New Jersey researcher Kay Bidle of Rutgers University recently extracted DNA and bacteria from ice core samples taken off a glacier in Antarctica. The long frozen bacteria were then thawed, cultured and revived in a laboratory environment. Based on the depth of the ice cores, the separate samples were dated at 100,000 and 8,000,000 years. According to Bidle, "[w]e tried to grow them in media, and the young stuff grew really fast" as it doubled in mass every seven days. Researchers do not believe that global warming's introduction of ancient bacteria will pose a threat to humans.

EDIT: Two years later ... Jersey Shore began. The threat is real.