What would push a rural historian in the 1950s to take an interest in climate? How does this fit into the Marxist influence of that time? The greatest concern of Emmanuel Le Roy Ladurie, who is the French pioneer of climate history, was to study the intersection of agricultural production with changes in population. He discussed this at a meating with Martin de la Soudière, Martine Tabeaud, and Anouchka Vasak in 2008. The result of these meetings was a decisive contribution to the notion of interdisciplinarity, for example with glaciology, meteorology, and literature.