Norbert Untersteiner, a pioneer in polar geophysics, passed away from prostate cancer on 14 March 2012 in Seattle, Washington. Much of the present interest in the role of the Arctic in global climate can be traced to Norbert, who founded the modern thermo-dynamic theory of sea ice.

Born on 24 February 1926 in Merano, Italy, Norbert was in Salzburg, Austria, in 1938 when Germany annexed the country. He studied physics at the University of Innsbruck and completed his PhD thesis on seiche waves with Albert Defant in 1950. Norbert then became an assistent to meteorologist and geophysicist Heinrich von Ficker in Vienna and honed his expertise in glacier mass and radiation balance. Thus it was not surprising that in 1954 he was approached by Reinhard Sander to be a scientific member of an expedition to Asia’s Karakoram Range.

As part of the International Geophysical Year (IGY), in January 1957 Norbert was appointed by the University of Washington (UW) in Seattle as scientific leader of Ice Station Alpha, one of two floating stations in the Arctic Ocean during that time. By June, Station Alpha was fully operational, and in 1958 Norbert became one of the few Western scientists to summer over on the ice; he stayed to November. He then returned to his post in Vienna and was awarded the Austrian Honorary Cross for Science and Arts, and in 1960 he was appointed Dozent, or instructor, at the University of Vienna. His research through 1961 appeared mainly in German, but his seminal IGY paper “On the mass and heat budget of Arctic sea ice” appeared in English. In 1962 Norbert returned to the UW, and by 1967 he was professor of atmospheric science—he chaired the department from 1988 to 1997—and of geophysics. He then went to the University of Alaska Fairbanks, where he held the Sydney Chapman Endowed Chair in Physical Sciences from 1998 to 2005.

To say that Norbert’s IGY experience and the subsequent theoretical work became an essential pillar of present-day sea-ice geophysics is an understatement. His ability to extract the essential behavior of a process from complex field data and to construct meaningful models peppers the literature of the 1960s. Most important is the thermodynamic sea-ice model that he developed in 1963 and later extended with Gary Maykut. All global climate models with sea-ice components use simplifications of Norbert’s vision.

Norbert established the UW’s snow and ice graduate curriculum in 1968 and hired world-class scientists to train generations of leading geophysicists. His growing understanding of the importance of sea ice in climate co-incided with the end of a decade during which impressive advances in logistical capability and field instrumentation had been made. Out of those advances emerged the Arctic Ice Dynamics Joint Experiment (AIDJEX). Norbert and Kenneth Hunkins were invited by the US Navy to draft a plan for the initiative. By 1969 it was a major interdisciplinary, multistation, multiyear project primarily supported by NSF, the Office of Naval Research, and the Polar Continental Shelf Project of Canada. In 1971 Norbert took the reins of the project, which became the template for all subsequent fieldwork in the Arctic.

It is difficult to convey the monumental task that constituted AIDJEX. Driven by ideas and individuals, it represented a new dimension of cooperative geophysical research: a project too big for one group to undertake but not big enough to become a governmental effort. It was an enormous logistical operation that depended on collaboration among groups of scientists and support teams. They simultaneously developed and implemented a vast field program incorporating data analysis, theory, and massive computational efforts. The project even published its own journal. After AIDJEX ended in 1978, the UW formed the Polar Science Center, which later became part of its Applied Physics Laboratory.

Norbert became scientific adviser for arctic and polar affairs at the Office of Naval Research in 1978, then director of the Ocean Programs Office at the National Oceanic and Atmospheric Administration two years later. He returned to the UW in 1981 to direct, until 1988, the Polar Science Center, where he helped establish the International Arctic Buoy Program, designed for long-term climate monitoring.

When in 1992 Senator Al Gore and CIA director Robert Gates spearheaded the formation of the Environmental Task Force to investigate the scientific uses of classified data, they naturally called on Norbert to be part of it. In 1994 the group known as MEDEA was formed to work with Russia in developing and releasing atlases and high-resolution satellite images for studies of Arctic climate; Norbert was a MEDEA leader through last year. Forty years after the IGY, he used the declassified data in an article examining the albedo of summertime sea ice.

Many of Norbert’s lasting accomplishments were invisible. They occurred in the byways of science, at odd times and in unexpected places, and reflected a unique type of unselfishness, expertise, and frank advice to young and old. He was unconcerned with getting credit for how understanding of a phenomenon came about. He thus influenced countless people and drove the field of sea-ice geophysics. Now that sea ice is central to understanding our present-day climate, we do well to remember that the methods and concepts for studying sea ice cannot be separated from Norbert’s contributions.

His passion for ice was only outstripped by that for his family and friends. From Innsbruck to the Karakorum, from the Arctic Ocean to the shores of Green Lake in Seattle, the father of sea-ice geophysics traveled far and wide, and his advice, support, charm, and indescribable sense of humor will be missed by those with whom he came in contact.

Norbert Untersteiner