A Cloudy Question: was ‘the pause’ caused by a change in global cloud cover?

Guest essay by Mike Jonas

I have been looking at some cloud data (from ISCCP: isccp.giss.nasa.gov all available monthly “EQ” data (equal-area grid)) and an interesting question arises. I haven’t seen the answer on WUWT or anywhere else.

Was there a near-global sea-change (no pun intended) in cloud cover around the turn of the millenium, and if so, what caused it?


Figure 1. Global ClearSky anomaly, 1-yr smoothing (centred).

The point is that eye-balling the above graph, it looks like ClearSky was increasing in the late 20thC and then stopped. ie, cloud cover was decreasing, then stopped.

The answer to that question might go a long way towards explaining the “hiatus” and resolving the entire climate science controversy.

If any WUWT readers can supply the answers, I would be most grateful.

– – – – –

A bit of background:

[Except where stated otherwise, graphs in this document are all of temperature anomaly, cloud anomaly over ocean only. The Cloud or ClearSky axis is on the left, Temperature axis is on the right. ClearSky% = (100 – Cloud%), so ClearSky anomaly = (- Cloud anomaly). Cloud anomaly is based on calendar month averages over all full years of cloud data. Temperature data is from UAH Lower Troposphere Ocean-only, provided by UAH in anomaly form but likely to have a different base period.]

There are short term and longer term correlations between cloud and temperature.

Short term (a month or two), cloud increases with temperature. Well, after about 1998 it does. This is only to be expected, because it is generally agreed that the water cycle increases with temperature, and the water cycle necessarily involves clouds. The relationship, as would be expected, is strongest in the tropics.

Figure 2. Monthly Temperature and Cloud anomalies in the Tropics.

Temperature moves first, which suggests that it’s the driver (in the short term). This says nothing about the rate at which the water cycle increases with temperature.

Long term, though, ClearSky increases with temperature. This is the Global picture with 11-yr smoothing:


Figure 3. Global Temperature and ClearSky anomalies, with 11-yr smoothing (centred).

There is no clear indication from the Global picture, as to which comes first, temperature or ClearSky. Temperature appears to trail ClearSky with a lag of a few years in the NH …

Figure 4. NH Temperature and ClearSky anomalies, with 11-yr smoothing (centred).

… and in the Antarctic …

Figure 5. Antarctic (to 60S) Temperature and ClearSky anomalies, with 11-yr smoothing (centred).

… but the pattern is much less clear in other regions.

That temperature increases as ClearSky increases, but with a lag, is to be expected because visible light [and some UV] penetrates many metres into the ocean thus warming it; reflective clouds affect the amount.

The IPCC claim a large positive cloud feedback (ie, that a rising temperature causes more warming by clouds [presumably they mean that higher temperature leads to less clouds, but I can’t see anywhere that they say it explicitly]. A long time ago I explained on WUWT how the way in which they derive the positive cloud feedback was invalid (https://wattsupwiththat.com/2015/09/17/how-reliable-are-the-climate-models/). The fact that the initial effect of temperature on clouds is in the opposite direction (Figure 2 above) suggests that the IPCC finding is mistaken, and that ClearSky is simply a significant driver of temperature over decadal+ periods.

It’s perhaps a bit odd that the ClearSky effect on Temperature is most visible in the Antarctic and the NH. I speculate as follows:

The period covered by the cloud data is simply not long enough to get a clear picture of the longer-term mechanisms. There are also a lot of other things going on which confuse the picture. For example, there are winds and ocean currents that flow from region to region, so regions are affected by what is going on in other regions. Over periods of a year to multiple decades, temperatures everywhere are affected by ENSO and other ocean oscillations. Clouds are presumably affected too. And then there is the short term effect of temperature on clouds, which is in the opposite direction to the longer term cloud-temperature relationship, and hence may confuse the picture further. And, of course, we always have to bear in mind that climate is a non-linear system.

ENSO in particular is strongest in the Tropics and south of the Tropics, and maybe this would make the cloud-temperature link more difficult to see there, particularly given the short period over which we have cloud data. Maybe that is why the ClearSky-Temperature lag is most visible in the Northern Extra-Tropics and the Southern Ocean.

The Southern Ocean is more isolated than other regions, if I have understood it correctly. It has virtually no incoming winds or surface currents from other ocean areas. The principal incoming ocean current is in the form of upwellings from the deeper ocean, and is therefore unaffected by weather/climate conditions in other ocean areas. Similarly, the principal wind direction is from the Antarctic continent (the katabatic wind) not from other ocean areas.

All other ocean areas, by contrast, have incoming surface ocean flows and winds from other ocean areas, and are therefore influenced by weather/climate conditions in those other ocean areas.

One implication of this is that the cloud-temperature relationship is more likely to reflect locally-generated conditions over the Southern Ocean than it is over other ocean regions. The fact that solar radiation is weakest there per unit area would suggest that a smaller temperature effect should be expected, but the effect appears to be just as strong.

The cloud-temperature relationship in the other ocean regions, as covered by UAH, is less clear than in the Southern Ocean. See worksheet Graphs in spreadsheet UAH_ClearSky.xlsx (Excel .xlsx 1.2 mb)

Mike Jonas (MA Maths Oxford UK) retired some years ago after nearly 40 years in I.T.


157 thoughts on “A Cloudy Question: was ‘the pause’ caused by a change in global cloud cover?

    • quite the opposite. chicken and egg is about positive feedback, A prompting B prompting A, resulting in exponential growth unless something else cap the thing.
      Here we are talking negative feedback : A suppressing B suppressing A ; stability usually result (also oscillations and chaos are not uncommon).

      • @daveburton
        If the feedback is less than 1, it’s negative. Only feedback greater than 1 (100%) is positive.

      • No, D.J., that is not correct. Negative feedback is less than zero. Positive feedback is greater than zero.

        Positive feedback which is much less than one amplifies a little bit. As positive feedback approaches one, the resulting amplification increases dramatically. If the feedback reaches or exceeds one, then the system becomes unstable, and the output swings until some nonlinearity imposes a limit by reducing the feedback ratio.

        I explained it at that link:

        A common misconception is that positive feedbacks necessarily “run away,” and make a system unstable. That is incorrect. Positive feedbacks of less than 100% don’t make a system unstable.

        For example, consider a linear system with a positive 10% (i.e. +1/10) feedback from the output to the input. An input change of 1.0 will “feed back” +10% to become, effectively 1.1. The “.1” (additional part) is also then amplified by 10%, becoming .11, etc. The +10% feedback ends up, in the long term, asymptotically approaching 11.1111111…% (i.e., +1/9 = ×10⁄9) amplification.

        Similarly, a +20% (i.e. 1/5) linear feedback causes a +25% (i.e., +1/4 = ×1.25) amplification, a +33⅓% (i.e. 1/3) feedback causes a +50% (i.e. +1/2 = ×1.5) amplification, and a +50% (i.e. 1/2) feedback causes a +100% (i.e. +1 = ×2) amplification. (Caveats: in the real world, delays in the feedback path may mean that the full amplification effect of a positive feedback isn’t immediately seen; also, most systems are not perfectly linear, though many are approximately linear over ranges of interest.)

      • Positive feedback of greater than unity results in an unstable system. Depending on the nature of the system it may ‘latch up’ or it may oscillate.

        Positive feedback of less than unity results in an increase of system gain or sensitivity, but for that increase to be significant the positive feedback has to be very close to unity. If the system is subject to outside perturbations then it will be hard to keep the positive feedback in the quite narrow range where it increases sensitivity but does not cause instability.

        A good example is early radios. Because valves (tubes) were expensive and had only low gain, a ‘reaction’ control applied positive feedback to make the sound adequately loud. Since these radios typically ran from batteries, continual adjustment was necessary to compensate for the gradually reducing voltage.

        Considering the number of perturbations in the climate system, it seems very unlikely that the ‘feedbacks’ touted by the IPCC could work the way they claim, and produce a controlled increase in the effect of CO2.

      • @daveburton

        “For example, consider a linear system with a positive 10% (i.e. +1/10) feedback from the output to the input. An input change of 1.0 will “feed back” +10% to become, effectively 1.1. The “.1” (additional part) is also then amplified by 10%, becoming .11, etc. The +10% feedback ends up, in the long term, asymptotically approaching 11.1111111…% (i.e., +1/9 = ×10⁄9) amplification.”

        Why wouldn’t your example go 1.0, 1.10, 1.21, 1.321, 1.453, 1.5983, etc. etc.

        iow, why doesn’t postive feedback work like compounding interest?
        It seems that people who argue that unobstructed positive feedback must runaway, they have in mind the process that is used for compounding interest.

      • No, SDB, your arithmetic “re-amplifies” the same input repeatedly, which is wrong.

        Your “compound interest” analogy assumes that the system “output” and “input” are a single entity, so the system starts with its input, and adds “interest” to it. In other words, it has a gain of greater than 1.0, by definition, and the only reason it isn’t immediately unstable is that there’s a delay before the interest accrues. If there were no delay, you could deposit $1 at an ATM, then walk inside the bank and withdraw a billion dollars, immediately.

        In a classical feedback system, the input and output are different things. The output is a function of the input, and the input is then affected by the output (and, also typically affected by other things; in climate systems those “other things” are called “forcings”).

        There are three cases (two of them with “real world” climate examples):

        1. Negative feedback: If the the total “feedback” gain around the loop is negative, then the effect of other inputs is reduced. For example, consider CO2 Fertilization Feedback (“greening”). Higher CO2 levels increase plant growth rates, which reduces atmospheric CO2 levels. The feedback loop is:
        More CO2 -> more plant growth -> less CO2 (i.e., it tends to stabilize CO2 levels)
        (AR5 estimates that this effect removes about 27% [p. 6-3] or 29% [Fig. 6.1] of anthropogenic CO2 emissions from the atmosphere, each year.)
        Negative feedbacks tend to attenuate (reduce) the effects of forcings on a system.

        2. Positive feedback, less than unity: that’s the sort of feedback that has climate alarmists in a tizzy. For example, consider CO2 / Water Temperature Feedback. The solubility of gases like CO2 (and CH4) in water decreases as the water gets warmer, so as the oceans warm they outgas CO2. The CO2, in turn, works as a GHG to cause warming, making this a modest positive feedback mechanism. The feedback loop is:
        Warmer water -> higher atmospheric CO2 levels -> greenhouse warming -> warmer water
        Positive feedbacks, less than unity, tend to amplify the effects of forcings on a system.

        3. Positive feedback greater than unity, which results in an unstable system, as Ian Macdonald mentioned.
        Fortunately, there are no real-world examples of this in climate systems, but there is one imaginary example, the favorite of innumerate climate catastrophists everywhere: the “methane bomb.” Theoretically, if the climate warms, it could melt some of the Arctic permafrost, and/or underwater methane clathrate (hydrate) deposits, causing the release of methane. Methane is a greenhouse gas, so this should increase warming, making it a positive feedback mechanism.
        That much is reasonable (though there’s no evidence that it is significant). But the climate catastrophists imagine that such a release will flood the atmosphere with so much methane that the methane will warm the planet by even more than the original warming which triggered the original release, and that greater additional warming will cause an even larger secondary release, which will cause EVEN MORE warming, etc., with the result that we’ll all roast, like Venus. If that chain of events were plausible, it would be an example of positive feedback greater than unity.

      • Clearly, reality has shown that the negative feed backs outweigh the positive feed backs as we did not get the predicted runaway warming.

      • I just intended to point the fact that “chicken and egg thing” was irrelevant; not to make a control theory expose. There are a lot of those online. My two line sentence obviously let room for misunderstanding: when A become 0.9A, the gain 0.9 is positive, the variation is -0.1A, negative, and both could be understood as the “feedback”. nothing to fuss about.
        My only mistake, that you should have pinpointed, is far worse. I wrote “negative feedback : A suppressing B suppressing A” where I should have: “negative feedback: A prompting B suppressing A”
        My bad.

    • When you DON’T have “Clear Sky”. Just what the heck do you DO have.

      Clear Sky tells you nothing about what is going on under non clear sky.

      Also when we talk about the effect of cloud variability, we are talking about changes that persist for climate time scales like ……. 30 years ….. We aren’t talking about the effect of last night’s high wispy clouds.


    • The relevant paper is Pinker et al., 2005, which said that a naturally-occurring reduction in cloud cover from 1983-2001 caused more than half of all radiative forcings over the period. After 2001, the cloud cover returned and temperatures more or less stopped rising.

      I wrote a paper for the World Federation of Scientists on this some years ago, which was published in their annual journal.

      • I spent much of the 1990s in Hungary, during the collapse of communism. During the transition period, many highly polluting plants were closed and air quality improved markedly. As an added benefit, cloud cover decreased notably. Therefore, my best guess is that the fall of communism reduced air pollution, leading to a reduction in cloud cover and a step up in temperature.

        The logic aligns with L. Monckton, but the cause is different.

      • M of B – I haven’t come across that paper. What I provisionally deduced from the data was that higher temperature => more cloud in the short term, but in the longer term cloud cover changed independently of temperature and less cloud => higher temperature. So, while the change in cloud cover has been observed, and its effect has been calculated, I think I have added something useful, and now the $64bn question is what caused the change in cloud cover?.

      • Yes, the Pinker paper (and a couple of others in 2005) dealt with the change in cloud cover and also there was a ‘brightening’ in the clear sky readings – meaning a drop in aerosol loadings (that began before the ‘clean air’ initiatives which were small in area and effect in comparison). I took this up with NCAR – amazingly, the experts there in 2010, had not noticed the 2000/2001 shift, but Takmen Wong at NASA has an article in one NASA newsletter (in 2008 about) stating the conundrum – either the cloud changes were natural and created most of the warming, or they were in response to warming (by CO2) – hence a feedback. I argued that if feedback, why did cloud cover which reduced by 4% from 1983-2000 (according to ISCCP) recover by 2% and stay level since 2001? All of this argument and the references can be found in my 2009 book, ‘Chill: a reassessment of global warming theory’.

        Mike – this is nice work with the time lags. My sense is that temperatures follow both changes in reflective low cloud and clearing of the atmosphere of aerosol – which occur in natural oscillations.

      • ). I took this up with NCAR – amazingly, the experts there in 2010, had not noticed the 2000/2001 shift, but Takmen Wong at NASA has an article in one NASA newsletter (in 2008 about) stating the conundrum – either the cloud changes were natural and created most of the warming, or they were in response to warming (by CO2) – hence a feedback. I argued that if feedback, why did cloud cover which reduced by 4% from 1983-2000 (according to ISCCP) recover by 2% and stay level since 2001?

        This is great to know, it’s all visible in the the CS I calculate from surface data, and when you look at min and max instead of average temp. Minimum temps follow dew point, and clear sky night time cooling is regulated to dew point, but I was looking for the cause of the shift I detected in the data, both before the 97 el nino, and at it’s end. Follow my name, all 3 show what you just describe in the data.

    • Yes, NEGATIVE FEEDBACK. System stability is impossible with positive feedback. To model it otherwise requires ignorance of reality and belief of young earth creationism.

      • We may be talking about different fields here.
        In electronics, a positive feedback means the output increases.
        Negative feedback means the output decreases. Any amplification is a positive feedback.

      • In electronics, a positive feedback means the output increases.
        Negative feedback means the output decreases. Any amplification is a positive feedback.

        This isn’t right, you have gain, and you have feedback in electronics, and they are different.

      • A nit, MarkW: positive feedback causes amplification (in any system, not just electronics). But the converse is not always true: amplification does not necessarily involve positive feedback. There are other sorts of amplification.

      • Keith, I agree that IPCC models incorporate far too strong positive feedback, and therefore do not reflect reality. So, the IPCC modelers are an example of some who model positive feedback in the earth’s climate. However, IPCC modelers would seem to be a group very unlikely to believe in young earth creationism. Can you show that they do?

        What is your basis for linking positive feedback with belief in young earth creationism? As no young earth creationist has come out in support of the positive feedbacks in those IPCC models (belief in runaway global warming would be contradictory), it appears you are grasping at straws for an excuse to bring denigration of young earth creationism into this thread.


  1. Do the IPCC models take into account that evaporation is endothermic (cooling), and that cooling should be equivalent of the energy (heat) that went into the evaporation. Therefore there is no feedback loop. It’s self regulating.

      • “Here we are talking negative feedback : A suppressing B suppressing A ;”

        This is not negative feedback.

        Negative feedback is A stimulating B which then inhibits A. [A promoting B suppressing A]

      • Re Higley.
        You are right: Suppressing A (atmospheric CO2) which suppresses B (T of the ocean) which suppresses A (atmospheric CO2) is actually a positive feedback. The word “suppress” makes it confusing but can be substituted by the word “increase” without changing the positive feedback consequence.

        Similarly (as you pointed out) with negative feedback;

        Stimulating A (T of the ocean by whatever process) which stimulates B (clouds) which inhibits A (T of ocean). Substitute “stimulate” for “inhibit” and vice versa still makes it a negative feedback. For example:

        Inhibiting A (lowering T of ocean) which will inhibit B (cloud formation by less evaporation) which will stimulate A (T of ocean) is likewise a negative feedback because it suppresses the effect of the lowering of T.

  2. Thank you for this interesting analysis. Is any major science institution sponsoring work in this area? Or is it all left to those outside institutions that care about understanding to bigger picture?

  3. I can show you where it happened, 20-30,35 North Lat, something changed at the end of the El Nino and the effective sensitivity to incoming when up and stayed up. I think it was related to a warm northern hemisphere pacific , but less clouds would show up the same.
    I’ve looked at some satellite water vapor movies of the time, looks like more water vapor though. But it should be investigated more.


    • To my thinking, this points to the overall understanding of el Nino phenomena. How it arises and how the Pacific equatorial warming persists until el Nino “breaks out”. This seems to be related to an increase in global temperatures. Those of us who don’t believe this is related to CO2 ( at least myself), see el Nino heat transformed into water vapour and sent North by natural convection to be radiated away from Earth in the Polar night. While the Antarctic seems to be more persistent and stable in this function, the Arctic appears to have some variability. With the equatorial heat hanging around on Earth as it transits North, the result is what appears as ‘Global Warming’. We know that the Arctic and Antarctic are separate and different. For some reason the Arctic processes this heat transition differently. Water instead of land, ice cover, seasonal differences, etc. But no reason to expect CO2 differences!

      • Chilly, that looked like a gradual change. What’s recorded by surface stations happen about the same time the el nino happened, in fact it looks just like it just continued.

      • could the gradual increase hit a point where the effect actually takes place ? just like the sea surface warming during el nino until the point the heat begins radiating to space ?

    • aveollila : When I downloaded the data – very recently – that’s all there was. I didn’t see any reason for it ending in 2009.

  4. I don’t like the title.
    It refers to “the pause” as something to be explained and implicitly the precedent warming as the “normal” thing.
    It pinpoint cloud cover as it is now as an anomaly, a thing that “changed”.

    I would have rather a title like (for instance)
    A Cloudy Question: did global cloud cover controlled ‘the warming’ and ‘the pause’ ?

    Remember that “it’s the clouds, stupid” is a serious thesis, only hindered by lack of data before satellite era (and, of course, to much focus on “it’s GHG” ) .

    There is an obvious negative feedback loop : (Warmer ->more water in atmosphere -> more clouds -> stronger albedo -> less energy in -> cooler). But in the loop, are clouds the feedback and the temperature the control knob being modulated … or the reverse ? The focus on temperature fools us : albedo, that is cloud cover, and rain, that is cloud cover again, are much more important to climate than temperature.

    Anyway we know for sure that climate things are complex. Trying to pinpoint a single factor, even a (the ?) major one like cloud clover, is a recipe for failure.
    Bottom line :
    Clouds, yes, sure, of course. Among other things …

    • paqyfelyc said: ‘Remember that “it’s the clouds, stupid” is a serious thesis, only hindered by lack of data before satellite era’

      Cloud Cover tends to suppress daytime high temperatures and tends to increase nightime low temperatures. So could we simply use the difference between daytime highs and nighttime lows as a proxy for cloud cover?

      Daytime High and nighttime low temperatures have been readily available for hundreds of years.

      The raw difference data might be noisy, but with some data smoothing, could this not become a useful proxy?

      • Met stations have been recording cloud cover for most of the aviation era so there is reasonable cloud data preceding the satellite era.

        I agree. We can’t ignore time of day. Clouds during the day and clouds at night have the opposite effect on surface temperature. link

      • Daytime High and nighttime low temperatures have been readily available for hundreds of years.
        The raw difference data might be noisy, but with some data smoothing, could this not become a useful proxy?

        Been doing this for 8 years. Plenty of data to look at. End result is min is not doing what a exponentially increasing ghg forcing would cause.
        You can follow my name, in the “…not co2…” page there’s a link to sourceforge, in the reports directory tons of data.

    • The other obvious negative feedback is that more water -> more clouds -> more precipitation, which in thunderstorms means formation of ice crystals near the tropopause, releasing the heat of fusion and vaporization (334 + 2260 = 2594 J/g) at high altitude, bypassing a lot of “greenhouse” effect absorbing and re-radiating at lower altitudes.

    • “The raw difference data might be noisy, but with some data smoothing, could this not become a useful proxy.” I guess not many of you ride a motorcycle at night. “some data smoothing”? I would say a lot of data smoothing along with wide error band span would be needed.

    • My only problem with the title is that it uses the past tense to describe the pause. With recent declines in temps, post last year’s El Nino, we may soon find ourselves with a rejuvenated “pause”, Then the warming crowd will have some ‘splainin’ to do. Or some “denying”.

  5. Svensmark and Kirkby have been suggesting that cosmic rays have something to do with cloudiness. If so, then the argument would be that cosmic rays act to desupersaturate the atmosphere but the droplets produced are too small to nucleate raindrops or are otherwise stabilized against coalescence, hence they form persistent clouds. So increasing solar activity would cause more effective cosmic ray shielding and allow the atmosphere to carry more supersaturation and remain clear. I’m not sure whether the water column data entirely supports this. Other things such as solar wind could be important. Strong solar wind injects more charged particles into the D layer, from which Tinsley says electrons precipitate into the troposphere which also could affect cloud droplets, the question is, how?

  6. ENSO teleconnections between oceanic and atmospheric systems produce all kinds of macro and micro oscillations in cloud cover outside of the major milanchovitch cycle extremes affecting axial tilt towards/away from the Sun’s solar incidence.

    • +1! Nicely stated!

      Hope you are doing okay — miss your former commenting frequency. Don’t be a stranger! And — keep warm out there.

  7. Essay Cloudy Clouds in ebook Blowing Smoke covers AR4 and AR5 concerning clouds and cloud feedback, citing specific numbered sections of both WG1. You cannot simply analyze clear/cloudy. The type of cloud, its altitude, its optical depth, and its entrained precipitation all matter. So a simple cloud analysis unfortunately isn’t viable.

    • The short answer is that we don’t know how much changes in cloud cover have affected climate change, and the uncertainty that this creates is as big as changes in GHGs.

      But another way to tackle the issue is changes in planetary albedo. Last time I checked MODIS/CERES data did not show any trend in albedo changes.

    • ristvan – One of the reasons that I limited the study to ocean-only was that it avoided just about all the issues you raise. The point is that everything to do with IR / cloud altitude / etc is virtually irrelevant over the oceans, because by far the largest factor is the visible light + UV that reaches the ocean.
      This seems to have been missed by a lot of people, because of the obsession with upward IR and atmospheric temperature. Clouds over the ocean affect ocean temperature directly, without the atmosphere having to be affected first, and without the involvement of any IR.

  8. I know it’s only localised, but seaside towns in the UK usually keep sunshine hour records. (so as to claim they are a better holiday destination than that rubbish place just up the coast!) They will probably go back to Victorian times. Has anyone looked at them?

  9. Given that the cloud cover has more or less tracked the solar magnetic activity on a fairly smoothed basis, I would have expected it to start to increase as the average magnetic activity started to roll over. Of course, there is the problem with the recent synchronization of the AMO cycle with the solar activity, so it might or might not be Svensmark cosmic rays and so forth. The 1300s were intriguing when the exit from the Medieval Warming period was coupled with reports of extensive cloud cover and storms. Anyway, winter is coming, if for no other reason, the AMO will not pump warm water up to the north pole.

  10. https://www.google.ca/url?sa=t&source=web&rct=j&url=/amp/s/tallbloke.wordpress.com/2012/02/13/doug-proctor-climate-change-is-caused-by-clouds-and-sunshine/amp/&ved=0ahUKEwiZmdXUv7rRAhVYwWMKHe25Bn8QFggcMAA&usg=AFQjCNFmqPLMh-ZgGgeWkfqAD6HFZI1f3Q

    I worked on this problem several years ago. I used “bright sunshine” hour variations over time and found a cyclical change in the UK data that, in association with PDO/AMO releases and absorption of oceanic heat, covered off most of the warming.

    I postulated a new time of increased cloudiness in the UK and dropping temperatures. I didn’t understand the El Nino coming through, so my predictions were off.
    The subject has been curiously under studied or the data was inadequate for a global analysis. I suggest that local data is adequate as we all know how immediate daytime surface temperatures respond to changes in cloud cover.
    Australia would be a great area of study as storms sweep across large areas and cause large scale changes in cloud cover.

  11. volcanic aerosols being purged from the stratosphere taking out man made pollution and condensation nuclei.

    El Chichon and Mt P both resulted in a net drop is TLS a few years after the eruption. This implies clearer, less opaque stratosphere and more energy making it into the lower climate system.


    analysis shows a net increase in energy entering climate system starting a couple of months after Mt. P. using ERBE data .

  12. More water vapor in the atmosphere doesn’t necessarily mean more clouds – clouds get more productive at producing rain and transporting heat. Since water vapor increases the efficiency of (cloudy) updrafts at transporting heat but does not affect the efficiency of (clear) downdrafts at transporting heat, the atmosphere would get less cloudy as a result of warming. But I think to a smaller extent than IPCC expects.

    A correlary is that clearing caused by warming would decrease the global tropospheric relative humidity. That would make the water vapor positive feedback less than what it would be if global tropospheric relative humidity remained constant.

    Meanwhile, I think a lot of the clearing that happened was not caused by feedback, but by a shift of one of the multidecadal oscillations.

  13. Our vast deep Oceans are the terrestrial factor that control earth’s climate. The AMO is a historically-known, 60-65 yr cycle, for which the drivers are unclear (AMOC?). The ISCCP ClearSky data is a recent innovation.
    The working hypothesis should be from what is known to what is a new observation. That is the AMO is the horse, the Cloud-ClearSky data the cart. Of course the cart can affect how fast the horse can go (damping).
    Hypothesis: AMO is controlling the major features of the Clear Sky data set. Smaller time scale features (ENSO, for ex) also show up.

    • plankton emit cloud condensation nuclei http://www.jameslovelock.org/page35.html
      plankton levels and species mix along with timing of blooms vary in the oceans in line with the warming and cooling cycles . the north atlantic oscillation is the driver of upwelling nutrients from beyond the continental shelf required for plankton growth.
      when in the positive phase plankton levels drop in the north east atlantic and vice versa for the negative phase. the last decade has been dominated by the negative phase of the nao.

      certain species of plankton can vary by orders of magnitude from the cool period to the warm period in north east atlantic waters. calanus finmarchicus in the north sea is one good example ,though it would appear those studying these things cite agw for the change (warming waters caused by agw, not warm phase of amo )from the limited amount of reading i have done on the subject.

      i agree on the possibility of the amoc bring the driver of the amo , possibly through its effect on arctic extent ?

      • the word “ice” should have appeared prior to extent in the above. apologies to joel for what looks to be a bit of a disjointed reply. one downside of being a thick brexiter ;)

      • That’s all right, chilly… We’re all a bunch of trumpsters, so we can easily relate to that. (☺)

    • joelobryan – The AMO and PDO do appear to drive temperature, but I couldn’t find any obvious sign that they drove clouds. I’m happy for someone else to find the link.
      BTW, ClearSky isn’t an ISCCP thing, I simply created it as an easy way to invert Cloud in the graphs. ‘ClearSky’ is simply the opposite of ‘Cloud’.

  14. if the sun heats up as it did the earth heats up as it did .. and more cloud is made as it has ..
    isn’t this what the earth has done for quiet a while now ? then the cycle starts again or the sun go’s very cold we all die and we have another glacial period ?

  15. High, whispy cirrus clouds are said to have a warming effect, because they are made of ice crystals, which makes them much more nearly opaque to outgoing longwave infrared than to incoming visible and near-IR solar radiation.

    Lower clouds, which are made of liquid water droplets, have a strong cooling effect in daytime, but a warming effect at night.

    This is an interesting article, but I think to tease out the relationships between cloudiness and temperature we need a lot more information that simply the global ClearSky anomaly.

    • “High, whispy cirrus clouds are said to have a warming effect, because they are High, whispy cirrus clouds are said to have a warming effect, because they are made of ice crystals, which makes them much more nearly opaque to outgoing longwave infrared than to incoming visible and near-IR solar radiation..” Are you saying Ice crystals do not reflect incoming short wave infrared which in turn warms the earth and produces longwave infrared radiation?

  16. Oil and surfactant pollution of the ocean surface reduces aerosol production both mechanical and biological. Fewer aerosols near the surface will reduce stratocumulus cover and thus lead to surface warming. It may be that we have now reached a situation where the surface pollution is so bad that the effect has saturated.Or biological systems have learned how to digest synthetic surfactants. Or both. If you search on Judith Curry’s website I did a post some years ago going on about this in details.

    Be wary of conflating high,medium and low level cloud cover.

    Google ‘nasa seawifs pollution’ to see how much light oil washes into the oceans.

    Look at how much light oil leaks from from extraction and runs into the Arctic.Then wonder why the Arctic warming is anomalously high.

    Remember Wigley and the frantic efforts to smooth away the’40s blip. Why the blip? A response to wartime sinking of oil carrying ships.

    I have seen a smooth hundreds of miles long by a hundred wide in the Atlantic between Portugal and Madeira. Where did the pollution come from? Dunno. Do smokers leak light oil?

    Examine NASA pics of the Gulf during the blowout — I see low level clouds fading as they are starved of aerosols.

    Etc etc.

    That should keep you busy!

    • This has crossed my mind numerous times but I have never before seen anyone bring it up, also what affect does the surface pollution have on evaporation thus on ocean cooling?

      Thanks Julian

      • Fish farmers in Israel experimented with oil on ponds to speed up warming, so I think it works for that — at least I can’t imagine that reduced albedo and fewer aerosols have much effect with a polluted pond.

        See http://www.youtube.com/watch?v=f2H418M3V6M for a demo.

        I had an exchange of posts with egb@duke re surface pollution and he said he couldn’t see it and his office looked out over the bay in …maybe North Carolina. I looked for a few images and you can see the telltale signs all over the place. A couple of teaspoons will smooth _acres_. People just don’t look, or, to quote Holmes, they look but they don’t see.

        Google Benjamin Franklin Clapham pond. Google Kipling Knights of the Joyous Adventure. The effect has been known for centuries.

        What we need is Willis to get interested and do a bit of number crunching. I always get lost in the zeroes, but I reckon the entire ocean surface is covered with light oil several times a year. It must be doing something. Arctic pollution would be comparatively long lasting and the Siberian Russian oil coming down the rivers is ideally placed to disrupt the retention of old ice.


        Oh, yes, someone could ask your new president to fund research into non-CO2 factors which contribute to warming, it’s an unacceptable failing in the IPCC that it has done no research into that.

      • we do also have natural light oil smoothing of the ocean surface. ever seen a shoal of tuna busting bait fish and the result ? cod and coalfish can create the same effect when feeding on species like herring and capelin.

      • That video is fascinating! Thank you for the link, Julian.

        rgb@duke is Prof. of physics Robert G. Brown, at Duke U., in Durham, NC. That’s about 35 km down the road from me, but about 230 km from the ocean. Oddly enough, though we’ve corresponded, I’ve yet to meet him in person.

        Congrats on your electoral victory, BTW!

    • There is a ’40s blip, with a drop afterwards. Part of the drop was caused by a shift in ship traffic between British and American, military and civilian. I don’t remember the exact details at this moment, but this affected the percentage of sea temperature readings being from engine room intakes and the percentage being from buckets. The ’40s blip is less in HadSST3 and greater in ERSSTv4. HadSST3 seems to me slightly cooked to report more warming than actually occurred, but it also seems to me as the best SST dataset there is for climate change matters. ERSSTv4 seems designed and highly cooked to show more and steadier warming since 1950 than actually occurred, without care about exaggerating the ’40s blip. One thing I see in ERSSTv4 is its intercalibration method being chosen to show around 1950 being cooler than it actually was, as well as around 1998-1999 being cooler than it actually was and recent times being warmer than they actually were.

      • Mosh, me do science? Naah, we both know it’s much more fun abandoning sceptical science and just doing clever flyby comments on WUWT.

        To do science you need training. To be a _good_ scientist you need to generate new ideas, use your training to test those ideas and then be sceptical about the results you have generated. Two out of three is not enough. (In my case one out of three, but that’s SF writers (failed) for you. We just do ideas.*) To be an _effective_ scientist you need those three and funding as well, unless you’re just sitting at a computer and playing with the models — I hear that’s pretty cheap, pays well, lets one mix with the big boys and makes one feel important.

        How would you test the science behind the idea that polluted ocean surfaces warm faster? You need planes,you need ships, you need the ability to examine the surface for minute thicknesses of pollutants. You need detailed cloud cover reports for the entire ocean surface. You need a clean patch of ocean and a lot of pollutant to chuck overboard and see what happens.** You need a team to look for correlation of oil outflows with reduced cloud cover.You need the resources of a whole world to prove that there are no contributors to warming other than CO2. It’s worth it. If CO2 is only one of the drivers and you find there is no emergency then you can save trillions.

        Grant me 10 million and I’ll get back to you. Hmmm, maybe 100 million. I’d like a new Jaguar XE.

        Janice, search for ‘Wigley, why the blip’ and look at the jiggery pokery that went on to hide it. The Climategate emails go into some detail about the bad practice that was needed. Climate Audit was good on this. Also, I’m sure I’ve seen SST graphs which before the bucket correction make the timing more plausible. But I bow to your expertise. Use SST graphs BTW, not US land.

        Not being a scientist I just think of reasons for warming — there are lots of possible scenarios — I wave my hands and speculate. When was the biosphere first subjected to e.g. synthetic surfactants? To new synthetic chemical pollution? When did large-scale ship sinkings begin? When did the big dissolved silica run-off from large-scale agriculture begin? etc.When/did/has ocean pollution damage/d the DMS production potential of phytoplankton? Why has the outflow of the Rhine warmed faster than the rest of the North Sea? Does fixing as much artificial nitrogen compounds as all of Nature do anything strange to the biosphere? Is it all just natural variation? Has the ratio of diatoms to calcareous phytoplankton changed, reducing the CO2 pull down and altering C12/C13 ratios?

        I don’t know. Does anyone know?

        CO2 will warm the atmosphere but we don’t know enough about feedbacks. Other things may also warm the atmosphere but no-one is looking at them. This is foolish.

        These are just questions, but they are questions that need to be asked and addressed. Judith Curry, to her credit, tried to get the aerosols over the Gulf oil spill monitored. She really is a scientist, she tried to answer a question.

        Enough! Bedtime!

        Roger, yes, rgb.

        *I recommend Ground Zero and other Stories.
        **Google the Braer shipwreck and see if you can find a video of what the oil pollution did to clouds. I saw that live and for miles downwind the clouds disappeared.

      • Steven
        “you been talking about that for as long as I can remember. You should actually do some science.

        Maybe if some of the ump-teen-million scientist that get paid by the governments of the world to prove that CO2 is the most important molecule in the universe, for political purposes, would shift their time and efforts to investigating other possibilities we might have answers to these questions. How about you! That way the people that are paying the bills won’t have to do all the thinking too.

  17. This analysis looks at ocean anomalies in temperature and cloud cover (or ClearSky) only. I’ll suggest another complication with a negative feedback on temperature but with a lag on the order of decades or more driven by an increase in CO2. In other words, over land the throttle for this feedback is CO2 with a negative feedback on temperature lagging by several decades or longer.

    Increasing CO2 is greening the planet, reducing deserts, with net increases in the carbon debris (peat) and plant life. This carbon debris and plant life (trees, top soil, tree roots, etc.) acts as a water reservoir (taking decades or more to build up) and reducing the runoff into the oceans. These new water reservoirs are available to generate clouds which would not have been generated without the new reservoirs. Hence, increasing cloud cover, and increasing reflectivity over land with a net negative feedback on temperature.

  18. Cause or effect? I would say it is a manifestation of the interconnectedness of things in a massive feedback system.

    The “pause” is the turning point of a medium term cycle of about ~60 years. It can be seen in sharp relief here:

    Once the latest El Nino works itself out, I expect temperatures to revert to the pattern. Which means we have a ways to go before it bottoms itself out.

    • More info: Each of those segments is the same size and same +/- slope. I made the first one in Powerpoint, then copied and flipped them as needed.

  19. Re: A Cloudy Question: was ‘the pause’ caused by a change in global cloud cover?

    For a moment or two, think about a global model for climate, which, after all, is defined as a global phenomenon. Global warming is a thermodynamic problem, which, like all thermodynamic problems, involves macrophenomena. Meso- or microphenomena, like cloudless patches, tropical peculiarities, ENSO, or tropospheric lapse rates, are distractions. They consist of temperature distributions that ride on top of the global averages, that is, climate.

    Think of the Kiehl-Trenberth budget that IPCC animated to create their Radiative Forcing model as IPCC thought of it, as a picture of global climate. AR4, Figure FAQ 1.1. There is one global cloud cover percentage involved. The surface, the atmosphere, and the top of the atmosphere are single nodes representing in all respects some sort of (weighted) averages for the entire Earth. The surface is ocean because landmasses and their local atmospheres have minimal heat capacities (climatologists call heat capacity inertia) to contribute to the whole.

    In this schema, cloud albedo is the most powerful feedback in all of climate. That comes from gating the Sun on and off, switching the overwhelmingly dominant source of Earth’s thermal energy. Cloud albedo is proportional to cloud cover, which responds to both the Sun and to humidity. (It does not respond to any significant degree to CCNs because CCNs are in surplus in the atmosphere, and because the ocean creates them. This explains why GCRs have no significant effect. If the atmosphere had a surplus of humidity, it would act as a cloud chamber to GCRs. It doesn’t.)

    Clouds form overnight due to atmospheric cooling and then burnoff in the morning heated by the Sun. Thus burnoff amplifies variations in the Sun, amplifies TSI, and is a positive feedback to the Sun. Cloud cover also increases as surface temperature increases, thereby increasing albedo, and creating a (powerful) negative feedback to warming from any imaginable cause.

    IPCC parameterizes cloud cover as constant — regional perhaps, but globally constant. That kills the dominant feedback in climate. At the same time, however, IPCC increases humidity according to the Clausius-Clapeyron equation. IPCC may also vary cloud albedo but by varying the reflectivity per square meter of clouds, and not by varying cloud cover, the square meters. For this global model, just keep the reflectivity constant. It is trivialized by cloud switching of the Sun.

    IPCC creates a positive cloud feedback to surface warming by increasing water vapor according to the C-C relation. This tends to make its RF model work by amplifying the CO2 response, which turns out to be too weak to cause a scary enough Greenhouse Effect. So again, IPCC creates not only a positive cloud feedback, but an increasing one, all in the effort to make its CO2 story work. IPCC zeroes cloud cover changes and the really big twin feedbacks of climate.

    Cloud cover lags both the Sun and surface warming a bit. But surface warming or cooling lags the cloud cover-amplified solar radiation to the surface by a couple of long time constants, roughly one and a half and a half century. See SGW, rocketscientistsjournal.com.

    Science doesn’t require models to have any fidelity to real world phenomena. It does require models to work, i.e., to have predictive power factually validated. But once a model fails the test, it is open to criticism for unreal physics.

    • Most interesting, Jeff

      Are you, in summary, agreeing with my strongly held view (though I can substantiate it but poorly myself) that the hydrological cycle involving evaporation from the ocean, and atmospheric humidity/clouds acts as a thermostat for the global system? Without it, it is very difficult to explain the observed short/medium term stability of the climate. Willis E has posted some stuff on mechanisms, and so have others. Should we not be looking for model physics in which a water thermostat is a basic assumption, and see what falls out? THEN see what sort of CO2 ECS numbers we get?

      • IPCC increases humidity according to the Clausius-Clapeyron equation.” mean they consider the entire atmosphere to be always saturated with water vapor?

        I don’t think so, but worse, saturated would be noticeable.
        They have a “mass conservation”, that they use to enforce this relationship. The equation that is a parameterization of water evaporation didn’t generate enough water vapor feedback
        here http://www.cesm.ucar.edu/models/atm-cam/docs/description/node13.html#SECTION00736000000000000000
        It is why models are warm, it was this “fix” that warmed them up in the 80’s, that they have been using aerosols to tune down, until we got better aerosol data.

    • Jeff G – You hit the nail on the head: “IPCC parameterizes cloud cover as constant — regional perhaps, but globally constant. That kills the dominant feedback in climate.“. I think that the data I have presented here shows a strong possibility that global cloud cover can change independently, and significantly, and thus that the IPCC have got it wrong. A longer data period would really help, but we can only work with whatever data is available.

  20. Taken at face value, clouds are a short term feedback to temperature changes and a long term forcing of temperature. This is similar to Spencer Braswell 2011 in which they were criticised heavily by Dessler and the green mob. Makes more sense than LWIR heating of the ocean due to CO2. Bob Tisdale, isn’t this part of your suggestion that ENSO is driving climate?

  21. Cloud forcing has been calculated at least in two papers and it is 0.11 C/cloudiness-%. It means that 1 % cloudiness change causes 0.11 C degrees change in global temperature. It is fairly easy to calculate from three measurable operating points of the Earth (cloudiness / albedo): = (0% , 53/342), (66 %, 104.2/342), (100%, 120/342). It means that the overall temperature increase of 0.85 C degrees since 1880 could be explained by the cloudiness decrease of 8 %. Of course there are other factors included.

  22. About the time of the “sea change” in clear sky is about the time China began massive increases in coal power production. I would be interested to see the relationship between China’s coal power production and cosmic ray counts in addition to temperature with regard to clear sky.

  23. @Mike Jonas
    “If any WUWT readers can supply the answers, I would be most grateful”

    I suggest you contact Willis Eschenbach; he has posted several interesting articles ( to the best of my poor memory ) about the subject(s) of you post.

  24. This question of clouds reminds me of Global Dimming, and Global Brightening. Of course both ideas demanded lots of grant money to investigate.

  25. we’ve been debating the cloud issue for years. I hold the (apparently minority) opinion that cloud cover can change without being caused by a temperature change, that is, clouds can act as a sort of forcing of climate change. I call this “internal radiative forcing” (as opposed to extrenal radiative forcing, e.g. from CO2), and we’ve published on it and I’ve blogged on it for years. Andy Dessler, in contrast, claims that all cloud changes are the result of feedback in response to a temperature change. So, in answer to the original question posed, it is indeed possible the pause was caused by a change in cloud cover.

    • Roy: As an outsider, it seems perfectly logical that changes in cloud cover can cause temperature change. However, I think it is self-defeating to say that clouds can “force” climate change. Forcing is caused by things that influence the radiative balance at the top of the atmosphere by a mechanism that is independent of surface temperature. Clouds clearly respond to surface temperature and therefore are feedbacks. We have naturally-forced variability and anthropogenically-forced variability. However, anthropogenically-forced variability is so slow that unforced variability (ENSO, probably AMO and PDO) is a bigger player in the decadal changes that alarmists calling “climate change”. So why not call it “unforced variability in cloud feedback” or “internal variability in cloud feedback”. Certainly chaotic changes in ocean currents and upwelling cause change in the cloud above that can persist for a long time – almost certainly for decades – even though the clouds themselves only last for a few days.

      If we properly define climate change as the difference between two periods of 30 years or longer, we don’t have the data needed to determine what role “unforced changes in cloud feedback” have played in climate change.

      • MikeN: Variability in our climate like ENSO (presumably and AMO and PDO) are not normally referred to as “forced change”. It is the result of deterministic chaos. Clouds can change for similar reasons.

        Given that the average water molecule spends about 9 days in the atmosphere between evaporation and precipitation and that clouds (suspended water droplets) last for a shorter period of time, it is awkward to say that clouds “force” much of anything. This language tends to produce a closed minded attitude, so I’m trying to express this concept in other terms. The best I can come up with is to suggest that a chaotic change in the ocean can drive a PERSISTENT change in cloud cover, either local or distant. (At the moment, changes in clouds over the Western US seems to be driven by events around Hawaii.) So I’m suggesting we more clearly link cloud “forcing” to unforced variability in the oceans. Above I suggested “unforced variability in cloud feedback”, but that is WRONG, because feedbacks are only important average a forced change. Unforced variability in albedo?

    • I hold the (apparently minority) opinion that cloud cover can change without being caused by a temperature change, that is, clouds can act as a sort of forcing of climate change.

      I agree Roy (like that really matters, but). The blob, was a high pressure zone(tend to clear skies), with iirc winds going around it, so it becomes self-reinforcing. Like a thumbprint that doesn’t go away (whatever caused it in the first place).

    • “…cloud cover can change without being caused by a temperature change”

      O.K., Dr. S., but what exactly is causing the change in cloud cover then? (what specifically happened there at the turn of the millenium?)…

      • what specifically happened there at the turn of the millenium?)

        I think the oceans shifted warm water north of the equator at the end of the el nino, since min temps follow dew points, more water vapor blew across more thermometers than about anywhere else on the planet, the band of 20-30,35 North Latitude.

      • He is not pegging 2000 as the change point, but an earlier time. That the global warming seen since the 1970s was caused by changes in cloudiness, and this forcing is being misdiagnosed as a positive feedback of CO2-caused global warming, thus making the amount of CO2-caused global warming even higher.

    • Roy – I think that the data I have presented supports your opinion that cloud cover can change without being caused by a temperature change, that is, clouds can act as a sort of forcing of climate change. The fact that cloud decrease appears to precede temperature increase by a few years in large regions (with no clear relationship elsewhere) suggests very strongly to me that clouds in their own right are driving temperature. I tried to say that in the article, but very cautiously as I didn’t want to jump to unjustifiable conclusions. If only we knew what caused the cloud changes …….

  26. Mike: Interesting article. I agree with some commenters above that changes in cloud cover are not a direct measure of changes in SWR absorbed. So the next step might be to look at CERES data for incoming and reflected SWR. Then you can see what effect clouds have on SWR absorbed and what effect absorbed SWR has on temperature.

    The following might provide a reality check. Given the heat capacity of a 50 m mixed layer of the ocean and the atmosphere, a +1 W/m2 radiative imbalance is capable of warming at an initial rate of 0.2 K/yr – if all of the heat remained in the mixed layer. The current 30% albedo (some at the surface) reflects 100 W/m2 back to space, so a 1% change is roughly 1 W/m2 or a drop of 0.3% in albedo. In practice warming will be less than this. First, as the planet warms it will radiate more heat to space, counterbalancing the increase in absorbed SWR. A black body (the Earth without feedbacks) at 255 K radiates 3.8 W/m2 more for every degK rise or 3.8 W/m2/K. If you think feedback is positive and climate sensitivity is 2, 3 or 4 K (take your pick), this becomes 1.9, 1.27 or 0.95 W/m2/K. Also as the mixed layer warms, some of that heat disappears into the deeper ocean.

    Paul_K did an excellent analysis of both phenomena during Pinatubo. He finds that about 2.7 W/m2/K left the surface/atmosphere/mixed layer for space (TCR 1.4) and 2.8 W/m2/K left for the deeper ocean and the effective depth of the mixed layer was about 35 m. So if an instantaneous reduction in cloud cover produces a radiative imbalance of 1 W/m2, warming at a rate of 0.3 K/yr would begin, but by the time warming had reached 0.1 K (4 months), heat loss to space and the deep ocean will be consuming about 0.55 W/m2 and the rate of warming will have been cut in half. Of course, if climate sensitivity is higher or other factors are different, a radiative imbalance can produce more warming.


  27. I have long been of the opinion that the retreat of alpine glaciers is better explained by a decrease in daytime cloudiness than by global-average temperature increases of a fraction of a degree over decades, most of which occurs at night and in the Winter. In Glacier National Park (USA), it appears that the glaciers with a south-facing aspect have retreated rapidly, while those in the shade on the north slopes have been more stable. I personally observed a significant retreat of the Fox Glacier (NZ) in the 1980s, when global temperature increases were low. I think that focusing on CO2 has blinded climate scientists to many other things that are occurring simultaneously.

    • so true.
      and focusing on “global warming” has blinded media and politicians to many other, far more important, things that are occurring, too.
      Focus on a microscopic aspect of a minute non-problem. Storm in a teacup.

  28. “I’ve looked at clouds from both sides now.” Daytime clouds reduce temps, night time clouds reduce heat loss. More daytime clouds=cooling, more night time clouds=warmer. Anyone got a chart showing clouds by day vs night over the years in question? Also, as pointed out above, latitude of same would be a factor. Relate these to global temperature might be enlightening, though a little complex given seasonality of where the sun shines and where it does not at higher latitudes north and south.

  29. Because CO2 forcing cannot explain the temperature decrease during the Little Ice Age and on the other hand IPCC’s CO2 forcing gives now 44 % too high values, the conclusion is that there are other forces in this game. Those forces are: solar radiation changes and harmonic cosmic resonance forces. Both these forces work in the final phase through cloudiness changes. Cloudiness changes affect the albedo and the Earth is very sensitive for the albedo changes.

    These cosmic forces are the reasons for the natural temperature variations as expressed by IPCC. This time I agree completely with IPCC. They are natural forces which have a big role in the global warming.

  30. I think my climate nursery rhyme sums it up, only time will tell.

    Mother Goose on Climate Prediction

    As record winds blow
    Unprecedented snow,
    Oh, where is our globe a’ warming?
    That depends on the sun
    And the ways oceans run,
    Plus clouds (with complexity) forming!

    Now, and for quite long,
    Climate models are wrong.
    So, what caused the pause in the warming?
    Yes, look to the sun,
    The ways oceans run,
    And the clouds, in complexity forming.

    CO2 is “too small”
    To stop temperature’s fall
    When the sun, clouds and oceans together,
    Begin to cause cold
    in a cycle so old…
    That no one alive can remember!

    So if I do some harm
    By just keeping warm,
    You’ll have to kindly forgive me!

    I find my solution
    Is carbon pollution…
    Ere Gaia would quickly outlive me!

    • The anthropogenic contributions to particulates and aerosols are small in comparison to natural sources. What more likely contributes to cloud nucleation is the cosmic ray flux. The heliospheric density and global temps tend to correlate.

  31. After years of mindless repetitions of ‘hottest ever’ years, it is refreshing to read an article about clouds which have remained the elephant in the room of Climatology. Mostly clouds are ignored although their effect can be massive. Modelling of clouds seems non-existant. Climate stations have been recording cloud cover for years so there should be no lack of data to work with. Clouds during the day hinder heating and clouds at night have the opposite effect on surface temperature. What is missing is a detailed understanding. CO2 can take a back seat.

  32. I think we should get Willis to run the CERES and ERBE cloud cover data again.

    I hate to say this, but GISS under James Hansen managed the ISCCP cloud project and nobody really believes the numbers that came out of it – even the climate scientists who believe anything that helps the cause of more grant funding.

    • Bill Illis,
      There is an alternative. For decades, the USGS evaluated Landsat satellite imagery by estimating the cloud cover as an aid to users. That is, giving the users some assurance as to how much if any of the image was cloud free. All that data exists in archives and could be analyzed to see if it agrees with what NASA has published.

  33. It’s the Sun. As solar activity decreases, it affords us less protection from the bombardment of cosmic rays from space. Cosmic rays act to seed clouds, which has already been established in the CERN cloud chamber. So with heavier cosmic ray bombardment we get more cloud cover. If the Sun does go into a minimum in the next few decades, as predicted by several solar scientists, the Earth will cool considerably. At least it will once and ever quash the idea that climate is regulated by CO2.

    • Except for the fact that when the shift happened (circa 2000) we were not only headed toward a solar maximum, but SC23 was still a fairly strong cycle…

  34. Why did cloud cover measurements stop in 2009? isn’t it an essential part of climate science?
    We are missing 17 years of data

    • I already made the same question. Why there is no global cloud data available? Bill Illis wrote that we should look at CERES and ERBE cloud data. Could you please show what are the links to these data sets?

  35. RE Aerosols. I thought it was Bit Chilly who wrote that aerosol levels are saturated, but I can’t find the post so it could have been anyone, my apologies.

    I’m not sure that is the case. If you Google ‘nasa ship tracks biscay’ you will see images of what happens when you add aerosols to an already well aerosoled* boundary layer The tracks which look like contrails have much higher albedo even when they are in areas which are already cloudy. This effect was the basis of Latham’s cloud ship proposal, which also comes up on that page.

    Bit Chilly is sound on plankton and DMS. The possibility of a major biological climate effect is very downplayed. A bloom of Emiliania huxleyi for example will alter albedo directly, and loss of that tiny denizen would also reduce CO2 pull down.

    *Sorry about that.

  36. My 2 cents – Lat nailed it at the very top with ‘chicken & egg’
    i.e. Did The Pause cause The Clouds or did The Clouds cause The Pause
    Then a load of peeps confused themselves confusing feedback and amplification. sigh

    Thinking that The Clouds did it is similar to a lot of Climate Scientist’s writings about clouds – I really get the impression they imagine that Eath has been endowed with a certain, fixed and immutable number of clouds.
    These clouds then manouver themselves around the planet causing weather and climate to occur, at certain places & times, in the manner that (presumably) some greater power deems to be required at said places and at said times.

    Clouds are weather, weather is clouds – in the same way fish can swim, birds can fly, LWIR is temperature and temperature is LWIR.
    They are inseperable, one does not cause the other.

    And this is where the chronically depressed brain comes in.
    To such a brain, one thing *has* to cause the other. The depressed brain needs that because then it has that thing under its power and control. Climate Change science sound familiar here????

    Things not in the control of the depressed brain are very scary, such things may do unpredicatable actions and the depressed brain instinctively knows it is not able to respond either quickly or appropriately. Unknowns are a deadly threat and we see that happening everywhere. From the massively increased surveilance in the UK (supposedly to counter terrorism) to the Social Cost of Carbon.
    Its all about control because otherwise, whatever it is scares the he11 out of the muddled, (physically and mentally) slow and depressed brain.
    And our dependance on glucose (carbohydrate food) is The Root Cause of that.

  37. This is why there is such a strong correlation with sunspots. The solar wind shields the earth from gamma rays which are part responsible for cloud formation. There was an essay on this site about it a number of months ago.

  38. This conversation prompted me to email the ISCCP, and ask them a question:

    I don’t see anything recent on the https://isccp.giss.nasa.gov/ web site, and Wikipedia says, “The International Satellite Cloud Climatology Project (ISCCP) was established as the first project of the World Climate Research Program (WCRP). Since its inception in 1982, there have been two phases, 1983–1995 and 1995–2009.”

    That makes it sound like the ISCCP ended some years ago. So, is the ISCCP still an an active project, or should it be referred to in the past tense?

    This morning I got a reply:

    Although the NASA website is not active and there is nothing available beyond 2009, the whole project is about to go operational at NOAA. The first task is to re-process the period 1983-2009 into the new version (slightly changed from the current version) and then to extend the record back to 1982 and forward to present — and continue. NOAA will also launch a new support website but the NASA one will be updated with some information, too. Given where we are now (about half of the old data re-processed), I expect we will release the data for 1982-2015 (maybe 2016) by this summer. So keep checking.

    • Was there a near-global sea-change (no pun intended) in cloud cover around the turn of the millenium, […]

      If there was, it was the cause of the step in temps after the El Nino, NOT co2. :)

  39. Considering feedback discussion, the solar constant is 1(100%). Everything inside the system (earth) is less than that. Which menas everything that happens on earth is MASSIVE negative feedback.
    There is nothing to worry about.


  40. Okay, so the Pause was now caused by the primary manifestation (clouds) of the most common greenhouse gas: water vapor?

    Well, (again in my humble laymen’s opinion), it seems to me that greenhouse gases seem to work more as a moderator of climate, rather than bringing out extremes. Clouds are a good example of the most simple example of this sort of thing. Clouds come in on a hot day, it cools off. Clouds come in on a cold day, it warms up. High greenhouse concentration gets you the tropics, low concentration gets you a desert. In the tropics, there’s not much change in day or night or seasonally, in the desert, it’s freezing at night, and scorching in the daytime. It’s also the difference between ‘lush’ and ‘arid’, or ‘barren’.

    You don’t need a doctorate in radioactive physics – that’s just observation.

  41. I used the raw data in the spreadsheet and analyzed it for cyclical behavior. I started with an OFT looking for 90 sinusoids. I then used those as inputs for further analysis. I think the results are satisfactory.


    Here is just a brief listing of the sinusoids.


    A 60-year sinusoid does show up. That is often talked about on this site. Perhaps, some of the other cycles shown will have mean something to people. With just the first seven sinusoids here is what happened.


  42. It occurred to me while looking at photos from the 80’s and 90’s that the sky in the background is usually clear while later pictures show clouds of some kind or another. Has anyone else noticed this (particularly from outside the US)?

  43. mothcatcher, 1/11/2017 @ 10:41 am asked if I agreed

    that the hydrological cycle involving evaporation from the ocean, and atmospheric humidity/clouds acts as a thermostat for the global system? … Should we not be looking for model physics in which a water thermostat is a basic assumption, and see what falls out? THEN see what sort of CO2 ECS numbers we get?

    A thermostat is not a good model because it involves a set point. Ice core reductions over the past 420 Kyr show four glacial cycles, during which the global temperature has varied nearly as a saw tooth wave between -9ºC and +3ºC. Earth is presently at about 2ºC. First order, peak-to-peak terms show Earth warming at 0.051ºC/century and cooling at 0.013 ºC/century, a 4:1 ratio, giving the saw tooth appearance. From the standpoint of life, this cyclic behavior is extreme.

    In this half million years, Earth cycled between a warm state much like today’s climate and the “snowball Earth” state. In the warm state, cloud cover amplifies the Sun instantaneously (relative to climate scales), and mitigates warming from any cause over periods of a few to ten centuries. During this time, the atmosphere is dominantly a by-product of the ocean. Global temperature is determined by ocean absorption of short wave radiation from the Sun. The brunt of the inbound heat is absorbed perpendicularly in dark waters at the Equator, fed by the cold bottom water return from the THC/MOC. That water, low in density not just from heat but also from CO2 outgassing, rides on the ocean surface. It slowly circulates back alternately to one pole or the other, cooling by absorbing more short wave radiation but losing even more heat by longwave radiation. In this warm state, the output of the Sun over the past few to maybe a dozen centuries determines Earth’s surface temperature, mitigated by the net effect of cloud cover, cloud albedo, and water vapor. This ocean current integration of solar energy is a low pass filter, which, like all low pass filters, has the twin effects of attenuating and delaying (lagging) what would have otherwise been the forcing-driven temperature excursion.

    And during this time, the atmospheric concentration of CO2 is regulated by Henry’s Law, yet to be discovered by IPCC scientists. The natural outgassing from a flow somewhere between 15 and 50 Sv, dwarfs man’s contributions, rendering them far too small to be measured. Mauna Loa sits in the plume of about half the outgassing from the Eastern Equatorial Pacific, a plume modulated by seasonally variable winds. Atmospheric CO2 follows the pattern of surface temperature, attenuated and lagged accordingly, as shown in the Vostok reductions.

    None of this applies during the snowball state, where the atmosphere is bone-dry and cloudless. The surface is snow white and the surface albedo is close to 100%. Earth is locked in; climate change is off.

    As satisfying as this two state model might be, it still has a clinker in the works. The glacial cycles and their snowball recovery correlate well with the variation in Earth’s eccentricity, and some observers have made a case that interglacial surface temperature does as well. But that is just one of the three Milankovitch cycles. The narrative needs to account for Ray Pierrehumbert’s caution:

    The gaping hole in Milankovic’s theory is that it predicts that ice ages should follow the precessional cycle. In particular, the Northern Hemisphere and Southern Hemisphere should have ice ages in alternation every 10,000 years, with the severity of the ice ages modulated by the eccentricity cycle. This is not at all what is observed.

    The problem is not that the amplitude of radiative forcing associated with Milankovic cycles is small: it amounts to an enormous 100 W/m^2, with the amplitude determined by the eccentricity cycle. The problem is that the forcing occurs on the fast precessional time scale, whereas the climate response is predominately on a much slower 100,000 year time scale. Pierrehumbert, R.T., Principles of Planetary Climate, 11/19/08, ¶7.5.1, p. 353

    Dan Pangburn, 1/11/2017 @ 1:47 pm asked does IPCC consider the entire atmosphere to be always saturated with water vapor?

    That assumption goes too far, and it asks for the unwritten collective opinion of a committee. IPCC does state that [some of] its models increase humidity according to the Clausius-Clapeyron equation. That appears to be a software patch so that water vapor can amplify the desired CO2 effects. CO2 absorption alone failed to cause near enough warming for IPCC’s preconceived ideas about climate that it wrote into its revision of its own charter on day one.

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