Just would like to add my two cents...The time frames all of these scientists are working with -- estimations of ages of ice, estimations in future climate trends, etc...who's to say any of these figures are accurate. Generally these figures have been quoted as being multiple lifespans of time, and though a project can be continued for such extended periods of time the transfers of data, and turnover of data collectors, as well as shifts in measurement systems -- not saying that it has happened recently, though who is ever to say -- who can really say what is accurate and speculative?