Many colleagues have read carefully the various sections of this online textbook and suggested modifications that improved significantly the quality of the published material. We would like to thank particularly André Berger, Vicotr Brovkin, Michel Crucifix, Eric Deleersnijder, Anne de Montety, Thierry Fichefet, Hans Renssen, Benoit Tartinville and Kevin Trenberth. We benefit of very useful advices from Françoise Docq, Marcel Lebrun, Denis Smidts of the Institut de Pédagogie universitaire et des Multimédias of the Université catholique de Louvain (IPM, http://www.ipm.ucl.ac.be). Antoine Barthélemy helped in the introduction of revisions in the text and on the textbook web site. We also want to acknowledge the organisations, publishers and scientists who allow us to reproduce their work without any charge. This work is supported by the Fonds de Développement Pédagogique of the Université catholique de Louvain in the framework of the project: "Réalisation de simulations interactives comme support à l’apprentissage dans le cadre du cours d’introduction à la physique du système climatique et à sa modélisation."