Harmon Craig was born March 15, 1926 in New York City. He entered the University of Chicago in 1943 and, after serving in the U.S. Navy as an ensign between 1944 and 1946, graduated in 1947. In 1951, he received his Ph.D. from the University of Chicago in geology-geochemistry, and stayed on as a research associate at the University’s Enrico Fermi Institute for Nuclear Studies until 1955. He joined Scripps Institution of Oceanography, University of California, in 1955 and served as chairman of the Department of Earth Sciences from 1965 to 1968. He would stay with Scripps, most notably as professor of geochemistry and oceanography, until his death in 2003, one day shy of his 77th birthday.
Over the course of his scientific life Dr. Craig ventured to some of the remotest spots on Earth in search of elusive gases, rocks and other materials that could provide clues to the composition of the Earth’s interior. He descended into the crater of an active underwater volcano, led the first dives into the 2-mile-deep Mariana Trough, and sailed atop an erupting undersea volcano to collect rock and gas samples. He led some 30 deep-sea oceanographic expeditions and made nearly 20 dives to the bottom of the ocean in the ALVIN submersible.
These and other daring adventures yielded a host of significant scientific findings that would greatly enrich mankind’s understanding of the workings of the oceans, atmosphere and the deep Earth.
In 1957, Craig published a paper on the distribution of radioactive carbon-14 in the Earth's atmosphere and oceans and concluded that atmospheric carbon dioxide is replaced once every seven years by an exchange with the oceans, and that the global oceans circulate vertically at a rate of once every 700 years. (A similar conclusion was reached independently by Wallace S. Broecker of the Lamont-Doherty Earth Observatory, who shared the 1987 Vetlesen Prize with him.)
In 1969 Craig helped demonstrate that the isotope helium-3, trapped in the Earth’s interior at the time of its formation, was being released from mid-ocean volcanoes and sea-floor spreading centers. Craig also analyzed the gases trapped in Greenland ice cores and showed that the methane content of the atmosphere has doubled over the past three hundred years, a finding which is important for studies of the atmospheric greenhouse effect.
In 1970, Craig joined forces with Broecker and colleagues at Scripps and Woods Hole Oceanographic Institution to create and direct an international oceanographic project called Geochemical Ocean Sections Study (GEOSECS) for the investigation of the chemical and isotopic properties of the world’s oceans. The results obtained by the GEOSECS program represented the most complete set of ocean chemistry data to date and contributed significantly to the advancement of chemical oceanography. Based upon the data obtained during this program, Craig was able to estimate the rate of oxidation of organic carbon in the deep ocean. Other notable findings included the discovery of lead and other trace elements in the deep sea, and the existence of two major primordial helium-3 plumes marking the cores of westward-flowing water at mid-depths from the East Pacific Rise. The discovery of these two jets revealed for the first time the direction of horizontal flow and the nature of the circulation pattern in this major region of the Pacific.
Harmon Craig was widely acknowledged one as of the most rigorous experimental scientists and his experimental data are still respected as the world standard. He also demonstrated remarkable insight into the physical and chemical mechanisms involved in these processes. In recognition of his achievements, Dr. Craig received a number of honors. He was elected to membership of the American Academy of Arts and Sciences and of the National Academy of Sciences in 1979. He received the V. M. Goldschmidt Medal of the Geochemical Society also in 1979, a National Science Foundation "Special Creativity" award in oceanography in 1982, the Arthur L. Day Medal of the Geological Society of America in 1983, and the honorary degree of Docteur de l'Université de Paris (Pierre et Marie Curie) in 1983. He was also awarded the Arthur L. Day Prize and Lectureship of the National Academy of Sciences in 1987 and, in 1993, was named an honorary fellow of the European Union of Geosciences. In 1998 Craig was the first geochemist ever to receive the Balzan Prize, considered the equivalent of the Nobel Prize in the field of natural sciences.