by K. Richard, Sept 5, 2022 in NoTricksZone
Abundant polar bear remains dating to 8000 to 9000 years ago have been found on Zhokhov Island, which is today surrounded by year-round sea ice (even in summer). This Arctic latitude (76°N) is too cold and thus too ice-covered for polar bears to inhabit today.
During the Early Holocene CO2 concentrations ranged between 255 to 265 ppm, and yet the Arctic was 5-7°C warmer than it is today and many regions that are now sea ice-covered were sea ice-free.
For example, Zhokhov Island is tundra and treeless today. It’s surrounded by permanent sea ice, making it inaccessible to wildlife.