A sizeable flow of stories started up today on news of an enormous inland basin of backed-up ice along the Amundsen Sea in West Antarctica that has begun a slow collapse toward complete destruction. This is next to the Ross Sea, home of McMurdo Station that so many reporters have visited, and toward the Antarctic Peninsula. New data seem to the experts to signal a runaway situation. Over the the next few centuries it is calculated to raise sea level two feet or so as a pent-up glacial mass slides off the continent (or floats free as it thins enough to rise from sub-sea level bedrock) and pours icebergs into the sea. That's a slow collapse. But this is just one ice drainage sector of West Antarctica and that region accounts for less than half of the whole place. Enough of these cases pop up in Antarctica and Greenland and we have trouble and I mean trouble in shoreline cities and shoreline everything else too.
Some of the headlines are hyperventilated. (UPDATE: See Andrew C. Revkin's caution to reporters, at his NYTimes Dot Earth blog, who ignore the popular meaning of "collapse" when quoting from a formal research paper). But it smells like significant news. If the 'collapse' is well and truly underway, it vindicates glaciologists who for years have been fretting that the combined Pine Island Glacier, known among cryosphere cognoscenti as PIG, and its neighbor the Thwaites glacier are West Antarctica's soft underbelly. A passel of experts have said their retreat will be unstoppable if and when the ice fronts pull back well inland of coastal sea-floor ridges that have been physically slowing them down. Ice has built up miles-thick inland for millennia. They rest on bedrock that is mostly below sea level, an innately unstable predicament. The new reports say just such unpinning has now happened. The resulting acceleration in ice loss has begun several decades sooner than most had expected. And as these and nearby parts of the ice sheet disintegrate, the process could spread across most of West Antarctica leaving only an archipelago of islands among the bobbing bergy bits.
Today's news arises from two papers. Their associated press releases are linked below in Grist. One is in the American Geophysical Union's Geophysical Research Letters by workers at UC Irvine and NASA's Jet Propulsion Lab among others. the second is in Science Magazine by authors at the University of Washington. NASA had scheduled a press conference for noon Eastern today on the first paper. Prompted by science writers who noticed the second paper is in agreement, Science's editors moved up the embargo for its paper to coincide with the news briefing at NASA on the GRL paper (it was not subject to embargo).
To glaciologists this news is, other than its detail, no surprise. Possibility of a generalized collapse has generated intense discussion and debate for years. That provides plenty of material for further reporting beyond today's news break. Should anybody want a taste, here is a 15-month-old thread at a site, used mostly by scientists, called Arctic Sea Ice Forum (it ranges well beyond sea ice around the north pole). Some will say that intense media attention to unstoppable Antarctic ice melt only breeds resignation and fatalism in the public, a sapping of will to do anything about it. Perhaps. But the news is the news. Keeping climate change before the public, while also reporting genuine reasons to believe there remains time to alleviate its worst impacts, is a topic for another day.
- Time Magazine – Bryan Walsh: Antarctic Glacier Loss Is 'Unstoppable,' Study Says ; Bryan remarks that the IPCC "had projected that sea level will rise by about 35.5 in (98 cm) at most by 2100, but that prediction will likely need to be revisited in the wake of these new studies." Right. Except that I've heard climatologists grumble that they don't make predictions, they make forecasts. Whatever distinction there might be in those terms eludes me at the moment.
- BBC – Jonathan Amos: 'Nothing can stop retreat' of West Antarctic glaciers ; Well, actually, a new ice age would do it. Could be awhile. Amos does of course write that this collapse is slow motion in people time, but adds terme like "point of no return" to be sure readers don't miss the point. The reason is warm water eroding the ice tongues and other sea-level parts of the glaciers involved. The words "global warming" come up. Amos reports that because most of the bedrock beneath the glaciers is below sea level the process is irreversible for a very long time. Given the times, most important quote may be "The results are not based on computers simulations or numerical models; thay are based on the interpretation of observations." Climate change skeptics will of course leap gleefully upon suggestion that scientists can be trusted to interpret anything.
- Bloomberg News – Alex Morales: Antarctic glacier melting appears 'unstoppable,' NASA study says ; Right, but Morales missed the Science paper – where editors lifted the embargo yesterday in plenty of time to alert the press generally.
- Climate Central – Andrea Thompson: Melt of Key Antarctic Glaciers 'Unstoppable,' Studies Find ;
- NYTimes – Justin Gillis, Kenneth Chang: Scientists Warn of Rising Oceans as Antarctic Ice Melts ;
- Guardian – Suzanne Goldenberg: Western Antarctic ice sheet collapse has already begun, scientists warn ;
- AP (no signer. !? Turns out it's a labor action: byline strike. I smell Seth Borenstein, but no proof of that) : NASA Spots Worrisome Antarctic Ice Sheet Melt; This version may have no signer but has a bonus: This is not only global warming at work, it says here, but of the ozone hole as well. Shifts in winds due to the changed thermal structure (I presume) wrought by ozone loss are adding to the erosion of the ice front.
- National Geographic – Brian Clark Howard: West Antarctica Glaciers Collapsing, Adding to Sea-Level Rise ;
- USA Today – Traci Watson: Antarctic glaciers melting 'past point of no return' ; Watson does not pin this on anybody, just says plainly that researchers feel that 'the fate of the glaciers is almost certainly beyond hope.' That doesn't quite parse, as the intended meaning is there is no other fate than complete melting within hope. But the sense of it is clear.
- ScienceNOW (AAAS) Thomas Sumner: West Antarctic Ice Sheet Is Collapsing ; Good quote here: "The next stable state for the West Antarctic Ice Sheet might be no ice sheet at all." That means the sea will follow the retreating ice all the way to the TransAntarctic Mountains? 'Tis understandable and of little consequence that while most accounts list the GRL paper first, it having triggered NASA's press conference, this piece from Science's news side went first with the paper in that journal.
- Christian Science Monitor – Pete Spotts: West Antarctic glacier loss: :"We have passed the point of no return." Pete does some sound logic, writing that 'if these results hold up, they suggest that even if all human-generated greenhouse gas emissions were to stop today, the climate would still continue to warm some, as the oceans release captured heat, and the loss of these glaciers would continue unabated."
- Mashable – Andrew Freedman: What Irreversible Antarctic Ice Melt Could Mean for Some US Cities; Freedman says this is bad news but that the findings "do not significantly alter short-term sea leve rise projections." That seems easily true of the ice that has been until recently hung up along the Amundsen coast of Antarctica. He does not address whether similar scenarios are easy to imagine elsewhere, bringing closer the time when sea level rise will become a global emergency.
- Space.com – Becky Oskin: Catastrophic Collapse of West Antarctic Ice Sheet Begins ;
- Wall Street Journal – Robert Lee Hotz: Scientists Warn of Melting Ice Sheet, Rising Sea Level ; A straight-up account from Hotz, a straight shooter. One cannot help but notice one paragraph that sits by itself, unconnected by transition from the text above or on to the text below: "In recent years, overall global surface temperatures haven't risen as quickly as in the past, even as emissions of so-called greenhouse gases have continued to grow, leading some skeptics to suggest that global warming has already peaked. In their view, predictions of dire future climate consequences – such as the ice melts and sea-level rises projected in the lastest findings – are overblown."
- Science News – Beth Mole: Antarctic glacier melt is unstoppable ;
- AFP – Kerry Sheridan: West Antarctic ice sheet collapse 'unstoppable', says NASA.
- Popular Science – Douglas Main: 10-foot Sea Level rise Now Unstoppable Due To Glacier Collapse ; For a short piece, very well done – including specific instruction to readers that "collapse" in this context does not mean whump, it's gone. It is a slow but self-maintaining disintegration and withdrawal till its next to gone, centuries from now. However, there is a somewhat muddled passage about the difference it makes if ice is floating rather than being so thick it rests on the sea floor. This implies that if such grounded ice thins to the point it floats it then displaces more water. Rather, when ice becomes grounded, its displacement is capped at that point – further thickening just piles it higher without squooshing more fluid water out of its way (unless, of course, it moves into deeper water).
Grist for the Mill:
Paper in Science: Univ. of Washington Press Release ;