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When The AMO Turns, Forget Global Warming

April 12, 2015

By Paul Homewood  




The Atlantic Multidecadal Oscillation, or AMO, is an ongoing series of long-duration changes in the sea surface temperature of the North Atlantic Ocean, with cool and warm phases that may last for 20-40 years at a time and a difference of about 1°F between extremes. These changes are natural and have been occurring for at least the last 1,000 years.

It is known to have significant climatic impacts on the Northern Hemisphere. According to NOAA:

  • Recent research suggests that the AMO is related to the past occurrence of major droughts in the Midwest and the Southwest. When the AMO is in its warm phase, these droughts tend to be more frequent and/or severe (prolonged?). Vice-versa for negative AMO. Two of the most severe droughts of the 20th century occurred during the positive AMO between 1925 and 1965: the Dustbowl of the 1930s and the 1950s drought. Florida and the Pacific Northwest tend to be the opposite – warm AMO, more rainfall.
  • The AMO has a strong effect on Florida rainfall. Rainfall in central and south Florida becomes more plentiful when the Atlantic is in its warm phase and droughts and wildfires are more frequent in the cool phase. As a result of these variations, the inflow to Lake Okeechobee – which regulates South Florida water supply – changes by 40% between AMO extremes. In northern Florida the relationship begins to reverse – less rainfall when the Atlantic is warm.
  • During warm phases of the AMO, the numbers of tropical storms that mature into severe hurricanes is much greater than during cool phases, at least twice as many. Since the AMO switched to its warm phase around 1995, severe hurricanes have become much more frequent and this has led to a crisis in the insurance industry.


What drives the AMO? NOAA explain:

Models of the ocean and atmosphere that interact with each other indicate that the AMO cycle involves changes in the south-to-north circulation and overturning of water and heat in the Atlantic Ocean. This is the same circulation that we think weakens during ice ages, but in the case of the AMO the changes in circulation are much more subtle than those of the ice ages. The warm Gulf Stream current off the east coast of the United States is part of the Atlantic overturning circulation. When the overturning circulation decreases, the North Atlantic temperatures become cooler.


As the graph at the top indicates, we are currently in the warm phase of the AMO, and probably will be for a further 5 to 10 years. In addition to the effects already mentioned, the AMO also has a big effect on Northern Hemisphere temperatures, so much so that it alternately obscures and exaggerates global warming.




The solid blue curve shows the observed northern Hemisphere temperatures and the dashed blue curve is a smoothed version. The red curve is the temperature history for a model that responds to the external forcing of greenhouse gases and solar variability but not to natural climate variations. The blue alternations about the red curve represent the natural AMO oscillations. When the AMO decreases, as from 1950 to 1975, global warming may appear to be reversed. When the AMO increases, as from 1975 to the present, the global warming (red) is exaggerated.



We can see just how closely AMO and Northern Hemisphere temperatures have tracked since the index bottomed out in the 1970’s.




There has been a rise in temperature of a full degree since 1976.  Note, though, how temperatures have flatlined in the last decade.

The question now is just how much temperatures will fall when the AMO index begins to track downwards, as it soon will. Regardless of what happens in the Southern Hemisphere, when this happens, we can then expect 30 years of cold in the north.

It will happen, it’s just a matter of when.





Jennifer Marohasy is concerned that using HADCRUT numbers may not give a true picture. I have therefore added the plot below using UAH satellite data.

As you can see, there is still a close track between the AMO and temperature.



  1. April 12, 2015 2:32 pm

    Reblogged this on Truth, Lies and In Between.

  2. Ines permalink
    April 12, 2015 2:37 pm

    What crisis in the insurance industry?

  3. April 12, 2015 2:49 pm

    Thanks for the reminder of reality.

    There are reports of an unexpected “warm blob” in the Pacific Ocean:

    Society can now ill-afford fraudulent temperature data manufactured by greedy pseudo-scientists.

  4. April 12, 2015 3:05 pm

    Yes, but what drives the temperatures of the great oceans?After some basic research, you will find it is driven [a lot] by the UV radiation allowed through the atmosphere. In its turn, that is controlled by the ozone, peroxides and nitrogenous oxides formed TOA>
    You still remember the ozone scaremongering? Well, my findings are that that was also a hoax; it seems to me CFC have little to do with the natural processes that happen TOA [because of what happens on the sun, of course]
    I can show some interesting results on ozone. Its concentration shows a sinusoidal as well.
    Ozone has started going up from 1995 and will continue its upward path until 2038.

    • Newsel permalink
      April 12, 2015 3:27 pm

      If you have a synopsis of the CFC hoax findings would appreciate your posting. Worked on an EPC project to build a HCF facility back in the ’80’s. Doubt that it was online for more than a year or two. What a waste of $$’s.

      • April 12, 2015 5:49 pm

        Hi Newsel

        I had wanted to spend some time on it, to put the theory together, as soon as I get that time. Let us agree that I will report it here, first, on this thread, as soon as I have put something reasonably comprehensive together. Just make sure you are notified of comments on this is interesting, for sure.

    • AndyG55 permalink
      April 12, 2015 10:36 pm

      I had a paper linked once that showed a very large difference of penetration of UV into sea water at different frequencies. (especially in the 300-350nm range iirc).

      Can’t find the link anymore, though 😦

  5. April 12, 2015 3:59 pm

    There is apparently more than one way to calculate the AMO. According to, the NOAAPSD method turned negative in 2009. And, but for the outlier 2012 cyclone, the summer Arctic ice minimum has been greater every year since the 2007 cyclic minimum, which tends to confirm this turn. Ice area, ice volume, and multiyear ice are all recovering. The timing suggests AMO rather than ‘pause’.

    • April 12, 2015 5:22 pm

      This might actually correlate better to the Sun going quiet. There are studies indicating that less activity there is associated with meridional zone flow become much more erratic in the NH, causing bigger dips in the jet stream. This may, at least in part, be causing much of the increase in ice extent we’ve been seeing lately. Maybe in conjunction with what you’re talking about re: AMO, maybe not.

    • April 12, 2015 5:58 pm

      If it was this paper, it was published in 2009!

      My figures from ESRL are actually the NOAAPSD ones.

      Past timings cannot be a guarantee of the future, but the evidence suggests a 50 to 60 yr cycle, which in turn gives a turndown around 2020.

      • April 13, 2015 6:24 pm

        The year 2020 is interesting. Solar cycles Schwabe, Gleisberg and Eddy are all due to bottom out 2022-2030. I think we’re in for some cold decades.

  6. markus permalink
    April 12, 2015 4:35 pm

    The “flatlining” in the last 10 years is not statistically signifiicant so shouldn’t be asserted as an actual feature.

  7. Brian H permalink
    April 12, 2015 5:25 pm

    The neg. current AMO seems not to have been followed by a decrease in official temperatures. Somebody has his thumb on the scale …

  8. BLACK PEARL permalink
    April 12, 2015 5:33 pm

    Would be interested in the CFC hoax findings as well …
    Also whatever happened to the consensus of scientists on acid rain a number of years back
    It’s a great pity info like this is not made widely available by media networks on the main ‘goggle box’ so the population at large can be more informed.
    I guess they dont have the stomach or the backbone for the back-lash crying heretic from the Green Blob that would ensue (so much for a free press another myth)
    Nothings changed over the centuries, those at the top or with influence have always played the plebs for what ever reason …. and so it goes on

  9. April 12, 2015 8:33 pm

    Reblogged this on the WeatherAction News Blog.

  10. Jennifer Marohasy permalink
    April 12, 2015 9:11 pm

    Given everything you have learnt Paul, about how flawed the methodology used to construct the global and northern temperature charts as shown above as the second and third figures, why do you persist in republishing them? On the one hand you know what the raw temperature shows, much regional variability, and in many places in the northern hemisphere the 1930s were as hot as the 1980s and 1990s. Yet you persist in publishing the official guff! You need to try for some internal consistency? Cognitive dissonance is not healthy.

    On Mon, Apr 13, 2015 at 12:25 AM, NOT A LOT OF PEOPLE KNOW THAT wrote:

    > Paul Homewood posted: “By Paul Homewood >” >

    • April 12, 2015 10:26 pm

      The real issue with the methodology is how the earlier warm period from the 1930’s and 40’s has been eliminated.

      However, there are clearly cycles in both the Pacific and Atlantic which bring warmer and colder intervals, and these have much relevance as to where we are likely to be headed for in the next 20yrs or so.

    • April 13, 2015 11:43 am

      I’ve added in a graph of the UAH figures, and these also track AMO closely, Jennifer

  11. April 12, 2015 9:17 pm

    For those interested in the link between solar activity and ozone my New Climate Model may be of interest.

    • April 13, 2015 9:02 am

      Hi Stephen, nice hearing from you again. There are not too many of us who figured the importance of ozone on the climate, and even you might be missing an important part. There is no “ozone hole” in the SH. Namely, above the oceans there is more moisture, so the reaction
      3O2 + UV (C) => 2 O3
      is simply in a bit of a competition with the other reaction
      2 [OH] + UV (C) => H2O2
      which still protects us (fauna) from the harmful UV (C)

      The problem is really that nobody is measuring peroxides TOA, so we would not know about it, would we?

      I will see if I have some time today to do a important postulation.Keep an eye out for it on this thread. I would like to hear your opinion about it.
      Best wishes

  12. Anon E Mouse permalink
    April 12, 2015 9:41 pm

    Other commentators have looked at this AMO and as well more general Oceanic interactions. Yet they have used them to **support** their argument for climate change action. I think any reduction in temperatures or the involvement of recently understood phenomena will be taken as yet further evidence of Global Warming…

    1. Pretty much exactly the AMO that you talked about here Paul

    Scientific American think we’re at the trough of AMO, and we’re due heating to resume soon.

    SA: “More heat is on the way:
    Based on previous trends, the current “cooling” cycle is likely about halfway over, he said. Rapid warming is expected to resume again in about a decade, though exact predictions are difficult to make.”

    2. Oceans as a more general factor in why there is any Pause at all

    Pop science commentators ( many like the affable Aussie Dr Karl Kruszelnicki ) say the missing heat has been stolen away by the oceans / PMO ; but we can rest assured the Heat will Be Back(TM): Arnold Schwarzenegger style[1] – implicitly the heat will be back with vengance & compound interest because the capitalist sinners amongst us have really pissed off Gaia this time… and She’s angry.

    [ On a side note Dr Karl also backs claims that some small North Pole shift is due to climate change [2]. I found that intriguing… ( we can’t argue much about well understood Physics like planetary motion.) However reading discussions of the paper[3] the researchers said that they used computer models and found something that could not be explained… and just scribbled ‘Climate Change’ on a post-it-note for their conclusion. Not very compelling. ]

    Back onto Oceans[1], Dr Karl said:

    “Over the last 50 years, the oceans have stored 250 zetajoules of energy. That’s 500 times the total annual energy generation capacity of the human race.

    Much of this heat will be transferred back into the atmosphere over the next few decades.” – Published 30 September 2014


    • April 12, 2015 10:18 pm

      Scientific American have it backwards. We are at the top of the AMO.

      The oceans are immensely more powerful than any CO2 in the atmosphere in terms of heat content, and changes can take decades or even centuries to come through.

      The idea that GHG can lead to any measurable difference in ocean temperatures over such a short period is laughable.

  13. THX1138 permalink
    April 12, 2015 10:46 pm

    Planetary motion is not well understood at all by consensus “scientists”! In a gravity-only universe, and according to Newton’s “Laws”, as assumed by mainstream “science”, the planets all should have flown apart long ago to go wandering through the universe. In fact, the “gravitational constant” is the most inconstant “constant” in the whole of physics, and changes continually, with extremes to many standard deviations. Since “scientists” are ignoring the Electric Universe model, and the existence of electrical flow among all bodies in the universe, there will be no understanding of planetary motion or of any other phenomenon in the cosmos.

    Additionally, since “scientists” are also ignoring the constant flow of electricity we receive from, locally, the sun, there cannot be any understanding of weather or climate, and in fact, earthquakes, volcanoes, and the geological formations of the Earth.

    So, yes, we can argue with the “well understood” physics we are taught is the absolute truth.

    synopsis |

  14. April 12, 2015 11:16 pm

    Thanks, Paul. You can get more AMO data points from if you make the final range year 2016.

  15. April 13, 2015 12:12 am

    Reblogged this on Centinel2012 and commented:
    We are in for a cold spell …

  16. April 13, 2015 3:45 am

    Models do not show as much variance (wiggle) as observations. So the fit in the Andronova graphic shown above shows a good fit to observations.

    When I read Andronova and Schlesinger, I conclude something else: the models they used were not worth much and so they came to the wrong conclusions.

    Why? It’s because the models are tuned to fit the observations.

    Figure 3 in Andronova is more telling. There are 4 bar graphs in Figure 3: A (1856-1990; B (1904-1944); C (1944-1976); D (1976-1990).

    In Figures 3.B and 3.C the residuals (natural factors) are overwhelmingly more dominant. In 3.C “anthro” is negative. In 3.D anthro and natural factors are evenly balanced.

    Only in 3.A for 1856-1990 is man-made warming dominant. What this tells me is that the conclusion in Andronova is biased by the period 1856-1904, the period we know least about among the period defined in the paper and the period in which modern industry was least developed.

    None of us remember what the world was like in 1904 but I did my M.A. thesis on industrialization during 1860 to 1920 and offer this webpage as a taste of things as they were:

    There is a better explanation for global warming: scientists observed some modest natural climate change and misunderstood it to have been caused mostly by mankind. Models were then designed to fit the observations. Now what is happening is the real world is diverging from the virtual world in the models.

    Computer gamers will understand well that climate models are elaborate computer games.

    Don’t take my word for it or Paul’s. Here is a link to the Andronova paper.

    Causes of global temperature changes during the 19th and 20th centuries
    NG Andronova, ME Schlesinger – Geophysical Research, 2000

  17. Matthew permalink
    April 13, 2015 8:20 am

    Does the AMO show up in the CET record? Any thoughts?

    • April 13, 2015 10:05 am

      To some extent. The 1930’s and 40’s show up as warmer than the 60’s

      Also note the cold interval between 1890 and 1920

  18. peejos permalink
    April 13, 2015 10:16 am

    It always seemed odd that straight rays from the sun, on reaching the poles of the Earth would miraculously bend downwards through the holes in the ozone and then presumably riccochet off the ice caps to the hazard of man kind

  19. April 13, 2015 12:09 pm

    To gain an understanding of the importance of ozone, peroxides and nitrogenous oxides, which are formed at the top of the atmosphere (TOA), consider how they get formed:
    3O2 + UV (C) => 2 O3
    2 [OH] + UV (C) => H2O2 + UV (C)=> HxOx
    N2 + O2 + UV (C) = > 2NO + UV (C) => NxOx
    This protects us on earth from the harmful UV (C), i.e. the particles with the lowest wavelengths that are coming from the sun that could basically kill us.
    These particles do vary in amount, depending on the state on the sun, i.e. when the sun’s solar polar fields become weaker, more of the most energetic particles are able to escape from the sun.

    Radiation transmitted by the atmosphere.

    It is important to understand this graph. A report by Trenberth showed that ozone on its own is responsible for the back radiation of about 25% of all that is back radiated [by GH gasses].
    He simply forgot about the peroxides and the nitrogenous oxides, which I will henceforth refer to as: “Trenberth’s missing energy”. The tragedy is simply that people have never measured peroxides and nitrogenous oxides in the atmosphere, so we have no idea about it.
    The substances manufactured by the sun TOA do have [some] absorption in the [normal] UV regions (A and or B) of the molecule. When hit by this radiation, it heats the molecule a bit, but it has little mass, so, if radiation of that absorptive wavelength hits the molecule, it just acts like a mirror here, sending a large percentage of that UV light back where it came from (i.e. to space). You can see this happening in the graph quoted, note the white area under the red line [that is radiation that never reaches earth… ]. If there is more ozone (and others) then obviously less energy (UV) will be allowed through the atmosphere, and the white area under the red line will become bigger.
    It is especially the UV radiation that is able to warm the waters of the ocean because it has the highest energy levels and water has some absorption here, and eventually, because here there is a lot of mass [of ocean water], this UV A + B has to convert to warmth.
    So remember: ozone and the other gases formed TOA are able to deflect a large percentage of incoming UV, and any variation in ozone & others ultimately would affect the amount of warming of the oceans.

    Here is the classic normal time series on ozone of Arosa, in Switzerland, NH, which is the oldest and longest time series that we have.
    It was postulated here that the results suggest human influence. Note the linear downward trend indicated (cause given: use of CFC) and upward trend indicated from 1995 (discontinued use of CFC’s)

    Anyway, I suspected that measuring ozone might not be that simple as it is made out to be. The books give the percentage of ozone in the atmosphere as 0.000004%, which is only ca. 0.04 ppmv. They give it in Dobson units and essentially this is also a volume measurement. So I asked myself: what if the volume in the atmosphere itself is not constant? A quick search revealed that the volume in the atmosphere is indeed not always constant. It varies over time. That could affect the results…..
    I used to measure carbon in steel with a Stroehlein apparatus and remember that we were happy if the measurement of CO2 after incineration gave us an error of less than 10% carbon on the actual of C content of the standard sample. I reckon that which such small amounts of ozone to be measured, we cannot expect to do much better than a 10% error. Note the number of different instruments used over time, (fig 7)
    where they already admit that different apparatus give different results (note the divergence of the blue line from the red line)

    Now let me have a look at the real figures as they are from Arosa, up until 2014:

    I am sure you can imagine from my arguments made above, that perhaps the initial results were a bit too high, which would mean that my best fit proposal might get down a bit, there in the beginning, and that would give me a perfect A- C sine wave, exactly as what I had expected to see, with bending points around 1951 and around 1995. These dates are important as I have previously shown that maximum temperatures [ = Energy-in] started increasing in 1951 and started declining again in 1995, exactly in line with the 87 year Gleissberg solar-weather cycle.
    Even if the reported downward [linear] trend of 0.25 DU per annum since 1926 were completely correct, the change in ozone concentration TOA might still be part of another natural solar cycle, namely the DeVries solar-weather cycle, which is about 210 year.

    • April 13, 2015 5:11 pm

      Hi Henry.

      That looks like good work which is consistent with my hypothesis that ozone variations are linked to solar activity.

      I would just add that to get latitudinally sliding jets and climate zones we need different ozone responses to solar change above poles and equator.

      If you can narrow down HOW the sun achieves such effects then that would be helpful.

      Thus far I have just asserted that it is a matter of changes in the mix of wavelengths and particles.

  20. jim murphy permalink
    April 13, 2015 1:57 pm

    why can’t I print your stuff

    • April 13, 2015 5:07 pm

      I’ve been asked that before. It may be your browser

      It prints fine on Mozilla if I use Print Preview.

  21. neil hampshire permalink
    April 13, 2015 2:20 pm

    Thank you Paul for an excellent summary of AMO
    Wood for the trees allows you to plot both global temperatures and AMO on the same chart

    • April 13, 2015 4:33 pm

      Yes, Neil.
      I think such correlation points to a possible causation of global temperatures by AMO.

  22. Paul2 permalink
    April 13, 2015 3:39 pm

    Off topic but one to put in your diaries.The great Andrew Neil and Harrabin host the “Environment and climate change debate on April 20 on BBC television.
    Neil really is the best qualified to expose the grand scam and hopefully He’ll do himself justice on the day.

  23. ulriclyons permalink
    April 13, 2015 4:20 pm

    “When the overturning circulation decreases, the North Atlantic temperatures become cooler.”

    Nonsense, they have it backwards. Negative NAO episodes drive low AMOC events, and that is precisely when there are warming pulses to the AMO and Arctic:

    The AMO moves anti-phase to sunspot cycles in its warm mode, and so was due to cool briefly around this sunspot maximum, and it will warm again strongly through the next decade because there will be lots of deep negative NAO episodes:

    • April 13, 2015 5:13 pm

      Can’t see any correlation on the graph.

      • ulriclyons permalink
        April 13, 2015 5:49 pm

        Which graph Paul?
        I see a very good correlation between low AMOC events and negative NAO episodes.
        The phase reversals of the AMO in respect to sunspot cycles according to its mode also is apparent in UK temperatures, but the opposite of the AMO, being in phase with sunspot cycles when the AMO is in its warm mode:

      • April 13, 2015 9:52 pm

        There is no correlation between the AMO cycle and sunspots

      • ulriclyons permalink
        April 13, 2015 10:41 pm

        Yes there is, the AMO follows the sunspot cycles in its cold mode, i.e in phase, in solar cycles 14 &15 and 21 & 22, and it goes anti-phase with the solar cycles in its warm mode, with a transition period of around one solar cycle between modes. The reverse of UK temperatures in my last link.

  24. April 13, 2015 7:07 pm

    Stephen Wilde says
    If you can narrow down HOW the sun achieves such effects then that would be helpful.

    Henry says
    I have tried to explain this several times, without much luck, I must say.

    Look at these results here:

    Clearly, you must see that in your mind you can draw a hyperbole from top to bottom and a parabola from bottom to top that show the average solar polar field strengths?

    Both binomials then come to the [lowest] field strengths around 2016.

    My various calculations, which include my results for global minima and – maxima, and the situation of the planets, all show that 2016 will be a dead end stop where a switch must happen to bring the field strengths up again. We are at a most interesting part of the total 87-88 year sun cycle. The switch that will happen in 2016 last happened in 1927. Next year the sun will be at its very brightest point in 88 years. Can you imagine putting a mirror at 2016 and seeing the whole scissors again, happening in the opposite direction?

    so, from 1995-2038 the sun will be in a quiet situation, the cooling part of the Gleissberg, that causes the global cooling.

    • April 13, 2015 7:22 pm

      I can see what you are suggesting but I was looking for a more chemistry based description of how those solar variations affect ozone amounts differently above equator and poles so as to alter the gradient of tropopause height between equator and poles.

      It is only by altering that gradient that we can achieve the observed variations in jet stream behaviour between zonality and meridionality.

  25. April 13, 2015 7:46 pm


    So the mechanism for the global cooling period that we entered, is as follows:

    declining solar field strengths =.> more of the most energetic particles released =.> more harmful UV (c) => more ozone, more peroxides, more nitrogenous oxides formed TOA =.> more UV/ & other sunlight deflected to space => less energy coming through the atmosphere and into the oceans=> differential T between poles and equator rises => more clouds around equator and less clouds and rain at certain top latitudes => more global cooling (due to the fact that insolation is 684 at the equator and 342 on average)

    It is all so simple, that I cannot understand that so few people actually get it.

    We have another problem. There is a 6-7 year delay between what happens exactly on the sun and what happens here on earth. Imagine 1927 = 2015/2016
    Where will we be in 5-6 years time? …..1932… all over again:
    I am saying that around 2021 we will see the great droughts coming back to the great plains of America again.

    That will be the beginning of a great disaster.

    Farmers will have to begin to move south, towards the equator, where you will find more rain and warmth during a global cooling period…..

    • April 13, 2015 8:08 pm

      A reasonable summary but not quite as per my hypothesis as set out in the Jo Nova article and elsewhere previously.

      We agree on the general gist though and it does seem consistent with your work.

      • April 15, 2015 4:43 pm

        Like I said before, there are not too many of us who figured it all out,
        most of it, anyway. I am not a weather man but I get your arguments for the change in direction of wind and/or changed weather pattern.
        They just all follow from my [uncontested] observations….

        Gen 41:27 The seven thin, sickly cows that came up behind them are seven years. The seven empty heads of grain scorched by the east wind are also seven years. Seven years of famine are coming

        Change in wind direction is also on the cards when we turn the 2015/2016 switch, except, like I said, there will be a delay of about 6 years or so.

        remember me when it happens all over again

        [it appears nobody listening to us, anyway, because of certain “money making agenda’s”, even at the so-called “skeptic” sites, and our pension money is also in the AGW nonsense….perhaps I must also become a non-skeptic?]

      • April 15, 2015 7:53 pm

        Don’t forget you were going to explain all about CFC’s or something!

  26. April 16, 2015 6:39 am

    maybe you missed it, start here
    and try and follow the discussion
    note how a small amount of ozone gas is able to make a “hole” in the incoming radiation.

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