Passing of Claude Lorius: A Pioneer in Polar and Climate Research

Claude Lorius met the polar regions at the time of the International Geophysical Year. He wintered over in 1957 as meteorologist and snow physicist with two other colleagues at the Antarctic station of Charcot. Then, instead of embracing a professional soccer career opportunity, he chose science and got a PhD, in 1963 in Paris. His work dealt with the use of Deuterium content of Antarctic snow and ice as a climate indicator, similarly to what Willy Dansgaard developed previously in Greenland, but with oxygen isotopes. In Paris, a small research group was then constituted around Claude Lorius and the French polar expeditions led by Paul Emile Victor. The snow and ice analysis were performed at the “Centre d’études nucléaires” of Saclay with the advice of Etienne Roth and Jacques Labeyrie. In 1969, Claude Lorius and his team moved to Grenoble, joining the “Laboratoire de Glaciologie” of CNRS, directed at that time by Prof. Louis Lliboutry. Claude Lorius contributed to the teaching courses in geophysics and glaciology created by Lliboutry, for PhD students. The new facilities built on the Grenoble University campus saw the emergence of an important staff of technicians and engineers for building ice core drilling systems, for ice core processing (clean rooms) and for ice core storage. Lorius became Director of the LGGE from 1984 to 1988.

The International Antarctic Glaciological Project (IAGP) initiated in 1967 by the US glaciologist Albert Crary, under the auspices of the Scientific Committee on Antarctic research (SCAR), became effective by 1970 with the objective to investigate the vast plateau of East Antarctica. This was done by the organisation of tractor traverses, by long range radio-echo sounding flights (led by G de Q Robin), allowing selection of sites for deep ice core drilling. IAGP gathered researchers from the USA, USSR, UK, France, Australia and Japan. After a series of reconnaissance traverses in Adelie Land on the way to Vostok, Lorius and his team, successfully performed a 900m deep ice core drilling at the Dome C, during the 1977-78 summer season, benefiting from the logistic support from the US NSF Department of Polar Programs (DPP). The resulting 30,000-year climate record provided access to the last deglaciation and revealed a 9°C temperature change between the last glacial period and the Holocene.

Notwithstanding in 1980, the setting-up of a new technique for CO₂ measurement by the geochemist Robert Delmas and his students, made an invaluable added value to the ice core research. In 1981, during IAGP and SCAR meetings, the USSR delegation (among them Nartsiss Barkov) proposed to Lorius and his team to collaborate for the study of their 2000m deep ice core, recently extracted at Vostok station. The US-NSF DPP agreed to support the field operations. During the field season 1984/1985, Claude Lorius, with his fellows Jean-Robert Petit and Michel Creseveur, reached Vostok station and selected several tens of ice core samples for further analyses in France. The major milestone of this “Antarctic cornucopia” appeared as three scientific papers devoted to the joint analysis of deuterium/hydrogen and carbon dioxide along the Vostok ice core, published in Nature in 1987. The papers described for the first time 160,000-year of combined climate and CO₂ evolutions and for the first time evidenced their close co-variations. This tryptic paper made a “big-bang” within the scientific community, especially for paleoceanographers as the carbon cycle appeared indubitably linked to climate. Top of this, a modelling paper led by Lorius and published in 1990 in Nature, evaluated the sensitivity of climate to greenhouse gas (CO₂ and methane) along with its implications on the expected global warming under continuing increased emissions due to human activities. In 2023, the sixth IPCC report confirms with certainty the role of human activities on climate, providing a relevant echo to this predictive 1990 Lorius et al.’s paper.

While USSR collapsed in 1989, the Vostok project continued though a 10 years USA-Russia-France tripartite collaboration. Lorius again played a key diplomatic role for such an agreement. In spite of field difficulties, thanks to the US NSF and French Polar Institute IPEV logistic supports, field operations resumed. The drilling operations reached more than 3600m of depth in 1998, extending the climate and greenhouse gas records over the last 400,000-years.