“This Is What a Holy Sh*t Moment for Global Warming Looks Like”

[Lodestar]

New Yorker
MAY 13, 2014
THE WEST ANTARCTIC ICE SHEET MELT: DEFENDING THE DRAMA

f you hang around climate scientists, you often hear the saying “Uncertainty is not our friend.” It came to mind yesterday, when two teams of scientists released papers that reached the same terrifying conclusion. A significant chunk of the West Antarctic Ice Sheet has begun to disintegrate and, owing to the ice sheet’s peculiar topography (much of it lies below sea level), this process, having begun, has now also become unstoppable. “Today we present observational evidence that a large section of the West Antarctic Ice Sheet has gone into irreversible retreat,” the lead author of one of the papers, Eric Rignot, a glaciologist at NASA’s Jet Propulsion Laboratory, said at a news conference. “It has passed the point of no return.” Rignot said that melting in the section of West Antarctica that his team had studied could cause global sea levels to rise by four feet over the course of a couple of centuries. Since the disappearance of some of its major glaciers could quite possibly destabilize the entire ice sheet, the ultimate sea level rise from West Antarctica, he said, could be triple that.

“Scary,” Stefan Rahmstorf, a professor of physics of the oceans at Potsdam University, who was not involved in either paper, tweeted. “One of the feared tipping points of the climate system appears to have been crossed.”

“This Is What a Holy Shit Moment for Global Warming Looks Like,” read a headline on the Web site of Mother Jones.

The vulnerability of the West Antarctic Ice Sheet, or WAIS, has been appreciated for a long time; all the way back in 1968, an eccentric Ohio State glaciologist named John Mercer observed that the WAIS was peculiarly unstable, and that it may have melted away in the geologically recent past. But Mercer (who, interestingly enough for a glaciologist, liked to do field work in the nude) published his observations in an obscure journal, and, according to the historian of science Spencer Weart, “did not push his views on colleagues.”

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