After a long battle against cancer, Jean-Marc Barnola passed away in september 2009, at the age of 53. This creative researcher will be remembered forever through his pionneering reconstruction of atmospheric carbon dioxide evolution over a full climatic cycle from the Vostok ice core, showing the tight relationship between climate and CO2 changes on such time scale. Beside pursuing then this work on longer time scales, Jean-Marc Barnola also strongly contributed to improve our understanding on the physics governing the diffusion and trapping of trace gases in polar firn and ice, which is key to evaluate the associated smoothing effects as well as the difference of age between trapped gases and the surrounding ice. This session will make a tribute to Jean-Marc Barnola's scientific career, going through the main different steps, but also highlighting his great humanism and sense of friendship, notably on the field in Antarctica.