COLUMBIA GLACIER, ALASKA
June 23, 2006
Columbia Glacier calves icebergs into Columbia Bay west of Valdez, AK. since 1984, the glacier has retreated 10.5 miles. This retreat is caused partly by global warming but mostly but dynamics of the glacier's drainage processes. When tidewater glaciers like this one reach an unstable phase, vast amounts of ice can be dumped very rapidly into the sea--and such processes are analogous to what will happen to the tidewater outlet glaciers of Greenland and Antarctica should those ice sheets reach a phase of instability caused by global warming. The ice shown in the bergs was deposited in the glacier centuries if not millennia ago, but is broken up and turned into seawater in a matter of years or decades once a recessional phase of the glacier begins.
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