Guest Post by Wim Röst
Introduction
Five million years ago, average temperatures were higher than they are now. During the Pliocene, the era just before the period of the Quaternary Ice Ages, ‘glacials’ did not yet exist because temperatures were too high. As cooling of the deep seas continued, temperatures became that low that large surfaces of the Northern Hemisphere became covered with snow. The earth’s albedo grew fast and large ice sheets started to develop. Only short warm interglacials separated the glacials. The emergence of the interglacials first showed a 41,000-year period (as proposed by Milankovitch) and in the last part of the Quaternary they showed a 100,000-year pattern. A difference that so far is not well understood. Here it is suggested that the continued cooling of deep sea temperatures is the cause of that diminished frequency of interglacials. Colder deep-sea temperatures resulted in lower sea surface temperatures that lowered the atmospheric temperatures. The general background temperature of the Earth became lower and lower, changing climate processes like the glacial – interglacial rhythm. As oceans cooled, atmospheric temperatures lowered and more energy was needed to get out of the glacial state. The extra energy came from combined favourable orbital circumstances, which only happens roughly once in 100,000 years.
5 Million years of ever lower temperatures
As figure 1 shows, during the last 5 million years, deep sea temperatures are falling. This cooling does not seem to be spectacular, deep sea temperatures are going down from an average of plus 2 degrees Celsius to minus 0.25 degrees Celsius, but – as will be argued – this lowering is of the utmost importance for the development of the Earth’s climate. At certain times the lowering of deep sea temperatures is important, even when the lowering is only fractional.
Figure 1: Falling deep ocean temperatures from Pliocene (to the left) into the Pleistocene (to the right in the figure). Time from left to right, in millions of years.
As shown in previous posts, the deep sea is directly connected with the sea surface by a process called ‘ocean upwelling’ sometimes shortened to simply ‘upwelling’. The ever colder deep ocean waters are welling up into the ocean surface layer in large quantities (more than a million cubic kilometres every year). This is a relatively slow process where the cold upwelling waters are warmed by the sun.
But, the lower the starting temperature of the upwelling waters, the colder the surface layer will be. The deep sea cooled more than two degrees Celsius during this period and therefore the sea surface has also cooled.
The world ocean surface comprises 71% of the Earth’s surface and it is generally accepted that the surface (air) temperatures at sea adapt to the temperature of the underlying sea surface water. Therefore, as sea surface waters cool, the atmosphere above 71% of the Earth is cooling. Colder currents will flow to the poles and colder air will be transported to poles and continents, diminishing the warming of those surfaces too. Convection will transport less and colder air upwards. In this way, the colder deep-sea temperatures end up not only in lower sea surface temperatures but also in a colder atmosphere – all other things remaining the same.
Figure 2: Estimate of global surface temperatures from the Pliocene into the Pleistocene, in degrees Celsius. In this figure, we see the same trend in figure 1.
A Deep Sea / Surface temperature Amplifier
It is interesting to see that a two degree C drop in deep sea temperature (figure 1) ends up as a 5 degree C lower surface temperature as shown in figure 2. This is a drop from 17 to 12 degrees Celsius. In this period, we see a large ‘amplification factor’ of around 2.5. A deep-sea temperature that is 0.2°C lower/higher, corresponds with a 0.5°C lower/higher surface temperature. As we shall see, the existence of this ´deep sea / surface temperature amplifier´ is important.
The ‘Earth’s General Background Temperature’
All climate processes on earth are taking place in a setting of a certain background temperature. As argued here, that general background temperature is set by the deep oceans connected with the surface layer that is connected with the atmosphere. The colder deep ocean is the cause of a colder atmosphere. Fluctuations (seasonal, annual, decadal, multidecadal, centennial, millennial) all occur against this ‘background temperature’ of the deep ocean.
The warm deep oceans fifty million years ago had an average temperature of more than 12°C (see figure 3). Those warm oceans created a completely different background temperature than our present deep oceans do. The present average temperature of all our ocean water (inclusive the warm surface layer) is only 3.9°C, the deep oceans themselves are several degrees colder. A difference of around 10°C. Therefore, our present ‘general background temperature’ is very low. Our cold oceans are even allowing glacial periods – that wouldn’t have occurred when the oceans were warmer. Our cold oceans brought us, or perhaps allowed us to have our very cold Pleistocene era. Figure 3.
(Remaining question: what made sea temperatures ending that many degrees lower after 55 million years? More about a possible / probable answer: in future posts)
Figure 3: Estimated deep ocean temperature in the last 65 million years by James Hansen et. al. 2013 Deep sea temperatures were highest 55 million years ago. In the last fifteen million years there is a nearly continuous downward trend.
From here, it is but a small step to find the solution for the 41,000 – 100,000-year problem.
The 41,000 – 100,000-year interglacial problem
During the first period of the Pleistocene interglacials, there was a 41,000-year glacial/interglacial cycle but during the last million years there was only a warmer period once every 100,000 years. See figure 4.
Figure 4: Temperature development in the last five million years according to the Antarctic Vostok Ice Core. The green lines show the 41,000 and the 100,000-year periods in the Pleistocene. The left side of the graph is the warmer Pliocene, the period that was still too warm to permit ice ages.
Milankovitch’ cycles played the dominant role in taking the Earth out of the glacial state. The glacial state is the normal state in the Pleistocene. Eight or nine of every 10 years in the Pleistocene were ‘glacial years’. Very cold. With rough and very changeable weather and climates, as is shown by the high variance in temperature – reflecting frequent and turbulent climate changes.
Javier explains the change in the frequency of interglacials as follows: “The 100 kyr problem is solved because there is no 100 kyr cycle, just a 41 kyr cycle that skips one or two beats.” Italics added.
The question remains: And what causes the skipping of one or two beats?
The answer is: it is the ever lower deep ocean temperature that is translated into ever lower atmospheric temperatures that makes it more difficult to come out of that ever more dominating glacial state. Renee Hannon recently: “The past four glacial cycles are increasing in duration from 89 kyrs to 119 kyrs.”
In the end of the period, because of the extreme cold of the deep sea, only the most favourable (combined) orbital conditions allow a glacial to enter the warmer interglacial state, which has more stable temperatures.
Mechanism
The difference between ‘snow’ and ‘water’ might be only one or two tenths of a degree Celsius. A temperature of + 0.1 °C means ‘melt’ and ‘rain’. A temperature of – 0.1 °C means ‘snow’ and ‘ice’.
The above-mentioned amplification factor comes into mind. Deep sea temperatures relate to (surface) air temperatures but with an amplification factor of around 2.5 for surface air. A 0.2 °C lower deep sea temperature is translated into a half degree Celsius lower atmospheric temperature. Therefore, even a difference of less than one tenth of a degree of the temperature of the deep sea can make a substantial difference in the presence of ice and snow over large Northern Hemisphere land areas. Areas that are covered with ice and snow have a much higher albedo. A rising albedo will further cool the Earth.
In this way, at a certain point, a fractional lowering of deep sea temperatures results in enhanced lowering of the Earth surface temperatures. First, because of the deep sea / surface amplification factor, and second, because of the additional ice and snow albedo amplification.
Once more the development of deep sea temperatures: figure 5.
Figure 5: Glacials and falling deep ocean temperatures from Pliocene into the Pleistocene. Glacials developed from a certain low deep ocean temperature. As cooling continued, interglacials switched their cycle from once per 41,000 years to once per 100,000 years. Added in the figure: squares and the corresponding periods below in the figure.
At the start of the Pleistocene, every obliquity cycle resulted in an interglacial. But later in the period the warming effects by obliquity alone were not enough to compensate the effect of the further cooling deep sea. Some help from other factors (eccentricity, precession and possibly non-orbital factors) was needed to reach that warmer and more stable ‘interglacial state’. As Renee Hannon concludes: “During the last 450 kyrs, the five major warm onsets with rapidly increasing temperatures are triggered by increases in the eccentricity, obliquity, and precession of Earth’s orbit. The nearly concurrent increase in these three astronomical forces appears a necessary component for a major warm onset”. Italics added.
The ‘Earth’s General Background Temperature’ continuously went down. The oceans cooled and processes changed.
Holocene
The oceans gained heat content during the Holocene: deep sea temperatures rose. But since the Holocene Optimum the ocean heat uptake showed a diminishing trend. During the Little Ice Age, the oceans even experienced a net loss in heat content. Important, because now we know at what average temperatures the Earth starts cooling her oceans. Figure 6.
Figure 6: Holocene reconstructions of intermediate water temperatures. (C) Changes in Intermediate Water Temperatures (IWT) at 500 m, and (D) changes in IWT at 600 to 900 m. All anomalies are calculated relative to the temperature at 1850 to 1880 CE. Shaded bands represent T1 SD. Note the different temperature scales. Source: Rosenthal et al.
Future
Only when the trend of continuously falling deep sea temperatures ends, the Earth will continue to be able to get out of a next glacial state. But, if this ever lower deep-sea temperature trend is not changed into a stable or a rising temperature, a ‘constant glacial state’ is what we can expect somewhere in the future.
Then glacials could continue without being interrupted by an interglacial and they could keep the Earth cold for a very long time – millions of years – in a barren glacial state. Which probably will be more severe than our Last Glacial Maximum, because the strong cooling during the glacial trend will not be ended by a warming climate state that could raise the deep-sea temperature to warm the Earth for a longer period.
Perhaps our Pleistocene glacial – interglacial rhythm was just a transition period to a more constant glacial state. The 41,000 → 100,000 trend might indicate such a future.
Conclusions
During the last 15 million years deep sea temperatures were continuously falling. Because of the process of oceanic upwelling the falling deep sea temperatures made sea surface temperatures fall as well. In turn, sea surface temperatures lowered atmospheric temperatures. A small decrease in deep sea temperatures resulted in an amplified surface temperature response. Surface temperatures responded 2.5 times the deep-sea response, such that a 0.2°C cooler deep sea resulted in a 0.5°C cooler surface temperature.
At a certain point, the falling deep sea temperatures resulted in atmospheric temperatures that enabled the development of large scale Northern Hemisphere snow and ice surfaces that increased the albedo of the Earth. That albedo caused a further cooling and resulted in even more snow and ice; another amplifier. Continental ice sheets developed. That was the moment the warm Pliocene terminated and the colder Pleistocene started.
Within the Pleistocene, short warmer and more stable periods – the interglacials – were alternating with glacial periods. During an interglacial the Earth reaches the more favourable ‘normal’ pre-Pleistocene state and is warmer and much more stable. Those interglacials first happened every 41,000 years, but as the deep-sea temperatures (and so atmospheric temperatures) decreased, more favourable orbital circumstances, rather than only increasing obliquity, were needed to get out of the cold glacial climate state. Because of the colder deep oceans during the last part of the Pleistocene the Earth only succeeded every 100,000 years in creating an interglacial.
If the 15-million-year trend of ever decreasing deep sea temperatures is going to continue, somewhere in the future the Earth will not be able to create a next interglacial. Millions of years of a deep and continuing glacial state might be in the future.
With regards to commenting: please adhere to the rules known for this site: quote and react, not personal.
In commenting: please remind you are on an international website: for foreigners, it is difficult to understand abbreviations. Foreigners only understand words and (within the context) easy to guess abbreviations like ’60N’ or ‘SH’.
About the author: Wim Röst studied human geography in Utrecht, the Netherlands. The above is his personal view. He is not connected to firms or foundations nor is he funded by government(s).
Andy May was so kind to read the original text and improve the English where necessary. Thanks Andy!
How About That
“Scientists discover 91 volcanoes below Antarctic ice sheet
This is in addition to 47 already known …. Geologists say this huge region is likely to dwarf that of east Africa’s volcanic ridge, currently rated the densest concentration of volcanoes in the world. Volcanic eruptions may not reach the surface but could melt the ice from beneath and drastically destabilise it”
https://www.theguardian.com/world/2017/aug/12/scientists-discover-91-volcanos-antarctica
Climate change shift ?
Thank you.
Your essay provides a great deal of food for thought.
Wim, thank you for your effort…
But let me show you my view point in consideration of your blog post.
Whatever your blog post information is about, from where I stand, even when I have to accept in face value that it mainly consist with no more or less than an expression of the actual general stand of the orthodox climatology, I still have to express my point of view, which consist more or less with a point of consideration where all about the info and intellectual reasoning happens to be and consist in the end of the day only as hot air and smoke.
You hopefully know the story of the ugly stubborn facts.
And from where I stand there is a fact, that is not only ignored and prohibited to consideration, but also it ends up directly confused and contradicted, which makes it a very ugly one when info like in your blog post considered……and it renders it all of it as fiction rather than reality.
This simple fact is the age of ice, the age of ice of the Antarctic ice shelf, or the age of ice of South Polar ice….
From my point of view is a fact that can not even be ignored, let alone contradicted……
But you see, you just done that in your blog post………
You ignore to consider an ice fact and switch to temp signal when considering time periods in an ice content context, without regard of the problem…..
And from there on you keep building this high tower of smoke and hot air,,,,,,, according to my point of view and my understanding….
bizarre!
cheers
Whiten, thanks for your remarks. As written elsewhere I am not yet finished so you will have to endure my writings a bit more.
Deep sea temperatures does not seem to have a direct relationship with ‘smoke and hot air’. When we think about ‘hot air’, isn’t that more about eh…..
Wim Röst
August 13, 2017 at 8:41 am
Wim. Thank you for the reply. Appreciated.
First understand that I am not judging you, or taking a judgmental position, I am just addressing your work, as per the blog post in question.
Second
No matter where are you aiming a get with it, that is not a problem,,,, the problem is at the starting point.
It seems to be flawed as it ignores a basic fact……
I have no problem with any hot air and smoke, unless when the argument about it consist no more than talking past each other….
Let me ask,,,,, do you understand the point made in my previous comment, and it’s implications?
Wim,
The correlation between lower deep sea temperatures and the Vostok ice core temperatures is very intriguing. It does shed light on the timing of glacials and why the last 4-5 glacial maximums are colder. Over the past 500 kyrs the temperatures of the interglacial periods appear to be hotter. Why doesn’t the colder deep ocean also temper the temperature of the interglacial warm periods?
The interglacials of over 400 Ka and over 100 Ka (the Eemian) were hotter, but the intervening two weren’t (~300 and ~200 Ka).
Renee, an intriguing question as well: “Why doesn’t the colder deep ocean also temper the temperature of the interglacial warm periods?”
It looks like you need an extra locomotive to get the more heavy train moving. But when it is moving it is more difficult to stop it because of its more heavy weight. Deep sea temperatures (figure 5) show later in the Quaternary a bigger difference between the coldest and the warmest temperatures.
Some mechanisms might be the following:
1. Because more cycles (obliquity, eccentricity, precession) become involved, the total energy they produce in a short period is higher. Perhaps the speed of warming is higher as well and so the speed of change.
2. Length of season is possibly playing a role. Length of season does not get much attention but I think it is very important, especially at mid and high latitudes, in the tropics length of season does not play an important role at least not in regard to temperature. But elsewhere, because of a longer/shorter season currents can change more. Pressure areas (different in winter and summer) will vary. Winds will vary more: summer seasons at the mid latitudes show a lower average wind speed. A longer summer season means: during a longer period less wind. This be of importance for point 3.
3. Upwelling. Upwelling is wind dependent. A longer season without wind can diminish (cold) upwelling in specific zones which has sea surface warming as result. And a shorter summer season could enhance cold upwelling and cool.
4. Because it has been cold during a longer period and colder as before, sea levels at the start of the temperature rise are lower than before. More sea streets are closed: think about the Australia – Indonesia blockade and the not/less entering of the Gulf Stream into the Caribbean. In the first case a huge piling up of warm waters in the west of the Pacific is possible. In the second case there are other effects on salinity, strength and direction of the Gulf Stream. In both cases there might be important changes in downwelling.
Those are the first things that come into mind. I think we must know more about zonal effects of the different orbital parameters and of specific effects of low temperatures on certain regions.
Wim a very interesting article, thank you very much. With regards point 3 @ur momisugly Aug. 13 11:44 am
I think your point 2 is very important. Perihelion is moving around our calendar at about 40 minutes a year. I know that’s not very fast. However we are now slowly moving away from the point where the Northern Hemisphere is not only at it’s shortest, but also takes place where we are closest to the Sun. In other words the best is now behind us and we can expect to see gradual cooling and also an increase in the rate of change of that cooling over the years.
Although we won’t see dramatic changes in actual temperature at any one place from this variable what we will see is a lowering of the altitude where precipitation lands as snow rather than rain. Here I’m reinforcing a point you made earlier regarding how critical temperature is to weather when that temperature is close to 0 deg C.
One of the first things I noticed when arriving in England in 2000 was that if it snows a lot before December the rest of the winter is cold. I know this is not very scientific but to me it seems snow makes its own weather!
Michael Keal: “Perihelion is moving around our calendar at about 40 minutes a year”
WR: At a time scale of thousands of years, 40 minutes a year is quite a bit. The cumulative effects are huge.
It is interesting to look at the functioning of orbit by looking at our present seasons. For example, the effects of long term ‘obliquity’ changes are (exaggerated) visible in our every year’s seasons. Every year we can experience the effects of a big change in obliquity during the year. While the angle changes, certain latitudes get more energy, others less. That during the year changing energy has huge consequences for the functioning of weather systems. And long term changes in orbital circumstances change not only weather- but also climate systems.
To understand how systems work, we can learn more from differences between the Northern Hemisphere and the Southern Hemisphere. There are huge differences, for example a 4-5 degrees (!) Celsius lower SH average summer temperature than the NH average summer temperature. To get an idea of the importance of this fact: how much is the difference between the average global surface temperature during the Last Glacial Maximum and our present global average surface temperature?
That 4-5 degrees difference between NH and SH is also (partly) an orbital effect. How do orbital changes during the year and over longer periods affect the NH and SH in a different way? And which part of that temperature difference between NH and SH depends on ‘other factors’? Which other factors? How?
Sorry to be pedantic, but shouldn’t the end of the first sentence below Figure 2 say “Figure 2” instead of “Figure 3”? Otherwise, an interesting and well-written article. Looking forward to reading the rest of the series.
Actually both figure 2 and figure 3 show a 5 degree drop. But, I think Wim is referring to figure 2, since it is surface temperature. You are correct, I’ll change it.
Lynn and Andy: thanks!
fixed
Wim, Good read and interesting thoughts.
How do you get the ocean amplification of 2.5 times?
Also, what are your thoughts which Phil brought up about change in ocean currents caused by the closing of the isthmus of Panama? Did that bring us into the Quaternary Glaciation period?
UIAK
Thank you UndercoverinAK. About your questions:
UIAK: “How do you get the ocean amplification of 2.5 times?”
WR: meant is the deep ocean / atmospheric amplification factor I think. I replied Nick for this question https://wattsupwiththat.com/2017/08/13/cooling-deep-oceans-and-the-earths-general-background-temperature/comment-page-1/#comment-2580275
But perhaps you mean what the mechanisms behind the amplification factor are. For now the only important thing for me was that there is something like the amplification factor. Because of that we must pay attention even to small changes in average deep sea temperatures. For now I will leave the answer concerning the eventual mechanism(s) behind the amplification to others.
UIAK: “Also, what are your thoughts which Phil brought up about change in ocean currents caused by the closing of the isthmus of Panama? Did that bring us into the Quaternary Glaciation period?”
WR: I did not yet react on most of the thoughts of WUWT readers, although I read the comments with big interest. In my next post I will tell about the (simple) mechanism that was (to my opinion) cooling the deep seas. In the post after that one I will elaborate on the working of that mechanism and at least some of the possibility’s mentioned here will be treated.
Wim,
Thanks. Missed that in initial read. Direct inference from the graphs. Empirical evidence. What a concept.
I assumed it was a very complicated model costing millions of dollars. 🙂
UIAK
What happened to the GHE? Is the atmosphere no longer increasing the surface temperatures some 33K above the infamous 255K?
What caused these high deep ocean temperatures?
Does this earth background temperature because of the cold deep oceans make it virtually impossible for the air temperatures to rise as much as the alarmists are fearing?
Mike B: “Does this earth background temperature because of the cold deep oceans make it virtually impossible for the air temperatures to rise as much as the alarmists are fearing?”
Interesting question. Short answer: yes, I think it does. There is a certain range that atmospheric temperatures can differ from the sea surface temperatures and a certain range that the average sea surface temperature can differ from deep ocean temperatures – but I don’t know which ranges exactly. I only can see that there are many stabilizing processes that keep ocean temperatures and atmospheric temperatures within a certain range. When we look at periods with rapid temperature rises in the last century (thirties and forties, eighties and nineties) we see that they are followed by cooling or ‘stabilizing’ periods. A lot of ‘missing heat’ is found back in the oceans: 90% if I remember well. But when the average surface temperatures went down during the LIA, the Ocean Heat Content was diminishing too. It all indicates that atmospheric temperature developments can’t differ too much from ocean temperature developments. As we saw in the Paleo data: if one goes down, the other goes down.
Puzzled by Fig 1. The reference below gives ocean bottom temperature as 1.67 to 2.78 degC, and the average as 3.9 deg C. The only way to get 0 degC water is freshwater at the surface under freezing conditions. Below zero temperatures at depth are not possible.
https://hypertextbook.com/facts/2007/LilyLi.shtml
Pochas94, your link gives the numbers 1.67 to 2.78 °C from one source which seems to me a popular one. Most common is 0-3 °C for the deepest water as mentioned by the University of Michigan, but Antarctic bottom waters even often are below zero: until minus 0.8 °C. Because the salty ocean water freezes around minus 1.8 °C (at about the same temperature as seawater has its highest density), deep ocean waters can really be very cold.
In theory at the bottom of the Marianas trench water would freeze at about -10 deg C or lower depending on how salty due to the high pressure.
https://www.quora.com/What-would-be-the-temperature-needed-to-freeze-water-at-the-bottom-of-the-sea
Excuse my ignorance but how can we possibly know what the historical deep ocean temperatures were with any degree of accuracy?
Michael Carter: “how can we possibly know what the historical deep ocean temperatures were with any degree of accuracy”
WR: Proxies are used. Remnants of sea animals (often calcerous remnants) show chemical traces that give information about the temperatures at the time the animal grew the calcerous parts. Cores of the sea bottoms contain those remnants and reveal the necessary information. As the comment of Bill Illis in this post illustrates, interpretation of the results can lead to big discussions.
What is being left out in these arguments is any discussion of how much heat in the deep ocean is being contributed by the earth’s core, especially along the tectonic fault lines. As long as this quantity remains an unknown, all other discussions regarding “causes” remain inadequate at best.
What is being left out in these arguments is any discussion of how much heat in the deep ocean is being contributed by the earth’s core, especially along the tectonic fault lines. As long as this quantity remains an unknown, all other discussions regarding “causes” remain inadequate at best.
Danny, see my comment: https://wattsupwiththat.com/2017/08/13/cooling-deep-oceans-and-the-earths-general-background-temperature/comment-page-1/#comment-2580163
Very good article by Shaviv explaining effects of Star Formation Rate (SFR) (10s of Myr cycle), Passage through galactic spiral arms (~145 Myr cycle), and Oscillations perpendicular to the galactic plane (~35 Myr cycle) on changes of the environment of the Earth. We just passed a passage through a galactic spiral arm and oscillation perpendicular to the galactic plane about 2-4 Myr ago resulting in a very cold period (Quaternary Glaciation) and hopefully subsequent warming in the next few million years. Shaviv’s figure 1.9 marries up pretty well with Figure 3 above ans subsequent cooling since this time.
http://www.phys.huji.ac.il/~shaviv/articles/ShavivChapter.pdf
Funny.
Deep ocean
We have like zero measurements.
Note ño skeptics objecting. Or objecting to an average deep ocean temperature or to precision of 1/100 th of a degree.
Steven Mosher:
Funny.
Deep ocean
We have like zero measurements
WR: Congratulations: your first Haiku!
+1
Wim
That has to be the most erudite and cultured slapdown in recent WUWT history!
And Mosh is just the person to appreciate it.
“Haiku” is a traditional form of Japanese poetry. Haiku poems consist of 3 lines. The first and last lines of a Haiku have 5 syllables and the middle line has 7 syllables. The lines rarely rhyme.
Apparently zero deep ocean measurements are enough to conclude that we are doomed by CO2 and zero is far too many already for any climate “scientist” to go after a grant to obtain more data. The oceans contain a thousand times the heat energy of the atmosphere and are DELIBERATELY IGNORED by climate science because they can’t figure out how to implicate CO2 from there.
It’s like the house is shaking and we’re blaming the cat’s purring while they’re blasting next door to build a rocket launch pad.
It makes me wonder what the questions would be on the reverse IQ test to get into klimit skule.
One sided ball busting does not become you no matter how often you do it.
Where is Wim going with this?
We’ll see soon enough.
Steven – While I consider myself a “Seeker” (of truth) I am a skeptic of any conclusion based on evidence that I consider tenuous. I have already commented above that (IMO) proxy evidence used to establish historical deep marine temperatures fall into this category. I agree with you that we haven’t even established strong constraints on the modern situation, let alone historical
One proxy pointed out here relates to chemical composition of shell material in deep marine cores. I am not an expert in the field but I do know that the most studied organisms are foraminifera. The only forams of any use are benthic and they decrease rapidly in abundance beyond 35 m in water depth. What are these shelled organisms that live in the deep marine environment? Skeletal material may be of use if one could find it in a core, but the abundance of deep marine life is such that a good record over time in cores is highly unlikely
Detritus can be swept into deeper water over time which muddies the ( research) waters as well
This all looks like arm waving to me and does no good to the skeptical cause
Regards
M
Michael Carter, Deep ocean temperature estimates are based on Mg/Ca ratios in benthic forams and ostracodes. One of the best studies is by Caroline Lear et al., 2002 ( http://adsabs.harvard.edu/abs/2002GeCoA..66.3375L ) They estimate that temperatures can be estimated +-1 degree C.
“Steven Mosher August 13, 2017 at 3:13 pm
Deep ocean
We have like zero measurements.”
Don’t worry Steven, Trenberth has a model you can use.
A number of other factors:-
1) plate tectonics – moving the land masses around effecting what they receive from the Sun and effecting the whole Earth climate situation.
2) the tilt and orbit of the Earth.
3) large meteorites causing the Earth to move away from the Sun.
I’m very anxious to see Wim’s follow up to this work. Like Christmas! Actual thoughtful, original and intelligent scientific investigative hypothesis! I wonder why nobody thought of trying this before!
Thank you for this article which definitely makes the dog wag the tail and not vice versa.
It all feels a bit circular for my liking…
The “general background temperature of the Earth” described here is an average over 500,000 years… longer than a glacial-interglacial cycle.
So the comparison is:
Late Pliocene – 0% glacial, 100% interglacial, averaged together -> 0.3C
Early Pleistocene – 75% young glacial, 25% interglacial, averaged together -> 0.2C
Late Pleistocene – 30% young glacial, 60% old glacial, 10% interglacial, averaged together -> -0.25C
(All else equal, this would imply interglacial temp = 0.30C, young glacial temp = 0.17C, old glacial = -0.55C)
How much of the decrease in this average since ~2.6Mya is merely an *expression* of glacial periods being longer?
Or to ask the question the other way, what is:
– the trend since 2.6 Mya of deep ocean water temperatures *specifically during interglacials*?
– the trend during the Pleistocene of deep ocean water temperatures *in the 1st obliquity cycle of glacials*?
(Sorry, couldn’t find the raw data)
I note that, (from Fig 1 at a glance) during interglacials, the deep ocean still warms to 0.3C – no colder than the late Pliocene. Deep ocean cold from one glacial is not carried over into the next. Also that the 4 very cold periods since 700kya were all *at the end* of a long glacial.
If the deep ocean temperature is an indication of some other *persistent* steadily cooling “general background temperature of the Earth” (in submarine permafrost, oceanic crust, or wherever) then I would have looked at the *rate of cooling* of the deep ocean over a particular section of the first obliquity cycle of each glacial onset.
Wim
Considering the climate system as one containing chaotic/nonlinear dynamics, then the trend to larger amplitude fluctuations since the MPR, between colder glacial maxima and warmer interglacials, looks intuitively like a system becoming unstable because it is approaching a phase or state transition. So “soon” something is about to change. This could indeed hypothetically be a drop down in temperature and a transition to a colder state of uninterrupted glaciation, no longer punctuated by interglacials. Our current interglacial could even be the last.
WR A great post. Thank you. I have been thinking about the effect of the Tethys Ocean on climate for some time. Here are my latest ideas:-
A Plate Tectonic Recipe for a Warm Water World.
The Atlantic /Arctic Ocean submarine ridge forms the basis a Meridional Ocean that dominates the plate tectonic structure of the modern world. This mid-ocean ridge stretches from its pole of rotation termination point that Tuzo Wilson (1976) identified in the Laptev Sea off the north coast of Siberia (see Continents Adrift and Continents Aground), to the antipodal point in the Weddell Sea between east and west Antarctica. Meridional Oceans are not optimally placed to intercept sunlight in the tropics, for that we need a Zonal Ocean. The Southern Ocean defines the locus of the world’s modern Zonal Ocean, but it is located in temperate latitudes and so it too is not in an optimal location to collect tropical solar energy.
The biggest change in our understanding of the latitudinal reach of the Hadley Cell is the realisation from modelling studies of planetary rotation that it is the speed of daily rotation of the Earth that determines the locus of tropospheric down welling. This is contra to the earlier view that the cooling to space of the air that was uplifted to the tropopause, after first being dried by rain-out in the convective thunderstorms of the equatorial ITCZ, defined the locus of down welling. Earth is a fast rotating planet and so the latitudinal reach of the Hadley Cell is limited to the tropics (Del Genio & Suozzo, 1987 and Hunt, 1979). This means that the return to the surface of the down welling air will guarantee clear skies under the summer sun of the Tropic of Cancer. If the surface is land, then we have the great deserts of the Sahara and Arabia. Paradoxically these great hot deserts cool the planet because the daily solar heating is quickly vented to space by direct thermal radiation from the ground and so lost from the planet’s long-term thermal storage system, namely the oceans.
Conversely if the Tropical of Cancer is located over a Zonal Ocean, such as the Cretaceous Tethys Ocean, then the incoming solar radiation is trapped in the surface sea water and can be stored within the ocean. Here another paradox comes into effect, evaporation causes cooling and the dry surface winds of the trade wind belt will remove water from the ocean, but seas are salt water bodies, evaporation also increases marine water salinity, warm saline water is more dense than cool less saline water and so we have the opportunity to generate, in appropriate coastal locations, warm dense deep bottom water that exports to and stores heat in the abyssal ocean. We see an example of this export process of warm saline deep water generation in our modern low carbon dioxide cold ocean world in the Persian Gulf where the warm dense saline water formed off the Emirates coast exits into the Indian Ocean as a bottom current through the Straits of Hormuz (Bower et al., 2000).
References
Bower, A.S., Hunt, H.D. and Price, J.F., 2000. Character and dynamics of the Red Sea and Persian Gulf outflows. Journal of Geophysical Research: Oceans, 105(C3), pp.6387-6414.
Del Genio, A.D. and Suozzo, R.J., 1987. A comparative study of rapidly and slowly rotating dynamical regimes in a terrestrial general circulation model. Journal of the atmospheric sciences, 44(6), pp.973-986.
Hunt, B.G., 1979. The influence of the Earth’s rotation rate on the general circulation of the atmosphere. Journal of the Atmospheric Sciences, 36(8), pp.1392-1408.
Wilson, J.T., 1976. Continents adrift and continents aground; readings from” Scientific American”. WH Freeman and Company.
Philip Mulholland, you only needed a half word, as we say in Holland. Well done, you will like my next post.
Een goed verstaander heeft maar een half woord nodig.
I think you flatter me, but thanks anyway.
Are you on Research Gate? If so please look me up there.
Test post.
Javier’s really done some great work on this over at Climate Etc. Rigorous, data-driven, and objective.
Forgot to add, this post is also very interesting — I hadn’t seen the deep ocean trend over this time period before. Based on the astronomical data, Javier’s pretty sure we won’t glaciate in the next 2000 years, but that next glacial period is still probably the most serious existential threat to our species.
This classic mantra of “climate science” constitutes a gross misrepresentation of fluid thermodynamics and oceanographic observations. There is no “direct” connection of the temperature of deep waters with surface temperature. Upwelling is not a global phenomenon, but is very much localized to continental shelves and margins.. Even where it’s strongest, around Antarctica, only a small fraction of the dense water parcels that sank elsewhere are spiraled up again to the surface. (see, for example: https://www.nature.com/articles/s41467-017-00197-0 ). And the sun cannot warm water below ~100 meters, especially during the long polar winter. In the words Carl Wunsch, the “great conveyor belt” of wholesale deep oceanic circulation–espoused by “climate science”–is a “fairy tale for adults.”
Good to see some sensible ideas 😉
Have to disagree on this though:
Solar energy seems able to maintain the temperature of the mixed surface layer some 15K above the deep ocean temperature. So if the temperature of the deep oceans is much higher then today, like in the Cretaceous, the surface temperatures will also be correspondingly higher.
These higher deep ocean temperatures can obviously (to you and me) not be caused by anything happening at the surface.
1sky1: “There is no “direct” connection of the temperature of deep waters with surface temperature”
WR: One million cubic kilometres from the deep ocean into the surface layer upwelling water isn’t a direct connection from the deep sea with the surface layer?
1ksy1: “Upwelling is not a global phenomenon, but is very much localized to continental shelves and margins”
WR: See map of major (!) upwelling areas:
NOAA: “This image highlights major upwelling areas along the world’s coasts in red. Upwelling occurs when winds blowing across the ocean surface push water away from an area and subsurface water rises up from beneath the surface to replace the diverging surface water. These subsurface waters are typically colder, rich in nutrients, and biologically productive. Therefore, good fishing grounds typically are found where upwelling is common. For example, the rich fishing grounds along the west coasts of Africa and South America are supported by year-round coastal upwelling.”
https://oceanservice.noaa.gov/education/kits/currents/03coastal4.html
Wim Röst August 15, 2017 at 7:24 am
Your text is about deep oceans. Deep is generally accepted as being below the permanent thermocline, so below 1500 – 1800m.
https://en.wikipedia.org/wiki/Deep_sea
All your major upwelling areas seem located over a continental shelf. Depth generally maximum 150-200m.
https://en.wikipedia.org/wiki/Continental_shelf
Temperatures at these depths are still under the influence of solar warming.
http://www.oc.nps.edu/nom/day1/annual_cycle.gif
So please show where the 1 million km^3 of DEEP ocean water is upwelling.
Ben Wouters August 15, 2017 at 1:18 pm: “Your text is about deep oceans.”
WR: Better would be to speak about ‘below thermocline waters’. ‘Deep ocean’ is used for both Intermediate waters and for what is called the ‘deep ocean waters’.
Ben: “So please show where the 1 million km^3 of DEEP ocean water is upwelling”
WR: you can see the temperature effect of the upwelling even on maps on world scale, west of the continents:
Upwelling is a process where wind is blowing the top layer away. Because of isostasy the water that is blown away has got to be replaced by other water. The only place where we can find that ‘other water’ near the coasts is: below.
Wim Röst August 15, 2017 at 5:44 pm
By far the largest upwelling/downwelling event on this planet is the El Nino/La Nina one.
https://wattsupwiththat.com/2016/12/15/do-over-the-199798-super-el-nino-via-latest-computer-animation/
In the animation it is clear that below ~300m nothing much happens.
All other upwelling will have even less influence depth wise.
So all this upwelling/downwelling is just one of the many mechanisms that mixes solar energy a bit deeper into the oceans, creating the mixed surface layer.
This is all happening ABOVE the permanent thermocline, and has no influence whatsoever on the deep oceans below the permanent thermocline.
https://en.wikipedia.org/wiki/Thermocline
Ben Wouters August 16, 2017 at 1:12 am: “This is all happening ABOVE the permanent thermocline, and has no influence whatsoever on the deep oceans below the permanent thermocline.”
WR: Please check the things you say. Because of upwelling the Thermocline raises.
http://www.nature.com/nature/journal/v461/n7263/fig_tab/461481a_F1.html
Upwelling waters are well known fishing areas. Because deep waters are nutrient rich, from the deep upwelling waters are rich in nutrients. Therefore upwelling regions are belonging to the best fishing grounds. Because of deep water that welled up.
The zones of cool surface water seen at moderate latitudes west of the continents are more the result of strong advection from high latitudes than of local upwelling.
1sky1 August 16, 2017 at 1:38 pm: “The zones of cool surface water seen at moderate latitudes west of the continents are more the result of strong advection from high latitudes than of local upwelling.”
WR: Perhaps reading a bit about the subject?
That the quasi-permanent hemispheric gyres manifest cool surface currents (e.g., Humboldt, Canary) flowing equatorward along the eastern margins of the ocean basins requires no reading beyond an introductory text in descriptive oceanography for non-scientists. Googling “eastern boundary currents” should readily produce accessible explanations why they are much wider and slower than the warm western boundary currents (e.g., Gulf, Agulhas).
1sky1 August 16, 2017 at 4:12 pm
“That the quasi-permanent hemispheric gyres manifest cool surface currents (e.g., Humboldt, Canary) flowing equatorward along the eastern margins of the ocean basins requires no reading beyond an introductory text in descriptive oceanography for non-scientists.”
WR: The fact that the existing of a current does or does not prevent upwelling is something you need to have checked before you make your statements. I am not here to continuously improve your comments. Again: read! And check your statements first if you want that I take your future comments seriously!
Wim Röst August 16, 2017 at 2:38 am
No body will dispute that upwelling occurs. You state that these upwelling waters are coming from the DEEP oceans since they are nutrient rich.
How does the linked image show that upwelling is coming from the DEEP oceans?
Ben Wouters August 17, 2017 at 2:54 am: “How does the linked image show that upwelling is coming from the DEEP oceans?”
WR: There is an upward arrow at the right, coming from below the thermocline. Your statement was: Ben Wouters August 16, 2017 at 1:12 am: “This is all happening ABOVE the permanent thermocline, and has no influence whatsoever on the deep oceans below the permanent thermocline.”
FAO has a lot of information about upwelling where you can get it all confirmed. Google on ‘FAO’ and ‘Upwelling’
Wim Röst August 17, 2017 at 3:27 am
If you blow (part of) the mixed surface layer to the west Pacific the thermocline will start a bit less deep or even at the surface. The PERMANENT thermocline will still reach down to 1000-1500 m or even deeper.
So no ice cold deep ocean water is surfacing due to wind effects, not even during a La Nina.
The water is coming from just below the surface and is a few degrees colder than the surface water it replaces. In the ENSO animation I linked to the temperature range for the anomaly is just 6 degrees and the entire event plays out in the upper 300m of the Pacific.
Missing image from this page: https://en.wikipedia.org/wiki/Thermocline
(second image)
Once again, the well-known oceanographic point I’m making about the origin of broad zones of cool water along the eastern boundaries of oceans is being totally missed, while falsely turning my statement into an ostensible claim that currents “prevent upwelling.” Such uncomprehending argumentation is lamentable!
What’s missing here is any professional awareness that upwelling is recognized most definitively not so much by cool temperatures–which can be due to several factors–as by chlorophyll concentrations. The latter provide sharp delineations of very-much-narrower zones typically lying close inshore parallel to the coast. An example of such is seen here: http://oceanmotion.org/western-boundary-sst.htm
1sky1
The existence of the deep ocean is yet another thing that warmist alarmists have to deny, in order to keep the dystopian faith.
If the deepest ocean was not in constant circulation (albeit with a centuries timescale) with the surface, then it would be anoxic.
The deep is not anoxic. This is sufficient proof that the THC conveyerbelt is real. It accounts for all climate change.
For the deep to be ventilated (the correct oceanographic term for this) and not anoxic depends on cold downwelling at the poles. Thus for instance in the Jurassic, with no polar ice and downwelling, the deep was anoxic.
Oceanic polar ice driven conveyerbelt circulation which ventilates the deep ocean also by virtue of upwelling, sustains the huge productivity of today’s oceans. That’s why we have whales now but there weren’t whales in the Jurassic.
In fact, there are large anoxic zones of deep water scattered around the globe. The entire Black Sea is one. For others see: https://www.accessscience.com/content/anoxic-zones/037400. Your sense of “deep” is very different from that of oceanographers.
While upwelling and THC indeed occur in certain places and certain conditions, that is simply not the same as the “wholesale deep ocean circulation” envisioned by the “great conveyor belt” meme, which often portrays super-dense deep water fancifully rising to the surface in the tropical Indian Ocean. The notion that it accounts for “all climate change” is as wrong-headed as the original Ptolemy’s geocentric theory.
Here are some anoxic basins:
Bannock Basin in Levantine Sea, eastern Mediterranean Sea;
Black Sea Basin, off eastern Europe, below 50 meters (150 feet);
Caspian Sea Basin, below 100 meters (300 feet);
Cariaco Basin, off north central Venezuela;
Gotland Deep, in the Baltic off Sweden;
L’Atalante basin, eastern Mediterranean Sea;
Mariager Fjord, off Denmark;
Orca Basin, northeast Gulf of Mexico, and
Saanich Inlet, off Vancouver Island, Canada.
Granted, not all are in deep water.
1sky1 August 16, 2017 at 3:56 pm: “All I do is simply take your wholly unreferenced claim of a million cubic kilometers of upwelled water (…)”
WR: Again: read first. That million cubic kilometres is explained in the first post on upwelling: https://wattsupwiththat.com/2016/12/26/warming-by-less-upwelling-of-cold-ocean-water/
1sky1: ” What does need to be said is that, generally being denser, it can’t remain near the surface very long, as some may assume.”
WR: once more: read first about the subject. As the upwelling seawater warms, the density is lowered fast, because of the expanding of the water.
What a splendid idea for someone who plainly has never assimilated an oceanographic text, provides no source here, and references his own previous WUWT posting, as if that settles the issue.
.
In fact, what that previous posting reveals is a conversion of total transport rates in a three-tiered ocean estimated by Ganaschaud and Wunsch (2000) into a volume based arbitrarily on a year’s transport. That “upwelled water” mass, which was claimed to cool the entire globe significantly, is now said to have its density “lowered fast” by surface warming. In reality, the very high heat capacity of water prevents “fast” warming, as this view of cool temperatures extending hundreds of kilometers off Sumatra during the SE monsoon clearly shows:
The condition found overwhelmingly throughout the oceans is quasi-permanent stratification, with temperatures declining gradually from the surface to the seasonal thermocline (marking the extent of the well-mixed layer) and even faster to the permanent thermocline, typically several hundred meters down. It is below that level where the deep ocean begins.
There simply are no measurements that show any coherence between surface temperature variations and those in the deep ocean over human lifetimes. Nor are there any known mechanisms that can preserve the temperature of water parcels as they migrate at snail’s pace through the water column, with the bottom waters being continually replaced by thermohaline circulation. Turbulent mixing along the way is what precludes any direct connection between the deep-water temperatures and those at the surface. While the mass volumes involved in upwelling over continental shelves and marginal seas may appear large to novices, they are dwarfed by the global volume of the oceans. Comparisons of Cretaceous and Holocene temperatures that fail to take into account the strikingly different states of planetary cooling are a red herring.
1sky1: “While the mass volumes involved in upwelling over continental shelves and marginal seas may appear large to novices, they are dwarfed by the global volume of the oceans.”
WR: You are trying to dwarf the effect of more than one million cubic kilometres (!) in the warm surface layer upwelling ice cold water.
Good luck!
A million cubic kilometers is a cube of 100km on each side. If we take 5km for the average depth of the ocean, this amounts to 20 areas of 10000km^2 each. The resulting 200000km^2 indeed is dwarfed by the ~360 million square kilometers of global ocean. Furthermore, the upwelling water is by no means “ice cold,” except around Antarctica. To be sure, this has a profound effect LOCALLY during the season of upwelling winds. On a global basis, however, the effect is minor.
1sky1 August 16, 2017 at 1:27 pm: “A million cubic kilometers is a cube of 100km on each side.”
WR: Wrong comparison. Deep water is upwelling into the surface layer, see my comment Wim Röst August 16, 2017 at 2:46 am (and the posts about this subject). That surface layer is a relatively thin layer, not 100 km deep. For that, the effects of 1 million cubic kilometres upwelling cold water are huge. You need to count for the effects on that surface layer, the layer that is important for surface temperatures and for processes at the surface.
It is perhaps a good idea first to read what is written?
Nowhere do I make that preposterous claim! All I do is simply take your wholly unreferenced claim of a million cubic kilometers of upwelled water and compare it to the total volume of the oceans. The latter is greater by a factor of ~1800. That the upwelled water is near the surface goes without saying. What does need to be said is that, generally being denser, it can’t remain near the surface very long, as some may assume.
I can see only one solution.
We must destroy the Isthmus of Panana!
The mechanism depressing sea surface temperatures by the cold unheated ocean below could be by conduction rather than convection and would happen slowly.