After her PhD, Masson-Delmotte began working as a researcher at the Commissariat for Atomic Energy (CEA), specifically the Laboratory of Climate and the Environmental Sciences.[1] She became head of a paleoclimate group in 2010, head of a research group in 1998, and completed her habilitation in 2004.[2] Since 2008, she has been the Research Director/Senior Scientist at CEA.[3][3] Her research includes water vapour monitoring and combines past climate variability (ice cores, tree rings) with simulations, to address current climate models.[4]