How Antarctica Caused Global Cooling or Why Earth Remains in Ice Age Mode for Next 200 Million Years
Oceans are a tremendous reservoir of heat. The upper 10 feet of ocean water holds more heat than the earth’s entire atmosphere.
Due to the formation of the Antarctic Circumpolar Current, enabled by plate tectonics, Antarctica became thermally isolated from the rest of the earth initiating 1) a permanent ice cap, 2) extensive sea ice that extruded cold brine that filled the ocean’s bottom water, and 3) Intensified upwelling that increased productivity that drew down atmospheric CO2 to current levels.
As a result of increasing cold Antarctic Bottom Water, oceans ventilated its its displaced ancient bottom water heat. As a result of a 50 million year cooling trend, the earth is now locked into a fluctuating balance between cold ice ages and warm interglacials
Jim Steele is Director emeritus of San Francisco State University’s Sierra Nevada Field Campus, authored Landscapes and Cycles: An Environmentalist’s Journey to Climate Skepticism, and proud member of the CO2 Coalition.
It appears that we might be on the same page here.
We Must Get Rid of the Carboniferous Warm Period
I was just going to post a link to that. It’s a shame you two seem to have fallen out.
Brilliant video Jim.
Whatever the various features of oceans and land masses the convective overturning circulation within an atmosphere will always adjust energy flows by reconfiguring itself to retain an average global surface temperature at the level required to match the upward pressure gradient force within the atmosphere with the downward force of gravity.
The adjustments required to neutralise any thermal effect from our CO2 emissions would be too small to measure.
The processes noted by the author of the above article and by Philip Mulholland previously are simply the system in action.
Philip and I have recently published extensive papers describing how the convective overturning circulation within all atmospheres both creates the surface temperature enhancement and forever thereafter keeps it stable.
Being mischievous, I would hasten to point out that we bang into and out of interglacials on a semi-regular basis. 😉
As far as I can tell, your statement is true for Venus, not very true for Mars, not at all true for the Moon, and approximately true for Earth. Also, as far as I can tell, it boils down to the question of how much heat can be removed from the surface by radiation and how much by convection.
Actually, the surface of the planet is not much of a heat sink, in terms of total joules stored. Most of the latent heat of the planet is stored within the core, the mantle, the crust, and the oceans that cover 70% of the surface and which are very deep (as measured in miles or kilometers) and in constant circulation, and which have both a much higher specific heat content than air, and a vastly larger mass based total heat energy content than the atmosphere.
The thermodynamic driving forces for climate are the sun’s insolarity, the latent heat within the planet, and all the other geophysical, geochemical, and biological processes that act to aid or suppress the collection and transfer of heat energy to the low altitude atmosphere. It is all highly interconnected with all sorts of feedback effects that tend to promote relatively slow changes in the equilibrium temperatures, humidities, air circulation patterns, and precipitation patterns that we call “climate.”
Geothermal energy: was that not the tiny stuff below 1 W/m²?
How does that compare with the solar energy reaching Earth?
While an oxyacetylene torch will have an unmeasurable impact on the average global temperature, it is still able to melt steel into a puddle at the local point of application. That is, while a small heat source may not have a measurable effect on global temperature, it can explain local phenomena better than rising global temperatures.
You really don’t understand how averages work, do you.
Then again, you think that wind and solar can power society.
What’s that for a pawlowian nonsense, MarkW?
I was talking about the comparison of geothermal and solar energy, and about nothing else.
Ice ages result from changes in insolation linked to the Milankovich cycles.
Changes in insolation will change the surface temperature and convective overturning will adjust to keep the necessary balance.
Clearly that doesn’t work for a body that has no atmosphere at all.
Have you calculated how much atmosphere is required to make your theory work?
There does seem to be a minmum required which some have been investigating.
I came across this video and it’s kinda interesting: https://www.youtube.com/watch?v=ziqeZTruWMY
I have read of the Arctic region becoming colder with expanded ice cover in the future as more of the Arctic ocean shrinks and the Continents encroaching in its place which would paint a dire future of an ice cover that will become permanent in the North.
And… which future did your source mention, if there is any?
I read a lot of stuff over the years, will not be able to post the source.
The Oceanic region is getting smaller very slowly……
” if there is any?”
Absent radiation active (greenhouse) gases in an atmosphere, how does an atmosphere shed energy gains? And at what rate can they shed this energy?
From the surface via radiation directly to space. Convective overturning will settle at rate that delivers enough energy back to the surface to both sustain the upward pressure gradient and match energy in from space with energy out to space.
Convection cannot be prevented due to surface density variations so such an atmosphere can never become isothermal.
In a planet sans GHG, does conduction become a larger factor to the atmospheric energy content? And yes, the atmosphere, having disparate density and energy, and a rotating earth, will naturally have convection, heating, and expanding contracting and sinking, and convective motion.
It seams logical that energy lost to the atmosphere from surface radiation in a non GHG atmosphere, would eventually be replaced by conductive energy accumulated in the same non GHG atmosphere. The atmosphere would heat slower, but eventually reach what T. ?
Just the headline and intro tell me all I need
And I’m sorry but ‘upwelling’ and ‘CO2 drawdown’ are Fluff & Nonsense from someone who is obsessed by The Emperor and not thinking clearly.Any anybody everybody with any experience of any ‘system’ will tell you a ‘steady decline’ in anything will not set off an oscillator – which is what the Ice Ages
And where that 200 million years comes from is pure day-dreaming
Its very simple.
Antartica is cold and dumping insane amounts of heat into the Stratosphere (thus outer space) for 2 main reasons.
1/ Yes it is isolated and that is exactly it. It is a chimey, average 2,500 metres high, made of high emissivity and high albedo stuff.
Because of its height it pretty well makes a direct connection into the Strat and thus, as far as any ‘energy’ that gets there, is a damn near perfect Black Hole
2/ The energy gets there exactly because of its isolation and via things generally/often called:
Very high speed (as far as Earth is concerned anyway) that carry huge amounts of ‘half-emm-vee-squared’ energy
They transport lots of energy but not a lot of temperature and they move as fast & furious as they do exactly because of that – Very Low Turbulence.
This harks right back to the very start of thermodynamics and Joule’s experiments to discover what a Joule was actually made of.
Why it all gets so cold and how it might not get cold in the future (harking to the frankly bizarre 200 million year claim)
There is nothing out there in the Southern Ocean to create turbulence in those hi-speed winds.
If there was, as Joule discovered/used in his experiments, large amounts of that half emm vee squared would become = (a rise in) Temperature
Thus, planting a continent or two in the path of those winds would slow them down, by creating turbulence and thus warm the place up
Is that what our story teller here is saying, does he know For Fact that that’s gonna happen otherwise he’s just winging it. Dreaming
Chances are we’re all driving around in vehicles with an ‘air-dam’ or ‘spoiler’ under the front bumper/fender.
Pleeeeeeze tell you know why its there, can explain why its there, otherwise we really are back in The Dark Ages and generally ‘f****d’
Slow down a little. Jim may have the continental drift of Antarctica away from polar location in mind when he presented the 200 million year figure. As an early student of Continental Drift I am constantly amazed that it is not taken into consideration by the majority of geologists, little alone by others. Remember a few years ago when an Antarctic polar vortex rushed north and crossed the equator, a first during recorded history? When ENSO is neutral, and the latitude winds are weak, these Antarctica cold wind outbreaks wreck havoc in South America, which, as a wine consumer, I assure you is true. The various complex controls on weather, or climate which is weather long-term, are moderatly understood, and I enjoy the work of Jim Steele trying to add actual data, mixed with ideas, to the study.
Indeed. I do see climate videos showing the earth some time back with the continents in exactly the same position as now. If that is the starting point for calculations….
All continents have never been in the same position as now.
For the past ~3.0 million years, they’ve been roughly as now, but are constantly moving.
Anyone who is not a scientific moron on a quest to suppress scientific inquiry and understands exactly what you explained to the ranting moron from Newark. Obviously Jim was speaking of the effects of plate tectonics on ocean circulation patterns which are well understood by most geologists, at least. The timeframes for plate tectonics are measured in tens of millions to hundreds of millions of years.
Don’t waste time explaining to or debating an unscientific moron like her. It is the proverbial and biblical admonition to “don’t cast your pearls before swine.”
Or, in the more recent vernacular, “Don’t get down in the mud to wrestle with a pig … you’ll only get dirty, and the pig loves it.”
You’re really not a very pleasant person, are you?
More pleasant than you, certainly. Loud mouthed know it all morons who seek to suppress normal scientific inquiry deserve to be called out as morons
Forecasting tectonic plate movements is a crapshoot, but here’s one guess:
It predicts Antarctic’s moving northward to join Pangea Próxima in the southern subtropics 250 million years in the future.
The sun will be more than two percent hotter then as well.
Wouldn’t any movement by Antarctica be, by definition, northward?
It could move farther south than it is now. If it moved westwards, the South Pole would be closer to the center of the continent. The Antarctic Plate is moving SW.
I don’t know why the prediction shows it migrating about due north from its present position, rather than NE or NW.
Alternative future supercontinents:
The last one would usher in another Snowball or Slushball Earth episode, despite increased solar radiation.
“The sun will be more than two percent hotter then as well.”
Will be, or might be?
3.4 degrees warmer based on CAGW.
“otherwise we really are back in The Dark Ages and generally ‘f****d’ “
Didn’t you get the memo?
Boris Johnson and Carrie Antoinette are leading us there in November.
It is your unintelligible and mindless rant that is bizarre.
Anybody who claims that the constantly varying climatic planetary equilibria over geological timescales are “simple” to explain is an utter moron.
Go back to your warmunist sisters and share your unscientific blathering and gossiping there – this is a website dedicated to actual scientific understanding, which is a perpetual quest and not a game of double jeopardy.
Come on, Duane, give Petard a break. He/She/It constantly eats mouthfuls of refined sugar, all while berating others for doing the same. So a certain amount of insanity should be expected.
Peta, Try standing in a gale force wind in the Antarctic at 60 below zero where there ARE mountains to create turbulence and see how much that turbulence warms you up. Very little land heating comes from wind energy passing over/through obstructions, the energy in the kinetic energy of wind is tiny compared to solar insolation.
I used to teach thermodynamics at a major university. To teach students the relative amounts of energy in different things, I had them calculate how much water could be completely boiled (as in boiled away) from the heat created in a fully-loaded semi-truck’s brakes from a single stop from 60 mph. About a cup. So why do truck brakes get so hot when trucks are going down a steep hill? The truck is constantly accelerating requiring the equivalent of many stops and the brakes don’t transfer heat to the passing air very fast until the brakes get very hot.
You often write stuff in a way that suggests that you believe that you know a subject when you obviously don’t.
NPCs and AIs tend to do that.
“Over the oceans, the penetration depth of the LWIR flux below the surface is 100 microns or less [Hale and Querry, 1973]. This means that the LWIR flux is fully coupled to the wind driven surface evaporation and cannot be separated and analyzed independently of the latent heat flux. Therefore an important parameter is the sensitivity of the latent heat flux to the wind speed.”
Key quote from PM
“So consider now the Carboniferous period with its shallow tropical seas and vast coastal equatorial coal swamps and remember that half of the surface area of our planet is located between 30 degrees North and 30 degrees South. The shallow seas of the tropics are huge solar energy collectors producing warm dense marine brines. Even in the Carboniferous with its gigantic Gondwana icecap the world was warm because in Oceanography marine water salinity trumps marine water temperature every time.”
Antarctic is the ideal location to isolate the impact of CO2 on temperatures. There is no Urban Heat Island Effect, level and constant albedo and no water vapor. The only significant variable, therefore, becomes CO2. What has increasing CO2 by over 30% resulted in? Absolutely no warming in Antarctica over the past 100 years. None, Nada, Zip. Blaming Antarctica on the ocean cycles is pure nonsense. Ice ages draw H2O from the oceans, There would be less ocean to warm the earth, and where would the extra heat come from to warm the oceans? The sun drives the ocean cycles, not Antarctica. Milankovitch Cycles are responsible for the variation. Anyway, simply look at the temperature data from Antarctica, they are the perfect result of a controlled experiment to isolate the impact of CO2 on temperatures.
Just the opposite is right, CO2 is cooling the Antarctic.
Plate tectonics likely have a vastly greater effect on climate changes than variations in Milankoitch cycles or variations, given the vastly greater specific heat content of liquid water vs. air, as well as total mass based heat content of the oceans relative to both the atmosphere as well as the relatively minor variations in insolarity due to astrophysical variations.
Think of climate at any point in time as being the sum of a series of effects that are not in sync. The total solar energy input from the sun, which varies relatively little, is the baseline energy content, along with latent heat stored within the core, mantle, and crust, including volcanism. On that baseline energy content is superimposed ocean circulation effects induced by tectonics. Then all the other effects such as atmospheric circulation due to the coriolis effect; geochemical effects (CO2, CO, O2, N2, SO4, oxidation of rocks, etc.); biological effects (albedo, uptake of CO2 and production of O2 via photosynthesis, sequestration of carbon in the skeletons of microscopic creatures as well as shellfish); etc etc.
Of all the effects or “forcings”, as the warmunists put it, the largest effects that have occurred over geological timeframes is plate tectonics and their effect on ocean circulation. Which is what Jim Steele is describing here.
The total does not change a huge amount but the annual variation over the water surface is highly significant. At the present time, the variation of solar input over oceans ranges from 330W/sq.m in July up to 400W/sq.m in January.
These values are just past their maximum difference for the current precession cycle. They will get closer together when perihelion occurs in July about 12kyr from now. However, overall the net solar input to the oceans is currently falling; slowing down evaporation and causing the ocean surface temperature, on average to rise – but colder in the southern ocean.
The Earth pulled out of the last glaciation just after perihelion occurred in July about 12kyr ago. Precession dominates glaciation. Before the Panama isthmus formed about 2Mya, glaciation just followed the precession cycle with about 24ky period. It now runs over multiple precession cycles, relying on reducing eccentricity to pull it out as well as precession having perihelion after July.
Antarctica is generally covered by snow. Snow has a high emissivity, about .97 at local temperatures, which is good for emitting heat to outer space. There is no sunlight for 6 months of the year so the Albedo of snow to incoming sunlight is irrelevant during that time. The rotation of the Earth makes the atmosphere bulge at the equator, so it is much less distance to the stratosphere for IR radiation to escape to outer space at the poles. The atmosphere is so cold that there is practically no water vapor in the air to catch and back radiate IR to the surface. The Antarctic plateau is fairly high altitude so atmospheric lapse rate is significant compared to the Arctic which is mostly at sea level. Adding all this together results in Antarctica being like a different and inhospitably cold planet. The effect of mankind’s CO2 emissions should be apparent there, but do not seem to be….hmmm….
” The effect of mankind’s CO2 emissions should be apparent there, but do not seem to be… ”
They are very well indeed, but in the Antarctica, the effect is the inverse of what happens anywhere else (except some very cold places in Northeast Siberia like Verhojansk and Ojmjakon):
Antarctic Specific Features of the Greenhouse Effect : A Radiative Analysis Using Measurements and Models
Unmasking the negative greenhouse effect over the Antarctic Plateau
Beat me to it ….
AbstractA paradoxical negative greenhouse effect has been found over the Antarctic Plateau, indicating that greenhouse gases enhance energy loss to space. Using 13 years of NASA satellite observations, we verify the existence of the negative greenhouse effect and find that the magnitude and sign of the effect varies seasonally and spectrally. A previous explanation attributes this effect solely to stratospheric CO2; however, we surprisingly find that the negative greenhouse effect is predominantly caused by tropospheric water vapor. A recently developed principle-based concept is used to provide a complete account of the Antarctic Plateau’s negative greenhouse effect indicating that it is controlled by the vertical variation of temperature and greenhouse gas absorption. Our findings indicate that unique climatological conditions over the Antarctic Plateau—a strong surface-based temperature inversion and scarcity of free tropospheric water vapor—cause the negative greenhouse effect.
Good, so we can all agree that Steig et al., Nature (2009) and the Nature front cover and associated ballyhoo was a pile of crap. Realists on here knew that in …….. wait for it …. 2009. Funny, I don’t recall there ever being a retraction by Nature or the Baghdad Bob Corporation. Could you guys tap them on the shoulder please for scientific integrity’s sake”
“Mean surface temperature trends in both West and East Antarctica are positive for 1957–2006, and the mean continental warming is comparable to that for the Southern Hemisphere as a whole 28. This warming trend is difficult to explain without the radiative forcing associated with increasing greenhouse-gas concentrations.”
Yes Bindidon, in my last sentence, I am referring to the overly simple viewpoint that “increasing CO2 causes warming” as being more complicated and actually incorrect in Antarctica. I assumed the “hmmm” would indicate a slight degree of further thought required….good links BTW
OMG! You were downvoted. I’m so sorry.
Indeed, the CO2 story is far more complicated than most think – regardless their opinion about its effect.
By accident, my native tongue is French; I thus had no difficulty at all to understand what was written in 2011 by two French scientists:
L’effet de serre atmosphérique : plus subtil qu’on ne le croit !
Jean-Louis Dufresne, Jacques Treiner
There is variability in the westerly winds that encircle the Antarctic continent. There is variability in the energy transfer across the belt of southern westerlies that cycle around the whole continent. There is variation in the ozone layer above the Antarctic continent. There is variation in surface air pressure as a result of the changes in ozone activity. This impacts on the katabatic wind system over the continent. There is variation in the extent of sea-ice surrounding Antarctica. There is variation in cloud cover over Antarctica. There is variation in the sea-surface temperature outside of the sea ice. So there are plenty of factors influencing air circulation and temperature over the Antarctic Continent, quite apart from CO2. Nothing is simple in global or regional climate.
Antarctica’s Cretaceous rain forest wasn’t tropical, but temperate or boreal, technically austral. It was akin to today’s Valdivian rain forest, although flowering plants were just getting going.
Wow! They had cameras back then?
Before cameras, just good painters
World of 90 Ma:
Note global oceanic circulation in mostly northern hemispheric tropical and subtropical latitudes, not possible today.
The Miocene warming was caused by the movement of the Scotia Plate through Drake Passage between South America and Antarctica. This shoaled that stretch of the Southern Ocean between its Pacific and Atlantic portions.
What I like and appreciate about Jim Steeles’s presentations, aside from their calm, non-propagandistic tone and scholarly approach, is that he clearly ties together all the many geophysical and astrological and geochemical and biological factors that affect climate over geological timeframes.
The warmunists claim that climate is all about carbon, nothing else matters, it is the sole thermostat for the planet.
Any real scientist recognizes that position and mindset as being the opposite of science, which is all about asking questions and not about claiming to have the sole answer … indeed it is anti-scientific and religious in its world view.
True Believerism as it’s worst.
“Everything looks simple when you don’t know what you’re talking about.”
Words to be live by.
how do we factor in the tilt of the earth? will this change?
I think Jim Steele’s point is that there are lots of effects on climate over time, and that one of the largest effects is due to plate tectonics and how they alter oceanic circulation over very long timescales. Yes, variations in the tilt of earth’s rotational axis affects climate. Ditto with the shape of earth’s orbit around the sun. And lots of others.
Anybody who claims that it is just one thing that serves as the planet’s thermostat is an idiot.
The current precession cycle began in 1585. Since then perihelion is again moving toward July. It presently occurs early January.
At the present stage of the cycle, the oceans get lowest heat input in July, That means lowest evaporation. The sunlight over water in the northern hemisphere has been increasing for the last 400 years. The Mediterranean is about 5,000 years away from being temperature regulated at 30C. That means it will see monsoonal conditions and the surrounding land masses will get a lot more rain.
Right now, January is the time of highest solar input to the oceans and the highest rate of evaporation. That manifests itself as high rainfall in the Amazon, Congo and northern Australia in December to February – the wet season.
As the precession cycle moves on, the heaviest precipitation will move further north.
Yes.. 6.8 % more solar energy in January.
“The difference in the distance between Earth’s closest approach to the Sun (known as perihelion), which occurs on or about January 3 each year, and its farthest departure from the Sun (known as aphelion) on or about July 4, is currently about 5.1 million kilometers (about 3.2 million miles), a variation of 3.4 percent. That means each January, about 6.8 percent more incoming solar radiation reaches Earth than it does each July.”
Which is about 90W/m2 more incoming each January.
“Due to slight Eccentricity of Earth’s orbit, instantaneous values of TSI above earth’s atmosphere varies annually between 1,412 W/m2 at perihelion and 1,320 W/m2 at aphelion .”
We don’t have runaway global warming with that, so the idea of a problem due to a reduction of outgoing by 3.53 W/m2 with a doubling of CO2 is beyond silly.
“doubled CO2 concentration decreases the amount of IR emission energy by 3.53 W·m–2.”
German cooling 😀
I’m so terribly impressed.
I remember that 22 years ago, after a super warm summer, we got a lot of snow on October 3rd, 30 km south of Berlin.
That was really ‘Germany cooling’.
That in Bavaria, Saxony, Thuringia nights can get pretty cold in October: nothing unusual for Germans.
Problems with Germans geography ? 😀 😀
Every year I have the chance to see crans crossing the Rhine near Mayence, or northwards in spring or southwards in late fall early winter.
In general, the ususal time is late November, early December. Usually they have a break in the southern countryside of Mayence as was s.t. reported in the past.
Today Oct. 10, early afternoon, I saw the first triangle flying southwards in an hight indicating that no break was planned.
I never saw them as early as this year,.
Then you msut be a very young person, Goose…
Because before 2000, we never saw any cran populations staying during the winter where we live.
It isn’t a question of age but of geography and time of the year. Today it’s a lot earlier as the former years.
What you see or saw where you live has nothing to do with my observations here since years.
I left Berlin in the mid 70ies as mid twen 😀 – so with my “youth” you are wrong too. 😀
I disagree with some parts. The tilt and things sun effects have a minor part in the cycle, it’s a buildup of heat with stratification of the oceans and immense buildup of heat energy in the oceans. The almost stoping of the currents pushing cold waters up allows stratification and a polar cooling planet. The planet goes through cycles of warm deepening oceans with cold poles and the Milankovitch cycles start up the deep water push which pushes up the warm waters to the poles, once this warm water is used up it gets cold and the cycle starts again.
Dansgaard–Oeschger events are where there is not enough built up heat and it fizzles as it uses up what it has and melts a bunch causing much warming over a short period of time and uses up the energy that is there. Current warming (1850’s )is from the building up of heat from the previous cold period (Little Ice Age) that is currently pushing Pacific and Atlantic waters into the Arctic called the Atlatification or Pacification of the Arctic waters. when this stored energy is used up it will get cold again.
“During the past 600 years, four of the 10 most extremely poor upwelling years occurred since 1950, and seven of 10 have occurred since 1850.”
Enjoy the warm weather while you can.
I came across some SkS propaganda, debunking sceptics.
“Greenhouse gasses – mainly CO2, but also methane – were involved in most of the climate changes in Earth’s past”
And I was thinking of how settled the science was that the current ice Age, with its glacial and interglacial periods, was due to changes in ocean currents.
CO2 changes follow temperature. As oceans warm, they release more CO2. As they cool, they absorb it from the air and retain it.
While videos are entertaining, and in some cases can display dynamics more clearly, they are not readily conducive to contemplation of complex details. Herein are many statements that deserve consideration but such consideration can require multiple repetition to be fully understood and extensive reference to other statements, charts, diagrams, etc.. This is difficult when the entire presentation is constantly moving forward. A transcript, where sentences can be reread as often as necessary, and compared with other statements at leisure, and graphics that will not disappear while one is trying to understand them, would allow deeper understanding of what is being presented – be it correct or defective.
As of today I will now add a transcript with each video. Here’s link to my website with this video’s transcript. https://perhapsallnatural.blogspot.com/2021/10/how-antarctica-caused-global-cooling-or.html
An excellent and focused article in a very few words. I agree with the essential point that Antarctica is the most important feature on the climate landscape.
In another article on Antarctica, you wrote of deep warm currents from outside the Circumpolar current melting the underside of ice shelves such as Pine Island (as opposed to a rapidly heating planet melting everything). Another article, which I wish I could find again, by an active researcher collecting data on station at one of those glaciers, wrote somewhat differently about the underwater melting. He clearly said that the “favorite” belief is that of warm water, flowing in underneath the Circumpolar current, providing the melting heat BUT, he wrote, no one has yet found any such deep current. Only the near surface warm water responsible for the melting can be detected or measured. Where it comes from is only speculation.
His article was written some years before yours, where you presented the outside current as fact. As you probably know, another hypothesis is that the heat is provided locally by geothermal activity at the ocean floor (as well as the CO2-is-burning-up-the-planet fear hypothesis). Since your older article did not mention there being any question about the heat source, I ask if that current, or currents, had finally been mapped. You did not answer, at least during the time that I monitored the article. Can you say anything more about it now? The definite existence of such a current, rather than just speculation, would seem to be quite significant in understanding what happens down there.
I think you misinterpreted what I wrote. I never argued for a warm “current outside the ACC” entering and melting glaciers. What I have written is that upper circumpolar deep water (UCDW) that already lies inside the ACC, is warmer than the winter surface water and warmer than the bottom water, and contains enough heat to melt the underside of glaciers like the PIne Island. That warm UCDW can be driven onto the continental shelves to cause basal melting along western Antarctica as the Amundsen Low’s location shifts closer and further away from the coast as well as causing coastal winds to alternate between westward and eastward winds (as seen in the attached graphic that was part of articles on this subject)
Here is. link to that article I blogged and cross-posted to WUWT.
Also on the subject of warm water currents near Antarctica.
Some have commented that warm water currents toward Antarctica in recent years must have been a factor for melting – contrary to the lack of evidence for warming or melt there generally.
However Morrison et al 2020 report an important finding that the warm currents toward Antarctica are being impelled there by cold water formation and downwelling at Antarctica’s margin:
Warm Circumpolar Deep Water transport toward Antarctica driven by local dense water export in canyons (science.org)
Specifically, the cold saline water formed around Antarctica – in part due to the freezing Katabatic winds howling radially out from the frigid and elevated continent interior – becomes super-dense and flows down via undersea canyons around the continent coastline to form cold deep currents flowing away from Antarctica.
Something has to flow toward Antarctica to make up for that cold downwelling, and that’s the explanation for the “warm” currents being pulled in toward the continent. So while many were happy to characterise those warm currents as a phenomenon of warming, it could be (if Morrison et al. are right) that in the bigger picture it is part of a cooling scenario. The end.
Widespread signals of Southern Hemisphere ocean cooling (and AMOC heat piracy) – Odyssey (wordpress.com)
So we need to fill up the gap between Argentina and the West Antarctic Peninsula with landfill and concrete to kill the ocean circulation.
Instead of the Great Wall of China, the Great Wall of Antarctica needs building. 🙂
This is a little off topic, but I’d like someone more more versed than me on the Milankovitch cycles to comment. Since it is becoming clear that the Antarctic is cooling and the Artic is warming, isn’t this a manifestation of the Milankovitch cycle? In addition, since most of the Earth’s land mass is in the northern hemisphere, wouldn’t this explain at least some of the current warming?
a) Nothing here
i.e. eccentricity, axial tilt, and precession, gives a hint on the Antarctic and the Arctic being differently influenced by these three cycles.
b) Why? The complementary effect is that in the SH, there is much less warming, due to more oceans and the extremely cold Antarctic.