Scientists have uncovered a six-million-year-old chunk of ice—the oldest of its kind ever found—and it’s helping experts reconstruct the planet’s ancient climate. A new study has revealed that ice samples previously thought to be the oldest are approximately 2.7 million years old; however, a recent discovery in the Allan Hills region of Antarctica is more than double that age.

In a statement, Sarah Shackleton, lead author and assistant scientist at the Woods Hole Oceanographic Institution in Massachusetts, said: “Ice cores are like time machines that let scientists take a look at what our planet was like in the past.”

“The Allan Hills cores helped us travel much further back than we imagined possible.”

The ice and air dates back 23 million to 5.3 million years ago in the Miocene age, when the Earth was warmer, sea levels were higher, and the Earth was filled with now-extinct creatures, such as sabre-toothed cats, okapi-like giraffes, Arctic rhinos, and the first mammoths, reports Live Science.

Ms Shackleton and her colleagues discovered the ice between 2019 and 2023 in East Antarctica’s remote region. The Allan Hills ice field sits approximately 6,500 feet above sea level.

The researchers drilled 330 to 660 feet down into an ice sheet to obtain samples, which they then dated by measuring radioactive decay in the argon isotopes present in the air pockets.

They were also able to determine that the Allan Hill region has undergone a steady cooling of approximately 12C over the past six million years, according to a statement released by Oregon State University, which was also involved in the research.

Antarctica and the Earth as a whole have steadily cooled over recent millennia. However, global temperatures are increasing rapidly as a result of the release of large amounts of heat-trapping greenhouse gases into the atmosphere.

The authors of the new study have shared that by investigating the ice cores, they were able to decipher ancient levels of greenhouse gases and ocean warming, allowing them to better understand the natural drivers of climate change throughout Earth’s history.