From the University of Washington and the department of Trenberth’s missing heat comes a claim that we’ll have to wait another 15 years for global warming to resume. Sounds like a goalpost mover to me.
The Oceans that Slowed 21st Century Global Warming
Why did the rapid global warming that characterized the latter part of the 20th century slow down over the last 15 years or so? Many different theories have been proposed, but a new study suggests that a massive movement of heat from shallow surface waters to deep regions of the Atlantic and Southern Oceans — but not the Pacific Ocean, as many researchers had predicted — might be responsible. Xianyao Chen and Ka-Kit Tung analyzed data from profiling floats, or oceanographic sensors that can move vertically throughout the water column, and traced the pathways that heat has taken through the world’s oceans since the turn of the 21st century. The oceans are capable of storing about 90% of the world’s surface heat content, and the researchers suggest that most of the excess heat that would have otherwise continued to fuel global warming is currently stored in the basins of the Atlantic and Southern Oceans.
The researchers also suggest that a sudden shift in salinity that corresponded with the slowdown of global warming at the beginning of the 21st century may have triggered this migration of heat to deeper waters. Historically, similar events have lasted 20 to 35 years, according to Chen and Tung. Consequently, the researchers suggest that global warming will pick back up in 15 more years or so, when heat returns to the surface waters.
Article #11: “Varying planetary heat sink led to global-warming slowdown and acceleration,” by X. Chen at Ocean University of China in Qingdao, China; X. Chen; K.-K. Tung at University of Washington in Seattle, WA.
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Following rapid warming in the late 20th century, this century has so far seen surprisingly little increase in the average temperature at the Earth’s surface. At first this was a blip, then a trend, then a puzzle for the climate science community.
More than a dozen theories have now been proposed for the so-called global warming hiatus, ranging from air pollution to volcanoes to sunspots. New research from the University of Washington shows that the heat absent from the surface is plunging deep in the north and south Atlantic Ocean, and is part of a naturally occurring cycle. The study is published Aug. 22 in Science.
Subsurface warming in the ocean explains why global average air temperatures have flatlined since 1999, despite greenhouse gases trapping more solar heat at the Earth’s surface.
“Every week there’s a new explanation of the hiatus,” said corresponding author Ka-Kit Tung, a UW professor of applied mathematics and adjunct faculty member in atmospheric sciences. “Many of the earlier papers had necessarily focused on symptoms at the surface of the Earth, where we see many different and related phenomena. We looked at observations in the ocean to try to find the underlying cause.”
The results show that a slow-moving current in the Atlantic, which carries heat between the two poles, sped up earlier this century to draw heat down almost a mile (1,500 meters). Most of the previous studies focused on shorter-term variability or particles that could block incoming sunlight, but they could not explain the massive amount of heat missing for more than a decade.
“The finding is a surprise, since the current theories had pointed to the Pacific Ocean as the culprit for hiding heat,” Tung said. “But the data are quite convincing and they show otherwise.”
Tung and co-author Xianyao Chen of the Ocean University of China, who was a UW visiting professor last year, used recent observations of deep-sea temperatures from Argo floats that sample the water down to 6,500 feet (2,000 meters) depth. The data show an increase in heat sinking around 1999, when the rapid warming of the 20th century stopped.
“There are recurrent cycles that are salinity-driven that can store heat deep in the Atlantic and Southern oceans,” Tung said. “After 30 years of rapid warming in the warm phase, now it’s time for the cool phase.”
Rapid warming in the last three decades of the 20th century, they found, was roughly half due to global warming and half to the natural Atlantic Ocean cycle that kept more heat near the surface. When observations show the ocean cycle flipped, around the year 2000, the current began to draw heat deeper into the ocean, working to counteract human-driven warming.
The cycle starts when saltier, denser water at the surface northern part of the Atlantic, near Iceland, causes the water to sink. This changes the speed of the huge current in the Atlantic Ocean that circulates heat throughout the planet.
“When it’s heavy water on top of light water, it just plunges very fast and takes heat with it,” Tung said. Recent observations at the surface in the North Atlantic show record-high saltiness, Tung said, while at the same time, deeper water in the North Atlantic shows increasing amounts of heat.
The authors dug up historical data to show that the cooling in the three decades between 1945 to 1975 – which caused people to worry about the start of an Ice Age – was during a cooling phase. (It was thought to be caused by air pollution.) Earlier records in Central England show the 40- to 70-year cycle goes back centuries, and other records show it has existed for millennia.
Changes in Atlantic Ocean circulation historically meant roughly 30 warmer years followed by 30 cooler years. Now that it is happening on top of global warming, however, the trend looks more like a staircase.
The temperature oscillations have a natural switch. During the warm period, faster currents cause more tropical water to travel to the North Atlantic, warming both the surface and the deep water. At the surface this warming melts ice. This eventually makes the surface water there less dense and after a few decades puts the brakes on the circulation, setting off a 30-year cooling phase.
This explanation implies that the current slowdown in global warming could last for another decade, or longer, and then rapid warming will return. But Tung emphasizes it’s hard to predict what will happen next.
A pool of freshwater from melting ice, now sitting in the Arctic Ocean, could overflow into the North Atlantic to upset the cycle.
“We are not talking about a normal situation because there are so many other things happening due to climate change,” Tung said.
The research was funded by the U.S. National Science Foundation and the National Natural Science Foundation of China.
(I expect we’ll see a rebuttal from Bob Tisdale soon) UPDATE: We have and it is here.
UPDATE2: The list of excuses is up to 38 now, and an updated permanent count is here on this WUWT page under “Climate FAIL files”: http://wattsupwiththat.com/climate-fail-files/list-of-excuses-for-the-pause-in-global-warming/
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The authors’ figure fails to show what came before the first “hiatus”. It wouldn’t be a hiatus in global warming had it not been preceded by warming. There is nothing the least bit unprecedented about the warming from c. 1977 to 1996 or 2006 (more likely 20 years than the 30 they claim), just as the current “hiatus” is also not the least bit unusual.
The “hiatus” or cooling from c. 1946 to 1977 (30 years) occurred during rising CO2. The subsequent warming of whatever length and magnitude, ditto. The present hiatus or cooling, ditto. The warming which preceded the post-War cooling or hiatus happened with falling CO2. Previous ups and downs occurred when CO2 was flat or rising just from natural warming. Thus, no correlation is observable between CO2 concentration and temperature changes.
Since the end of the Little Ice Age, there was pronounced warming in the 1860s-70s, followed by sharp cooling in the 1880s-90s, followed by warming, by cooling and by warming. It’s natural, driven, as Bob points out in the next blog post, by solar activity and factors modulation its influence.
In the 18th century, coming out of the depths of the LIA in the 1690s-1700s, a warming interval (1710s-30s) longer and bigger than the late 20th century warming occurred. Naturally.
But at least the authors appear to recognize, without stating so plainly, that naturally occurring oceanic oscillations control climate, so that man-made GHGs aren’t the primary driver of climate change.
Presumably, this massive movement of heat remains an active process in 2014. If an oceanographic expedition were to be immediately launched to send the appropriate research vessels and the appropriate temperature measuring equipment to the locations where this process is theorized to be happening, could the theorized massive movement of heat be detected and confirmed?
The warm is turning.
The bandwagon has a flat tire.
The natives are getting restless (EU Elections).
It’s the end of the beginning.
Psuedo-eco-theologic dogma!
Those who subscribe to the Global Warming propheteers (or profiteers) of CO2 enduced armegedddon have to come up with some excuse explain why Global Warming stopped, other than admitting that their psuedo-eco-theological anthropogenic doomsday prophesies were wrong. Rather than admit that it is natural cycles or the Solar Cycles, they have to come up with another dogmatic explanation to justify their false religion.
I am getting tired of this endless stream of model output masquerading as fact. What happened to the good old days when data and observations were facts, and model output was nothing more than that, just model output. And everyone understood the difference.
http://nhill.files.wordpress.com/2014/08/climatescienceposter.jpg
Any heat that has gone into the deep ocean has raised the temperature there by only hundredths of a degree, so sorry Climate Worriers it ain’t gonna have diddly effect on surface temperatures ever again. If that ain’t so then I’m going to the beach tomorrow to get some of that deep water to heat my home this winter.
philjourdan says:
August 21, 2014 at 11:29 am
When they get to 100, sell!
=============================================
Why wait? Sell now and avoid the rush!
ahTUNG CHEN! Ve vill stoat (weasel) our vay out of dis little problem…
That’s longer than the recent warming rise. In fact it is equal to the generally accepted period of climate being 30 years of weather data. The models certainly did not project this, as they were already in serious trouble with 17 years of hiatus.
Judith Curry has a more sympathetic assessment http://judithcurry.com/2014/08/21/cause-of-hiatus-found-deep-in-the-atlantic-ocean/
A couple of points: 1) the statement that about 50% of the late 20th century warming is due to ocean oscillations is good to see, because IPCC have implied all of it was man-made and that none of the warm-peaking ocean cycles (AMO, PDO, AO and ENSO) had any significant impact – obviously highly unlikely; and IPCC itself admits that prior to 1950 no significant part of the warming could be attributed to human emissions, 2) this means that 75% of the warming since 1900 is natural.
In ‘Chill’ I estimated 80% from looking at surface radiative flux data from 1980-2000 and John Christy when asked by the BBC, said his estimate was 75% natural. I still think these figures are generous toward AGW because the radiative flux data at the surface (NASA data) showed about 4 watts/square metre increase in short-wave radiation (caused by a 4% decline in low-cloud cover), compared to about 1 rising to 2 watts computed for GHGs’ long-wave radiation during those two decades.
I have never been convinced that the AMOC has a great deal to do with shorter-term cycles of warming and cooling – to be convinced I would like to see some old-fashioned back-of-the-envelope calculations of radiative flux and the quantity of heat that the North Atlantic can sequester – maybe the paper has such, I will check once I have negotiated the paywall.
Finally, the Arctic has been maintaining its warming through the first decade of the 21st century, despite the hiatus elsewhere. My reading is that the ‘missing heat’ was shipped into the northern oceans and the surface warming in the Arctic is the heat actually leaving the planet. It is not missing, nor is much hiding in the oceans – its actually mostly gone to space. The data should be available to check this – radiative fluxes are available for gridded zones, but I have not the resources to check it.( a job for Willis??).
Peter Taylor says:
August 21, 2014 at 1:53 pm
That is correct. The warm PDO carries oceanic heat to the Arctic, melting ice there, whence it ascends to heat heaven.
Please excuse me for being simplistic. Each day the temperature rises in the afternoon (after high sun), in a year the temperature rises in the summer (after the equinox). In the 20th Century solar activity rose until the early sixties after over 100 years of increase. Why is it so surprising that temperatures increased for a while and have now stopped rising. “Heavy water on top of other water plunging the heat down” – oh yeah I get it now sorry to be so stupid.
I can understand how desperate Ph.D. candidates would write such fiction about OHC at depths greater than 1000 meters prior to the 2003 start of ARGO and beyond 300 meters prior to ALACE in 1990. They should choose something else to study for their dissertation, but I can understand how in desperation they may grasp as such straws where data collection is so poorly sampled and geographically biased. “It comes out of a computer, so it must be right”
What I cannot understand is how any university or professor who values a reputation contributes to such studies where the data does not exist with the geographic sampling and accuracy to support ANY conclusions.
Beyond the tripe of “knowing” the temperature or heat content of the oceans in 1950-1990 from 300 meters to 2000 meters, the top illustration has two fatal flaws in my opinion.
1. the upper graph says “Global Mean Temperature Anomaly” which has to do with the surface air, not the water. It is misdirection by association and ambiguous titling.
2. the central chart has a color scale that goes up to 1×10^20 J. It might be a technicality, but as a density plot, the units have to be J/m of depth — if that what it really is.
I was looking for a plot of actual temperature instead of heat. There isn’t one because it isn’t alarming.
It takes 27.5 ZJ (1 ZJ = 10^21 J) to raise the 0-2000 m water column a grand total of 0.01 deg C. So, it takes 0.14 ZJ to raise each meter of water by 0.1 deg C.
The maximum scale, even with most generous accuracy in depth resolution, can only show 0.07 deg C the upper few meters of water. Maybe with 100,000 ARGO profiles per year, we know the 0-2000 meter water average temperature to a few hundredths of a deg C. But it does not follow that we know each meter of water to the same precision – the uncertainties, even with heavy dependence, don’t work that way.
Prior to ARGO, we don’t have anywhere near the data collection to support such precision.
Studies of ocean heat content for intervals deeper than 1000 meters and times prior to 2004 should be shredded on first reading.
And why wasn’t the previous warming streak the result of an upwelling of previously down-dropped, non-CO2 caused, warm water?
Because today is Special. History does not apply because, like us Gaia-loving liberals, today is Special.
There is no recourse to the “today is Special” excuse.
“Rapid warming in the last three decades of the 20th century, they found, was roughly half due to global warming […]“. So the global warming was half caused by itself.
Well, if the apparent 60-year cycle held we’d be well into a cooling phase already, with 13+ years to go until warming again. So mebbe warming is actually occurring due something else.
[“Guessing Alert” ;-]
(I say 13+ because a slow arming trend that people say is evident since about 1750 would shift the return of warming downstream a bit, depending on relative rate of both phenomenon.
Of course difficult to detect point of turnaround if the cycle is sinusoidal, as rate of change is lowest at bottom and top.)
Has anyone noticed anything odd about the graph of heat content?
The period when the heat is supposed to have “sunk” starts around 1995. And the period of “cold in the depths” starts around 1970.
These both coincide with the AMO warm and cold periods.
Think this through! The current “heat” has not sunk into the depths, the heat extends to the surface. Equally, during the cold phase of the AMO, the cold extended to the surface.
This can be seen clearly on the graphs, which extend up to 0m.
In other words, since 1995 the heat is not “hidden in the depths”. Instead it is actually at the surface, offsetting the cold phase of the PDO.
When both the AMO and PDO both go cold in the 2020’s, what will happen then?
Hey no wait i have seen this – is this the part where Peter Lorre punches Kirk Douglas in the stomach?
Just been on the BBC news website, where they’re suddenly coming out with ‘the pause’. It’s only within the last few days that they were going on about melting Arctic ice again, and heatwaves! Big question is whether the gentle viewers will be able to spot the contradictions…..
People who walk around wit their brain disengaged, eyes closed and their hands over their ears shouting “naah naah naah nahh CAGW” ad infinitum rarely hear or spot ANYTHING.
[“Subsurface warming in the ocean explains why global average air temperatures have flatlined since 1999, despite greenhouse gases trapping more solar heat at the Earth’s surface.”]
No it doesn’t explain this, subsurface warming occurred while the surface global temperatures were warming. When the subsurface warming stabilized so did surface global temperatures.
[“There are recurrent cycles that are salinity-driven that can store heat deep in the Atlantic and Southern oceans,” Tung said. “After 30 years of rapid warming in the warm phase, now it’s time for the cool phase.”
Rapid warming in the last three decades of the 20th century, they found, was roughly half due to global warming and half to the natural Atlantic Ocean cycle that kept more heat near the surface. When observations show the ocean cycle flipped, around the year 2000, the current began to draw heat deeper into the ocean, working to counteract human-driven warming.]
30 years of warming in the rapid phase is actually closer to 20 years or less and numerous scientists were suggesting many years ago, the cool phase would happen due to the change in the PDO and AMO. This can be explained by natural ocean cycles and CO2 has no noticeable contribution towards it. Where’s this half global warming contribution come from? You cant blame a 4-5% global cloud albedo decline increasing solar radiation into the ocean on CO2.
That is why you have had the ocean/atmosphere wrong and why alarmist climate scientists are wrong now.
“……..roughly half due to global warming and half to the natural Atlantic Ocean cycle”
The reality should be “……roughly half due to urbanization and half to …….”
This was pointed out almost 6 years ago on this website – that the north Atlantic ocean cycles have a huge part to play and the real warming rate is only half of that which is portrayed. [Wayback machine capture since the images have dissappeared into Internet purgatory].
http://web.archive.org/web/20090626174702/http://wattsupwiththat.com/2008/11/25/adjusting-temperatures-for-the-enso-and-the-amo/
Anthony, you have become a victim of bogus temperature data when you ask “…Why did the rapid global warming that characterized the latter part of the 20th century slow down over the last 15 years or so?” There is no such thing as a rapid global warming that characterized the latter part of the 20th century. The temperature chart you show with it is phony and those dots representing yearly temperatures are inaccurate, misleading, and useless. I should show you a real temperature chart but this comment does not allow it so you will just have to be content with looking up Figure 15 in my book “What Warming?” and following my commentary. The figure is an annotated satellite temperature record from 1979 to 2010 that includes that “rapid warming” region of your chart. You will note detail that is impossible to show with a yearly temperature chart. On the left there are outlines of five El Nino peaks, separated from one another by La Nina valleys. The temperature difference between the tip of an El Nino peak and the bottom of the adjacent La Nina valley is about half a degree Celsius. Ground based data, if they show them at all, show this as a mere 0.2 degree difference. The half way mark between the El Nino peak and its adjacent La Nina valley is their mean temperature. You will find these points marked with yellow dots in Figure 15. To find the history of global mean temperature you must connect these dots. There is a small amount of scatter but a a straight horizontal line fits them well. It runs from 1979, where the chart begins, to 1997, where the super El Nino of 1998 starts forming. This is a stretch of 18 years of no warming, a period comparable to the current pause/hiatus, but completely wiped out in fake ground based temperature curves. What you will find is that instead of a horizontal straight line indicating no warming, their mean temperature rises by one tenth of a degree in this region. This is false and I pointed it out in my book but nobody seems to care. It changes a no-warming region as long as the present pause/hiatus into that of a phony “late twentieth century warming.” This is true of GISTEMP, HadCRUT, and NCDC temperature sources, one of which has you believing in it. This is not the only thing that they have in common. All three were computer processed, quite likely with the aim of coordinating this fraud. But they screwed up and the computer left its calling card on all three data sets in the form of high spikes sticking up above the temperature curve. They are all near the beginnings of years and their locations are exactly the same in all three data sets. That is proof of secret temperature machinations that demands an explanation. The row of five normal El Nino peaks I just described is followed by the super El Nino of 1998. It is sharply defined so I left off the red band that covers the rest of the graph. It is also twice as high as the other five peaks are. This difference in height is lost in ground-based data which reduce he super El Nino to a pancake. Checking global temperature records it is clear that the super El Nino of 1998 is the only super El Nino during the entire twentieth century. Clearly it has to have an additional source of warm water which is added to the normal ENSO circulation. Theoretically there are just two possibilities – either the southern warm pool or the Indian Ocean. Right after the super El Nino recedes, however, there is a short step warming. It starts in 1999, in only three years raises global temperature by a third of a degree Celsius, and then stops. This step warming most likely is related to the large amount of warm water the super El Nino carried across the ocean. There has been no warming since then because what follows it is our friend, that pause/hiatus. This step warming is actually the only warming during the entire satellite era that begins in 1979. This is why the temperature of the twenty-first century is higher than that of the eighties and nineties before it. Hansen noticed that too and pointed out that nine out of ten warmest years occurred in the decade between 2000 and 2010. He had no knowledge of the step warming and put it down to greenhouse warming. And then neglected to tell us that there was no warming whatsoever during that entire decade. The super El Nino of 1998 itself is not part of the normal ENSO oscillation and does not count as part of any rapid global warming these fake warming people babble about. There actually was a rapid global warming, caused by that step warming, but it lasted only three years and had nothing to do with the global warming myth they sell. None of this has been investigated because the billions allotted for climate research by governments were all spent trying to prove that the greenhouse effect is real. Apparently it is not real because existence of the pause/hiatus proves that there cannot be any such thing as greenhouse warming.