Overview
- The paper published in Science on Thursday reports that the Barnes Ice Cap on Baffin Island began re-expanding about 2,000 years ago, a change the authors interpret as the start of a new glacial phase.
- Researchers reconstructed that history by dating bedrock with beryllium-10 exposure ages and by radiocarbon dating plants that were entombed and then re-exposed as the ice advanced and later retreated.
- Field measurements and historic aerial photos show the ice cap continued to grow until about the 1960s, then reversed course and has averaged roughly 4 meters of edge retreat per year since the 1980s.
- The study and outside experts link the post-1960s retreat to rising temperatures from fossil-fuel emissions, and glacier models cited by the authors project the Barnes Ice Cap could vanish within the next few centuries.
- The findings prompt scientists to rethink how glacial periods are defined because early renewed ice growth can precede continental ice-sheet build-up, and the loss of the Laurentide remnant could change how future glaciations begin and how researchers reconstruct past climate cycles.