[en] The authors propose a synthesis of current knowledge on past and future evolutions of climate. The first part addresses what is sure. The authors present and comment data published by the IPCC which show that global warming is certain. They present methods of investigation used by experts, scientists and researchers to identify and understand the past evolutions of climate on Earth, and then describe these evolutions. They describe the greenhouse gas effect and show that mankind is responsible for climate change, and comment the evolution of the debate on climate change at the international level and in France. The second part addresses predictions for tomorrow. The authors describe the consequences of climate change for ice floes, glaciers, seas, marine life and biodiversity, and of course for society and human life, and show how the French landscape is already modified by climate change. The third part addresses the issue of a de-carbonated or low-carbon future. The authors recall and present the various past and current international negotiations, outline recent positive evolutions in the commitment of countries, and give an overview of the various possibilities to mitigate global warming by the development of a low carbon economy (renewable energies, sustainable buildings, energy transition for industries). The last parts address the adaptation to climate change and French perspectives in relationship with the French environment policy