The Long-Extinct Polar Bears

So, we're told that with the arctic ice cap melting, polar bears are in danger of extinction due to loss of habitat and (as implied by bear-on-iceberg pictures) drowning. If that's so, then I have awful news for all polar bear lovers:

Recent mapping of a number of raised beach ridges on the north coast of Greenland suggests that the ice cover in the Arctic Ocean was greatly reduced some 6000-7000 years ago. The Arctic Ocean may have been periodically ice free.

Little-to-no Artic ice = no polar bears, ergo polar bears have been extinct for 6000 years. Q.E.D. Why, to believe otherwise would imply that animals can actually adapt to different climates and environments -- and everyone knows that the ecosystem is crippled by Waterford crystal-level fragility. So, dear readers, I urge you to do something earth-friendly today... in memory of the polar bears.