Warming Early Mars With A Dense Atmosphere Of Co2 And H2: A Review Of Recent Numerical And Experimental Advances M. Turbet, F. Forget, J.M. Hartmann, H. Tran, W. Fakhardji, Laboratoire De Météorologie Dynamique, Ipsl, Cnrs, Sorbonne Université, École Normale Supérieure, Psl Research University, École Polytechnique, 75005 Paris, France (Martin.Turbet@Lmd.Ipsl.Fr), D. Mondelain, Univ. Grenoble Alpes, Cnrs, Liphy, 38000 Grenoble, France, C. Boulet, Université Paris-Saclay, Cnrs, Institut Des Sciences Moléculaires D'Orsay (Ismo), 91405, Orsay, France, O. Pirali, Ailes Beamline Soleil Synchrotron, L'Orme Des Merisiers, Saint-Aubin 91190, France ; Institut Des Sciences Moléculaires D'Orsay, Cnrs, Université Paris-Saclay, Orsay 91405, France. Introduction: To This Day, The Enigma Of Mars' Ancient Climate Remains Unexplained (Wordsworth Et Al. 2016, Haberle Et Al. 2017, Kite 2019). What Was The Atmosphere Of Mars Made Of At The Time When – Near The Late Noachian Epoch – Lakes And Valley Networks (See E.G., Fassett & Head 2008a,B, Hynek Et Al. 2010, Goudge Et Al. 2015) Were Formed? Although There Is A Broad Consensus To Date That Liquid Water Is The Main Culprit, The Nature Of The Atmosphere At The Time (I.E., The Atmospheric Pressure And Composition)