The 2011 Hans Oeschger Medal is awarded to Robert Delmas for his seminal contributions to ice core glaciochemistry and his pioneering research on reconstructing changes in the composition of the atmosphere.
Robert Delmas has devoted his career to studies of the chemical composition of the atmosphere, as viewed through the archives obtained from polar and alpine ice cores. His careful analytical research led to an entirely new field of research—glaciochemistry—which is now a fundamental discipline in ice core glaciology. Delmas was the first to recognize that there had been large changes in atmospheric carbon dioxide in past glacial periods and that the past record of explosive volcanic eruptions could be recognized in remote ice core records, which became a critical tool for establishing the chronologies of ice cores. His studies of anthropogenic pollutants in ice cores have provided a clear picture of the effects of human activity on the global atmosphere. He also undertook pioneering studies of sulphur and nitrogen isotopes in ice cores, making important contributions to global bio-geochemistry. In all of this research, Robert Delmas has been especially supportive of others, encouraging younger scientists and those from other countries to develop and apply his ideas to new palaeoclimate records.