🧪🌊🧵"experts believe a global rise in sea level of at least three metres may now be inevitable as a result of the break-up of Antarctica’s giant western glaciers" observer.co.uk/news/interna...
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I always wanted beachfront property. Now that I moved over 100 miles inland. Maybe I’ll get it. 😏
aug 25, 2025, 9:24 pm • 2 0 • view
Thank you very much for sharing the article. And for your work. Over what time frame are we talking about up to 3 meters? Current studies project global warming to reach 3°C by 2050. What would that specifically mean for sea level rise?
aug 26, 2025, 12:02 pm • 2 0 • view
“If you just walk through the world with open eyes, it already feels very dystopian. By now I think: the world isn’t going to end, it has already ended. And what surrounds us is only the afterglow.” — Lars Eidinger, German actor (translated from German)
aug 26, 2025, 4:43 pm • 0 0 • view
Very good and pertinent questions. I’m just not sure they know the answers to them 😮💨.
aug 26, 2025, 1:21 pm • 1 0 • view
As I understand it, a realistic sea level rise by 2050 with around 3 °C of global warming will likely be in the range of 0.2–0.5 m, based on IPCC data and regional models.
aug 26, 2025, 4:42 pm • 1 0 • view
Long-term risks: According to the Observer, scientists warn of a potential tipping point in the West Antarctic Ice Sheet. This could lead to a global rise of ≥ 3 m, but spread over centuries.
aug 26, 2025, 4:42 pm • 2 0 • view
Costs & impacts: Even a rise of 20 cm by 2050 would have enormous consequences, including damages worth trillions per year in the world’s largest coastal cities.
aug 26, 2025, 4:42 pm • 2 0 • view
Key point: In the short term, until 2050, sea levels will rise gradually – with severe consequences such as more frequent coastal flooding. In the long term, a scenario of several meters of sea level rise remains relevant, though within a much longer timeframe.
aug 26, 2025, 4:42 pm • 2 0 • view
“If you just walk through the world with open eyes, it already feels very dystopian. By now I think: the world isn’t going to end, it has already ended. And what surrounds us is only the afterglow.” — Lars Eidinger, German actor (translated from German)
aug 26, 2025, 4:44 pm • 1 0 • view
The rise over the past century was about 20 cm, and many of the world's largest costal cities have invested huge amounts in flood defences to protect themselves from this.
aug 26, 2025, 9:51 pm • 1 0 • view
Spread over centuries may seem like "oh well, that's fine then," ... but is it? All, that, land. Lost to the sea. By choice. We should act asif it was tomorrow, becasue for someone, a whole generation of humanity infact, and every one to follow, it will be.
aug 26, 2025, 7:09 pm • 3 0 • view
Please don’t get me wrong. I don’t want to downplay this. I see it the same way. Even 20–50 cm can have serious consequences: this seemingly small rise permanently raises sea levels.
aug 27, 2025, 6:01 am • 2 0 • view
It means storms and surges start from a higher baseline, overtopping dikes more often, reaching further inland and flooding coastal areas more severely. Ports, beaches, and entire ecosystems come under pressure, soils become salinized, infrastructure is damaged.
aug 27, 2025, 6:01 am • 2 0 • view
The costs for coastal protection and repairs run into billions, and millions of people are at risk.
aug 27, 2025, 6:01 am • 2 0 • view
We are on the same page my friend. I didn't mean to insinuate otherwise, it was more a public statement of what I believe than any criticism of you. 👍🏽
aug 27, 2025, 6:51 pm • 1 0 • view
🤝😊🌍
aug 27, 2025, 6:58 pm • 2 0 • view
Also bear in mind that flooding can become a serious problem in coastal areas long before mean sea level rises above them. Coastal flooding events start occurring when storm surges coincide with spring tides, and ..
aug 26, 2025, 9:42 pm • 2 0 • view
And saltwater seeping into the soil, sabotaging farming.
aug 26, 2025, 9:49 pm • 2 0 • view
And also potentially sabotaging reservoirs built in areas vulnerable to coastal flooding, but Anglian Water seem to be pushing ahead with plans to build one anyway.
aug 26, 2025, 9:58 pm • 1 0 • view
Nuclear power stations...
aug 26, 2025, 9:59 pm • 1 0 • view
rise in sea level can greatly reduce the recurrence interval between water levels exceeding a critical level. In many areas it takes a surprisingly small amount of sea level rise to turn the once a century event into one that happens once a decade.
aug 26, 2025, 9:46 pm • 2 0 • view
Actually there's a memorial in my childhood hometown to the 1953 flood, so that does come to my mind perhaps more than most folks.
aug 26, 2025, 10:06 pm • 1 0 • view
The are markers showing the 1953 flood level at various points along the east coast. Here's one I saw recently in a cafe in Sea Palling. Peak water levels during the 2013 storm surges were actually higher but costal defences built after 1953 prevented it becoming a disaster.
aug 26, 2025, 11:04 pm • 2 0 • view
Last night I watched a documentary on ARTE TV. It was about rising sea levels and the region in Bangladesh. People there have a CO₂ footprint of, I think, about one ton per year – just a fraction of what we in Europe are responsible for.
aug 27, 2025, 6:31 am • 3 0 • view
At the same time, the rise in sea levels is already so drastic there that hundreds of thousands to millions have had to leave their region, and those who were already living in poverty are now living in even greater poverty. They don’t have to wait until it’s 50 cm or even 1 m higher.
aug 27, 2025, 6:31 am • 2 0 • view
as a result of us warming up earth.
aug 26, 2025, 11:51 am • 1 0 • view
I'd prefer the sentence I quoted in the post above to have been phrased "latest scientific results point to loss of marine-based areas of the West Antarctic Ice Sheet now being inevitable, implying a commitment to more than 3 metres of global mean sea-level rise", but you get the picture.
aug 25, 2025, 4:48 pm • 10 2 • view
Yes, but don't get me started on the things that are wrong in that graphic. I spent a lot of time iterating with a graphic artist recently to eliminate a number of misconceptions and gross distortions in similar schematic figures.
aug 25, 2025, 10:37 pm • 1 0 • view
That’s great, and necessary, because it takes some effort to understand this icecap. Where will this be published?
aug 25, 2025, 10:54 pm • 1 0 • view
Initially these are figures that will be part of an infographic on the International Thwaites Glacier Collaboration website (thwaitesglacier.org) explaining some of the methods used to study the glacier. They might subsequently appear in what we're referring to as an "accomplishments" paper.
aug 25, 2025, 11:08 pm • 0 0 • view
There's another one I advised @icebird.bsky.social on that I included in commentary published in Geophysical Research Letters a couple of years ago. doi.org/10.1029/2021...
aug 25, 2025, 11:14 pm • 0 0 • view
Thank you, very kind 👌
aug 26, 2025, 7:22 am • 1 0 • view
"Believe" should never feature in a sentence about science.
aug 25, 2025, 4:49 pm • 16 2 • view
Just a simple "experts think ..." would be a big improvement.
aug 27, 2025, 3:30 pm • 1 0 • view
It would, but I think "consider" or "conclude" would be still better.
aug 27, 2025, 6:19 pm • 0 0 • view
And yet many climate models “believe” low climate sensitivity despite scientific proof of very high climate sensitivity. Many climate scientists “believe” slow decadal warming of 0.2C per decade despite scientific evidence of 0.4C decadal warming.
aug 25, 2025, 9:03 pm • 4 0 • view
📌
aug 25, 2025, 9:14 pm • 0 0 • view
There are companies and individuals who are directly responsible for turning whole economies away from reducing fossil fuel use. Most people are trapped in the systems that exist ... but these people are directly, personally, and legally responsible for what is happening and what will happen.
aug 26, 2025, 4:39 pm • 3 0 • view
That's not cool or punny.
aug 25, 2025, 6:14 pm • 0 0 • view
This is why China has built all those empty cities! Why else
aug 25, 2025, 6:17 pm • 4 0 • view
aug 25, 2025, 6:18 pm • 1 0 • view
Can’t wait until Mar A Lardo is underwater!!!
aug 25, 2025, 6:45 pm • 5 0 • view
Okay. Bye bye, Amsterdam!
aug 25, 2025, 10:28 pm • 1 0 • view
Not necessarily. It depends on how high you can afford to build the dykes defending it. There are certainly difficult adaptation decisions to be made though. Ultimately this will probably mean abandoning some cities. Howver, Netherlands is further ahead in thinking about this than most countries.
aug 25, 2025, 10:42 pm • 3 0 • view
I sure hope so, because I live a few metres below sea level 😅
aug 25, 2025, 10:48 pm • 1 0 • view
Have estimates of the timelines accounted for the climate sensitivity of 4.5C per doubling of atmospheric CO2 that Dr James Hansen has found to be the most realistic estimate of climate sensitivity? Have these estimates also taken into account the 0.4C per decade warming Prof Rahmstorf estimates?
aug 25, 2025, 9:01 pm • 3 0 • view
Wrong questions. Timeline estimates depend more on better understanding of the processes that control ice loss from marine-based glaciers than on atmospheric warming projections. The latter depend on future emissions pathways anyhow.
aug 25, 2025, 10:32 pm • 5 0 • view
Seems to me likely like a mutually reinforcing feedback loop we will increasingly trigger here for which warming rates and upper ocean-atmosphere coupled circulation changes provide the overall environment for all the local processes to mutual amplify or in some cases dampening the insitu melt rates
aug 26, 2025, 11:57 am • 1 0 • view
The warming rate <-> circulation interaction is the key point to consider. If a set of cold models project 2039 to be roughly between 1.7C-1.9C above 1850 while a set of hot models project 2039 to be roughly between 2.2C and 2.4C above 1850, then the circulation impact would be quite different.
aug 26, 2025, 12:09 pm • 1 0 • view
It seems like that every tens of a degree difference matters - the higher the temperature the larger the difference but only to a certain point I would guess At least it seems strange that at a 4.5°C warmer world a additional increase by 0.1°C would matter much anymore But just a feeling...
aug 26, 2025, 12:29 pm • 1 0 • view
There are also circulatory tipping points or tipping ranges where oceanic heat transport currents can function very differently relatively abruptly at different ranges of temperature. Thus if 2039 is at 1.8C, heat transport currents function very differently from if 2039 is at 2.3C.
aug 26, 2025, 12:11 pm • 1 0 • view
Or if you get higher warm rates the melt rates increase faster leading to higher density changes of the high latitude waters which are important also for currents, and gyre circulations same with mid latitude heat uptake (meridional density changes) which accelerates with higher warming rates.
aug 26, 2025, 12:27 pm • 1 0 • view
For example if you get higher warming rates the mismatch of upper ocean heat uptake and warming at deeper depths increases with a faster increase in upper ocean stratification driving the acceleration of surface currents and slow down of deeper currents.
aug 26, 2025, 12:25 pm • 0 0 • view
One difference of a faster warming seems to be gradients that intensify faster then if you warm the climate slower and its these gradients that drive current changes so a faster warming should have non-proportional effects...
aug 26, 2025, 12:20 pm • 1 0 • view
But could be wrong here, as I follow AMOC discussion but it has no priority for me as it will likely collapse decades from now so we have lots of changes that are occurring now and that are therefore more important.
aug 26, 2025, 12:19 pm • 1 0 • view
Further a Pacific overturning cell has to develop to compensate for AMOC collapse, so more would be transported into the North Pacific - that is also a detail that is discussed. So likely heat transport into the Atlantic will be affected
aug 26, 2025, 12:18 pm • 1 0 • view
If AMOC slowdown does occur much more rapidly, it could mean that more heat remains trapped in the Southern Ocean.
aug 26, 2025, 12:12 pm • 1 0 • view
Its an open question - the system channels warm water into the Atlantic, but in how far the overall transport will be affected is a open research question as its not clear in how far the warm water will just reach lower latitudes in the Atlantic - heat build up possible If I remember right
aug 26, 2025, 12:16 pm • 1 0 • view
Indeed - the main point being that ocean circulation is likely quite dependent on rate of warming. A slowly warming planet will not reach a new disrupted ocean circulation in 2039 as projected by cold models, while a fast warming planet might reach a new disrupted ocean circulation in 2039…
aug 26, 2025, 12:18 pm • 1 0 • view
Ocean circulation trumps everything else in the climate system as the currents transport much more energy than the atmospheric circulation but the atmosphere has a large control function of ocean currents via density changes - warming, precipitation, and cloud feedback enhancing ocean heat uptake
aug 26, 2025, 12:31 pm • 1 0 • view
And in between you have all the processes that interact and drive often synergistic the subsurface melting driven by warm water intrusions under the subsurface resting glaciers.
aug 26, 2025, 11:55 am • 0 0 • view
Then we have all these melt driven buoyancy forcings on the Antarctic slope current, which is projected to intensify and bring more water to the ice shield, and the projected intensification of the surface ACC and slow down of its deeper parts also connected with OHU and melt rates
aug 26, 2025, 11:52 am • 0 0 • view
Or this one which shows the magnitude of this saltiness signal caused also by sea ice losses triggered by sea surface temperatures and coupled atmospheric changes which feeds back on sea ice and possibly on subsurface ice melt and atmospheric forcing on ice shelve disintegration...
aug 26, 2025, 11:50 am • 0 0 • view
Here how changes in the atmosphere - precipitation - could have triggered a saltiness surface signal which lead to more downward mixing and upward warm water mixing bringing up saltier water creating a self-sustaining feedback loop
aug 26, 2025, 11:44 am • 0 0 • view
Here how warm core eddies transport warm water near the ice shelves driven by enhanced westerlies: "Persistent warm-eddy transport to Antarctic ice shelves driven by enhanced summer westerlies"; www.nature.com/articles/s41...
aug 26, 2025, 11:42 am • 0 0 • view
Here how winds in the Bellingshausen Sea control upwelling of warm water - guess less sea ice helps... "Amundsen Sea circulation controls bottom upwelling and Antarctic Pine Island and Thwaites ice shelf melting"; www.nature.com/articles/s41...
aug 26, 2025, 11:40 am • 0 0 • view
Ice loss drives warmer surface oceans, stronger storms which gain a stronger surface forcing on the upper oceans: "Record-low Antarctic sea ice in 2023 increased ocean heat loss and storms"; www.nature.com/articles/s41...
aug 26, 2025, 11:37 am • 0 0 • view
Here a study on sea ice and the atmosphere and how they interact synergistic on ice melt: "Synergistic atmosphere-ocean-ice influences have driven the 2023 all-time Antarctic sea-ice record low"; www.nature.com/articles/s43...
aug 26, 2025, 11:36 am • 1 0 • view
And on the feedbacks that are now increasingly driving the warming Important: Synergistically interacting changes, trends, and regime shifts around, over, and under Antarctica are to a major part driven by the warming rate Likely, all changes are warming rate dependent, non-linear one may add
aug 26, 2025, 10:37 am • 9 2 • view
Thereby, the warming rate could be the main trigger of the abrupt changes and regime shifts we now observe and the one that are predicted I will give later various examples via recently published studies Further, that it's a ocean-ice-atmosphere coupled system and the coupling intensifies...
aug 26, 2025, 10:41 am • 2 0 • view
Exactly. Heating a large body of water slowly has different dynamics compared to heating the same body of water at a faster rate. Add to that the removal of a large % of all moving organisms moving around in the body of water through industrial global bottom trawling, and you need new models.
aug 26, 2025, 10:42 am • 4 1 • view
Especially, if you heat it from the top... Then the rate of warming becomes a game changer that never happened at such speeds throughout Earths history Big experiment...
aug 26, 2025, 11:29 am • 1 0 • view
If the global average temperature in 2039 is 2.3C above 1850 average temperatures rather than 1.8C above 1850 temperature like most erroneous cold models seem to project, Southern Ocean surface temperatures hitting Antarctic ice sheets will be much warmer. That *will* increase the melt rate.
aug 26, 2025, 5:21 am • 2 0 • view
Global average temperature and Southern Ocean surface temperature are not the same thing. The latter affects sea ice extent but would have to increase a lot more to have a direct effect on Antarctic Ice Sheets. It's upwelling deep water that does the damage.
aug 26, 2025, 5:58 am • 4 0 • view
That is entirely true. And the deep water temperature will *also* be much higher in 2039 than the erroneous cold models project precisely because they have a very low climate sensitivity that is scientifically proven to be wrong.
aug 26, 2025, 6:17 am • 1 0 • view
Actually no, because heat conduction through the water column is very slow and the upwelling deep water is very old. It has not mixed with other water masses for more than a thousand years, as shown by the apparent radiocarbon ages of organisms living in it. 1/2
aug 26, 2025, 6:55 am • 2 1 • view
The important questions are how global climate change controls the amount of deep water incursion onto parts of the Antarctic continental shelf, and how efficiently it melts continental ice in the places they come into contact.
aug 26, 2025, 6:57 am • 2 0 • view
There is certainly asymmetry of ocean heat uptake in the Southern Ocean as this study shared by @umsonst.bsky.social a few months ago shows. All things being equal the deep ocean is also increasing in heat content alarmingly fast.
aug 26, 2025, 7:01 am • 3 1 • view
Deep water warming is a secondary issue to where the already relatively warm water goes. The main concern regarding changes in the deep part of the Southern Ocean is the decline in bottom water production.
aug 26, 2025, 8:18 am • 2 0 • view
All of that is detail. If the planet was 10 degrees colder or 10 degrees warmer, all of that detail is secondary. Getting the basic level of planetary heat wrong on a global scale will lead to disastrously incorrect melt rate projections.
aug 26, 2025, 9:10 am • 0 0 • view
Bottom line: anyone relying on projections from erroneous cold models that have a climate sensitivity of only 3.0C per doubling of atmospheric CO2 will be severely underestimating melt rates, regardless of the understanding or misunderstandings of melt processes.
aug 26, 2025, 6:23 am • 0 0 • view
cc @leonsimons.bsky.social @drtomharris.bsky.social @umsonst.bsky.social
aug 26, 2025, 5:23 am • 1 0 • view