In reply to Denni: Calving is a pretty common way in which glaciers lose mass anyway. Chunks have been coming off the end for ages, and, in periods of equal mass balance (i.e. the glacier stays the same size, material in=material out) are replaced by just as much snow.
A calving event is no evidence of global warming, it just looks good on the news.
Having said that...most glaciers are in net mass loss anyway as a result of global warming. Just a little bugbear of mine when people go "whoa, look at that massive chunk of ice coming off, that global warming is messing things up".