05-28-2007 - Earth

sagar: Author=’Jorge Salazar’ program=’5169′ video=”Listen to a 6-minute podcast with David Vaughan discussing the uncertain fate of the West Antarctic ice sheet. A person stands underneath a natural arch in a glacier at Norsel Point, Anvers Island, Antarctica. See more photos of Antarctica at the Antarctic Photo Library.Antarctica is speeding up its delivery of ice and snow to the ocean, and scientists aren’t sure why.

What’s unclear is whether or not humans, through the emission of greenhouse gases that warm the atmosphere, are responsible.

That’s according to glaciologist David Vaughan of the British Antarctic Survey. He spoke to Earth & Sky about Western Antarctica.

David Vaughan: _This part of Antarctica is too cold at the moment. It doesn’t get any melting, even in the warmest summer days. So, it’s not just a question of atmospheric warming causing more melt. Actually, what we think is the cause is changes in the oceans. And the oceans, either the temperature of the water into which these glaciers are flowing or perhaps the amount of warm water that’s delivered to the edges of these glaciers may be causing a change._

It’s estimated that yearly net losses of Antarctica’s ice total about 25 billion metric tons.

David Vaughan: _Recent observations of just how rapidly the West Antarctic ice sheet, and also Greenland, are changing means that we don’t at the present have enough information to make concrete predictions about how these things are going to change in the future._

Those changes, Vaughan added, could significantly add to sea level rise.

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Written by EarthSky