Scientists Drill 1.7 Miles Into Antarctic Ice, Revealing 1.2 Million Years of Climate History

Scientists have drilled 1.7 miles deep into Antarctica, pulling up an ice core sample that dates back at least 1.2 million years.

They expect the sample to offer new insights into the evolution of Earth’s climate and atmosphere throughout history.

A team of 16 scientists and support staffers spent four summers drilling through Antarctic ice until they finally reached bedrock. To accomplish their goal, they endured average temperatures of -25.6 degrees Fahrenheit at a site known as Little Dome C, located near Concordia Research Station.

They removed the ice core in pieces, which they will load onto an icebreaker ship called the Laura Bassi for transport to Europe, according to a statement. On the vessel, the ice cores will be kept at -58 degrees Fahrenheit in specialized cold containers, reports CBC News.

The pieces can be reassembled once they reach their final destination. At 1.7 miles long in total, the ice core is longer than eight Eiffel Towers stacked on top of each other.

Ice core cleaning-cutting

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Previously, the same group had extracted an ice core from Antarctica dating back 800,000 years through an initiative called the European Project for Ice Coring in Antarctica (EPICA). But they wanted to reach ice that was even older, so they launched the Beyond EPICA - Oldest Ice project, which was funded by the European Commission.

The oldest ice ever extracted from Antarctica was gathered in 2017 and dates back 2.7 million years. However, that sample was collected closer to the surface, thanks to natural processes that push up layers of older blue ice. The new ice core represents the longest continuous record of Earth’s past climate from an ice core. 

Scientists say ice core samples are useful tools for investigating how the planet’s climate has changed over time. When snowflakes fall in the polar regions, they capture chemicals and particles from the air, according to the National Science Foundation. When they land, the snowflakes compress into layers of ice, which build up year after year—similar to the rings of a tree.

The chemicals and particles are frozen into the layers, along with air bubbles.

“Sometimes you see ash layers coming from volcanic eruptions,” says Carlo Barbante, a glaciologist who coordinated the Beyond EPICA project and serves as the director of the Polar Science Institute at Italy’s National Research Council, to BBC News’ Georgina Rannard. “You see the tiny bubbles inside, some bubbles of air that our ancestors breathed a million years ago.”

When scientists extract ice cores, the youngest ice is at the top, and the oldest ice is at the bottom. These frozen columns effectively allow researchers to look back in time.

“[Ice cores] are really the closest you can get to going back in the time machine and being able to measure what the atmosphere was like in the past,” says John Higgins, a geoscientist with the National Science Foundation’s Center for Oldest Ice Research and Exploration (COLDEX), to CBC News.

With the latest Antarctic ice core, scientists hope to learn how levels of greenhouse gases have changed over millennia. Scientists say that understanding Earth’s climate history can help them make more accurate predictions about what might happen with the climate in the future.

From the 800,000-year-old ice core, for example, they gleaned that greenhouse gas concentrations have never been as high as they are in the modern era.

“Today we are seeing carbon dioxide levels that are 50 percent above the highest levels we’ve had over the last 800,000 years,” Barbante tells the Associated Press’ Paolo Santalucia.

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Sarah Kuta is a writer and editor based in Longmont, Colorado. She covers history, science, travel, food and beverage, sustainability, economics and other topics.