused on the ?core' of territory policies composed of the ?transportation/buildings/land occupancy? system that amounts to near 60% of the emission of greenhouse effect gases and that is the main leverage for action at the local authority scale. Although the project focuses on this ?core' system, other parameters (the role of Information and Communication Technologies, feeding, etc) and other approaches (ecosystemic approach, life cycle assessment, etc) are considered in the project and are evaluated in the frame of the state of the art, and are implemented when possible. The method both includes a top-down approach based on the analysis of scientific works and of available expertises, and a bottom-up approach based on the territory evaluation of 3 local authorities at the city area scale. First, it consists in developing a conceptual model of the urban system defined by its sectorial, spatial, and governing interactions. Secondly, this model allows for proposing a consistent warning data set for short and mid-term monitoring of the PCETs, as well as building a simulation scenario (with System Dynamics / Agent Based models) that forecasts long term effects (until 2050 for this project) of a wide range of possible urban policies. Finally, the method is a decision making tool for local authorities about planning actions in respect with the importance of predictable impacts and the assigned objectives (e.g. ?factor 4? objectives). The project is supported by a consortium composed of 3 research laboratories (CSTB, EIFER, LVMT) and 5 engineering companies (BURGEAP, EGIS MOBILITE, ICE, ISEE, Tracés Urbains).