Last Tuesday, this glaciologist with strong convictions passed away at the age of 91, leaving behind him a rich legacy of discoveries and adventures to the scientific world, but also to a wider public who became aware with him and his teams that global warming was on its way.
Last week the climate was in the spotlight, the synthesis of the latest IPCC report was released. A Senate committee consulted with French experts to further refine their polar strategy. But also, unfortunately, Claude Lorius has passed away, he who was a driving force for polar science. In the face of this bereavement his family wishes to remain discreet. His passing has also brought sadness to a community of scientists who were influenced by one of the pioneers of ice core science, and more broadly to those concerned with polar latitudes or climate history.
By answering an ad in a newspaper to go on a mission, Claude Lorius gives up his career as a soccer player. He then took part in the Charcot expedition of 1958 and wintered in Antarctica with two comrades in a small station under the snow. He measures the weather and the height of the snow in harsh conditions. “He was an adventurer, he participated in this first daring wintering, he was an old-fashioned explorer with an amateur radio that worked more or less well, that shaped his character,” describes the explorer Jean-Louis Etienne.
A well-launched career that will continue with the exploits of ice-coring. We all know by now the anecdote of the glass of Whisky and the ice releasing air bubbles after hundreds or thousands of years of embrace, which he shares with the Australian glaciologist Bill Budd. The man not only had intuition, but also strong convictions. Strong enough to see his projects through to the end. In his profession as a glaciologist, he shone above all in his ability to convince, animate and activate networks.
He was the one who obtained the analysis of the Vostok ice samples, he had the knowledge of the international financing and research systems and above all an international network of colleagues and friends,” explains Catherine Ritz, a climatologist and research director at the Institute of Environmental Geosciences. He knew well glaciologists like the Australian Bill Budd [1938-2022], Dick Cameron of the National Science Foundation [NSF], he kept in touch with the Dane Willi Dansgaard, or the Swiss Hans Oeschger [1927-1998]. He was close to Russians like Nartsis Barkov or Volodya Kotlyakov director of the Moscow Geographical Institute. He was president of the Scientific Committee for Antarctic Research [SCAR] a little before 1990; to do this you have to know people.
“He managed to bring the Americans to the center of Antarctica by plane, to the Soviets in the middle of the Cold War,” adds Catherine Ritz. The latter was a student in glaciology in 1976 in Grenoble where Claude Lorius was teaching. She remembers seeing her team prepare for the first drillings in the ice of Dome C at 3,233 m on the Antarctic ice cap before defending her thesis in 1980 before a jury that also included Claude Lorius.
During the deep ice drilling at Dome C, between 1977 and 1978, we went down to 900 m,” says Dominique Raynaud, a researcher emeritus at the CNRS, who was Claude Lorius’ first thesis student on the subject of air bubbles in the ice. The USA had drilled in Greenland with the Danes, then near the Byrd station in Antarctica at a depth of more than 2,000 m. The Americans then stopped a bit, but not Claude Lorius.
“He was an extraordinary man and he was convinced that in Antarctica we could go even deeper. Claude had a vision, and he had the intuition that we were going to find the composition of greenhouse gases in the past, that was his common thread, his red thread as we say,” adds Dominique Raynaud. He had a halo of a polar hero, when he came back from a mission with a tan complexion from the reflection of the light on the ice, that fascinated me.
When Dominique Raynaud was just finishing his studies, he wrote to Paul-Émile Victor asking him to go to Antarctica. The latter had answered him, that a certain Claude Lorius could perhaps propose him a subject of thesis. “He had his office in an attic of the Collège de France, near the Sorbonne,” added his first disciple.
The climate archives
Claude Lorius played a coordinating role so that scientists from different disciplines could decipher the history of the atmosphere and climate in the ice cores. I was in the gas group for CO2 and methane measurements,” recalls Dominique Raynaud. I was in charge of the quantities of air bubbles in the ice. At the same time, Jean Jouzel was working on the isotopy of the ice, which allows us to decipher temperature variations. There was also a group of chemistry and dust of the atmosphere. He had surrounded himself with specialists.”
Claude Lorius transmitted the isotopic values measured by Jean Jouzel and his acolytes from Paris to Catherine Ritz in Grenoble, for example. From the isotopic composition and the depth, I was trying to find the age of the ice,” she explains. Over time, as the ice layers sink, they become thinner. To determine their age, I had to reconstruct the mechanical history of the glacier and the precipitation.” This is the only archive where we measure both the composition of the atmosphere at the time, and the temperature through water isotopes. “Except maybe bubbles stuck in amber,” she adds.
There was a paper by Robert Delmas (1940-2023), a glacio-chemist who succeeded in refining the measurement of CO2 in ice cores and suggested that ice formed during cold periods was depleted of carbon dioxide. Then, the first dome C campaigns allowed to trace the beginning of the climate history curve and to go back 30 thousand years. With the observation that it was about 10°C less in Antarctica 20 thousand years ago for a lesser amount of CO2.
“Although CO2 has been known for a century for its warming potential, the measurement of greenhouse gases in ice cores has shown the link between these gases and climate. The warmer it is, the more CO2 and methane there is in the atmosphere. We then understood that these gases amplified the warming of the climate,” adds Catherine Ritz. Thus, there was Vostok I, the curve went back to 150 thousand years. In Vostok II, the curve has been traced back to 400 thousand years and several glacial-interglacial cycles have been documented. Finally with Epica (dome C II) in the 2000s, the European scientific community has reached 800 thousand years of records. “This was the peak of Claude Lorius and his team,” says Dominique Raynaud.
Claude Lorius has become, through his pedagogy, an inspiration to become aware of the threats to the future of the climate,” confides Jean-Louis Étienne. “I have always referred to this curve and the field work experience of Claude Lorius.” The explorer and the glaciologist have crossed paths on several occasions, such as at the end of Jean-Louis Étienne’s Antarctic crossing by sled dogs, during the recovery of the expedition organized by Elsa Pény-Étienne, who had chartered the icebreaker Yamal. “He had come to give lectures on board to more than 150 passengers,” she completes, “He was warm and human.”
Claude Lorius was a true leader of men, enthusiastic about ice, science and Antarctica. Communicative, he had a power of presence by his voice and his personality, he knew how to be listened to and to make a generation of young people want to follow his path.
We were like a family that got along quite well and the older Claude got, the more friendship welded me to him,” admits Dominique Raynaud. He was a great man.
Camille Lin, PolarJournal
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