Doubting Carbon Dating

As an introductory side-node, it is interesting that I found this article not via any of the intelligent-design sites I read, but via slashdot.

Anyway, the article says that a group of scientists have found that we need to "[rethink] how geologists interpret varations in the ¹³C/¹²C ratio throughout Earth's History."1 Or in other words, we really do not know how old anything that has been carbon-dated is.