André Léon Georges Chevalier Berger (born July 30, 1942, Acoz) is a Belgian climatologist and professor. He is best known for his significant contribution to the renaissance and further development of the astronomical theory of paleoclimates and as a cited pioneer of the interdisciplinary study of climate dynamics and history. Biography Trained in mathematics, Berger holds a PhD in sciences from the Université catholique de Louvain (1973) and a master of sciences in meteorology from Massachusetts Institute of Technology (1971). He has received honorary doctoral degrees from Paul Cézanne University Aix-Marseille III (1989), Toulouse III - Paul Sabatier University (1999) and the Faculté polytechnique de Mons (2004). He is presently emeritus professor and senior researcher at UCLouvain. Berger works in the field of paleoclimatology, and worked on the astronomical theory of paleoclimate (also known as the Milankovitch theory) in the 1970s, and to its promotion and development in the following decades. He has renewed this theory and improved the accuracy of the long term variations of the astronomical parameters used for the calculation of the incoming solar radiation (insolation) over the last and next millions of years. He became known in 1977 for his paper in Nature and later in the Journal of Atmospheric and Terrestrial Physics (1978), delivering all the spectral components of the long term variations of orbital eccentricity, obliquity (axial tilt) and climatic precession. His contributions have played a key role in the time scale calibration and interpretation of paleoclimate records and in the modelling of glacial-interglacial cycles. He has mainly worked on the simulation of past and future climates in close collaboration with physicists and geologists worldwide. He was at the origin of the very first Earth systems model of intermediate complexity. He was full professor of meteorology and climatology at UCL, maître de conférences at the Université de Liège where he was Chaire Francqui in 1989, visiting professor at the Vrije Universiteit Brussel, and has been invited to many other universities in Europe, America and Asia. He was invited to deliver the Union Lecture of the International Union of Geodesy and Geophysics (IUGG) in 1987, the Society Lecture of European Geophysical Society (EGS) in 1994 and the Slichter Lecture at the University of California Los Angeles in 2001. He was chairman of the Institute of Astronomy and Geophysics Georges Lemaître from 1978 to 2001, a period during which he started to develop climate research there.