Princeton University-led researchers have extracted 2 million-year-old ice cores from Antarctica that provide the first direct observations of Earth's climate at a time when the furred early ancestors of modern humans still roamed.
Gas bubbles trapped in the cores - which are the oldest yet recovered - contain pristine samples of carbon dioxide, methane and other gases that serve as "snapshots" of prehistoric atmospheric conditions and temperatures, the researchers recently reported in the journal Nature. The cores were collected in the remote Allan Hills of Antarctica.
First author Yuzhen Yan, who received his Ph.D. in geosciences from Princeton in 2019, explained that because ice flows and compresses over time, continual ice cores only extend back to 800,000 years ago. The cores he and his co-authors retrieved are like scenes collected from a very long movie that do not show the whole film, but convey the overall plot.
Gas bubbles trapped in the cores contain pristine samples of carbon dioxide, methane and other gases that serve as "snapshots" of the ancient climate. Because ice flows and compresses over time, the cores the researchers retrieved are like scenes collected from a very long movie that do not show the whole film, but convey the overall plot.
"You don't get a sense of how things changed continually, but you get an idea of big changes over time," said Yan, whose graduate research on ice cores supported by a 2016 Walbridge Fund Graduate Award for Environmental Research from the Princeton Environmental Institute (PEI) was a basis for the current work.
The ice cores reported in Nature are the latest to come out of the research group of senior author John Higgins
