Willi Dansgaard, a great pioneer of climate research, died on 8 January 2011 at the age of 88. He was born on 30 August 1922 and grew up in the centre of Copenhagen where his parents had an engraving shop. He finished his university degree in physics, mathematics and astronomy in 1947 with a gold medal award for a thesis on X-ray dosimetry at the Biophysics Laboratory of the University of Copenhagen. From 1947 to 1951 he was employed by the Danish Meteorological Institute where he worked in geomagnetism and meteorology. In 1947–1948 he spent a year at the geomagnetic observatory in Qeqertarsuaq, Greenland, and this led to a life long affection for that country.
In 1951, Dansgaard was given the opportunity to return to the Biophysics Laboratory when a position opened for the operation of a new mass spectrometer. There were very few tasks for the mass spectrometer however, so he began to search out opportunities for himself and rebuilt the mass spectrometer for the analysis of water isotopes. In June 1952, Dansgaard made a discovery that came to influence the rest of his scientific career. He discovered that it was possible to determine the temperature of the precipitating clouds by analysing the stable isotopic composition of rain water. In the following 12 years, he systematically collected water samples from all over the world in collaboration with the Danish East Asia Company, contacts in Greenland, a French expedition under Paul Emile Victor and later the International Atomic Energy Agency and World Meteorological Organization. He obtained his doctorate for this work, and in 1964, he published the paper: ‘Stable isotopes in precipitation’ in Tellus. This was a ground breaking paper in geophysics and geology.
During his collection of water samples in Greenland, Dansgaard visited the American base, Camp Century in 1964. Camp Century was a base set up during the cold war under the surface of the Greenland ice sheet some 200km east of Thule Air Base. Here he learned about a continuing activity by the U.S. Cold Regions Research and Engineering Laboratory (CRREL), Hanover, New Hampshire of drilling through the ice sheet. In 1967 he entered a collaboration with Dr. Chester Langway, and his group soon began systematic analysis of stable isotopes along the Camp Century ice core, and a few years later along the U.S. Byrd ice core from Antarctica. This work demonstrated that not only did the ice cores contain a detailed archive on past climate changes but also that past climate underwent many large and abrupt changes. Together with Langway and Professor Hans Oeschger, University of Berne, Dansgaard led the very first climate research motivated ice core drilling through the Greenland ice sheet at Dye-3 in south Greenland in 1979–1981. Dansgaard is therefore recognised by many as the founder of modern ice core climate research.
In 1972 Dansgaard became leader of the Geophysical Isotope Laboratory at the University of Copenhagen. He assembled a strong group of 6–7 researchers and here the scientific work on ice cores intensified and the foundation stone was laid for a continuous strong Danish presence in the forefront of international ice core research.
During the 1980s the results from the Dye-3 ice core were published and they confirmed the Camp Century findings. Dansgaard was particularly interested in the discovery of a sequence of abrupt climate changes during the last ice age. Results showed that past climate had been unstable and that most of the climate changes had been very abrupt indeed. Internationally, the abrupt changes are now known as Dansgaard/Oeschger events.
His last great efforts were made from 1985 to his retirement in 1992. To his great disappointment it became politically impossible to continue the collaboration with the U.S., so he established a European collaboration which led to the GRIP ice core drilling in 1989–1992. GRIP became a project that generated results with a large impact, and the seeds were sown for the large European ice drilling projects in Antarctica, EPICA Dome C and EPICA Dronning Maud Land and the Greenland project NGRIP (now with U.S. participation). These four projects were completed with drilling technology developed by his group in Copenhagen.
The scientific results and political effects of these projects have been significant. The climate curves and the greenhouse gases from the ice cores have been central to the scientific contribution to the political discussions on global climate change.
After retirement in 1992, he kept up his working relationship with the group until age and fragile health forced him to slow down. The group has continued, and is today a centre of excellence for Ice and Climate at the Niels Bohr Institute funded by the Danish National Research Foundation.
As teacher and ‘boss’ Willi Dansgaard was never dull. Whole gererations of students within medicine, geology, geography and physics have felt his sharp tongue when he experienced ‘sluggishness and sloppiness’ in his physics classes. However nobody doubted his competence. His style of leadership in the group was marked by his hot temper, his very short patience with ‘details’ and his strong focus on the scientific goals. He was very good at including everybody, senior as well as very junior, in important decisions and this created a very strong team spirit. Apart from his scientific productions, Dansgaard also wrote several books and popular articles on his work and he authored comprehensive teaching material which is still in use.
Willi Dansgaard received the Hans Egede Medal from the Royal Danish Geographical Society, the Vega Medal from the Royal Swedish Society of Geography and Anthropology, the Tyler Prize from University of Southern California, the Seligman Crystal from the International Glaciological Society and the Crafoord Prize, which he shared with Professor Nicholas Shackleton. He was member of the Royal Danish Academy of Science and Letters, of the Royal Swedish Science Academy and the Icelandic Science Academy.
Willi Dansgaard will be sorely missed by the researchers at the Centre of Ice and Climate; but he lives on in our research. He leaves behind three children and 6 grand children.
