The glaciologist Claude Lorius, who has just passed away at the age of 91, was one of the first to highlight the role of CO2 in global warming, thanks to numerous expeditions to Antarctica, this continent that he loved so much.
"
I did not choose science, I chose adventure
", had confided to AFP this pioneer of climatology, born on February 27, 1932 in Besançon (eastern France).
"
We were extraordinarily lucky because Antarctica happens to be the best place to realize that there is a planetary environmental problem
", noted the man who often preferred "
we
" to "
I
".
Many polar expeditions
In the great tradition of Paul-Émile Victor, Claude Lorius will have led 22 polar expeditions, in Greenland but especially in Antarctica, where he will have lived, in total, six years, since his very first mission in 1957. Already octogenarian, he was there returned for Luc Jacquet's film, "
The Ice and the Sky
", presented at the close of the 2015 Cannes Film Festival and devoted to the career of this extraordinary scientist.
In 1955, Lorius, a freshly graduated student from the Faculty of Sciences of Besançon, answered an advertisement to participate in a mission within the framework of the "
international geophysical year
", a research program carried out by 67 countries to unravel the mysteries of cold continent.
At the Charcot base, 320 km inside Antarctica, reached after two months of navigation and four weeks of raids, he faced extreme living conditions for a year: 20 m2 of "burrow" for three
researchers
, -40°C outside, no refueling possible, isolation due to faulty radio.
"
We stayed for months cut off from the world, that's where I learned the ability to live together, solidarity
," he recalled.
A lover of the white continent, Claude Lorius would often return there, working with Americans and Russians in the midst of the Cold War, surveying the frozen desert, and contributing to founding a new science: climatology.
Because little by little, researchers are reconstructing the evolution of past climates by studying the isotopic composition of increasingly ancient ice, taken from increasingly deep cores.
An ice cube in his whiskey
In 1965, the reaction in his whiskey of an ice cube (taken from a carrot!) puts Lorius on another track: the ice contains air bubbles... which are all samples of an old atmosphere!
It reveals “
the impact of man on the life of the planet
”: “
There are even traces of the fallout from French nuclear tests!
recalled the researcher.
Years of analysis enabled him to publish in 1987 in the journal Nature, with several colleagues, an article establishing the link between temperatures and greenhouse gas content over 150,000 years.
A discovery that will contribute to awareness of the reality of global warming and to launch in 1988 the IPCC, the group of experts under the aegis of the UN on climate.
In early reports, he contributes chapters on changing climate balances and rising sea levels.
A visionary"
For his colleague and friend Jean Jouzel, Claude Lorius was a “
visionary
” and “
a clan leader, the first Frenchman to believe in the potential of glaciology in the polar region
”.
Claude Lorius “
came to a revelation that concerns us all.
Everyone has to appropriate this part of history
”, emphasizes the researcher Jérôme Chappellaz, who succeeded him at the Laboratory of Geophysics and Glaciology in Grenoble.
The role of CO2 emissions of human origin prompted Claude Lorius to theorize, in a book published in 2011, the advent of a new geological era: the Anthropocene, when man has become "the determining agent
"
. of life on Earth.
"
We have the impression that the world finally understands that we are going into a wall
", he said as the Paris climate conference approached at the end of 2015. "
But the implementation of solutions is something else
“, he noted, worried about the countries of the South, “
very threatened
” by global warming.
He liked to recall that in the 1950s, the States knew how to go beyond the Cold War to sign the Antarctic Treaty.
“
Solidarity is the only way to get out of vital difficulties
”, said this father of three children, member of the Academy of Sciences, the first Frenchman to receive the Blue Planet Prize.