Thwaites Glacier kept losing ice for 150 simulated years with ocean melting switched off
Thwaites Glacier kept losing ice for all 150 simulated years in three models with ocean melting set to zero, New Scientist reports. The setup is physically impossible, so it shows the glacier's momentum but not how much sea level will rise.
The Scientist · Science desk
Thwaites lost ice over the 150 simulated years, though the rate slowed; Pine Island re-advanced and grew more stable. Williams says ice was expected to re-advance. Morlighem says at best Thwaites does not lead to West Antarctic collapse. Williams says more ocean warming means faster loss.
- Who's exposed exposure Thwaites Glacier Kept losing ice over the entire 150 years of the zero-melt simulations, though the rate of loss slowed, claim 4
- What's now possible capability Pine Island Glacier Re-advanced and became more stable in the same simulations, claim 3
- What doesn't add up contradiction Rosie Williams, BAS Says the general expectation was that with ocean melting off, the ice could thicken and re-advance, claim 15
- What it limits constraint West Antarctic ice sheet Morlighem says in the best case, if ocean melt stops, Thwaites does not lead to its collapse, claim 10
- Who has to decide decision Emissions Williams says more ocean warming means faster ice loss, so bringing down emissions controls that rate, claim 9
| Who | How | Kind | Claim |
|---|---|---|---|
| Thwaites Glacier | Kept losing ice over the entire 150 years of the zero-melt simulations, though the rate of loss slowed | exposure | 4 |
| Pine Island Glacier | Re-advanced and became more stable in the same simulations | capability | 3 |
| Rosie Williams, BAS | Says the general expectation was that with ocean melting off, the ice could thicken and re-advance | contradiction | 15 |
| West Antarctic ice sheet | Morlighem says in the best case, if ocean melt stops, Thwaites does not lead to its collapse | constraint | 10 |
| Emissions | Williams says more ocean warming means faster ice loss, so bringing down emissions controls that rate | decision | 9 |
What happened
- Pine Island Glacier, run under the same zero-melt condition, re-advanced and became more stable, so the two neighbours ended on opposite paths.
- Thwaites lost ice through the whole 150 years in the simulations, though the rate of loss slowed as the runs went on.
- The ocean beside Thwaites is projected to warm at triple the historic rate through the 21st century.
- A separate study published the same week, using a more precise glacier-ocean model, indicates Thwaites might retreat more rapidly.
Why it matters
- What doesn't add up contradiction New Scientist calls Thwaites ice loss unavoidable under any mitigation path, but Williams says emissions still set how fast the ice goes.
- What it limits constraint An ocean with no melt cannot occur, so the result bounds the glacier's momentum and cannot be converted into a sea-level figure for any real emissions path.
- Who's exposed exposure The 5 metre West Antarctic scenario depends on full collapse, and Morlighem says even the best case of melt stopping does not produce it.
The design is a counterfactual. In three ice-sheet models, Rosie Williams of the British Antarctic Survey and her colleagues turned off all ocean-driven melting, a condition impossible in reality, and watched 150 years [2]. Ocean melting is the main cause of ice loss at Thwaites and neighbouring Pine Island, according to New Scientist [14]. The team wanted to know whether the ice would recover once that driver was gone.
Williams said the general expectation was that the ice would thicken and re-advance [15]. "It's somewhat of a surprise that Thwaites glacier can't do that," she said [5]. Pine Island, run under the same condition, is the comparison: a setup that forced all ice to shrink would have shrunk it too, and it re-advanced [3].
Why Thwaites cannot recover is, so far, an interpretation. The researchers think the glacier is still responding to extreme El Nino conditions in the 1940s that destabilised Antarctic glaciers and started their retreat [6]. "They have a long memory," Williams said of glaciers [7]. Ted Scambos of the University of Colorado Boulder, who was not involved, added a recent layer. In his account, about four decades of ocean heat from anthropogenic warming has pushed the Thwaites system into "an inherently unstable configuration" [8].
New Scientist writes that the result means future ice loss from Thwaites is unavoidable even under the most optimistic mitigation scenarios [16]. The study does not run mitigation scenarios. It runs an ocean with no melt at all. In our view that run is best read as a floor, with every realistic ocean sitting above it, because Williams's own account is that more ocean warming means faster loss [9]. The finding also applies to one glacier. Its neighbour went the other way [3].
The thing this doesn't tell you is how much ice. New Scientist's account does not include a volume or a sea-level figure for the 150 years, and the models are not named. The realistic case is the open question, and Williams said she is now working on it [13].
What to watch
- Williams's runs at realistic ocean temperatures, which would be the first to give a sea-level figure tied to an emissions path.
- The paper itself, to see whether it reports the volume of ice lost over the 150 years and how closely the three models agree.
- Peer review of the same-week study that finds faster Thwaites retreat with a more precise ocean-interaction model.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence45
- Adoption
- Insufficient
- Hype gap+30
- Incentives
- Insufficient
- Confidence50
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
A new study shows Thwaites Glacier will continue to lose ice for at least the next 150 years, even under the impossible scenario of extremely cool oceans.
- [2]
Rosie Williams of the British Antarctic Survey and colleagues turned off all ocean-driven melting, a condition impossible in reality, in three different computer models of the ice sheet and watched what would happen over the next 150 years.
- [3]
In the same simulations, Pine Island glacier re-advanced and became more stable.
- [4]
Over the entire 150 years of the simulations Thwaites continued to lose ice, although the rate of loss slowed over time.
- [5]
Williams said: "It's somewhat of a surprise that Thwaites glacier can't do that."
- [6]
The researchers think Thwaites is still being affected by extreme El Nino conditions in the 1940s which destabilised Antarctica's glaciers and kick-started their retreat.
- [7]
Williams said of glaciers: "They have a long memory."
- [8]
Ted Scambos of the University of Colorado Boulder, who was not involved in the analysis, said ocean heat delivered to the base of the ice over the past four decades or so as a result of anthropogenic warming has pushed the Thwaites system into "an inherently unstable configuration".
- [9]
Williams said that under the zero-melt scenario Thwaites still loses ice, but the more warming there is in the ocean, the faster the ice is lost, so it is still essential to bring down emissions and control that rate of ice loss.
- [10]
Mattieu Morlighem of Dartmouth College, who was not involved in the study, said: "We haven't crossed the point of no return." He said that in the best case, if melt from the ocean stops, Thwaites does not lead to a collapse of the West Antarctic ice sheet.
- [11]
If Thwaites glacier collapses completely, it is expected to trigger more widespread loss of the ice sheet covering West Antarctica, causing sea level rise of 5 metres.
- [12]
The temperature of the ocean adjacent to Thwaites glacier is projected to rise at triple the historic rate throughout the 21st century, leading to increased ice melting.
- [13]
Williams said the big question for the future is what happens with realistic ocean temperatures, and that she is now working on this.
- [14]
Together with neighbouring Pine Island Glacier, Thwaites is the area of Antarctica losing the most ice, mainly due to melting by warmer ocean waters.
- [15]
Williams said the general expectation was that if ocean melting were turned off, the ice would be able to thicken and re-advance.
- [16]
New Scientist writes that future ice loss from Thwaites is unavoidable, even under the most optimistic climate mitigation scenarios.
- [17]
Another study published the same week, using a more precise model of how the glacier interacts with the ocean, indicates that Thwaites might retreat more rapidly.
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Sources
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- newscientist.comAntarctica’s ‘doomsday’ glacier will keep melting even if oceans cool
1 article · October 15, 2026
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