Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with information on fascinating discoveries, scientific advances and much more..
CNN
—
An international research team has successfully drilled and recovered a 9,186-foot (2,800-meter) long ice core from Antarctica, dating back 1.2 million years. The sample extended so deep that it reached the bedrock beneath the Antarctic ice sheet.
The core, almost as long as 25 football fields end to end or six and a half times taller than the Empire State Building to the tip of its antenna, is a “time machine” that captures “an archive extraordinary of the earth’s climate. said Carlo Barbante, coordinator of Beyond EPICA, or the European Antarctic Ice Coring Project, the team that collected the core.
The team cut the core into 3.2-foot (1-meter) pieces stored in insulated boxes so they could be studied, said Barbante, a professor at Italy’s Ca’ Foscari University of Venice and a senior associate member from the Institute of Polar Sciences of the National Research Council of Italy.
The core was collected from Little Dome C, one of the most difficult and extreme places on Earth. The site is 34 kilometers from the Italian-French Concordia research station and is constantly subject to strong wind gusts and near-constant temperatures below minus 40 degrees Fahrenheit (minus 40 degrees Celsius).
The ice, one of the oldest formed on Earth, could provide answers to the biggest remaining questions about how the planet’s climate has changed over time.
“Air bubbles trapped in the ice core provide a direct snapshot of past atmospheric composition, including concentrations of greenhouse gases like carbon dioxide and methane,” Barbante said by email. “By analyzing them, we can reconstruct how Earth’s climate responded to changes in climate forcing factors, such as solar radiation, volcanic activity and orbital variations. These data help us understand the complex relationship between greenhouse gases and global temperature over hundreds of thousands of years and now up to 1.2 million year(s) and hopefully at beyond.
Scientists also hope the ice will shed light on what caused a sudden change in the timing of ice ages on Earth about 1 million years ago, an event that nearly caused ancient ancestors to become extinct humans, according to recent research.
The researchers collected the core during the fourth campaign of the Beyond EPICA — The oldest ice cream projectfunded by the European Commission. The campaign took place during the last Antarctic summer, between mid-November and mid-January. In total, experts from 12 European scientific institutions spent more than 200 days drilling and processing the ice over the past four summers.
The program builds on the objectives of the original EPICA project which ran from 1996 to 2008. During this period, researchers drilled a deep ice core which uncovered links between climate and greenhouse gases. atmospheric greenhouses over the last 800,000 years. The core collected during the latest campaign marks a new milestone, creating a continuous record of Earth’s climate that stretches back even further.
Studies of the original EPICA core showed that Earth’s climate has experienced a 100,000-year cycle of cold glacial periods, or ice ages, interspersed with warmer periods. But this discovery does not match marine sediments that revealed Earth experienced ice ages 41,000 years before 1 million years ago.
The Beyond EPICA project began in 2016 with the aim of finding older ice that could explain why this change occurred, and the search for the right site began with the use of radar surveys.
Radio echo-sounding technologies helped team members zero in on the ice likely to contain the time capsule they were searching for, said Frank Wilhelms, a principal investigator in the field and an assistant professor at the University. in Göttingen and at the Alfred Wegener Institute in Germany.
“We needed a Goldilocks site – ice thick enough for a well-resolved climate record at the greatest depth, but not so thick that the oldest ice had already melted,” said Dr Robert Mulvaney, glaciologist and paleoclimatologist at British Antarctic. Investigation.
“This can happen when heat escaping from the Earth’s mantle is trapped by a thick layer of insulating ice. If the ice is too thick, we can lose the lowest, oldest ice layers due to melting,” Mulvaney said. “That’s why we put a lot of effort into studying candidate areas to find the right site before drilling began.”
Little Dome C sits high on Antarctica’s central plateau, reaching an altitude of 10,498 feet (3,200 meters) above sea level, which presents many challenges. The team had to work to avoid drilling failures and ensure the electromechanical core drill progressed through the ice layers. Each meter of ice can hold up to 13,000 years of climate data, said Julien Westhoff, lead scientist in the field and a postdoctoral researcher at the University of Copenhagen in Denmark.
When the team members retrieved the core, they found what they were looking for. The lowest 688 feet (210 meters) of the core above bedrock consists of old ice that has been heavily deformed, likely mixed, refrozen and of unknown origin, the team said.
Analyzing the ice could help test theories about how it refroze beneath the ice sheet. Researchers will also determine whether even older ice, such as that of pre-Quaternary Period 2.58 million years ago, is present and helps date rocks beneath the ice to determine the last time this region of Antarctica was ice-free.
“It was exciting to see the ice age as we drilled deeper, and especially when we knew we were drilling ice older than the EPICA record, which ended 800,000 years ago,” Mulvaney said of the British Antarctic Survey in a press release. “This 1.2 million year record will give us several 41,000 year glacial cycles to compare with more recent data from the original EPICA core.”
The Middle Pleistocene transition, which occurred between 1.2 million and 900,000 years ago, marks a fundamental shift in Earth’s glacial cycles, Barbante said.
“This transition remains a scientific mystery, particularly regarding the role of greenhouse gases and ice sheet dynamics,” he said. “The Beyond EPICA ice core provides an unprecedented opportunity to directly measure atmospheric conditions during this pivotal period, which could potentially reveal answers about why this transition occurred and how it shaped the climate system of our planet.”
During the Middle Pleistocene transition, glacial periods became longer and more intense, leading to lower temperatures and dry climatic conditions. The global population also fell to about 1,280 breeding individuals between 930,000 and 813,000 years ago, then remained that small for about 117,000 years, according to a 2023 study published in the magazineScience. The study authors argue that this event “brought human ancestors closer to extinction,” but others are more skeptical.
Either way, the ice core could contain evidence as to why the change in the length of ice ages occurred.
Ice cores contain layers of snow that have been compressed over time, trapping air bubbles and particles that can be analyzed to reveal changes in Earth’s temperature and atmosphere.
They could help scientists understand how Earth’s climate has behaved in the past, better predict how things might change in the future, and provide context for how our planet responds to different concentrations of greenhouse gases.
“Antarctic ice cores are like Rosetta stones,” said Jim White, Craver family dean of the College of Arts and Sciences at the University of North Carolina at Chapel Hill, in an e- email. “They are unique in that they speak the language of temperature as well as (carbon dioxide) levels, allowing us to see how these two key climate variables interact.”
White was not involved in the recovery of the ice core. But he added that ice has the potential to provide a vast amount of information “about the fundamental dynamics of climate change on our planet, and the importance of this cannot be overstated.”
While preliminary analyzes took place on site, the ice core slices will be transported to Europe aboard the icebreaker Laura Bassi in specialized refrigerated containers to maintain the ideal temperature. Barbante anticipates the research will last several years as scientists delve deeper into measuring concentrations of gas and dust particles in the ice.
Meanwhile, the Beyond EPICA project, along with other international associations, will search for older ice that could reveal longer climate records. But such efforts will require more advanced technology and planning, Barbante said.
“We need to find other places in Antarctica where we can recover continuous climate records similar to the one we are studying,” he said.