The field site in East Antarctica, which has been frozen for more than 14
million years.
(December 15, 2015) Antarctica
was once a balmier place, lush with plants and lakes. Figuring out just how
long the continent has been a barren, cold desert of ice can give clues as to
how Antarctica responded to the effects of past climates and can perhaps also
indicate what to expect there in the future as Earth’s atmospheric
concentration of carbon dioxide grows.
In a new study in Scientific Reports, University of
Pennsylvania researchers use an innovative technique to date one of
Antarctica’s ancient lake deposits. They found that the deposits have remained
frozen for at least the last 14 million years, suggesting that the surrounding
region, the East Antarctic Ice Sheet, or EAIS, has likewise remained intact.
The work adds new support for the idea that the EAIS did not
experience significant melting even during the Pliocene, a period from 3 to 5
million years ago, when carbon dioxide concentrations rivaled what they are
today.
“The Pliocene is sometimes thought to be an analog to what
Earth will be like if global warming continues,” said Jane K. Willenbring, an
assistant professor in the Department of Earth and Environmental Science in
Penn’s School of Arts & Sciences. “This gives us some hope that the East
Antarctic Ice Sheet could be stable in today’s and future climate conditions.”
Willenbring collaborated on the study with lead author and
Penn graduate student Rachel D. Valletta, as well as Adam R. Lewis and Allan C.
Ashworth from North Dakota State University and Marc Caffee from Purdue
University.