Scientists have been warning that West Antarctica's glaciers might be melting for years now, but two new studies appear to confirm it — and that the melting is past the point of no return. (Via Wikimedia Commons / Dave Pape) The two studies both agree that large portions of the West Antarctic ice sheet are in decline, and that the water they stand to contribute to Earth's oceans could raise sea levels by four feet all over the world. (Via NASA) The two papers used different techniques to arrive at the same conclusion: one used sophisticated computer models, the other satellite observations. What they found is that warm water from the oceans is eroding the Greenland-sized ice sheet from below. This animation from NASA shows how. Much of the ice sheet is below sea level, allowing the warm water to impact more and more of the glacier over time. And because of the geography of the land below, there's really nothing there to stop it.
A NASA researcher said in a press release, "The collapse of this sector of West Antarctica appears to be unstoppable." He also told LiveScience, "These glaciers will keep retreating for decades and even centuries to come and we can't stop it." It's been hard for scientists to measure the ice melt. On the surface, Antarctica's ice sheet doesn't appear to be shrinking over time. (Via National Snow and Ice Data Center) But the papers say that's because the sea ice, which grows outward, is being fed by melting land ice, which makes up the bulk of the glacier. Basically, the ice sheet is getting larger, but is also spreading thinner and with less ice underneath it. If there's some good news out of the story, it's that the timeline is a little forgiving. The New York Times reports, "The rise may continue to be relatively slow for at least the next century or so." So we have a little breathing room, but the paper then adds, "Sometime after that it will probably speed up so sharply as to become a crisis." The most forgiving estimates say it will take nearly 1,000 years for the ice shelf to completely collapse, but at the soonest that could come within two centuries.