[en] This report deals with the main challenges of climate change, and attempts to answer some questions: what is the temperature increase foreseen by scientific experts? Who will be affected by the consequences of climate change? Are there technologies to reduce emissions? If yes, why are they not diffused? Is it justified to ask developing countries to do something? Are concurrence distortions a real problem? Which are the main sectors where emissions are to be reduced? Are tools developed at the international level efficient? What is the present assessment for the clean development mechanism? What can be thought of technological partnerships developed with the United States? Then, the report comments the present status of international discussions, proposes a brief assessment of the Kyoto protocol ten years after its implementation, and proposes some improvement pathways