London, September 19: A new study has determined that a 740,000-year-old wedge of ice discovered in central Yukon Territory, Canada, is the oldest known ice in North America, thus suggesting that permafrost has survived climates warmer than today’s.
“Previously, it was thought that the permafrost had completely disappeared from the interior about 120,000 years ago,” said Duane Froese, an earth scientist at the University of Alberta in Edmonton, Canada, who is the author of the study.
“This deep permafrost appears to have been stable for more than 700,000 years, including several periods that were warmer and wetter,” he added.