Over the last few decades there has been an overall decrease in the amount of ice at the North Pole, and an increase in the amount of ice at the South Pole. Should all the remaining ice melt at the North Pole it will have hardly any effect on global sea levels because it is sea ice not land ice. Should all the ice melt at the South Pole, well this could cause global sea levels to rise by quite a bit.
I wrote something along these lines during that Glasgow talkfest. I received various emails telling me that it was not the sea ice I should be concerned about, but rather the glaciers.
There are some very large glaciers at the South Pole. For a time there was concern about the Pine Island Glacier, but then it stabilised. Then there is the Thwaites Glacier. It is about the size of Britain, and melting.
I got chatting with my friend Arthur Day about this glacier, asking him whether we should be concerned, and he explained:
By far the main glacier of concern is the Thwaites glacier and its ‘rapidly’ thinning ice shelf.
This enormous glacier, described in the mainstream media as ‘the world’s most terrifying glacier’, is about the size of Britain. It is one of the largest glaciers on Earth. It has recently gained notoriety because it is currently undergoing a phase of relatively rapid flow into the sea. There is a fear that the faster flow is the beginning of an ‘irreversible collapse’ that will eventually contribute a ‘devastating amount’ of meltwater to sea level rise. Fuelling this fear is the knowledge that the glacier feeds a marine ice sheet where almost all of the basement supporting it is well below sea level, potentially making it unstable. Currently it is believed this glacier alone could already be contributing about 4% to global sea level rise.
If its ice shelf is weakened from beneath due to melting by ‘warm’ sea water, then it could lead to destabilisation of the main glacier behind, making it flow into the sea much faster than otherwise. This in turn could contribute to a faster rate of sea-level rise. While there is a lot of concern about this, there is no actual evidence it is anything more than a natural process. The glacier flows into the Amundsen Sea along the West-facing coastline of the Antarctic Peninsula and, today, its movement can be easily measured. However, just because it has been possible to easily measure the flow of the glacier over the few decades since the satellite era began in 1979, it cannot be claimed that ‘fast’ glacier flow is a ‘new’ phenomenon and, therefore, ‘unprecedented’. Glacier flow and ice shelf melting needs to be assessed from a much longer-term historical perspective with one eye on what glaciology teaches us about the complex dynamics of ice flow. For example, glaciers can start and stop moving again for no apparent reason, as has recently been demonstrated by the sudden stabilisation of the Pine Island Glacier.
In January 2020, an expedition by the US-UK International Thwaites Glacier Collaboration melted a 30 cm wide and 600-metre-deep hole through the floating ice shelf in front of the Thwaites glacier. For the first time they were able to directly measure the temperature of the ‘warm’ sea water right at the point where the ice meets the sea. The water temperature was 2°C. But this is just one measurement. A single temperature snapshot in time and place does not constitute a trend!
The seawater beneath the ice shelves is linked to an upwelling of ‘warm’ circumpolar deep water carried on an offshoot of the Antarctic Circumpolar Current. This is the strongest and most important ocean current on Earth. It is the only current linking all the major oceans. It flows around the Antarctic continent from west to east, at least in part whipped along by the drag from the strong westerly winds that blow around the polar regions. It is estimated that this current transports somewhere between 100 and 150 million cubic metres of heat-carrying sea water per second. Without the Antarctic Circumpolar Current, and its impact on planetary heat redistribution, the global climate would be very different. One of the curiosities about the Southern Ocean is that the deep water circulating Antarctica, the ‘Circumpolar Deep Water’ and the ‘Antarctic Bottom Water’ circulations, are warmer than at the surface. This happens because the deep water is also more saline, making it denser despite its higher temperature.
The Southern Ocean is a critical component of the global climate system because it is a key region for the upwelling of deep ocean waters to the surface. These upwelling waters are very old and have not been to the surface of the ocean for centuries or even millennia. It means that this water has not interacted with the atmosphere since well before the industrial era, certainly not since any human impacts on the atmosphere due to increasing CO2 were even possible. These upwelling waters bring heat to the shallower seas of the Antarctic continental shelves. When an offshoot of this current emerges along the western coastline of the Antarctic Peninsula, it can find its way to shallower depths and interact with the ice shelves in front of marine-terminating glaciers such as the Thwaites Glacier. Assisted by the prevailing westerly winds, enough heat can be transported to locally warm the climate of West Antarctica, so this current has potential consequences for the marine-terminating glaciers and the stability of the West Antarctic Ice Sheet. If the current or the assisting winds change, then the local climate can change. In fact, careful analyses suggest the strength of the upwelling and the associated currents experience significant inter-decadal variability, perhaps driven by changes in the westerly wind patterns.
What really counts in terms of judging human impacts on this natural process is whether any mooted acceleration in melting at the ice shelves can be attributed to human activity, or not. Are any short-term changes, such as they are, simply a function of natural variability in the temperature, speed, and distance at which the ‘warm’ currents pass along the coastline, or are they ‘unprecedented’ changes that lie outside the range of natural variability? It remains entirely unclear how the circulation of circumpolar deep water might change in the future. If the cause of changes in circulation is unknown, then changes could simply be random and a function of entirely self-contained ‘internal’ natural variability in the flow of the current. Imagine for a moment the flow of water in a turbulent stream. Watching closely, does the water always follow exactly the same path past any point? Ocean currents are the same but they operate on vastly greater scales over much longer time frames. In climate science, natural internal climate variability is a well-established fact. It is most pronounced at the local scale within individual climatic regions. The volatile climate of polar regions like West Antarctica is a good example.
In any case, the combined amount of ice in the affected ice shelves is only a fraction of the total amount of shelf ice that fringes the rest of the Antarctic continent. The threat that ice shelf thinning poses to the stability of the glaciers behind them is the subject of extremely challenging computer modelling. Theoretical understanding is still incomplete and there are not enough measurements in the critical areas. While of concern and worthy of monitoring, because the Thwaites Glacier behind the ice shelf is ‘the size of Britain’, should a ‘collapse’ commence at some time in the coming centuries then it would still take many thousands of years to unfold. That is because a glacier this size cannot simply ‘collapse’. It is just too big for that to occur. Geological studies of past events over the last million years show that the transition between glacial, intermediate, and collapsed states takes one to several thousand years. This is an entirely natural process, but it hasn’t stopped the Thwaites being dubbed the ‘doomsday glacier’ in headline-grabbing news articles such as one by the BBC entitled ‘Antartctica melting: Climate change and the journey to the doomsday glacier’, which is an impression cemented into folklore by many similar articles.
There is an extensive body of scientific literature that documents the past geological and climate history of West Antarctica. It documents a multi-thousand-year record of entirely natural climate volatility. This record is stored in both the offshore sediments, beneath the ice shelves, and within the ice sheet itself. The geology shows there is no evidence that current-day natural swings in climate along the West Antarctic coastline are in any way unprecedented. The ice sheet has undergone multiple massive volume changes over just the last million years alone in response to the global ‘ice age’ glaciation cycles. At times, parts of the West Antarctic Ice Sheet have disappeared almost entirely, along with its associated massive Ross and Ronne-Filchner ice shelves which combined are hundreds of times more massive than the Thwaites ice shelf. But each time, the ice has returned and, ten thousand years ago, the ice sheet on the Marie Byrd Land coast in West Antarctica was actually more than 700 m thicker than today.
These ice sheet cycles have been repeating for millions of years and therefore any current thinning of the ice beneath the ice shelves cannot simply be attributed to human activity, just because we now have the technology to measure it.”
But Arthur, they are! By those who have no concept of our climate history, or of how much ice there is in Antarctica.
My friend Stuart Ireland scuba dove under Antarctica a few years ago and made a little video about it. I’ve taken a clip from this for the feature image and adjusted the tone curve on it to make him look colder. Stuart told me that one of the most painful things he has ever experienced is defrosting his fingers after staying in the water with the sea lions for so long. He did get some brilliant footage.
There is a whole section in my book ‘Climate Change: The Facts 2020’ about Antarctica including a chapter about volcanoes by Arthur.
Uwe Roland Gross says
Richard Bennett says
A sensible commentary on the Thwaites glacier and Antarctica in general with none of the lazy journalism normally associated with the mainstream media.
Ian Thomson says
That’s very informative. Thanks for informing us Arthur.
Fascinating that the water can virtually “disappear” to the depths for so long.
The video is beautiful.
Thanks Jen for putting it all out there.
There is a small inlet bay near the Rothera Research Station on the Western Peninsula which is heated by sub-volcanic activity to the point where it is possible to bathe in “normal” swimming trunks.
Most people refuse to believe that is possible – swimming in only normal swimming costumes, surrounded by glaciers in -10C (summer) conditions – but I have done it during a mapping exercise, as have countless others. It is even a stop-off point for summer cruise ships, I’m told.
None of this scuba diving in water which is on the edge of freezing, though, as Jennifer’s friend did. One of the most fascinating observations of salt water on the constant edge of freezing is its’ thixotropic properties – any disturbance causes spreading ripples, of course, but at a slow walking pace.
Interesting post Jennifer and truly beautiful video. I’ll have to get back to recent Antarctic temp trends for the Peninsula and the main continent.
BTW here Steve McIntyre is STILL looking at the Climategate HACK and seems to have found the obvious access was ( perhaps) through Prof Keith Briffa’s online account.
Here’s a recent post from Steve and he’s certainly a warrior and a tiger for data and evidence. Here’s his conclusion in a recent post.
“The Climategate hack did not involve malware: no X-Agent, X-Tunnel, Fancy Bear or Cosy Bear. Nor did it involve spearphishing emails or any of the paraphernalia that usually define “hacking”.
“The first avatar of Mr FOIA in the CRU network was almost certainly via password access to Keith Briffa’s online account (through proxy servers). I’ve received a first-hand statement that Briffa’s password was exposed and available to the public in the period immediately prior to the “hack”. Signing on to Briffa’s account with this password via a proxy server did not require CIA or KGB level skills. Once in, according to the Mother Jones cybersecurity expert, the rest was “not rocket science”. The encrypted passwords were more or less in plain view and decryption of the sys admin password could be accomplished in a few hours or couple of days using open source software.
Nothing in the hacking technique or timeline points to Russian intel services or US fossil fuel corporations. I don’t know the identity of the Climategate hacker nor do I even have a guess. What we do know is what we knew more or less since the beginning: that Mr FOIA was a reader of Climate Audit, Watts Up, Real Climate and other climate blogs; that he was careful both in his use of proxy servers; and, that, unlike Guccifer 2, he had no interest in leaving a massive social media trail.”
“By Stephen McIntyre
| Posted in Uncategorized | Comments (35)
The 2017 Olivia et al study shows no warming at the Antarctic peninsula since 1998. And similar result for the BAS Turner study for the same period and cooling has occurred since 1998.
The UAH V 6 satellite data shows no warming for the South pole since DEC 1978, or the last 43 years.
Emil Holtz says
As usual, dig below the simplistic picture and there is nuance. This is a remarkable contribution for the Climate truthers. My father was a simple farmer who adapted to the changing seasons, I had to leave Europe when there was too much correctness. Keep up the good work!
Another record cold 6 month period for Antarctica from April to September 2021. The temperature has been recorded at minus -60.9 c.
Here’s a good summary of the 2016 UK BAS, Turner et al study, that found cooling at the Antarctic peninsula since the 1990s.
The Gore donkey said this was the fastest warming place on Earth but now we know he was wrong. In fact the last 2000 year proxy studies have found many periods of warming and cooling and the so called modern warming started in the 1920s.
OH and co2 levels in 1920 were just 303 ppm and today about 415 ppm. Gosh something doesn’t seem to correlate very well for their much loved theory AGAIN?
The 2020 Nature study of the Antarctic continent from Singh et al found no warming since 1950. Here’s the Abstract and the link. Willis Eschenbach linked to this very recent study when he tried in vain to find their so called Climate emergency. Yet we’re supposed to spend endless TRILLIONS $ on this idiocy for decades into the future?
BTW co2 levels in 1950 were about 310 ppm and today about 415 ppm.
“The Antarctic continent has not warmed in the last seven decades, despite a monotonic increase in the atmospheric concentration of greenhouse gases. In this paper, we investigate whether the high orography of the Antarctic ice sheet (AIS) has helped delay warming over the continent. To that end, we contrast the Antarctic climate response to CO2-doubling with present-day orography to the response with a flattened AIS. To corroborate our findings, we perform this exercise with two different climate models. We find that, with a flattened AIS, CO2-doubling induces more latent heat transport toward the Antarctic continent, greater moisture convergence over the continent and, as a result, more surface-amplified condensational heating. Greater moisture convergence over the continent is made possible by flattening of moist isentropic surfaces, which decreases humidity gradients along the trajectories on which extratropical poleward moisture transport predominantly occurs, thereby enabling more moisture to reach the pole. Furthermore, the polar meridional cell disappears when the AIS is flattened, permitting greater CO2-forced warm temperature advection toward the Antarctic continent. Our results suggest that the high elevation of the present AIS plays a significant role in decreasing the susceptibility of the Antarctic continent to CO2-forced warming.”
Geoffrey Williams says
The video clip is just stunning.
Many thanks to Stuart Ireland . .
The video is stunningly beautiful. The editing quality really makes the images tell a powerful story.
If we ever do return to data and observational science, I believe we will find that sort of science incompatible with modern climate science.
Here’s a taste of some of the earlier ( 2012) battles Steve McIntyre had to endure and the clueless allegations from David Karoly etc.
Steve’s maths and stats expertise had forced the withdrawal of the early PAGES 2 K study and had left many so called scientists with very crushed egos.
Around this time Steve had invented the term “UPSIDE DOWN MANN” to describe Mann’s use of the Tiljander proxy series. Funny thing though Michael Mann ignored Steve’s allegation and later sued Mark Stynes instead.
Here’s the latest ENSO wrap up from the BOM and we’re definitely into a La nina pattern and should receive higher rainfall over Eastern Australia until Autumn.
And the positive SAM would normally tend towards higher rainfall as well EXCEPT for western Tassie.
Indian ocean Dipole is returning to neutral from Nov- DEC and have little impact for further rainfall for our summer.
Let’s hope that farmers can harvest their crops in time if further rainfall persists in NSW ,Vic and SA.
Peter Etherington-Smith says
There is some additional information needed to place the issue in perspective. The Thwaites glacier is not melting because of slightly warmer sea water. That is only peripheral. Glaciers move primarily according to what happens at their base. Antarctica comprises two very different parts. Eastern Antarctica, the bulk of the continent (probably 80% or more of the ice and snow) which has been getting colder and accumulating ice for millennia. In the last three decades, the Filcher-Ronne and Ross ice shelfs have a mixed result, with some gains and some losses. Western Antarctica and the northern extension Antarctic Peninsula are indeed partly melting, but it has absolutely nothing to do with human activity or atmospheric changes (or very little of any consequence). Western Antarctica sits on a major rift system, where the mantle is being pulled apart as new ocean plates are being made and eventually the continent will split into at least two separate plates. Consequently almost all volcanoes in Antarctica (some 140 at last count) are located there, under the ice. The geothermal gradient is estimated at about 285 mW/m2 (milliwatts per sq.m) which is three to four times the global average of 70-85 mW/m2. Iceland sits on the mid-Atlantic ridge and has similar high flux rates and is noticeably much warmer than adjacent Greenland. During recent decades, studies by British Antarctic Survey (2017) and University of California (UC), Santa Cruz borehole study in 2015, have identified many hotspots beneath the Thwaites and other glaciers and countless subterranean freshwater lakes, caused by heat and pressure. These assist seaward movement of the glacier, assisted by ice and water streams some as much as 100 km wide. Volcanoes also erupt beneath the ice and one, Mount Casertz, is thought to be active now under Thwaites, causing some 70 millions tonnes of water to melt each year. Crustal movements, (plate tectonics) take place over millions of years but sometimes the impact can be quite strong locally. That is the case here. Evidence of warming can be seen in ice cores. The one from James Ross island in the Peninsula shows temperatures decreasing steadily for several millennia but then increasing for the last 600 years (contrary to the surface cooling of the Little Ice Age). Similar effects are seen in other Western Antarctic cores.
The comments on ocean currents also need clarification and additional information to that already given. The reference to the BBC is probably to the piece written by Justin Rowlatt (28 Jan 2020). Mr Rowlatt is not known for his scientific knowledge, only his devotion to the BBC policy of extreme bias in favour of climate alarmism (this was agreed internally in 2006 when the IPCC was declared to be the only authoritative source and impartiality was explicitly rejected as being no longer necessary – sanctioned by Lord May, one time President of the Royal Society, an organisation supposedly dedicated to rigorous scientific inquiry). Rowlatt made the entirely false statement “The key is the warm seawater, which originates on the other side of the world… This is where our changing climate comes in”. Mr Day’s observations about the ‘doomsday glacier’ designation are entirely correct, it is typical BBC mendaciousness.
To be clear, the relevant ocean current is the Global Conveyor Belt which starts as the Atlantic Conveyor Belt (there are several variations of nomenclature). In the Northern Atlantic it is very cold and dense water that sinks (warm water does not normally sink) containing a lot of CO2 (in pure seawater, ignoring any biological or other effects, CO2 is much more soluble in cold water than warm) that will provide nutrients in other parts of the world. This current runs deep towards Antarctica and then heads East to the Indian and Pacific oceans where various streams split off, upwell and provide nutrients for phytoplankton and up the food chain to major fisheries (the Humbolt current along Chile that facilitates some of the most productive fishing grounds, is one offshoot). The returning Pacific water is a bit warmer (1 or 2 deg C) and therefore shallower and flows past Western Antarctica to return to the North Atlantic to start the cycle again. The whole circumnavigation takes 1,000 to 1,500 years, so Rowlatt’s comments are even more stupid. The slightly warmer water lapping the seaward edge of the Thwaites glacier has very little impact on its movement. These descriptions are necessarily only a short summary and there are inevitably estimates and assumptions made, derived from various sources.
Steig et al. (including ‘hockey-stick’ Mann) (2009) have tried to suggest that a warm atmosphere sits neatly and continuously over Western Antarctica steadily melting the ice and yet the rest of the continent is somehow completely unaffected. This is rather baffling, especially as the Antarctic is a ferociously windy and stormy environment that would disrupt any static warm air. Nature can be very strange, but this takes some convincing, especially in light of the subglacial evidence. There is an air of desperation on the part of climate alarmists to avoid admitting the non-atmospheric cause of melting here. The IPCC climate models are notorious failures, but nowhere more so than the Antarctic and this has been noted even by scientists working for the IPCC.
As a geologist, oceanographer and engineer by training, with many years researching coral reefs in the Red Sea, Indian Ocean and Persian Gulf (too many years ago in my university days) I have some relevant background for these observations and hope they may be helpful. I have not even begun to comment on the mendacity and outrageous behaviour of the IPCC and unethical scientists surrounding coral reefs and ocean pH. Much has already been said about the appalling treatment of Prof Peter Ridd and the suppression of academic freedom of speech.
Those such as Gore or Attenborough, who shriek about Antarctica disappearing (and much else to help swell their bank balances or self-importance), can no longer qualify as scientists (if they ever did) when they engage in the suppression of rigorous scientific inquiry by denigrating and intimidating those designated as ‘deniers’ and spread deliberate exaggeration and lies (publicly demonstrated, not just my conclusion). Unfortunately many ordinary citizens have insufficient knowledge to be able to question what they hear, and intimidation and emotional blackmail are powerful motivators to coerce people to put up and shut up and accept effective tyranny – which is extraordinary and worrying to behold in supposed democracies.
Peter Etherington-Smith says
I realise that my previous comments may have appeared to dismiss the observations by Arthur Day. That was unintended and I apologise if it came across like that. My purpose was to emphasis that the movement from land should be little impacted by any melting of the seaward front by water. There may indeed by some additional effect of slightly warmer water, as currents have shifted – and the tracking of changes in ocean currents is often very uncertain. But that melting can only happen once the glacier has reached the sea. I would describe that as a consequence rather than a cause. So in that sense it would be peripheral, but not unimportant. I favour the recent studies supporting the view that it is the basal geothermal warming, rather than any atmospheric effect that facilitates the movement from land, for which there is a great deal of logic and sound geological reasons. There have also been some recent studies of mostly coastal meteorological stations that suggest both Eastern and Western Antarctica surface environments have been cooling since at least 1979 (and probably long before that). That would further support high basal geothermal flux rates as the main cause of glacial ice and water outflows. Thank you
So here is a question:
Where in the oceans do deep waters at 0o C exist?
It seems to be a safe working idea that is actually quite rare at the depth of the glacier’s base.
This strongly implies that more is going on than has occurred to us so far, since the glacier is ancient.