Far south of the populated world, the Thwaites Glacier, long nicknamed the Doomsday Glacier, has entered the arithmetic of coming centuries once again. A new model that lets seawater creep beneath its grounded ice points to as much as about 30 millimeters of sea-level rise by 2100 from this one glacier alone, roughly double earlier averages. The ice has given way before, in the warm intervals between ice ages, and the seafloor still holds the evidence of those collapses. The question now is less whether the sector has moved before than whether a species in a hurry will listen to what the ice h
Past Thwaites-Region Collapses Offer a Warning as New Model Doubles Sea-Level Projection
The Amundsen Sea sector has collapsed before, more than once
Mark
So what actually changed in this model?
Mimi
It lets seawater seep beneath the grounded ice of Thwaites. With that included, the projection for 2100 reaches up to about 30 millimeters from that glacier alone, roughly twice the earlier average.
Mark
And the seafloor clay, how does that fit in?
Mimi
It's evidence that West Antarctica has lost large amounts of ice before. The Nature paper says the Amundsen Sea sector, where Thwaites sits, collapsed repeatedly during late Pleistocene interglacials.
Luke
Let me slow us down. Is 30 millimeters the headline or the floor?
Mimi
The summary describes it as a scenario the authors call a lower one, but the text cuts off, so I can't tell you what that scenario assumes.
Luke
Right, so we know it's described as a lower scenario but not what it's lower than. That's a real gap.
Mark
Does the past collapse prove the future one?
Luke
No. The records show it happened under past warm periods. They don't by themselves say when or how fast it would happen now.
Mimi
Fair. They're a warning about vulnerability, not a forecast.
Mark
And the climate summit link?
Luke
That's The Scotsman's framing. The research doesn't say anything about negotiations.
Mimi
Agreed. What's left is whether policymakers start treating this as near-term.
Le Pouls
- A new Thwaites model lets seawater slip under grounded ice, and the projected sea-level rise by 2100 roughly doubles the earlier average.
- Seafloor clay and Pleistocene records reveal the Amundsen Sea sector collapsing repeatedly when the climate warmed, so the past is pressing hard on the present.
- Commentators are tying the glacier's warning to a climate summit they describe as dithering, sharpening the sense that negotiations are running behind the ice.
- The 30-millimeter figure covers Thwaites alone and reflects a lower scenario, yet it lands as a stark signal that Antarctic loss may be nearer than policymakers assume.
Far south of the populated world, the Thwaites Glacier, long nicknamed the Doomsday Glacier, has entered the arithmetic of coming centuries once again. A new model that lets seawater creep beneath its grounded ice points to as much as about 30 millimeters of sea-level rise by 2100 from this one glacier alone, roughly double earlier averages. The ice has given way before, in the warm intervals between ice ages, and the seafloor still holds the evidence of those collapses. The question now is less whether the sector has moved before than whether a species in a hurry will listen to what the ice has already recorded.
A new model of Thwaites Glacier, the one often called the Doomsday Glacier, projects up to about 30 millimeters of sea-level rise by 2100 from that glacier alone. That is roughly double the earlier average. The shift comes from a single change: the model allows seawater to seep beneath the grounded ice rather than stopping where the ice lifts from the bedrock.
The projection arrives alongside research that looks backward. Clay drawn from the seafloor records dramatic ice loss in West Antarctica in the past, and a study in Nature describes the repeated disappearance of the Amundsen Sea sector during warm interglacials. Thwaites lies in that sector. The lesson is plain: this region has collapsed more than once when the climate warmed.
The number needs careful reading. Thirty millimeters is a little over an inch, and it reflects only Thwaites, not the rest of Antarctica, Greenland, or the swelling of warming oceans. It is a figure for 2100, not for the glacier's full eventual loss, which would be far greater over longer spans. The authors reportedly describe it as a lower scenario, though the available text does not say what that assumes.
Coverage has also linked the glacier to upcoming climate talks, with one outlet describing the summit as dithering. That framing belongs to the commentary, not to the research. What the material does establish is narrower: the new model roughly doubles the earlier estimate, and the sector has a long record of collapse. Methods, uncertainty ranges, and researchers' names are not given in the excerpts. What to watch is whether this projection enters wider sea-level assessments and whether policymakers begin to treat Antarctic ice loss as a near-term risk.
A new model of Antarctica's Thwaites Glacier, the one often nicknamed the Doomsday Glacier, projects up to about 30 millimeters of sea-level rise by 2100 from that glacier alone. That is roughly double the earlier average projection. The difference comes from one change in how the model treats the ice: it lets seawater seep beneath the glacier's grounded ice, rather than stopping at the point where the ice lifts off the bedrock.
The figure arrives alongside two other pieces of research that look backward rather than forward. One, reported by Phys.org, describes clay recovered from the seafloor that reveals dramatic ice loss in West Antarctica in the past. The other, published in Nature, concerns the repeated loss of the Amundsen Sea sector of the West Antarctic Ice Sheet during late Pleistocene interglacials, the warm intervals between ice ages. Thwaites sits in that sector.
Taken together, the studies make a simple point: the Amundsen Sea region has collapsed before, more than once, when the climate warmed. Gizmodo framed the past collapses as a warning for the future, and the new model gives that warning a number. The authors describe their 30-millimeter figure as coming from a scenario they characterize as a lower one, according to the summary carried by The Watchers, though the available text cuts off before saying exactly what that lower scenario assumes.
That caveat matters for reading the number. Thirty millimeters is about an inch and a bit, and it covers only Thwaites, not the rest of Antarctica, Greenland, or the expansion of warming oceans. It is also a projection for 2100, not a description of what the glacier's full loss would eventually mean, which would be far larger over longer timescales.
The coverage has also been tied to the political calendar. The Scotsman, in a piece by Ian Johnston, set the glacier's warning against a COP climate summit that it described as dithering. That is the newspaper's framing of the negotiations rather than a finding of the research itself.
What the material here does establish is limited but clear. A model that allows seawater beneath grounded ice produces about twice the earlier average estimate for Thwaites's contribution by 2100. Seafloor sediments and Pleistocene records show the sector has gone through repeated collapses. The excerpts do not give detailed methods, uncertainty ranges, or the names of the researchers.
What to watch next is whether the new projection is absorbed into wider sea-level assessments, and whether negotiators and policymakers begin to treat Antarctic ice loss as a nearer-term risk rather than a distant one.
Citations marquantes
The 30 mm figure comes from a scenario the authors call a lower one.— Summary of the new Thwaites model, as carried by The Watchers
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