From The Daily Mail
- The Little Ice Age brought colder-than-average temps around the 17th century
- Researchers say temperatures in deep Pacific lag behind those at the surface
- As a result, parts of the deep Pacific is now cooling from long ago Little Ice Age
By Cheyenne Macdonald For Dailymail.com
As much of the ocean responds to the rising temperatures of today’s world, the deep, dark waters at the bottom of the Pacific Ocean appear to be doing the exact opposite.
A Harvard study has found that parts of the deep Pacific may be getting cooler as the result of a climate phenomenon that occurred hundreds of years ago.
Around the 17th century, Earth experienced a prolonged cooling period dubbed the Little Ice Age that brought chillier-than-average temperatures to much of the Northern Hemisphere.
Though it’s been centuries since this all played out, researchers say the deep Pacific appears to lag behind the waters closer to the surface, and is still responding to the Little Ice Age.
‘Climate varies across all timescales,’ said Peter Huybers, a professor at the Harvard John A. Paulson School of Engineering and Applied Sciences.
‘Some regional warming and cooling patterns, like the Little Ice Age and Medieval Warm Period, are well known.
‘Our goal was to develop a model of how the interior properties of the ocean respond to changes in surface climate.’
The Medieval Warm Period was a period lasting between the 9th and 12th centuries during which Earth’s climate leaned on the warmer side.
It was followed not long after by the Little Ice Age, which lasted from the 16th through 19th century, though some argue it began even earlier.
According to researchers from the Woods Hole Oceanographic Institution and Harvard University, this long-ago cooling period could still be showing its face in the temperatures of the deep ocean.
‘If the surface ocean was generally cooling for the better part of the last millennium, those parts of the ocean most isolated from modern warming may still be cooling,’ said Jake Gebbie, a physical oceanographer at Woods Hole Oceanographic Institution.
To test this, the team compared measurements taken during the 1870s by scientists on the HMS Challenger to modern data.
During the study in the late 1800s, the researchers of the time dropped thermometers deep down into the ocean between 1872 and 1876, collecting more than 5,000 measurements in total.
‘We screened this historical data for outliers and considered a variety of corrections associated with pressure effects on the thermometer and stretching of the hemp rope used for lowering thermometers,’ Huybers said.
As expected, the comparisons showed most of the world’s ocean has been warming up over the last century.
In the deep Pacific Ocean, however, temperatures are dropping. This effect could be seen at a depth of around 2 kilometers (1.2 miles).
Read the full Daily Mail story here.
H/T David L Hagen and MarkW
And the from Phys.org.
January 4, 2019 by Bob Yirka, Phys.org report
“The model showed that the Pacific Ocean cooled over the course of the 20th century at depths of 1.8 to 2.6 kilometers. The amount is still not precise, but the researchers suggest it is most likely between 0.02 and 0.08° C. That cooling, the researchers suggest, is likely due to the Little Ice Age, which ran from approximately 1300 until approximately 1870. Prior to that, there was a time known as the Medieval Warm Period, which had caused the deep waters of the Pacific to warm just prior to the cooling it is now experiencing.”
More information: G. Gebbie et al. The Little Ice Age and 20th-century deep Pacific cooling, Science (2019). DOI: 10.1126/science.aar8413
Read more at: https://phys.org/news/2019-01-bottom-pacific-colder-possibly-due.html#jCp
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‘Some regional warming and cooling patterns, like the Little Ice Age and Medieval Warm Period, are well known…
Regional? This is what the hockey-stickers say, the deniers of past climate change. (Hey, turn-about is fair play.)
Seems the authors elsewhere talk about the earth warming and cooling over these periods but then what is this “regional” business?
Their own research would seem to support LII and MWP as periods of lower and higher global average temperature. Surely regional differences would have mingled into an average temperature by the time they affect the ocean bottom hundreds of years later.
Regional only if Europe, North America, Asia, South America and New Zealand belong to the same region:
https://link.springer.com/article/10.1007/s00382-013-1876-8
https://www.sciencedaily.com/releases/2018/07/180724174309.htm
And southern Africa, of course:
https://www.researchgate.net/publication/230751443_The_Little_Ice_Age_and_medieval_warming_in_South_Africa
A collection of studies about global MWP you will find here Every paper is about a local event, but worldwide speaded. 😀
If anyone thought their temperature readings were gonna be used 150 years hence, to upset world economies, they might have demanded a better wage.
OR…..you could argue that they were earning what they deserved, as they were likely blissfully unaware of how accurate their data actually was. Two miles of any kind of rope is quite heavy, easily stretched, and easily moved around by currents. If its density were much above the water it was in, it would stretch, and break from its own weight. If its density were much below the water, it wouldn’t sink at all to the depth that was played out. In addition, as it soaked in the water, its displaced density would be slowly changing.
At near neutral density, it would be quite sensitive to local currents, which would also make the perceived depth to be quite wrong. All this doesn’t even address the accuracy of “max-min” mercury thermometers. Assuming they were played out slowly enough to respond to the temperatures they were passing through, they would obviously reading the max-min temperatures of the water they passed through, not necessarily the water at depth. I’m sure there are many more issues that could be possible.
All this being said, I do commend them for their measurements. As with any true experiment, The greatest gain in knowledge comes from the first data point taken. As the data points go from zero to the percentage gain is infinite. It’s just that this is hardly enough data to use to destroy the world’s economy.
Regarding climatic events before 1880 I recall that the big conference in 1985 at Villack, Austria declared that as we did not have accurate thermometers prior to that date, all mention of major climatic events earlier than that date were to be disregarded.
So as they did not apparently occur, we must not mention them.
So says the wise ones in the UN IPCC.
MJE
Let me please rephrase what I read:
They have gone to the same depths at almost the same locations of historical expedition of 1870+ to record deep ocean temperatures.
They have found that at certain depths today’s temperature are lower than that of 1870s.
Hence they conclude that the LIA cooling of deep seas is ongoing.
Question:
Was the temperatures at the end of MWP was warmer than 1870s?
Is it possible that deep ocean has been cooling since Younger Drayas?
They have only found that temperature is cooler that 1870s but they have not refuted at least these two possibilities.
Does anyone have links to other temperature reconstructions that show the MWP and the LIA and, thus, show that Mann’s hockey stick temperature reconstruction is an outlier?
Also, how did we come up with the temperature reconstructions that show the MWP and LIA? Did they come from other tree rings, ice cores, or another proxy?
Thanks,
Daniel
Thought all of the extra heat was hiding deep in the oceans?
Meh, my interpretation is that in current time cooling at the bottom of the ocean is happening today. As Antarctica loses it’s shelves it allows cooler waters to push down towards the bottom of the ocean and cool it off. Later causing the re-glaciation.
Because more water is exposed to the cold air? Makes sense to me.
been busy, so I reread stuff to keep it light. Been reading Ringo’s “The Last Centurion” published in 2008, and he had this statement in the book that currents are affected by temps for hundreds of years after the events due to some lag in the system. The Mail is a bit behind on this (oh, sorry, it’s the Daily Mail. . . it is always behind)
It is not possible to cool the cold deep oceans with warmer surface water. The Daily Mail did not understand the story or tried to fool everyone: “As a result, parts of the deep Pacific is now cooling from long ago Little Ice Age”. WR: wrong, cooling from the Medieval Warm Period!
Science tells: “The ongoing deep Pacific is cooling, which revises Earth’s overall heat budget since 1750 downward by 35%.” Source: http://science.sciencemag.org/content/363/6422/70.
WR: as I read it: the previously estimated total heat content of the oceans in 1750 has been estimated too low, because there was warmer Medieval water down in the Pacific which has not been known at the moment of the previous estimation.
Therefore the Oceans did not warm as much as previously estimated. Pacific deep oceans already were warmer than thought.
And the hockey stick also was not correct: the Medieval has been warmer than last century. We can still find the Medieval fingerprint in the temperatures of Medieval water in the Deep Pacific: Medieval down welling water was warmer than the down welling water from last [‘warm’] century that was replacing that layer.
The above is revealed in the very last sentence of the following excerpt from https://phys.org/news/2019-01-bottom-pacific-colder-possibly-due.html#jCp
“The model showed that the Pacific Ocean cooled over the course of the 20th century at depths of 1.8 to 2.6 kilometers. The amount is still not precise, but the researchers suggest it is most likely between 0.02 and 0.08° C. That cooling, the researchers suggest, is likely due to the Little Ice Age, which ran from approximately 1300 until approximately 1870. Prior to that, there was a time known as the Medieval Warm Period, which had caused the deep waters of the Pacific to warm just prior to the cooling it is now experiencing.”
WR: The Little Ice Age cooled the surface that much that the surface still is recovering and still not has reached the temperature the surface had during the Warm Medieval. Nothing new, present warming.
Looking at Figure 3, “Difference between WOCE and Challenger temperature…”, which shows the difference between the 19th-21st century Pacific and Atlantic temperatures, the 95% confidence uncertainty bars between 2500 m and 1000 m are about ±0.05 C.
However, the Miller-Casella thermometer used on the Challenger was accurate only to about ±0.15 C (±0.25 F). That means the minimal 95% uncertainty is ±0.3 C. And that is under ideal (laboratory) reading conditions.
So, the published uncertainties are about 6 times smaller than the best resolution available using that thermometer.
That lower limit of resolution makes the Figure 3 Pacific and Atlantic temperature differences indistinguishable from zero. There may be a real temperature difference, but it’s not resolvable in the Challenger data.
Further, the WOCE ocean temperatures are from Argo float measurements.
The few field-calibrations of Argo floats using high-accuracy ship-borne CTD instruments indicated ±0.6 C errors in the Argo temperatures. The usual approach in consensus climatology is to assume these errors all
subtract away when taking differences (anomalies). Or that all the systematic errors are normally distributed and average away. However, neither assumption has never been tested, and I don’t buy it at all.
Taking differences, i.e., Challenger minus WOCE, requires combining the uncertainties as the root-mean-square. The minimum uncertainty in any anomaly is no less than ±0.15 C — the Challenger lower limit, and
likely much more given the field performance of the Argos.
Regarding the ocean model simulations, Carl Wunsch has noted that ocean models don’t converge. That makes the simulations in the paper pretty much physically meaningless.
Wunsch says that ocean modelers dismiss the ‘doesn’t converge’ criticism because the model results “look reasonable.”
That’s OK for movie graphics, but not for science.
It appears that all the measurement and model errors and uncertainties are neglected in order to be able to say something.
So, all-in-all, Figure 3 (and the entire paper) looks like fantasy science to me.
‘Our goal was to develop a model of how the interior properties of the ocean respond to changes in surface climate.’
None of their models ever foresaw the winter 2018 / 2019.
Why should anyone trust their “models. “
(Very late to this discussion. Life and computer issues.)
Hmmm…. “The Missing Heat” is supposed to hiding in the oceans, or so said one the CAGWist.
Hmmm…. The Hockey Stick puppeteer says there was no “Little Ice Age”.
Gosh! What some claimed never happened might be the solution to the “missing heat”? It got iced by reality?