Conveyor Belt Model Broken

News has come that the famed ocean conveyor belt, subject of countless TV documentaries and science lessons, is not as simple as scientists believed. The 50 year old model of global ocean circulation that predicts a deep Atlantic counter current below the Gulf Stream has been called into question by an armada of drifting subsurface sensors. As shocking as this news is to oceanographers it is even worse for climate modelers—it means that all the current climate prediction models are significantly wrong.

It is known by many names: the meridional overturning current (MOC), the thermohaline circulation (THC), and, popularly, the great ocean conveyor belt. It has been the subject of study by oceanographers for half a century and is known to be a fundamentally important part of earthly climate regulation. It is the primary mechanism for transferring heat from the tropics to higher latitudes, the proximate reason that the occasional palm tree grows on the south coast of England. Until now, scientists thought they had a pretty good handle on how the current flows, the mechanisms that drive the circulation and affect climate world wide.

A new report by Amy Bower of Wood’s Hole and Susan Lozier of Duke University et al., to be published in a forthcoming issue of Nature, has rocked the climate community's complacency. A bevy of subsurface RAFOS floats, drifting 2200 – 4900 feet (700 – 1500 m) deep, have shown several fundamental assumptions about the structure of the current to be wrong. RAFOS floats (SOFAR spelled backward) are floating instruments designed to move with the water and track the water's movements. It seems that 75% of the RAFOS floats escaped the Deep Western Boundary Current (DWBC) and drifted into open ocean. Only 8% of the RAFOS floats followed the DWBC conveyor belt current, according to the Nature report.

Track of a float crossing the North Atlantic Current (top) with corresponding temperature and pressure records (bottom). Courtesy of the RAFOS Float Group at University of Rhode Island.

This confirms suspicions that that first began surfacing in the 1990’s, that things were not quit as neat and simple as oceanographers had thought. Earlier observations had led to the widely held view that the DWBC is the dominant pathway for the export of cold Labrador Sea Water (LSW) from its formation site in the northern North Atlantic towards the Equator. The new findings indicate that instead of the single, orderly current flow previously envisioned, the conveyor belt is actually comprised of many slower, more variable and possibly wandering eddies in the interior ocean. Quoting from the report:

Here we show that most of the recently ventilated LSW entering the subtropics follows interior, not DWBC, pathways. The interior pathways are revealed by trajectories of subsurface RAFOS floats released during the period 2003–2005 that recorded once-daily temperature, pressure and acoustically determined position for two years, and by model-simulated 'e-floats' released in the subpolar DWBC. The evidence points to a few specific locations around the Grand Banks where LSW is most often injected into the interior. These results have implications for deep ocean ventilation and suggest that the interior subtropical gyre should not be ignored when considering the Atlantic meridional overturning circulation.

Triggered by a bunch of drifting ocean monitoring instruments, this new revelation represents a major paradigm shift in ocean circulation theory. Even more dramatic is the impact on current ocean circulation models, major components of the general circulation models (GCM) used to predict climate change. To understand how global climate changes in response to natural and human generated changes, it is essential to determine how quickly and by what pathways climate change signals are transported throughout the global ocean. Ocean currents not only redistribute surface warmth, the oceans themselves are a vast reservoir for heat and carbon dioxide, affecting both short term and long term climate change.

“Everybody always thought this deep flow operated like a conveyor belt, but what we are saying is that concept doesn't hold anymore,” said Duke oceanographer Susan Lozier. “So it's going to be more difficult to measure these climate change signals in the deep ocean.”

This has been a particularly disquieting week for the climate change establishment, with new discoveries regarding the importance of aerosols' impact on sea surface temperatures (SST) and cloud formation, and the halving of predicted sea-level increases due to ice sheet melting coupled with predictions of significant change in Earth's gravity field and rotational axis if Antarctica even partially melts. Add the news regarding the THC and one has to ask, how many revelations of erroneous assumptions are necessary before climate modelers admit that their computer programs are incapable of accurately predicting future climate change?

Climate skeptics are sometimes accused of selectively interpreting scientific data in order to bolster their case against anthropogenic global warming (AGW). The term used is “cherry picking.” When a theory makes certain predictions it is totally acceptable, even obligatory, to investigate those predictions. When a theory is based on certain fundamental assumptions regarding underlying science it is perfectly logical to question that theory when its underlying assumptions are shown to be in error. This is not cherry picking, it is how science works. It may discomfort those who complacently believe in the “consensus view” of AGW, but that is of no importance to science.

In this blog I have showcased a dozen or more scientific papers that end with a statement saying “the climate models need to take this into account,” or words to that effect. Time after time the theory of global warming and the models it rests on have been shown to be lacking. Sometimes in small ways, sometimes in large, fundamental ways (as is the case here) holes in the AGW theory keep appearing. The IPCC and the climate modeling crowd have constructed complex models of a chaotic system based on incomplete and erroneous assumptions—they have built a house of cards and asked us all to move in without checking the soundness of the foundation. Thankfully, anthropogenic global warming is dying the death of a thousand cuts—this is often the fate of flawed theories.

Be safe, enjoy the interglacial and stay skeptical.

Early prototype floating ocean monitors.

Your Sunspot Widget

FYI, when I clicked upon your sunspot widget, I was presented with an image dated more than a year ago.
You might want to look into that.

Leo Morgan

For an update see...

For an update on the ocean circulation model controversy see “Ocean Conveyor Belt Dismissed.” Oceanographers have finally accepted that their old model is outdated and incorrect. Quoting from the new post:

After nearly 50 years of acceptance, the theory that a great ocean “conveyor belt” continuously circulates water around the globe in an orderly fashion has been dismissed by a leading oceanographer. According to a review article in the journal Science, a number of studies conducted over the past few years have challenged this paradigm.

re: "Conveyor Belt Model Broken"

What I'd like to see described is how the so-called "e-floats" relied upon for this study and its conclusions are modeled. I've also seen this term used before in another study, so I assume this study is a follow up to something published perhaps a year ago. But the questions remain, such as: What is used to create the "e-floats" expected pathways? How many are there in proportion to the actual floats? Where are they released with respect to the actual floats? Do the study's conclusions draw more heavily on the actual floats, the model of everything, or the e-floats?

This *might* be all good science (and I'm willing to give the researchers the benefit of the doubt, at least for the moment), but the use of "e-floats" suggests a computer modeling exercise that *may be* (or may NOT be) far from reality.

In any case, this appears to be valuable research, and the research team is apparently walking a very fine line (tightrope without a net?) between reporting real results honestly and not being considered "heretics" among many of their fellows. After all, one should not want to see the funding for such work curtailed and that's a risk if they do not somehow weasel-word conclusions and perceptions to suggest that nothing may be wrong with today's GCMs and so forth. I does seem that there should be implications for the GCMs, of course. As noted, by other commenters there is so much we do not understand about ocean circulation patterns, and if we do not understand it, we cannot even hope to model reality with any accuracy ... unless we depend entirely on luck.


Thanks for the post. I forwarded this article to a friend who will find it very interesting. Hopefully he'll be a frequent visitor of your site now. cheers!

argy bargy of know it all skeptics

Doug L Hoffman.
You have taken someone else's research (ie hard work and perseverance), and with blatant disregard for the intelligence of your readers, twisted it to support your pre-exsisting ideas. this blog is a joke.

To quote Sir Isaac

“If I have seen further than others, it is by standing upon the shoulders of giants.”

Hi Doug, I used your blog to

Hi Doug,
I used your blog to say a few words on another blog in Australia. You can find my comments here
What happened next was that the blogger contacted Susan Lozier and asked if what you had said was correct. This was how she answered

Do you have any comment.


I'm sorry, but Dr Lozier is wrong

I have read Dr Lozier's response to my statement that her work has helped to contribute to proving GCM modeling to be wrong. Here is her response to my statement:

The statement in the linked article that our research “means that all the current climate prediction models are significantly wrong” is clearly nonsense. Our research shows that the Deep Western Boundary Current is not the main conduit for the equatorward transport of Labrador Sea Water. This finding has implications for where physical oceanographers should measure the southward transport of these waters, but has little impact, if any, on climate models. The North Atlantic waters are indeed overturning, flowing equatorward at depth and returning poleward at the surface, but we are now suggesting that the flow at depth is not confined to a narrow boundary current, or “conveyor belt”. The climate models care first and foremost about the return of the surface waters and our research has no bearing in the slightest on those waters.

I stand by my statement. Simply because the waters are flowing with the same volumes as previously claimed and that the surface flows remain largely unaltered because of this work does not mean that the affect on long term predictions by GCM is insignificant. The ocean circulation models, which are a significant part of overall climate models, are very careful to model multiple layers of ocean water and how those layers interact. This is because the ocean is a huge reservoir of thermal energy that helps dampen out temperature changes in the climate as a whole by absorbing or releasing energy.

If you change the assumptions on how the deep sea currents flow you are changing the boundary conditions between different masses of water. This cannot help but alter the long term reaction of the ocean to the energy flowing through it. Dr. Lozier is correct in observing that current conditions remain unchanged, obviously things are as they are. It is when you try to run a model out 25, 50 or 100 years into the future that the subtle changes to the circulation system can change the simulation results. It is interesting to me that the paper specifically says that this result changes the parameters of the meridional overturning circulation (MOC), specifically: “These results have implications for deep ocean ventilation and suggest that the interior subtropical gyre should not be ignored when considering the Atlantic meridional overturning circulation.”

In other words, the system may behave under changing conditions in ways not anticipated by current models. A change in the way the MOC functions can alter weather, cloud cover and interanual variation. Shifting currents can also alter nutrient distribution and upwelling, possibly leading to changes in carbon dioxide release or uptake. I have read over several of Dr. Lozier's papers and she seems to be deeply involved with the study of currents and their impact. Given her statement above I can't help but think that she is willfully ignoring the ripple effect this paper could have on overall model behavior.

GCM perform millions of iterations to calculate climate system responses out into the future. Even small variations in the initial conditions or the equations used can have a surprisingly large impact on long term predictions. I'm not saying this change taken in isolation will have a radical affect on GCM, but that possibility is undeniable. It is this uncertainty that falsifies the current models. GCM are so complex, that for anyone to make an blanket statement about the affect a particular change will or will not have is unsupportable. Saying that changing the MOC will have no effect at all, now that is clearly “nonsense.”

Give the lady a break. She's

Give the lady a break. She's very bravely submitted a paper which reports what she and her colleagues have observed, and drawn some directly related conclusions from it. Even this borders on the insanely career threatening in the current climate. Asking her to answer leading questions that favour specific agendas is rather unfair. She had little option than to answer the question the way she did if academic suicide was to be avoided. She's not a climate modelling expert - best leave the wider implications of her work for others to prognosticate on.

As someone else asked her the question and you've been asked to comment you can afford to be "generous" in response without expecting that she share your perspective.

Inappropriate comments

Dr Lozier is a scientist and I afford her the same respect that is due to a colleague or any other academician. To suggest that I should "give the lady a break" is sexist and condescending to her and offensive myself. I am being "generous" when I say that patronizing misogynistic wankers should think twice before commenting—and then not comment at all.

Earth History

I like the concept of selective perception. The earth's history of 6 billion years is replete with heating and cooling over that time period. Anthropogenic is as simplistic as ethnocentricism. Nicholas Copernicus refuted the pope because as everyone knew then the sun revolves around the earth because that is what the pope said. Google aurignacian oscillations and read the second and third pages of pdf.s AGW is a farce and no different than the popes ethnocentric view of the cosmos. The sun warms and cools and so does earth in response. Use some science and not pseudoscience and ethnocentric projection.


The debate that time was whether it was geocentric or heliocentric, and AGW is NOTHING like that debate. Don't compare yourself to Copernicus for being ignorant. That is just as stupid as using the word ethnocentric to describe planetary movement.

[Careful, ad hominin attacks are not permitted — Admin]

New Data is never Bad News for Scientists

Your claim that this is bad news for climate modelers is nonsense.

One of the benefits to come from this Wood's Hole study is a new model of North Atlantic circulation. New data giving better resolution and improved modeling of ocean circulation will improve climate models - good news to scientists including climate modelers.

New data is never Bad news for Scientists

But sometimes it is for political ideologues working with flawed models as if they hold all the truths of nature in their acolyte hands. We, humanity, need the best science before we jump off the train that has produced not only all of our wealth, but the labs and schools and research programs all of you have been benefiting from. Destruction of Western Industrialized economies, if done based on flawed theory that has been sold as the only truth is insane. Keep searching, the truth may save you as well as our society.

Faulty logic

You said:

Climate skeptics are sometimes accused of selectively interpreting scientific data in order to bolster their case against anthropogenic global warming (AGW). The term used is “cherry picking.” When a theory makes certain predictions it is totally acceptable, even obligatory, to investigate those predictions. When a theory is based on certain fundamental assumptions regarding underlying science it is perfectly logical to question that theory when its underlying assumptions are shown to be in error. This is not cherry picking, it is how science works. It may discomfort those who complacently believe in the “consensus view” of AGW, but that is of no importance to science.

That is indeed wholly true and wholly admirable

But it has nothing to with your point here.

This paper discusses ocean current. That does indeed affect the models of *how* the the heat from AGW will be distributed, and so the models may have to change their predictions of precisely which areas will warm.

But AGW is caused by totally different things (ie the IR absorbtion of CO2). Nothing in this paper remotely changes that: the fundamemntal assumptions are untouched.

As an analogy:
if I pour ink into a bath it mixes and the water goes dark.
If I set up a current by stirring the bath the ink might instead stay circulating currents, in rings - at least for a while.

This paper discusses those rings. But the ink is still in the bath, and the water is still going inky.

The THC might not be as modelled, but the heat trapped by CO2 is still in the atmosphere and AGW is still happening.


The oceans play the MOST significant part in driving the Earth's climate, even more so than the Sun because of their buffering effect lasting hundreds of years, because without them this world would be a very hostile place. So to dismiss these findings as having no effect on AGW because it's all caused by a gas that composes just 0.0385% of our thin atmosphere shows just how frustrating it must be to be a real scientist these days, with so many snake oil salesman banging out the same old lines month after month and year after year.
Just what will it take before this is put to rest, except maybe the inevitable end to this inter glacial?

AGW is caused by totally different things

"But AGW is caused by totally different things (ie the IR absorbtion of CO2). [...] but the heat trapped by CO2 is still in the atmosphere and AGW is still happening."

I suspect you have in mind the wrong model of how the greenhouse effect works. The greenhouse effect does not involve IR being 'trapped'. It is a consequence of the convection-driven adiabatic lapse rate combined with the average altitude of direct radiation (mainly from water vapour) to space.

The *top* of the troposphere is cooled to -54 C, also by the greenhouse effect. That's not something that can be explained by 'trapping'.

But that's nit-picking. The main problem with the claim is that 2xCO2 on it's own can only cause about 1.1 C warming, or about 0.5 C by 2100, since the rise in CO2 is about 40% per century. (That's the IPCC number, by the way.) More than 2/3rds of the projected rise (and *all* the predictions of disaster) is due to theorised time delays and feedbacks in the rest of the climate system amplifying this.

The storage of heat in the oceans is absolutely *critical* to the AGW hypothesis. Since the effect of CO2 on temperature is logarithmic (again, IPCC orthodoxy), each 40% has roughly the same effect. We had 40% over the 20th century, we expect about 40% over the 21st (actually, we expect a bit less, but exponential rise is a conservative assumption) so the rise ought to be about the same - i.e. about 0.7 C. (That's even assuming it was all due to CO2, which obviously sceptics doubt.) The discrepancy between that and their projections has been explained by a combination of aerosol cooling (which is in the wrong places to explain the observed geographic temperature trends) and ocean heat storage.

We don't know what effect this will have on the models. They may well announce that with the corrections this requires this makes AGW even *more* credible. But every time you change a hypothesis to adapt to new data, you have to start testing it all over again from scratch, with new data. To test it with the old data that you generated the hypothesis from is circular reasoning. I somehow doubt it will be presented that way, though.


Yes, that's a basic point which I find it hard to get pro-AGW modellers to accept or comprehend (they generally fall back on the "precautionary principle": we can't afford to wait for valid results!).
The INSTANT you touch and alter ANY of the assumptions or equations in a model, you MUST start ALL OVER AGAIN waiting for new data to accumulate! All the data you collected before is now just sketchy background helping you make new guesses; it cannot be used as proof any more.

Faulty Logic

AGW hypothesis is based on many faulty assumptions, Anonymous. And one of the is CO2 presumed heat absorption (much higher than the real one), and the amount of increase in atmosphere heat by a doubling of its concentration. It does not take into account the logarithmic characteristic of such doubling, so the temperature increase predicted by models are based on a faulty assumption.

Another faulty assumption is that the sun has not a overwhelming influence on climate, as shown by so many flawed "studies" by Hathaway, Mike Lockwood (taking into account only TSI, leaving out solar magnetic fields, slenght of solar cycles, baricenter placement in the solar system, etc.) purporting to dismiss the sun as a climate driver.The present sun condition is demolishing such an insane view.

And it is amazing the denialist position taken by the AGW crowd regarding the interaction between the Solar and ocean factors in driving the climate. Claiming that only CO2 is the driving factor is the MOST faulty assumption made by them. Of course, it is more related to obscure business than to science.

Faulty logic yes, but not mine

You are correct in stating that the paper in question discusses ocean thermohaline circulation. The point of the paragraph that you quoted is that this is yet another example of a false pretense upon which the case for global warming is made. Changes in the way heat is distributed by ocean currents can affect other factors, such as sea ice, which in turn affect Earth's albedo, or rainfall patterns that affect desertification (ditto) or erosion patterns, which can affect absorption or release of CO2 (depending on what is being eroded). A change in one factor can affect the behaviour of the entire system. Your assertion that this discovery changes nothing, that the heat is still there is simplistic and incorrect—there is no way to tell what the heat is doing without further study.

The case for AGW is totally based on predictions from computer models. Those models are, in turn, based on certain fundamental assumptions about how the world works. If you change those assumptions the model results will change, sometimes radically. I know this well because I have been writing computer models for more than thirty years. This is a significant change to the way things were represented in all existent models. That means all those models were wrong and their results are not to be trusted.

Your argument seems to be that we should still accept their predictions anyway. If that isn't faulty logic, what is?

Broken Models

" means that all the current climate prediction models are significantly wrong."

The fact that they didn't work escaped everybody's notice.

Escaped everybody's notice

Not everybody's. Read our book, The Resilient Earth.

Ocean warming

Someone please explain how a trace gas, CO2, can in any why cause oceans to gain heat as they reportedly have since 1993, then stopped in 2003.

How can anything but short wave solar radiation warm the oceans deep? I submit it is a perpetuum mobile to assert LW IR has a larger effect than direct solar radiation. One must believe the sun is counted twice or more by assuming back-radiation is responsible for ocean warming.

It is an unphysical process.

Nobody said that LW IR heats

Nobody said that LW IR heats the Oce3an more thn the Sun. The greenhouse gses result in less net radiative loss to outer space from the Ocean surface, until a higher temperature is achieved.

BTW, what happens at 2000 meters deep in the Atlantic is of little effect on surface temps. All of the Ocean below 500 meters is near freezing. Look up 'thermocline.'