A variety of news outlets has covered two papers published this week indicating that the Weddell Sea area of Antarctica might be susceptible to faster-than-expected ice loss, but most went astray in one way or another.
The most troublesome of the bunch was the piece from Reuters whose lede reads:
Scientists are predicting the disappearance of another vast ice shelf in Antarctica by the end of the century that will accelerate rising sea levels.
The ice shelf in question, named Filchner-Ronne, sits along the northwest coast of the continent and buttresses both West and East Antarctic ice sheets (it’s the sheets, which sit atop land, not the shelves, which affect sea level). Reuters reported that Filchner-Ronne is located “on the eastern side” of Antarctica, but that wasn’t its biggest mistake.
A paper published this week in the journal Nature describes how changing ocean currents could bring relatively warm water into contact with Filchner-Ronne’s underside, substantially increasing it melt rate. That could lead to a 20-fold increase in annual ice loss from the shelf by 2100—and accelerate flow from the ice sheets—but the paper does not say that the shelf will disappear by then.
How did Reuters come to that conclusion? The answer seems pretty clear.
Following a common practice among his peers, the study’s lead author, Harmut Hellmer, an oceanographer at the Alfred Wegener Institute in Germany, made a much stronger statement in a press release, predicting that Filchner-Ronne would “disintegrate by the end of this century.” Then, following a common practice among its peers, Reuters ignored the paper and quoted straight from the press release. That’s a problem.
“Hellmer put the right intensity in the paper and I think the press release probably went a little too far,” said Robert Bindschadler, a NASA glaciologist who has studied Antarctica for the past 25 years, in an interview.
That’s not to say that Filchner-Ronne isn’t in danger, or that if it were to disappear, the Antarctic ice sheet wouldn’t be imperiled. Ice shelves float atop the sea, so their breakup or melt doesn’t add to global sea level rise, but if they’re removed, the land-based ice sheets behind them can flow more quickly into the sea, and that does raise the water level. But headlines like one in Science News, which read, “Big Antarctic ice sheet appears doomed,” misrepresented what the Nature paper said. As Bindschadler explained:
That headline is a bit strong because it communicates this impending doom and implies a timescale that isn’t necessarily that short. So, I don’t like it in that regard. Now, we have evidence that every time the world has gotten warmer, sea level has gone up and ice sheets have shrunk. So the ice sheet probably is, in that sense, doomed. But that information isn’t all that helpful to people making policy decisions. We have to do better than that from the science side, and we have to emphasize timescale when we make statements like that.
If the Nature paper didn’t exactly spell doom for the Antarctic ice sheets, however, it did raise important new concerns about them, particularly the East ice sheet, which has long been considered more stable than its Western brother and holds vastly more ice.
An article from MSNBC.com, quoting Bindschadler, explained that the Filchner-Ronne ice shelf “is unusual in that it ‘sits on the fence’ between Antarctica’s two ice sheets, so it ‘can affect both sides.’”
A nice piece by Climate Central’s Michael Lemonick also addressed this aspect of Filchner-Ronne’s location:
Since the Filchner-Ronne is mostly fed by ice from the West Antarctic Ice Sheet, it’s natural to think that the much larger East Antarctic Ice Sheet, which holds enough ice to raise sea level by 160 feet or more, is safe But the safety is by no means guaranteed: the two sheets, which are separated by the Transantarctic Mountains, aren’t completely isolated from each other. If you lose the Filchner-Ronne, [Martin Siegert of the University of Edinburgh] said, ‘there will be knock-on effects. There will be consequences for East Antarctica.’
Both the MSNBC.com and Climate Central articles made clear that the East ice sheet hasn’t started to erode yet. Indeed, the West ice continues to be the focus of concern.
Siegert, who was quoted in Climate Central’s story, was one of the authors of the other paper about the Weddell Sea area published this week, which appeared in the journal Nature Geoscience. That study reported that the part of West Antarctic ice sheet next to the Filchner-Ronne ice shelf sits on ground that is below sea level and slopes steeply downward going inland, which could cause instability.