Scientists scrambling to understand current climate and pollution trends are peering centuries into the past, long before the dawn of the industrial age. Late this past summer researchers and engineers from France, Italy and Russia extracted three ice cores from France’s Col du Dôme Glacier in a race to preserve valuable information about climate change before rising temperatures wash it away.
There is ample reason for concern. According to NASA’s September 2016 climate data, the previous 10 months have been the hottest on record for each of those months out of the last 136 years—since modern weather recording started. In fact, for a few days in July 2015, the Col du Dôme’s surface temperature rose above freezing, causing alarm among weather scientists.
The Col du Dôme mission, in the Alps’s Mont Blanc massif at an elevation of 4,300 meters, marks the beginning of an ambitious project to collect ice cores from other parts of the world as well. According to Patrick Ginot, a research engineer at the Institute of Research for Development in Marseille and project leader of the Protecting Ice Memory project, ice cores are important in studying climate change and the environment because they contain vital information related to both. Gases including methane and CO2 are trapped in bubbles found in ice, Ginot says.
Ginot and his team of researchers can also track aerosols—small particles in the atmosphere that fall with snow and get trapped and stored in the ice, layer by layer, as the years pass. “We use sulfate and black carbon concentration tracers to track pollution, for example,” Ginot says. Black carbon is an aerosol emitted by incomplete combustion from vehicles and factories. Sulfate is emitted by human activities in addition to natural emissions such as volcanoes. “With these techniques we can reconstruct evolution of environmental parameters and atmospheric conditions of the past,” he says.
In storing these ice cores for future generations, the scientists say they hope to create an archive that has never been attempted on this scale. “We want to preserve the information contained in the glaciers before they start melting,” says Carlo Barbante, professor of analytical chemistry at the University of Venice and a co-founder of the project. “It is urgent because in the last 10 years the annual mean temperature on the Col du Dôme has risen by 1.5 degrees C, from –14 degrees Celsius to –12.5 degrees Celsius.”
Water from the Col du Dôme’s melting surface could easily infiltrate the glacier’s underlying layers and damage chemical data, says Jérôme Chappellaz, Protecting Ice Memory co-founder and a research director at the National Center for Scientific Research in Paris. Frozen water has an isotopic composition that gives clues about past temperatures, Barbante says. An isotope is a variant of an element that has the same atomic number but different mass number. “During the evaporation of the water from the ocean, the water molecules formed by lighter isotopes will get preferentially evaporated, while during condensation the heavier isotopes will condense more effectively,” he says. This process is a function of the temperature, so in looking at the isotopic composition in the different dated layers of the ice, scientists can study the temperature of the past.
Ice cores must be extracted before global warming melts them. “Ice cores are like books,” Barbante explains. “They contain information of climate and environment year by year. Snow entraps dust from the atmosphere, and glacial ice contains information about the composition of the atmosphere from the past.”
The project began August 15, when helicopters plopped the researchers onto the Col du Dôme Glacier. In 12 days the team pulled ice cores from three different sites, drilling down 130 meters at each stop. Each cylindrical core is a meter long and 102 millimeters in diameter, Ginot says. “For each site we drilled for one meter, extracted the core and started again—130 times. We extracted samples and packed them in boxes. Each box contained six samples and weighed 50 kilograms,” he says.
The boxes were taken by helicopter and freezer truck to the city of Grenoble, where they are now stored in huge freezers. The cores from one of the sites will be analyzed at Venice and Grenoble; those from the remaining two will be transported by a research ship equipped with advanced freezing systems—and then by tracked vehicles to the Concordia Research Station in Antarctica in 2020. France’s Polar Institute Paul-Émile Victor and its partner, Italy’s National Antarctic Research Program manage the station, which is 3,800 meters above sea level and has an annual average temperature of –55 degrees C. Ultimately, the project would store dozens of ice cores from glaciers around the world, safely dug into the snow in the world’s safest freezer, Chappellaz says.
There is an urgent need for such climate study projects in temperate regions across the world, says Eric Rignot, principal scientist at the NASA Jet Propulsion Laboratory’s Radar Science and Engineering Section. He was not involved in the Protecting Ice Memory project. “There are already places in the Andes, for instance, where records of the last 30 to 40 years have disappeared because of surface ice melting,” Rignot says. “There are other places in the world from where the record of the past decade is melting away. If we wait any longer, we will lose records of not just the last few decades, but of up to a century or more.”
Ginot’s team is not alone. Lonnie Thompson, an earth scientist at The Ohio State University’s Byrd Polar Research Center who also is not part of the project and has been drilling ice cores on the world’s highest mountain ranges for 38 years. Although the successful recovery of the cores from Mont Blanc is an excellent first step, the recovery of the anticipated future cores will be much more difficult due to logistical challenges and the fact that the programs will have to be conducted in numerous politically diverse countries such as India and China, he says.
Ice archives are in principle an intriguing idea, but Thompson said he worries about long-term physical and political accessibility of the Antarctica archive as well as how the ice cores will be safeguarded from the ravages of time. There are several factors, including different people and different governments with different priorities as well as the alteration of the archive that occurs over time via such slow processes as ice sublimation and recrystallization.
Barbante says his team plans to set up an international steering committee with rules accepted by everybody. “Antarctica has no sovereignty,” he says. “It is international governance that will guarantee accessibility to everybody in the future.”
The French-led team from Protect Ice has now set its sights on Illimani Glacier in Bolivia, with an expedition tentatively scheduled for next May. That glacier is 6,300 meters above sea level, and Ginot says it will be far more challenging than Col du Dôme. For one, helicopters cannot fly at that elevation. “Most instruments will be transported on researchers’ shoulders or on mules as far up as we can, and then we climb on our own,” he says. “It won’t be easy. It will be both an alpinist and a scientific expedition.”