André Léon Georges Chevalier Berger (born July 30, 1942) is a Belgian climatologist and professor from Acoz. 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 an 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 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 calculating 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. He was the supervisor of 22 doctoral degree theses and continues to serve as a jury member for academic tenure and habilitation.
Berger is the author of Le Climat de la Terre – un passé pour quel avenir?.Berger A., 1992. Le Climat de la Terre, un passé pour quel avenir. De Boeck Université, Bruxelles, 479pp. He started to contribute, as early as in the 1970s, to the awareness of society to global warming and the impact of human activities on climate change.
Works Berger's field of research is geosciences and more specifically the astronomical theory of paleoclimatesBerger, A., 1988. Milankovitch Theory and Climate. Reviews of Geophysics, 26(4), pp. 624-657. and climate modelling.Berger, A., Gallee, H., Fichefet, Th., Marsiat, I., Tricot, Ch., 1990. Testing the astronomical theory with a coupled climate-ice sheet model. in: L.D. Labeyrie and C. Jeandel (Eds), Geochemical variability in the Oceans, Ice and Sediments. Palaeogr., Palaeoclimatol., Palaeoecol., 89(1/2), Global and Planetary Change Section, 3(1/2), pp. 125-141. In the 1970s, he improved significantly the accuracy of long-term variations of obliquity and climatic precession used for calculating the incoming solar radiation (insolation).Berger, A., 1978. Long-term variations of daily insolation and Quaternary Climatic Changes. Journal of the Atmospheric Sciences, 35(12), 2362-2367. He calculated the periods characterizing the variations of the astronomical parameters,Berger, A., 1977. Support for the astronomical theory of climatic change. Nature, 268, 44-45. showing that, in addition to the known 40-ka period of obliquity (ka = thousand years) and 21-ka period of climatic precession, there are periods of 400 ka, 125 ka, 95 ka and 100 ka in eccentricity, of 54 ka in obliquity and of 23 ka and 19 ka in climatic precession. Under the leadership of Nicholas Shackleton,Shackleton N.J., Berger A., Peltier W.R., 1990. An alternative astronomical calibration of the lower Pleistocene time scale based on ODP site 677. Phil. Transactions of the Royal Society of Edinburgh: Earth Sciences, vol. 81 part 4, pp. 251-261. he contributed to improve the age of the Brunhes-Matuyama reversal. He identified the instability of the astronomical periods and the existence of a 1.3-Ma period (Ma = million years) in the amplitude modulation of obliquity.Berger A., Loutre M.F. and Melice J.L., 1998. Instability of the astronomical periods from 1.5 Myr BP to 0.5 Myr AP. Paleoclimates Data and Modelling, 2(4), pp. 239-280. He demonstrated the relationship between the different periods of the astronomical parameters,Berger A., Loutre M.F., 1990. Origine des fréquences des éléments astronomiques intervenant dans le calcul de l'insolation. Bulletin Sciences, 1-3/90, pp. 45-106, Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique. estimated the value of these astronomical periods over tens to hundreds of millions of years,Berger, A., Loutre, M.F., Dehant, V., 1989. Pre-Quaternary Milankovitch frequencies. Nature, 342, p. 133. and showed the origin of the 100-ka period in astronomyBerger A., Melice J.L. and M.F. Loutre, 2005. On the origin of the 100-kyr cycles in the astronomical forcing. Paleoceanography, 20(4), PA4019, . and, under the leadership of J. Imbrie, in paleoclimates.Imbrie J., Berger A., Boyle E.A., Clemens S.C., Duffy A., Howard W.R., Kukla G., Kutzbach J., Martinson D.G., McIntyre A., Mix A.C., Molfino B., Morley J.J, Peterson L.C., Pisias N.G., Prell W.L., Raymo, M.E., Shackleton N.J., and J.R. Toggweiler, 1993. On the structure and origin of major glaciation cycles. 2. The 100,000-year cycle. Paleoceanography, 8(6), pp. 699-735. He delivered an easy-to-handle and accurate calculation of the long-term variations of the daily, seasonalBerger A., Loutre M.F. and Q.Z. Yin, 2010. Total irradiation during the interval of the year using elliptical integrals. Quaternary Science Reviews. 29, 1968-1982 and caloricBerger, A., 1978. Long-term variations of caloric insolation resulting from the Earth's orbital elements. Quaternary Research, 9, 139-167. irradiations. With his team, he developed one of the first Earth Model of Intermediate Complexity (EMICs).Gallee, H., van Ypersele, J.P., Fichefet, Th., Tricot, Ch., Berger, A., 1991. Simulation of the last glacial cycle by a coupled sectorially averaged climate - ice-sheet model. I. The Climate Model. Journal of Geophysical Research., 96, pp. 13,139-13,161 Based on such climate models, he showed the importance of the long-term variations of insolation to simulate the glacial-interglacial cycles,Berger A., Loutre M.F., and H. Gallee, 1998. Sensitivity of the LLN climate model to the astronomical and CO2 forcings over the last 200 kyr. Climate Dynamics, 14, pp. 615-629.Yin Q.Z. and A. Berger, 2010. Insolation and CO2 contribution to the interglacials before and after the Mid-Brunhes Event. Nature Geoscience, 3(4), pp. 243-246. the possible exceptional length of our interglacialBerger A. and M.F. Loutre, 1996. Modeling the climate response to the astronomical and CO2 forcings. Comptes Rendus de l'Académie des Sciences de Paris, t. 323, série II a, pp. 1-16.Berger A. And M.F. Loutre, 2002. An Exceptionally long Interglacial Ahead? Science, 297, pp. 1287-1288. the importance of the 400-ka period in searching for analogues of our present-day and future climate,Berger A. and M.F. Loutre, 2003. Climate 400,000 years ago, a key to the future? in Earth's Climate and Orbital Eccentricity: The Marine Isotope Stage 11 Question. Geophysical Monograph 137, A. Droxler, L. Burckle and R. Poore (eds), American Geophysical Union, pp. 17-26. the relative role of the multiple feedbacks involved in the explanation of the glacial-interglacial cycles, water vapour in particular.Berger A., Tricot C., Gallee H., and M.F. Loutre, 1993. Water vapour, CO2 and insolation over the last glacial-interglacial cycles. Philosophical Transactions of the Royal Society, London, B, 341, pp. 253-261. More recently he initiated research on the origin of the east Asian summer monsoon in ChinaYin Q.Z., Berger A., and M. Crucifix, 2009. Individual and combined effects of ice sheets and precession on MIS-13 climate. Climate of the Past, 5, pp. 229-243. and started to work on the diversity of climate over the last nine interglacials.
Functions Berger has served in many international bodies involved in the development of present-day and past climate research. He was chairman of the International Climate Commission of the International Union of Geodesy and Geophysics (1987–1993) and of the Paleoclimate Commission of the International Union of Quaternary Research (1987–1995); president of the European Geophysical Society (2000–2002), co-creator of the European Geosciences Union of which he is honorary president; member of the First Scientific Steering Committee of the International Geosphere-Biosphere Programme on Global Changes of the Past (1988–1990), Committee which is at the origin of PAGES. In 1991, he was the initiator of the Paleoclimate Modelling Intercomparison Project (PMIP).
For the Commission of the European Communities, he was chairman of the Coordination Group on Climate Processes and Climate Change of the Climatology and Natural Hazards Program (1988–1992), of the External Advisory Group on Global Change, Climate and Biodiversity (2000–2002) and member of the Contact Group of the Climate Programme on Reconstruction of Past Climate, Climate Models and Anthropogenic Impacts on Climate from 1980 to 1983 (groups which are at the origin of the CEC Framework Programme).
For the Scientific Committee of NATO, he was chairman of the Special Programme Panels on the Science of Global Environmental Change (1992) and on Air-Sea Interactions (1981) and of the programme Advisory Committee of the International Technical Meeting on Air Pollution Modelling and its Applications (1980–1985).
He was also member of committees in charge of advising policy makers and scientific institutions, in particular the European Environment Agency (EEA, 2002–2009), the European Science Foundation (ESF), Gaz de France (1994–1999 ) and Electricité de France (1998–2009). He was a member of the scientific committee of universities and research institutes, among which Laboratoire des sciences du climat et de l'environnement, Laboratoire de Météorologie Dynamique, Département Terre-Atmosphère-Océan de l'Ecole Normale Supérieure, Institut Paul Simon Laplace et Collège de France in Paris, Laboratoire de Glaciologie et de Géophysique de l'Environnement and the European University and Scientific Pole of Grenoble, LEGOS in Toulouse, Météo-France, Hadley Centre for Climate Prediction and Research in Great-Britain and Beijing Normal University. He is a voting member of the BAEF (Belgian American Educational Foundation, Herbert Hoover Commission for Relief in Belgium) which he was fellow in 1970–1971.