Princeton University researchers have unearthed a trove of climate history by extracting 2 million-year-old ice cores from Antarctica containing trapped samples of ancient atmosphere. Analysis of the frozen bubbles affirms the link between greenhouse gases and global temperature, while also answering long-held questions about how our current glacial cycle emerged.
The historic ice cores were collected in the remote Allan Hills of Antarctica by the research group of John Higgins, associate professor of geosciences, led by Yuzhen Yan, who received his Ph.D. at Princeton in geosciences.
A previous team led by Higgins recovered a 1-million-year-old ice core from the Allan Hills, which was the oldest ice core ever recorded by scientists when it was reported in 2015. The cores were dated by measuring isotopes of argon gas trapped in bubbles in the ice, a technique developed by Michael Bender, professor of geosciences, emeritus.
Gas bubbles trapped in the cores contain pristine samples of carbon dioxide, methane and other gases that serve as “snapshots” of prehistoric atmospheric conditions and temperatures.