Jean Jouzel's career occurred mostly at the CEA (Commissariat à l'Energie Atomique), the French nuclear public organization.

In 1991 he became vice-president of LMCE, the CEA laboratory dedicated to environment and climate; in 1995 he became its research director.

From 2001 to 2008 he was director of the IPSL (Institut Pierre Simon Laplace), a major federative laboratory on climate research in the Paris region, including CEA LMCE-LSCE.

After the 1970s, he combined his effort with the prominent French glaciologist Claude Lorius and he has contributed to the project of deep ice drilling in Antarctica, first in Vostok, then in EPICA (European Project for Ice Coring in Antarctica), which he led from 1995 to 2001, producing 800,000 years of climate history.

[2] From 2002 to 2015 Jean Jouzel was vice-chair of the Scientific Working Group of the Intergovernmental Panel on Climate Change (IPCC).