Evidence is Mounting: Oceans Make Climate

Update May 28, 2015, with additional detail from Dr. McCarthy

Update May 29, 2015, with additional context from Bob Tisdale

The RAPID moorings being deployed. Credit: National Oceanography Centre

A new study, by scientists from the University of Southampton and National Oceanography Centre (NOC), implies that the global climate is on the verge of broad-scale change that could last for a number of decades. This new climatic phase could be half a degree cooler.

The change to the new set of climatic conditions is associated with a cooling of the Atlantic, and is likely to bring drier summers in Britain and Ireland, accelerated sea-level rise along the northeast coast of the United States, and drought in the developing countries of the Sahel region. Since this new climatic phase could be half a degree cooler, it may well offer a brief reprise from the rise of global temperatures, as well as resulting in fewer hurricanes hitting the United States.

The study, published in Nature, proves that ocean circulation is the link between weather and decadal scale climatic change. It is based on observational evidence of the link between ocean circulation and the decadal variability of sea surface temperatures in the Atlantic Ocean.

Lead author Dr Gerard McCarthy, from the NOC, said: “Sea-surface temperatures in the Atlantic vary between warm and cold over time-scales of many decades. These variations have been shown to influence temperature, rainfall, drought and even the frequency of hurricanes in many regions of the world. This decadal variability, called the Atlantic Multi-decadal Oscillation (AMO), is a notable feature of the Atlantic Ocean and the climate of the regions it influences.”

The strength of ocean currents has been measured by a network of sensors, called the RAPID array, which have been collecting data on the flow rate of the Atlantic meridonal overturning circulation (AMOC) for a decade.

Dr David Smeed, from the NOC and lead scientist of the RAPID project, adds: “The observations of AMOC from the RAPID array, over the past ten years, show that it is declining. As a result, we expect the AMO is moving to a negative phase, which will result in cooler surface waters. This is consistent with observations of temperature in the North Atlantic.”


Some additional detail from Dr. McCarthy:

Results from the RAPID array

Gerard McCarthy, David Smeed, Darren Rayner, Eleanor Frajka-Williams, Aurélie Duchez, Bill Johns, Molly Baringer, Chris Meinen, Adam Blaker, Stuart Cunningham and Harry Bryden

“The RAPID/MOCHA/WBTS mooring array at 26ºN in the Atlantic has been delivering twice daily estimates of the strength of the AMOC since 2004. A unique array, the observations have revolutionised our understanding of the variability of the AMOC on sub-annual, seasonal and, most recently, interannual timescales. An update to the AMOC timeseries has recently been produced.   As well as extending the data, the timeseries to October 2012 contains several improvements to the calculation.

A dramatic low in the AMOC was observed in winter 2009/10, where the AMOC declined by 30%. This has been shown to have resulted in a sustained reduction in heat content of the North Atlantic. The 2009/10 dip in AMOC strength was followed by a second dramatic low in 2010/11. Historical analogues of double minima in successive winters have been identified in NEMO runs where they are associated with extreme negative values of the Arctic oscillation and have been linked with ocean re-emergence. Interestingly, there is also a link with surface air temperatures and, consequently, European wintertime conditions.

The latest update of the AMOC time series to October 2012 shows a continuing trend in the circulation at 26ºN switching from an overturning to a gyre circulation. This leads to weakened southward transport of lower North Atlantic Deep Water, the strength of which from 2004-2012 is weaker than in historical measurements. The IPCC report in 2007 reported that the AMOC was ‘very likely’ to weaken in the 21st century. Maintaining the sustained observations of the RAPID array is key to observing this climate metric.”

Rapid Project Webpage is here: http://www.rapid.ac.uk/rapidmoc/

Figure 1:Ten-day (colours) and three month low-pass (black) timeseries of Florida Straits transport (blue), Ekman transport (black), upper mid-ocean transport (magenta), and overturning transport (red) for the period 2nd April 2004 to mid- March 2014. Florida Straits transport is based on electromagnetic cable measurements; Ekman transport is based on ERA winds. The upper mid-ocean transport, based on the RAPID time series, is the vertical integral of the transport per unit depth down to the deepest northward velocity (~1100 m) on each day. Overturning transport is then the sum of the Florida Straits, Ekman, and upper mid-ocean transports and represents the maximum northward transport of upper-layer waters on each day. Positive transports correspond to northward flow.

Additional info here: http://www.livescience.com/50998-jet-stream-controls-atlantic-climate-cycles.html


Getting a reprieve from the dangers of global warming would be good news, but these facts were not well received by everyone last month at a conference in Vienna, as tweeted by Dr. McCarthy:

Bob Tisdale provides additional context on the AMO and on this paper, as well as critiques of some other papers here: https://bobtisdale.wordpress.com/2015/05/29/new-paper-confirms-the-drivers-of-and-processes-behind-the-atlantic-multidecadal-oscillation/

For more on this topic see:




  1. Pingback: Is The AMO Beginning To Turn Cold? | NOT A LOT OF PEOPLE KNOW THAT
  2. David A · May 28, 2015

    The correlation of the AMO with NH T is striking, and may have greater power then the Pacific. (Note de-trended)

    It will be interesting to see how much the strengthening El Nino counters this. If the El Nino, in conjunction with the “blob” fails to move the GMT much, then it may truly be game over for CAGW enthusiasts, especially if the PDO turns negative over the next year or two. (Mann’s recent paper, a poor attempt IMV, striving to blame any such cooling on CO2 emissions affecting the Atlantic currents, could be a somewhat desperate attempt to anticipate this clearly natural cycle.)

    If, and I admit a big if, the PDO goes negative, (Blob goes away) and we have a correlating strong La Nina (the opposite of 98) along with an AMO moving definitively negative, then I could see a .4 drop in satellite GAT, 100 percent removing all satellite warming since 1979, the “Ice age scare”. I wonder if this would produce a step down, just as the 98 El Nino appeared to produce a step up in GAT.


    • Ron Clutz · May 28, 2015

      David, you’ve put your finger on the issue. In 2011, Joe Bastardi said the weather would soon be hit by a triple whammy of cooling: PDO and AMO cooling phases, quiet solar cycle and volcanic activity. The alarmist push for Paris COP in December will be enormous.


      • ulriclyons · May 30, 2015

        The last solar minimum in the late 1800’s had a warm AMO mode, because negative NAO was increased by weak solar activity. Look carefully at the RAPID data series, and you’ll see that low AMOC events happen during negative NAO episodes.


  3. Hifast · May 28, 2015

    Reblogged this on Climate Collections.


  4. wolsten · May 28, 2015

    This will of course give everyone on the gravy train a plausible excuse (at least in the eyes of the believers):

    “I know we said we only had X years to save the planet many times in the past, and those claims have been looking increasingly ridiculous, but this new research shows we were right all along, we just got the timing out by a few years. Please be patient, we will all die eventually.”

    And then of course the gravy train can keep rolling.


    • Ron Clutz · May 28, 2015

      Agreed that there will be excuses and postponing of when warming will resume. But I do think that actual cooling, not just a plateau, will serious undermine the warming narrative, and other scientists like these will be emboldened.


      • wolsten · May 28, 2015

        I hope you are right Ron but I am not sure we live in a world of common sense, logic and reason, where such thinking would prevail. Arrived home last weekend to find the house had been ransacked by burglars so I am probably feeling even more cynical than usual.


      • Ron Clutz · May 28, 2015

        Condolences. When reason and science are abused in favor of herd instincts, then we are facing the barbarians at the gates.

        Liked by 1 person

  5. ArndB · May 28, 2015

    Thanks for addressing again and again: “Oceans Make Climate”, as some still believes the earth is flat.

    Quite a while ago N. S. Keenlyside, M. Latif et al (2008) in a paper “Advancing decadal-scale climate prediction in the North Atlantic sector”, NATURE, Vol 453|1 May 2008, predicted:
    “….over the next decade, the current Atlantic meridional overturning circulation will weaken to its long-term mean; moreover, North Atlantic SST and European and North American surface temperatures will cool slightly…. “
    That was objected with a post at ‘realclimate’: “Global Cooling-Wanna Bet?” by the well-known climatologists Stefan Rahmstorf, Michael Mann, Ray Bradley, William Connolley, David Archer, and Caspar Ammann, at: http://www.realclimate.org/index.php/archives/2008/05/global-cooling-wanna-bet/ saying:
    ___“Global cooling appears to be the “flavour of the month”. First, a rather misguided media discussion erupted on whether global warming had stopped, based on the observed temperatures of the past 8 years or so. Now, an entirely new discussion is capturing the imagination, based on a group of scientists from Germany predicting a pause in global warming last week in the journal Nature”… cont. “….will this forecast turn out to be correct? We think not – and we are prepared to bet serious money on this….cont“
    ___see also : “The Global Cooling Bet – Part 2”, http://www.realclimate.org/index.php/archives/2008/05/the-global-cooling-bet-part-2/ , and ___ “So how did that global cooling bet work out?” http://www.realclimate.org/index.php/archives/2010/11/so-how-did-that-global-cooling-bet-work-out/#more-5345

    Whether Keenlyside (2008), and Gerard McCarthy (2014) are ready to accept that “Oceans Make Climate” is not yet clear. After all AMOC is not a physical force but only a technical mean..


    • Ron Clutz · May 28, 2015

      Thanks for tuning in, Arnd. Can you elaborate on your last sentence, both about Keenlyside and McCarthy, and also the difference between and physical force and a technical mean?


  6. ArndB · May 28, 2015

    With “technical means” is meant, that a specific location (AMOC – McCarthy: “associated heat transport at 26°N in the North Atlantic”) or area (NOA) is selected and used as “….the projections of AMOC decline in the future due to climate change” (McCarthy (2014).

    That does not give a clear picture, presumably even less when N. S. Keenlyside, M. Latif et al (2008) (link previous comment) – which I had in mind when referring to “physical force”- explain it in this way
    —-p. 85….”in particular the North Atlantic Oscillation (NAO), which plays a key role in forcing multidecadal MOC variations. Consistently, observed NAO variations lead simulated MOC changes by several years, but inconsistently, they are not well related to simulated Labrador Sea convection, except perhaps on multidecadal timescales (Fig. 2). Although the simulated NAO index does not correspond well with the observations, it strengthens during the simulated period, and thus probably also contributes to forcing MOC variations.”, having earlier stated:
    ___p.84, The North Atlantic is a region with large natural multidecadal variability. Observations suggest that Atlantic multidecadal variability may be oscillatory, with a period of 70–80 years. Palaeo-evidence and coupled general circulation models support the oscillatory nature of Atlantic multidecadal variability, and hence the existence of a low order mode of natural variability. Although major uncertainties exist in the mechanisms of Atlantic multidecadal variability, it is widely accepted that the meridional overturning circulation (MOC) plays an important role in driving multidecadal SST variations, as shown by ocean and coupled model simulations. “

    At http://people.oregonstate.edu/~schmita2/pdf/S/schmittner07agu_intro.pdf
    „Ocean’s Meridional Overturning Circulation” is explained by Andreas Schmittner, John C.H. Chiang, and Sidney R. Hemming, as follows:
    ___The meridional overturning circulation is a system of surface and deep currents encompassing all ocean basins. It transports large amounts of water, heat, salt, carbon, nutrients and other substances around the globe, and connects the surface ocean and atmosphere with the huge reservoir of the deep sea. As such, it is of critical importance to the global climate system. This monograph summarizes the current state of knowledge of this current system, how it has changed in the past and how it may change in the future, its driving mechanisms, and the impacts of its variability on climate, ecosystems and biogeochemical cycles. “
    What to make – for example – from such sentence ( p. 1)
    ___Ultimately, these deep waters have to return to the surface. However, where and how exactly the ocean upwells is poorly understood. Presently it is believed that most deep water returns to the surface in the high latitude Southern Ocean…. Cont/”


    • Ron Clutz · May 29, 2015

      I am trying to understand the heart of your concern. You seem to suggest that such observations are so limited a sample of the oceanic reality that no generalizations can be drawn from them. I am hearing that changes in measures of SST are not comprehensive enough to support any paradigm such as the “conveyor belt”. In that sense, I hear you and Carl Wunsch saying similar things: http://ocean.mit.edu/~cwunsch/papersonline/rmsbookpaper.pdf.
      Is this the thrust of your thinking here? Do you think the RAPID project is meaningless?


    • Ron Clutz · May 29, 2015

      I recall some others who are seeking better observational evidence for oceanic effects:http://sites.duke.edu/mslozier/files/2010/11/Burkholder.Lozier-2014.pdf
      Interestingly, Lozier is running the companion Project to RAPID


  7. ArndB · May 29, 2015

    Indeed the essence of my concern is that AMOC- “observations are so limited a sample”, was AMOC is “characterized by a northward flow of warm, salty water in the upper layers “ and “There is growing evidence that fluctuations in Atlantic sea surface temperatures, hypothesized to be related to fluctuations in the AMOC” ,according http://www.eoearth.org/view/article/150290/ . In so far it is mainly a temperature matter, a field of research still insufficiently understood, and unclear when , McCarthy’s paper speak – e.g.- about “AMOC decline”. But better this way than not at all.

    Carl Wunsch was one of my first “hero” in the late 1980th, addressing in a 1984-book the ocean circulation in climate, from which I cite two excerpts:
    (1) The role of the ocean in climate and climate change is unlikely to be demonstrated and understood until observations become meaningful in terms of physics being tested.
    (2) Because “climate” means so many things to different people (depending upon their particular interest), it is difficult to rule out any component of oceanic motion as being unimportant in the climate regime.
    Source: ed. John T. Houghton, “The Global Climate” 1984, Ch. 10 – The ocean circulation in climate., Cambridge, p. 189ff.,
    C. Wunsch notion about the term “climate” (2) is still grossly ignored by all sides involved in this field, and largely used as everyone feels it fit is interest best. That does not serve the climate debate.

    Having read the Kristin C. Burkholder and M. Susan Lozier’s Abstract and Summary/Conclusion there seems to be little that provides a better understanding, but any paper in this respect serves as reminder that more observational evidence is needed, and therefor welcome


  8. Dan Pangburn · May 29, 2015

    The net of ocean cycles explains the 64 year period of climate. When combined with the sunspot number anomaly time integral (which is a proxy for solar effect on clouds) and compared to a 5-year moving average of reported average global temperature measurements, R^2 = 0.97+ since before 1900. CO2 has no significant influence.

    Proof that CO2 has no significant effect on climate and identification of the two factors that do cause climate change are at http://agwunveiled.blogspot.com


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