Ice in the Pacific Northwest is temporary, mainly forming in winter and melting in summer. For studying ancient climate changes, scientists turn to Antarctica, where ice has accumulated for over 13 million years. Researchers from Oregon State University’s Center for Oldest Ice Exploration (COLDEX) have discovered the oldest directly dated ice, estimated to be 6 million years old, at Arran Hills.
This ice, pushed to the surface by slow currents, allowed the team to drill only 300 to 600 feet deep, much less than typically required in Antarctica. By analyzing trapped gas concentrations, the team could infer past temperatures and atmospheric CO2 levels, revealing that Antarctica’s climate has cooled by over 20 degrees Celsius in the last six million years, but is now warming rapidly—more than 5 degrees Celsius since 1950. This research helps contextualize current human-induced climate change.
The findings are published in the Proceedings of the National Academy of Sciences.
