The 2013 Alfred Wegener Medal & Honorary Membership is awarded to Edouard Bard for pioneering and innovative work in palaeoceanography and palaeoclimatology. He has used accelerator mass spectrometry to correct fundamental dates in climate history, detect past sea level changes, and investigate climate and solar variability.
Edouard Bard is one of the most brilliant and creative researchers of his generation, who has been acknowledged by numerous awards and honours. Since 2001, he holds the Professor Chair in Climate and Ocean Evolution at the Collège de France in Paris, and he is also a member of the Academia Europaea and the French Academy of Sciences.
He has been a pioneer in the development of the accelerator mass spectrometry (AMS), which makes it possible to measure radiocarbon (14C) directly on samples of very small size. This enabled him in particular to quantify the penetration of 14C of thermonuclear origin in the oceans, which is a direct way to follow the fate of CO2 of anthropogenic origin. Bard showed that radiocarbon dates between 10,000 and 40,000 years B.P. (before present) were systematically too recent by several thousand years. He was thus able to correct fundamental dates such as the date of the last glacial maximum to 21,000 years B.P. instead of 18,000 years B.P., and the duration of the Holocene period to about 11,500 years, instead of 10,000 years.
Another field in which Bard’s research was pioneering is the study of past sea level changes. By applying mass spectrometry to the measurement of U-Th isotopes, he carried out a detailed study of the variations in sea level during the last glacial cycles, using samples from coral reefs in the three oceans; this study is now used to model the geophysical response of the Earth to the eustatic changes. One of the major results is the discovery of abrupt variations of the sea level at rates sometimes greater than several meters per century, which are much faster than the rise predicted for this century.
Bard has also studied in detail the 14C measured in tree-rings and beryllium 10 taken from Antarctic ice cores. These two cosmogenic nuclides are formed by cosmic rays in the upper atmosphere, but their production rate is modulated by the magnetic field of the Sun. Bard published a solar variability reconstruction over 1000 years that is widely used by climate modellers to study the link between solar variability and climate.
As a professor at the Collège de France, Bard provides extensive scientific information to the general public by writing popular articles and books, organising open conferences and scientific exhibits and advising French politicians in various official panels. Further, over the past 20 years, Bard has participated as convener, chairman or invited speaker in several sessions of the EGU General Assembly meetings. His peers have noted that Bard has no equal under the age of 60 in terms of the diversity of his many contributions and the impact his work has had in the Earth sciences. It is thus most timely that he is awarded the Alfred Wegener Medal and Honorary Membership.
Video of the Alfred Wegener Medal Lecture given at the EGU General Assembly 2013.