Jack stated in the first episode, "Now I'm just a regular Human" But, he also said that he returned to Earth as a result of the email mentioning Torchwood, meaning he was likely still off-world when the whole event went down. Does this mean that it is a temporal event affecting all Humans regardless of location (maybe even those time-travelling from this time? AKA AMY/Rory) Or is it a localized, planetary event that Jack just happened to be on the planet for?