Uli Siegenthaler lost his long battle with cancer on July 14,1994. His death is a great loss to both his family and the scientific community. For decades, as one of a select few involved in developing Earth system science, he contributed to a balanced and competent view of the multifaceted aspects of complex climate and environmental issues.
Siegenthaler was born in 1941 in the Bernese Oberland, Switzerland. After his studies of Physics at the Eidgenössische Technische Hochschule in Zurich he joined Hans Oeschger's group at the Physics Institute of the University of Bern. In 1971 he completed his doctoral studies there—with summa cum laude—on the application of stable isotopes to the water cycle. He married Ilse, and they raised a family of two children in Bern.