AMERICAN GEOPHYSICAL UNION
WASHINGTON–New research reveals temperatures in the deep sea fluctuate more than scientists previously thought and a warming trend is now detectable at the bottom of the ocean.
In a new study in AGU’s journal Geophysical Research Letters, researchers analyzed a decade of hourly temperature recordings from moorings anchored at four depths in the Atlantic Ocean’s Argentine Basin off the coast of Uruguay. The depths represent a range around the average ocean depth of 3,682 meters (12,080 feet), with the shallowest at 1,360 meters (4,460 feet) and the deepest at 4,757 meters (15,600 feet).
They found all sites exhibited a warming trend of 0.02 to 0.04 degrees Celsius per decade between 2009 and 2019 – a significant warming trend in the deep sea where temperature fluctuations are typically measured in thousandths of a degree. According to the study authors, this increase is consistent with warming trends in the shallow ocean associated with anthropogenic climate change, but more research is needed to understand what is driving rising temperatures in the deep ocean.
“In years past, everybody used to assume the deep ocean was quiescent. There was no motion. There were no changes,” said Chris Meinen, an oceanographer at the NOAA Atlantic Oceanographic and Meteorological Laboratory and lead author of the new study. “But each time we go look we find that the ocean is more complex than we thought.”The challenge of measuring the deep
Researchers today are monitoring the top 2,000 meters (6,560 feet) of the ocean more closely than ever before, in large part due to an international program called the Global Ocean Observing System. Devices called Argo floats that sink and rise in the upper ocean, bobbing along in ocean currents, provide a rich trove of continuous data on temperature and salinity.
The deep sea, however, is notoriously difficult to access and expensive to study. Scientists typically take its temperature using ships that lower an instrument to the seafloor just once every ten years. This means scientists’ understanding of the day-to-day changes in the bottom half of the ocean lag far behind their knowledge of the surface.
Meinen is part of a team at NOAA carrying out a rare long-term study at the bottom of the ocean, but until recently, the team thought the four devices they had moored at the bottom of the Argentine Basin were just collecting information on ocean currents. Then Meinen saw a study by the University of Rhode Island showcasing a feature of the device he had been completely unaware of. A temperature sensor was built into the instrument’s pressure sensor used to study currents and had been incidentally collecting temperature data for the entirety of their study. All they had to do was analyze the data they already had.
“So we went back and we calibrated all of our hourly data from these instruments and put together what is essentially a continuous 10-year-long hourly record of temperature one meter off the seafloor,” Meinen said.Dynamic depths
The researchers found at the two shallower depths of 1,360 and 3,535 meters (4,460 feet and 11,600 feet), temperatures fluctuated roughly monthly by up to a degree Celsius. At depths below 4,500 meters (14,760 feet), temperature fluctuations were more minute, but changes followed an annual pattern, indicating seasons still have a measurable impact far below the ocean surface. The average temperature at all four locations went up over the course of the decade, but the increase of about 0.02 degrees Celsius per decade was only statistically significant at depths of over 4,500 meters.
According to the authors, these results demonstrate that scientists need to take the temperature of the deep ocean at least once a year to account for these fluctuations and pick up on meaningful long-term trends. In the meantime, others around the world who have used the same moorings to study deep sea ocean currents could analyze their own data and compare the temperature trends of other ocean basins.
“There are a number of studies around the globe where this kind of data has been collected, but it’s never been looked at,” Meinen said. “I’m hoping that this is going to lead to a reanalysis of a number of these historical datasets to try and see what we can say about deep ocean temperature variability.”
A better understanding of temperature in the deep sea could have implications that reach beyond the ocean. Because the world’s oceans absorb so much of the world’s heat, learning about the ocean’s temperature trends can help researchers better understand temperature fluctuations in the atmosphere as well.
“We’re trying to build a better Global Ocean Observing System so that in the future, we’re able to do better weather predictions,” Meinen said. “At the moment we can’t give really accurate seasonal forecasts, but hopefully as we get better predictive capabilities, we’ll be able to say to farmers in the Midwest that it’s going to be a wet spring and you may want to plant your crops accordingly.”
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Notes for Journalists
This research study is freely available through November 15. Download a PDF copy of the paper here. Neither the paper nor this press release is under embargo.
Paper title:
“Observed ocean bottom temperature variability at four sites in the northwestern Argentine Basin: Evidence of decadal deep/abyssal warming amidst hourly to interannual variability during 2009-2019”
Authors:
Christopher S. Meinen, Renellys C. Perez, Shenfu Dong: NOAA Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida, United States;
Alberto R. Piola: Naval Hydrography Service, Buenos Aires, Argentina; University of Buenos Aires, Buenos Aires, Argentina; Franco-Argentine Institute on Studies of Climate and its Impacts, National Council for Scientific and Technical Research, Buenos Aires, Argentina;
Edmo Campos: Oceanographic Institute, University of São Paulo, São Paulo, Brazil; Department of Biology, Chemistry and Environmental Sciences, School of Arts and Sciences, American University of Sharjah, Sharjah, United Arab Emirates.
The following press release and accompanying images are available online at: https://news.agu.org/press-release/the-deep-sea-is-slowly-warming/
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For decades, climate crisis skeptics have offered alternative theories to explain recent climate observations, but they are generally dismissed with a hand-wave because these theories do not come with a complete understanding of the physical mechanisms involved. For example, if you suggest that periodic ocean cycles are responsible for most of the changes, it is required that you explain how and why the ocean cycles exist before your theory is even considered.
On the other hand, people like Trenberth proclaim that the Earth’s atmosphere is not warming as fast as expected because the heat is going into the deep oceans, while offering no explanation of how that might be possible. Apparently scientific arguments weakening the AGW theory must be subjected to the highest scientific scrutiny and rejected at the slightest deviation from perfection, while arguments supporting the AGW theory require only a proclamation to be considered true, and the scientific method be damned!
It’s bad and getting worse. It’s also poorly studied and we need more money to show more bad and getting worse in minute differences without context.
Clearly the sea floor and what is below it has no effect. It’s all the fault of Hom sap.
Why do they bother other than getting their names into print or even lights?
fretslider
You asked, “Why do they bother …?” For a salary squeezed out of the grant.
I wonder if this paper corrected for other influences? Didn’t read it but ….
Wasn’t 2009 a La Nina year? Wasn’t 2019 an El Nino year? That alone could account for the warming. Remember, they stated seasonal influences were detected. Therefore, other short term influences would almost surely affect the measurements.
That implies a sudden heating of the deep water by warm surface water, questionable…..
“this increase is consistent with warming trends in the shallow ocean associated with anthropogenic climate change”
It is not the atmosphere that heats the oceans (nor IR radiation from CO2), but rather short wavelength radiation that penetrates deep into the oceans. If anything, this heating of the deep oceans shows an increase in the sun’s energy penetrating the oceans.
“Because the world’s oceans absorb so much of the world’s heat, learning about the ocean’s temperature trends can help researchers better understand temperature fluctuations in the atmosphere as well”
The oceans control the atmosphere. If one needs to ‘learn about the ocean’s temperature trends, then it is a tacit admission that one is clueless about what is happening to atmospheric temperatures. The inability of ‘climate models’ to resemble reality is a testament to this cluelessness.
“..a significant warming trend in the deep sea where temperature fluctuations are typically measured in thousandths of a degree.”
They are?
With what instrumentation?
In the above article’s third paragraph, notice how this phrase was just slipped in, without any further scientific reference or justification, as if it were as obvious to everybody as the Sun rising in the East: “. . . this increase is consistent with warming trends in the shallow ocean associated with anthropogenic climate change . . .”
So, where is the peer-reviewed, science-based paper that shows by direct experimental data the percentage of global warming that is attributed to mankind (“anthropogenic”)? Any response must include the period of 1940-1975 that had measured global atmospheric cooling, and the documented hiatus (aka “pause”) in global warming that occurred over 1988-2015.
This is, all things considered, a very simple question to ask.
Was there actually a belief that the deep seas were quiescent? Considering the constant rain of debris from above the deep seas should have been anoxic. Although mixing in the deeper ocean is so slow that temperature and salinity are almost conserved quantities, I’m not sure that anyone believed the quiescent part.
There is a slow over turning of this water as cold/saline water in regions of bottom water formation continues to sink. Where does this water go if it doesn’t replace “quiescent” water currently occupying the bottom? The time scale is probably thousands of years. We are to accept that a warming trend begun at most a hundred or so years ago at the surface ago is now detectable at depth — like a tape recording of earlier changes at the surface? Perhaps, but measurements alone are not enough to convince me. I want to see a credible explanation based on physical principles.
“The time scale is probably thousands of years”
More like 1,000 years. In an icehouse world like the current one has been for 35 millon years the deep sea is rather well ventilated and oxygenated. As long as Antarctica remains frozen there will be a constant supply of cold, salty, oxygen-rich bottom water.
When Antarctica is ice-free and vegetated at least along the coasts things might change.
Or maybe not. There will still be North Atlantic Deep Water (NADW) unless the Panama Isthmus sinks back below sea-level.
Kevin
You said, “I’m not sure that anyone believed the quiescent part.” I would say that the belief originated with geologic evidence. Very fine-grained rocks like shales are improbable if the water is turbulent. What is seen more commonly is bioturbation of the muds. Then the manganese nodule fields strongly suggest areas are undisturbed for millions of years, with extremely slow deposition of layers on the nodules.
I didn’t get past the headline. We have poor surface temperature records for any time span over the vast majority of the earths surface, but I’m supposed to believe that now we know what the deep sea was like during the Little Ice Age (or any other time in history)!?
The ludicrous Communist lies keep coming.
Deep ocean waters are only a few degrees above freezing . . . let’s say 2 °C, or about 275 K. The above article states: “They found all sites exhibited a warming trend of 0.02 to 0.04 degrees Celsius per decade . . .” So, together the “warming trend” accounts for an average absolute change ration of .03/275 per decade, or about 1 part in 10,000 per decade.
In comparison, the amount of global sea level rise over the decade of 2009-2019 was about 30 mm, presumably mostly from the overall melting of land-supported ice (i.e., only a very tiny amount would be due to thermal expansion based on the above-noted temperature changes). This increased water level would result in increased pressures at all depths.
Now, the above article also states, referring to temperature data from anchored moorings used in the above-cited research: “The depths represent a range around the average ocean depth of 3,682 meters (12,080 feet).
Thus, we have the situation of an absolute SLR-induced pressure change ratio at the instrumentation depth of 0.03 m/3682 m, or about 1 part in 100,000.
Given that the ΔP/P is 10% of the ΔT/T at the average depth of the measurements used, I’m just wondering if the adiabatic compressibility of seawater might account for a significant portion of the temperature increase discussed in the above article.
Anyone want to take a stab at doing the detailed calculation for this (I’m thinking the energy of adiabatic compression will be partitioned between the internal energy of the water and its sensible heat, but maybe not)?
There is no indication that this factor was even considered by the authors of the AGU article summarized above.
Water is so near non-compressible that any adiabatic processes are negligible (between 4 and 5×10−10 Pa−1).
And yet: https://www.sciencedirect.com/science/article/pii/S0967063714000041
I *still* want to know how that heat got into the deep ocean without first traversing the ocean surface!
Is there a cloaked Enterprise in orbit above us using their transporter to move heat into the deep ocean?
According to Fourier’s law: q = -kAg
k is the coefficient of thermal conductivity
A is the area involved
g is the temperature gradient, i.e. dt/dL where dt is the infinitesimal temperature change over the infinitesimal distance L.
We can also write q = (k/x)(t1 – t2) or (t1-t2) = qx/k
where x is the distance between the measured points.
This implies that the ocean surface (t1) will always be warmer than the deep ocean (t2). So where is all the surface temperature causing the warming of the deep ocean?
Cold water everywhere sinks below warmer water, especially when the cold water is of higher salinity. When polar ice freezes (and refreezes) the salt is eventually eliminated. The cold salty brine is denser than than warmer subsurface waters. It sinks to the bottom. Warm evaporated water from the Red Sea also sinks beneath cooler less salty water. –AGF
The deep water from the Red Sea however has to cross the shallow Hanish sill at Bab el Mandeb, so not much gets out in the ocean.
The only significant source of warm, oxygen-poor (and very salty) deep water today is the Mediterranean.
Back in the Hothouse World >35 mya this type of water was dominant in the deep sea, and ocean anoxia could then develop fairly easily. Not so now.
try
This nice paper from 2020 by Marcantonio et al shows – perhaps paradoxically – from
meticulous sediment isotope data over nearly 200k years, that higher atmospheric CO2 results in higher deep ocean oxygenation. They found that deep ocean anoxia, indicated by the presence of a chemical form of uranium, was associated with glacial periods of low atmospheric CO2 less than 200ppm.
https://www.nature.com/articles/s41598-020-63628-x
This suggests that healthy levels of CO2 in the atmosphere enhance planktonic primary production which among other things (like supporting nearly all life in the ocean) result in more oxygen being carried down to the ocean floor.
That’s interesting since it suggests that cold alone is not sufficient to oxygenate (ventilate) the ocean floor. Robust atmospheric CO2 is also needed.
All further evidence of course of how bad and dangerous CO2 is (/sarc).
AG,
Which still implies that the surface has to be hotter than the depths. Exactly what the formula says. If the ocean depths warm then the water will *rise* past colder water above it, just like you said, which would still leave the surface warmer than the depths.
The Enterprise doesn’t have a cloaking device.
Not sure where you learned your science.
sarc (if its necessary)
Pat
Yes, it is a Klingon conspiracy.
What is the precision and accuracy of their instruments?
Precision is probably very much better than accuracy. This is typical for temperature sensors.
This means that you can detect very small changes, provided that you calibrate frequently and have a good overlap between old ad new sensors.
Right. Is the change they are measuring within the error or capability of their measuring equipment?
Precision is basically repeatability of a measurement. The ability of a device to read the same thing multiple times is very dependent upon environmental factors. Voltage fluctuations, temp changes of a degree, parts aging, and so on. Accuracy, Ha! No way in Hades. There is a reason labs offering measurements of this precision spend millions every year insuring their equipment meet NIST standards.
Deep ocean warming in one place over 10 years.
Over the southern hemisphere as a whole there are widespread signs of cooling:
https://ptolemy2.wordpress.com/2020/09/12/widespread-signals-of-southern-hemisphere-ocean-cooling-as-well-as-the-amoc/
Send money!! Or we’ll round our data averages up some more and do more extrapolations.
I looked through and couldn’t find any link to the data. Does anyone know where it is to be found?
w.
Data Availability Statement
The PIES data used herein are freely available to the public from the NOAA National Centers for
Environmental Information (NCEI) via accession numbers 0125596, 0175745, and 0205725; the PIES and
CTD data are also available on request from the authors and at the project web page: http://www.aoml.noaa.
gov/phod/research/moc/samoc/sam/.
Maybe ask Mickey Mann 😉
The effect of depth on temperature accuracy is -0.73 milli kelvins /metre.
Not sure if the 0.73 value is the same for salt water as it is for pure water.
Much research is going on to refine the 0.73 value.
See here in section 6.6 for a straight forward discussion in:
http://www.isotechna.com/v/vspfiles/pdf_articles/A%20Technical%20Guide%20and%20Standard%20for%20the.pdf
For a more complete discussion see Fig 1 in: https://www.bipm.org/utils/common/pdf/final_reports/T/K3/CCT-K3.1.pdf
Where the temperature changes for each centimeter of depth increase.
Followed the references about temperature sensor performance and concluded as follows, after seeing a makers claim of resolution of 0.00001 deg C.
A typical climate researcher seems to look at the graphs of temperature over time, to conclude that this (exquisite?) new data shows useful patterns about climate change.
OTOH, the seasoned hard scientist seems to find a complex mishmash of noise and wonders if one can extract a vald signal.
So, we ask people like lab chemists, or researchers in measurement labs, who set standards, what their experience shows. The lab chemists will likely say that it requires lots of money, special gear, lots of attention to detail, etc to consistently measure water at ambient temperature with accuracy better than +/- 0.05 deg.
The standards lab metrician might well recount experience that an accuracy of +/- 0.005 degrees is possible for a short time with much dedicated effort and frequent recalibration.
Dear reader, form your own conclusions. Remember that accuracy is not precision is not resolution and all contribute to uncertainty. Remember what national measurement lab specialists can achieve, then contrast that with the claims of these authors dealing with water in remote and unexplored deep seas.
Geoff S
What Geoff said ⤴︎
Also, the claims from climate scientists of accuracy, precision, and resolution generally sell on my planet at about a 75% discount from retail …
w.
Geoff and others
There are really two kinds of problems. One is measuring something with a constant value, such as a high-precision ball bearing. Assuming that things like temperature are controlled, and the same observer uses the same instrument for repeated measurements, the variations are largely random and speak to the precision with which the fixed value can be measured. A large number of measurements can improve the precision by averaging out the random variation.
In the second case, measuring something that does not have a fixed value, one still has the issue of random variation. However, more importantly, the parameter being measured varies over time, and possibly also varies with other influences, and it is highly likely that the temporal variance swamps the random variance. One is never measuring the same thing (e.g. temperature) twice, nor using the same instrument for all measurements. And, the variance is almost certainly not Gaussian. Thus, the appeal to the Central Limit Theorem to increase precision is NOT justified. In the case of a variable, what measurements lead to is the central value of the sample, and the probability that subsequent measurements will be within z number of standard deviations from the mean. ALL the measurements are limited by the characteristics of the measuring system and will not exceed the precision of any single measurement.
I have previously pointed out that the Empirical Rule in statistics strongly suggests that the standard deviation for the global average temperature is several tens of degrees Fahrenheit. Anyone who supports the claim that one can improve temperature precision for the global average (or even stations) by taking thousands of measurements, has to explain why the Empirical Rule can be violated.
https://wattsupwiththat.com/2017/04/23/the-meaning-and-utility-of-averages-as-it-applies-to-climate/
It’s absurd to think the current network of deep-ocean temp monitors is capable of accurately tracking temp anomalies to thousandth of degrees Celsius per decade….
Leftist CAGW advocates have agendas and can easily “adjust” datasets with algorithms to get their desired “results” to assure their livelihoods and propaganda..
The penultimate example of manipulated data is, of course, Dr. Michael Mann’s hilarious Hockey Stick graph whose algorithms were so manipulative, one could input random National Hockey League game scores and still get a hockey stick looking graph….
Isn’t modern “#SCIENCE!!!(TM)” wonderful?
Powerful deep Arctic Ocean geological heat flow forces are melting the ice, says geologist James Edward Kamis.
In an article entitled “Heat From Deep Ocean Fault Punches Hole in Arctic Ice Sheet,” Kamis punches his own holes in the “humans-are-melting-the-ice”chorus.This world class plate tectonic pull-apart rift is a 1,000-mile-long fault system on the seafloor that has in recent past pulsed massive amounts of heat into the overlying ocean and thereby melting large portions of the ice that floats above the heated ocean column.
Natural forces play dominate role in sea ice extent it is clear to most scientists, he continues, that non-atmospheric natural forces play the dominate role in sea ice extent and thickness.
These natural forces include variations in the Earth’s orbit, long-term cyclic changes in deep-ocean currents, and most importantly geologically induced heat and chemically charged fluid flow from deep ocean faults and volcanoes.
Source: https://climatechangedispatch.com/heat-from-deep-ocean-fault-punches-hole-in-arctic-ice-sheet.html/Second source:Explosive volcanism on the ultraslow-spreading Gakkel ridge, Arctic Ocean.Roughly 60% of the Earth’s outer surface is composed of oceanic crust formed by volcanic processes at mid-ocean ridges.
Explosive volcanism on the ultraslow-spreading Gakkel ridge, Arctic Oceanhttps://www.researchgate.net/publication/5275125_Explosive_volcanism_on_the_ultraslow-spreading_Gakkel_ridge_Arctic_Ocean
https://www.nature.com/articles/nature07075
Their analysis is much worse than I had previously thought! marginalized analysis hardest hit!
Quiet in the depths. Really? I just wrote him this on the actual scale of variable submarine volcanism in the deep oceans:
https://www.dropbox.com/s/eqoebgjxmoyk50r/Another%20and%20Variable%20Source%20of%20Deep%20Ocean%20Heating.rtf?dl=0
Those interested in useful discussion about proper ways to measure accuracy, precision, etc, please see this 2010 paper by Pat Frank.
http://meteo.lcd.lu/globalwarming/Frank/uncertainty_in%20global_average_temperature_2010.pdf
If you read it, a lot more of the discussion above will have clarity and implications. Geoff S