HadCRUT4 strikes out

By Roger Andrews

HadCRUT4, a joint production of the UK Met Office Hadley Centre and the Climatic Research Unit of the University of East Anglia, is the world’s “official” global surface temperature time series. It’s the time series that tells us how much the Earth has warmed. It’s the time series the IPCC uses to “verify” its climate models and to support its claim that the warming was dominantly anthropogenic. It’s the time series that underpins the world’s efforts to cut carbon emissions and transition to a “sustainable” energy future. It’s difficult to overstate its importance.

Figure 1: HadCRUT4 “global surface temperature” time series

One hopes and trusts it’s reliable.

Unfortunately, however, it isn’t.

HadCRUT4 exists because it’s believed that we need a single global surface temperature time series to properly evaluate global warming. We don’t have a consistent set of temperature measurements covering all of the earth’s surface, but we do have surface air temperature measurements in land areas and sea surface temperature measurements in ocean areas, and so we construct what is believed to be a representative global surface temperature time series by combining the two.

We therefore construct HadCRUT4 by taking an area-weighted average of the CRUTEM4 land surface air temperatures, which contribute ~30% of the final HadCRUT4 value, and the HadSST3 ocean sea surface temperatures, which contribute the remaining ~70%. The three series are plotted in Figure 2:

Figure 2:  CRUTEM4 land, HadSST3 ocean and HadCRUT4 land+ocean time series

And immediately we see that CRUTEM4 shows roughly twice as much warming as HadSST3 since 1890 (and also since 1970), raising the question of whether HadCRUT4 isn’t averaging apples and oranges. The response is to present comparisons like Figure 3, which shows a good match between HadSST3 and HadMAT surface air temperatures (measured on board ship) over the oceans. It’s claimed that such comparisons confirm that the differences between CRUTEM4 and HadSST3 occur simply because the land warms faster than the ocean and not because of any fundamental difference between SSTs and surface air temperatures:

Figure 3:  HadMAT marine air temperature series vs. HadSST3

These results indeed look fairly convincing if we take the Figure 3 data at face value. The problem, however, is that they have been “corrected”. Figure 4 shows what the comparison looked like before the “corrections” were applied.

Figure 4: Figure 3 data before “correction” (mean both data sets = 0)

If corrections this large are needed to support the claim that there are no fundamental differences between surface air temperatures and SSTs then clearly the claim clearly isn’t a very robust one. The fact that the specific goal of the corrections was to match the SSTs to the air temperatures also doesn’t help. As a result we can’t dismiss the possibility that HadCRUT4 really is averaging apples and oranges, in which case it won’t be representative of anything, except possibly a lemon.

Strike one.

The IPCC also uses a “HadCRUT4 equivalent” variable rather than direct climate model output to project 21st century surface warming. The AR5 projections come from the CMIP5 suite of climate models, which directly output only one global temperature variable – surface air temperature (tas). They can also output tas over land (equivalent to CRUTEM4) and tos over the oceans (equivalent to HadSST3), but these data sets aren’t global. Figure 5 plots the CMIP5 model means through 2100 (RCP85 scenario) for these three variables. They give quite different warming projections:

Figure 5: CMIP5 multi-model means, RCP85 case 

Which one should be the “official” global surface temperature projection? Global surface air temperature is at least global, but it ignores the oceans, which show considerably less surface warming and which contain over 99% of the heat in the atmosphere and the oceans. Alternatively we could use the HadSST3 projection, but this ignores the atmosphere, which is where we live. Obviously we can’t define” global surface warming” with a single number. But the IPCC insists on doing it this way, so it makes up a “HadCRUT4 equivalent” model variable by averaging tas over land and tos over the oceans in the same way as it averages CRUTEM4 and HadSST3, and then it adopts this number as its official “global surface temperature” projection:

Figure 6: CMIP5 multi-model means plus “HadCRUT4 equivalent”, RCP85 case

But what does this number mean? Nothing. It doesn’t refer to the air, it doesn’t refer to the ocean. It refers to a medium consisting of 70% sea water and 30% air, which doesn’t exist as a physically-definable entity. It’s pure apples and oranges, and the result in this case is unquestionably a lemon. (A good way of looking at it is to assume that the HadCRUT4 projection is accurate and that the warming is evenly spread across the globe. Where on the Earth’s surface will you experience a temperature rise of 4.2C relative to 1860 in 2100? There isn’t anywhere.)

Strike two.

And now it gets worse.

CRUTEM4 and HadSST3 have been “corrected”.

It’s not possible to say exactly what corrections have been applied to CRUTEM4 because no one publishes a land surface air temperature time series that uses only raw records. However, a few years ago I put together a surface air temperature time series from scratch using ~1,000 selected and unadjusted Global Historic Climate Network (GHCN v2) records, and Figure 7 compares it with CRUTEM4:

Figure 7: CRUTEM4 vs. author’s global surface air temperature series

The short-term fluctuations match closely, but CRUTEM4 shows about 0.3C more overall warming since 1890. It’s likely that this warming is manufactured by “corrections”, in which case CRUTEM3 will show about 0.3C more surface air temperature warming over land areas during the 20th century than has actually occurred, but I can’t be sure about this so I can’t call strike three here.

The “corrections” applied to HadSST3, however, can be quantified simply by plotting the difference between HadSST3 and the ICOADS SST series, the raw data set from which HadSST3 is derived:

Figure 8: HadSST3 vs. unadjusted ICOADS SST series

I reviewed these corrections in detail a few years ago (a pdf documenting the results of the work is here) and found that they were based almost entirely on ad-hoc assumptions and backed up by effectively no hard data (as was the case with the Figure 4 data, the goal of the corrections was again to match the SSTs to surface air temperatures). They are certainly wrong to some degree and quite possibly seriously wrong. At the very least a case can be made that a data set that needs corrections this large to make it “correct” was too heavily distorted to have been used in the first place.

Yet HadSST3 contributes ~70% of the final value of HadCRUT4.

And HadCRUT4 is the data set that underpins the world’s efforts to cut carbon emissions and convert to a “sustainable” energy future.

Strike three, and you’re out.

Data sources:


ICOADS SST & marine air temperatures, HadMAT from KNMI Climate Explorer

 The author’s surface air temperature time series data are available on request.

This entry was posted in Climate change and tagged , , , , , , . Bookmark the permalink.

53 Responses to HadCRUT4 strikes out

  1. Euan Mearns says:

    Roger, so if I understand things correctly sea surface air temperatures have been adjusted arbitrarily to fit sea surface water temperatures and then they say hey sea surface air temperatures match sea surface water temperatures we can use the latter to model the former.

    In fact, comparing Figure 4 with 3 we see that the sea surface water temperatures are also adjusted – as you show in Figure 8. So what we in fact have are sea surface water temperatures warming much faster than the official record? (should we not be worried?) Air temperatures not warming at all.

    What on earth was going on in 1940-1945? And also 1850.

    Given that HadCRUT4 more or less matches the GIS reconstruction, and others, they too must be applying the correction wizardry?

    • Hi Euan:

      Roger, so if I understand things correctly sea surface air temperatures have been adjusted arbitrarily to fit sea surface water temperatures and then they say hey sea surface air temperatures match sea surface water temperatures we can use the latter to model the former.

      The way it works is this:

      1. We assume the raw SST data are biased

      2. We assume that SSTs should match surface air temperatures above the ocean

      3. We can therefore use the SST-air temperature differences to quantify the SST biases

      4. We then subtract the biases from the raw SST record.

      5. The SST record now matches the surface air temperature record

      6. Proving that the initial assumptions were correct.

      The raw ICOADS air temperature measurements, incidentally, were adjusted a) by throwing out all the daytime data, which are assumed to be contaminated (they don’t fit, so they must be), b) by applying a “deck height correction” to allow for increasing ship size with time and sometimes c) by adjusting them to match the SSTs.

      So what we in fact have are sea surface water temperatures warming much faster than the official record? (should we not be worried?) Air temperatures not warming at all. What on earth was going on in 1940-1945? And also 1850.

      Unadjusted SSTs actually show about the same amount of warming as air temperatures. The difference is in the timing. Figure 18 of the attached pdf in fact shows SST and SAT oscillating around each other with sine-wave regularity. As to what was going on in 1940-45, it’s all in the pdf.

      Given that HadCRUT4 more or less matches the GIS reconstruction, and others, they too must be applying the correction wizardry?

      The GISS equivalent to HadCRUT4 is the GISS Land-Ocean Temperature Index (LOTI) and the NOAA equivalent is the NCDC “Land and Ocean Temperature Anomalies. Both use the NCDC “ERSST” SST series, which has been “corrected” in much the same way as HadSST3.

  2. bobski2014 says:

    To a sceptical, dedicated but not scientifically trained watcher such as myself the really depressing aspect of posts such as this is the slow rate of take up by the general populace of the awsome scale of the scam. Which ignorance continues to facilitate the dismal parade of rubbish at best, and lies at worst, of the BBC, politicians, etc.

    Cannot do more than congratulate you chaps, and hope you continue the good work which at least I disseminate as well as I can. Your efforts and those like you are all that stands between us folk and a total lack of trust in science in general. I used to try communicating with UEA and the Met Office but as you will know, that is a waste of time

  3. Joe Public says:

    Thank you Euan, for proving Disraeli correct.

    • Euan Mearns says:

      Joe, its Roger’s post. And for us youngsters, why does this prove Disraeli to be correct?

      • Joe Public says:

        Ooops, sorry for misattributing the post.

        “Lies, damned lies, and statistics”

        However, looking at WikiP:-

        “The term was popularised in the United States by Mark Twain (among others), who attributed it to the 19th-century British Prime Minister Benjamin Disraeli (1804–1881): “There are three kinds of lies: lies, damned lies, and statistics.” However, the phrase is not found in any of Disraeli’s works and the earliest known appearances were years after his death. Other coiners have therefore been proposed, and the phrase is often attributed to Twain himself.”

  4. Bernd Palmer says:

    Areal eye opener: It’s worse than I thought.
    Thank you for your valuable analysis. As simple as it seems. nobody in the climate establishment seems to have done it, at least, nobody has pointed publicly to this gross uncertainty or artificial distortion. A distortion in the same order as the alleged “warming”.

  5. Euan,
    Could you provide a short bio for Roger Andrews?

    • Euan Mearns says:

      I’ve been meaning to post a bio for Roger up top alongside my own. Roger is UK born, but lived in the USA for most of his life. He is a geologist / geophysicist and worked for the mineral exploration industry, I believe spending a lot of time looking at geochemical assay data. His background is not too radically different to mine which was more geochemical / oil industry. He is now retired to the West coast of Mexico where he sits under a palm tree sipping tequila and blogging.

    • Euan Mearns says:

      Roger now has a full bio up top beside mine. I’m off fishing today, back about 20:00.

    • Craig Crosby says:

      Thanks, Todd.

      I think we’ll be waiting a while for any reasoned response, however.

      Still, I enjoy that Euan is probably a true skeptic, and am saddened that he may be taken in by spurious material.

      Of course, I really hope these guys are right. The lives of my children and grandchildren are, after all, involved. The probabilities seem to me to be overwhelming. By which I mean to say that, given a 5% chance that doing nothing to limit carbon emissions will lead to catastrophic consequences, and imperil the health, happiness and even lives of millions of individuals, then doing nothing is unthinkable.

      The only possible alternative would have to be a nearly 100% certainty that nearly all of the climate scientists are wrong. I hope Euan is not arguing that premise.

      • Euan Mearns says:

        Todd and Craig, I am genuinely confused by these comments. Keep things factual, but pleas explain where you are coming from.


        • Craig Crosby says:

          It appears (to me, at least) that the lead article is an attack on a position that been withdrawn by the climate science community. In other words, a straw man chosen because at one time it has been espoused by same.

          It would be the same as if someone attacked the Catholic Church based on some encyclical that was written years before and had been withdrawn. Like Limbo, for example.

          At least that is how I read the November, 2013 item.

          I know your position. Frankly, there are some parts of climate science that are a mystery to me, a lay person. The reason I personally choose to position myself as in favor of limiting co2 is because the people who actually study it and live in it are obviously alarmed.

          Also, I fail to see who would benefit from a fraud. The only claim I have seen made is that somehow the climate community is trying to create a new world order, or some such fantasy from the far right.

          Anyway, as I said, I recognize you are a genuine skeptic and respect your position. I read with an open mind, and expose both sides to the same sort of scrutiny.

          Best regards,


          • A C Osborn says:

            “Also, I fail to see who would benefit from a fraud.”
            Then you have not looked at it closely enough.
            Do you realise how many $Billions have been spent on “Climate Science”?
            Do you realise how much money ($1.6Trillion) has been invested and profit made combatting the so called Man Made Global Warming by changing from Fossil Fuels to so called “Renewables”?
            You can’t see because you either haven’t looked properly or it is against your beliefs

          • Craig Crosby says:

            I realize that people have invested and made money, exploiting the problem with solutions that cannot work. Most renewables do nothing to reduce co2 – the processes of production, transportation, and so forth (for wind and solar) all are energy intensive and provide little relief.

            However, in the US at least, we are still subsidizing fossil fuels, thus encouraging excess use. And, the earliest problems from that are going to come by way of economic difficulties.

            Of course we should all keep in mind that, even in the eyes of the climate cartel, the problem is self solving when production and use of fossil fuels becomes prohibitively expensive.

            The danger that I see is that, by modifying the temperature of the planet, we disturb oceanic methane and create a run-away increase. No one knows, or pretends to know, when or whether that will happen, so we are actually experimenting in an area where there are known dangers, and where there is some danger that is yet unquantifiable.

            The thing about the climate scientists is that they are not paid to find any particular thing. They are using data that is in many ways questionable, and using real time data to modify past data to determine how to model for the future. My statement was that they have no axe to grind in the matter. In fact, any one or more of them who found some smoking gun showing actual conspiracy to alter data would become somewhat of a hero.

            Instead, I see them being quite public about what they are doing.

            For instance, they know that we are observing a hiatus in atmospheric warming, and they are puzzled as to why, since they know that the observed amount of co2 entering the atmosphere has increased, and by how much. They also know from replicable experimentation that the amount of observed increase should have caused an increase in temperature that did not occur. They are therefore looking to see whether they find where that heat went. It either remained inside the envelope, or it did not. At present their thinking is that it was taken up by the oceans, and they are in the process of measuring various oceanic depths. The problem is the lack of reliable past data with which to compare their present measurements.

            Again, many of the data dumps that I have seen have little meaning to me as a lay person. I can understand that as knowledge increases, past methodologies are seen to be wrong, or are verified. Those that are falsified are withdrawn, as the HadCrut4 data seems to have been. Since it is no longer in use, they using it as a whipping boy for denialist propaganda seems a bit fascile.

            When I began watching the climate debate, I was initially skeptical about the role of co2 in warming since past data all seemed to show that co2 was a following, rather than a leading, indicator of overall global warming. I researched, and found that what most scientists were finding was that there was usually an initial event or condition that began the cycle, and that when warming began it was reinforced by co2. Also I learned that there are cycles of warmth, and of cold, that are caused by preturbations in Earth’s orbit and by geophysical events on the planet – volcanoes, mountain creating, sunspot cycles, oceanic currents and the like. These events follow regular cycles, and one of the things that the scientific papers I researched pointed out is that what we are seeing today is not in the normal range of events.

            I remain skeptical about both the science and the denial side. I tend to view the science as more reliable because I have never seen an advertising spot sponsored by scientists, and have seen many sponsored by fossil fuels. To point out again, I am not in favor of most alternatives, though I am open minded about them. I do favor limiting use of fossil fuels for two reasons, one of them is that they are finite resources, the other is that there is that small, yet real, danger that the warming we are seeing will create a self-sustaining event, perhaps endangering the lives and well being of billions of souls on planet Earth. And, I believe the dangers outweigh the benefits overwhelmingly.

            Therefore, considering all that I know, I do not feel that attacking straw men is advantageous, and will call out that and any other logical fallacy I observe, on either side.

            Thank you.

    • Euan Mearns says:

      Craig and Todd,

      I’m still not managing to follow your arguments. For example the article Todd links to says this:

      Science deniers have resorted to once again using a flawed discarded chart from an earlier draft of the AR5 IPCC report. This time to consider the new paper by Cowtan and Way, which I’ve already written about here.

      The denialati didn’t have to use a flawed, discarded chart. Though it’s kind of cute that they’ve finally found something produced by the IPCC which they like. Most of the time science deniers reject everything from the IPCC but when it comes to something the IPCC has rejected, they suddenly decide they’ll embrace it.

      Which discarded IPCC chart do science deniers hang onto so tenaciously? No, it’s not the discarded chart showing short term projections (to 2015) for “Estimated changes in the observed globally and annually averaged surface temperature (in °C) since 1990 compared with the range of projections from the previous IPCC assessments”. It’s the discarded IPCC chart showing short term projections (to 2015) for which “the focus is now on the range of selected scenario projections from AR4”.

      Not only do the deniers want to use a discarded chart, they want to use a discarded chart that uses older AR4 CMIP3 models (see below), not the discarded chart using CMIP5 models used by AR5.

      At first read this comes over as trash to me. I don’t know what it is about and its written in a language I don’t understand. I don’t see that this article is about HadCRUT4 at all. It seems more to be about the uncertainty linked to derivative forecasts based on it.

      As far as I’m aware the climate science community has in no way discarded their belief in the veracity of the warming trend portrayed by HadCRUT4. The focus of Roger’s post is to look at the validity of the methodology employed in developing that reconstruction and he goes on to examine how different approaches to “managing” this data may impact (bias) forecasts. There is a very real difference between an uncertainty envelope around valid data and uncertainty created by biasing the way the data are produced.

      Roger is summarising vast amounts of data and has been doing so for a very long time. The key charts for me are 3 and 4. I’ve gone in to look at the data sources this morning but its a vast data base and it would take me a long time to find my way around – and I’m going salmon fishing today 🙂 If you want to persuade me there is a weakness in what Roger has explained here then you need to show that figures 3 and 4 are somehow false. This is part of the function of blogging – instantaneous peer review. I am often very nervous about some of the posts I write based on large amounts of complex data lest I make an error.

      Roger links to a pdf of an earlier article he wrote:

      Another interesting feature of the wartime SST spike is that it coincides with spikes in the ICOADS marine air temperature (Tair) and cloud cover series (17) (Figure 6). The chances that all three series would have spiked naturally during World War II are vanishingly small, so we can be confident that the three spikes are spurious. (The right-scale plot of the bivariate ENSO index (18) shows that they are not related to the 1940-41 El Niňo.)

      Now I understand that.

      My PhD mapping area was in west Norway. The base geological map for the whole area was made by members of the resistance in WWII. They of course didn’t do any mapping at all. They just made it all up. But after the war the map got published by the Norwegian Geological Survey. Everyone knew it had just been made up and yet because it was published folks found it difficult to not believe it.

      • Euan Mearns says:

        I might add that some geologists went on to publish papers interpreting the geology of W Norway based on data that was just made up.

        And if you look at Figure 6 in Roger’s pdf you’ll see the nature of the WWII data problem. There are four possibilities. 1) Roger has made up the data, 2) there was an extraordinary climatic event that coincided exactly with WWII 3) The Germans (or someone else) spewed out vast amounts of something that affected the global climate instantaneously 4) the official data are wrong (probably made up).

        In the latter case the correct scientific approach is to accept that you don’t have valid data and must therefore have a gap in your data series. You don’t try to correct data that are potentially just made up.

  6. A C Osborn says:

    The nice work that Roger has done here has just confirmed the work others have done on the NCDC/USHCN/GHCN/GISS/BOM data.
    It starts with NCDC applying “Quality Control” adjustments to the raw data, the same algorithms appear to used by CRU & BOM, but GISS add some more of there own, especially in terms of Spatial adjustments.
    The only data that should be used is RAW data, the rest of it has been adjusted to fit the Hockey Stick and CO2 increases.

    BEST use a different technique to achieve the same biased result, in fact they agree that their final values are what the Computer models say they should have been and are not actual reality.

    • AC. Thank you for your kind words 🙂

      But I’m afraid that what I’ve done here doesn’t confirm the work that others have done on “land” series like CRUTEM4, GISS and BEST. These series undoubtedly overstate warming, but the data I present here aren’t sufficient to prove that (remember that I couldn’t call a strike on CRUTEM4). I have data that I think do prove it, but I’m not ready to present them yet.

      The point I was trying to get across is that the big problem isn’t with the land series at all but with the ocean SST series like HadSST3 and the similar NCDC ERSST series, which contribute over twice as much to the HadCRUT4 global series than the land series and which are probably far more screwed up by bogus “corrections”.

      But for some reason everyone fixates on the land series. No one ever seems to look at SSTs. I suspect this is because many people don’t recognize any difference between land and ocean temperature series even though the difference is fundamental.

  7. I agree that sea and land temperatures should be examined separately. However one can use them in combination not by taking their (70-30-weighted) mean but by examining trends in their difference. Trends have the benefit of being insensitive to arbitrary choices of anomaly reference temperatures since their slopes are invariant under change of reference.

    In my talk at last December’s AGU Fall Meeting I showed how trends in land-sea temperature differences can be used as a diagnostic to locate the origin of a given global heating event. If LAND minus SEA trends down it indicates SEA as the origin, and if up then LAND (more precisely, lower troposphere). Slides 5-9 caricatures the physics underlying this behaviour.

    I pointed out that this LAND-minus-SEA difference trended strongly down during 1860-1880, more weakly down during 1910-1940, and strongly up during 1970-2000. From this I concluded that when multidecadal climate is expressed as a sum of a 60-year period and a monotonically rising component, the cycle is more likely to originate in the sea than from any cyclic behavior in radiative forcing, regardless of whether the latter is attributed to volcanic aerosols, other aerosols, clouds, or greenhouse gases.

    • Roger Andrews says:

      Vaughan: Your copper tube analogy is an interesting one, but could you please explain how heat flows from the land to the sea? There’s not enough heat in the air over the land to make any difference to the sea temperature, even when you include the air over the ocean, and the ocean surface is generally warmer than the air above it anyway. Apologies if I’ve misunderstood you here.

      You might take a look at Figure 18 from the pdf that I posted higher up the thread to see what you can make of it. It’s likely to be more representative of actual land-ocean temperature differences than the CRUTEM4 and HadSST3 data you used. An interesting feature is that the increase in SST relative to SAT between ~1910 and ~1970 coincides with the rapid increase in TSI over the same period.

  8. Euan Mearns says:

    Roger, having dug around a little bit more and understand more about the data I now realise that removing the WWII data from the temperature series there is pretty well a continuous warming trend from 1910 (Figure 4). That’s a whole new ball game.

    • Euan: Since I wrote the pdf two more variables that go haywire during WWII have been added to the list – zonal and meridional wind speed. SLP is the only variable I’ve found that doesn’t show any obvious signs of wartime distortion.

      The WWII ICOADS data are obviously fit only for junking, yet Hadley and NCDC continue to use them and they still underpin the enormous HadSST3 “corrections”. What does this tell us about the analytical skills of the correctors? Or could it be that the merry-go-round is moving too fast to jump off? The HadSST3 corrections have been around in one form or another since 1982, and admitting we’d got them all wrong for the last 32 years would be embarrassing to say the least.

  9. clivebest says:

    CRUTEM4 increased post 2000 warming over CRUTEM3 to make 2010 the hottest year. They added 628 statins in arctic regions which they knew were warming while removing stations in south america which showed cooling.


    You can of course calculate the absolute average temperatures for land stations rather than the ‘anomalies’. This is instructive because it shows biasing in station locations it also shows how tine the effects are.


    Since 1950 there has essentially been no warming in the SH. Note also the spike in CRUTEM4 in 2008.

    The coverage bias of the sampling can be seen below where I plot the number of missing grid cells versus year.


    Most of Africa still has very poor coverage.

  10. Sorry but can’t reply because I keep getting the “Invalid security token” message.

  11. Roger, I’m consistently getting my replies to your messages bounced with the dreaded “Invalid security token” message, yet much shorter comments like this get through fine.

  12. [To get around WordPress’s “Invalid security token” problem I’ll try breaking my reply into several short parts.]

    @RA: could you please explain how heat flows from the land to the sea?

    Excellent question, Roger, especially given that much of the online discussion I’ve seen seems to assume radiation as the primary heat transport between the sea and the atmosphere.

    However, much higher thermal conductivity is achieved via the mechanism of ocean spray, which is present in all but the calmest weather. Spray gives rise to an ocean-to-air heat flux during storms which NOAA estimates at 2000 W/m2. If radiation, conduction, and convection are the only permitted heat transports then spray would most naturally come under the heading of convection.

    There is furthermore a constant molecular flow of evaporation and condensation at the surface which gives excellent thermal coupling even in the calmest weather. Since thermal conduction, like evaporation and condensation, occurs at the molecular level, the evaporation-condensation process, in which water molecules are continually being exchanged back and forth between the sea and the air at very high speed, would most naturally be classified as conduction.

  13. [Great, part 1 of my reply got through, here’s part 2.]

    You might take a look at Figure 18 from the pdf that I posted higher up the thread to see what you can make of it.

    Your sentence following Figure 16, “As to what to do with the SST series, we clearly cannot ignore it because the heat content of the oceans greatly exceeds the heat content of the atmosphere.” is a non sequitur. The rapid exchange of water vapor molecules and water droplets between the ocean surface and the air ensures high thermal conductivity there, which the Ocean Mixed Layer (OML) propagates down several tens of meters to the prevailing main thermocline there.

    The thermocline exists because thermal conductivity there and below is negligible compared to that of the air-sea surface and the OML, as a consequence of the negligible disturbance there and below. In effect the thermocline is a very effective thermal insulator.

    It follows that the heat content of the portion of the ocean having any bearing on Sea Surface Temperature is negligible compared to that of the whole ocean, which is orders of magnitude deeper than the OML.

  14. [Sadly part 3 didn’t make it. Here’s part 4.]

    An interesting feature is that the increase in SST relative to SAT between ~1910 and ~1970 coincides with the rapid increase in TSI over the same period.

    Yes, but starting in 1970, when CO2 really got going, SST and SAT both climbed, which is what got me to graphing trends in their difference last year. Your Figure 18 looks entirely consistent with the analysis in my talk. In fact you don’t even need to look at the trend in the difference, you can just separately plot the 1970-2000 trends in the red and blue curves of Figure 18 to see that GISS Air is climbing faster than SST, consistent with the direction of heat flow being from air to sea.

    • Vaughan:

      Thanks for the comments that got through.

      I have no problem with the concept of evaporative heat transfer from the sea to the air but I still have difficulty with the concept of heat transfer, by any mechanism, from the air to the sea. According to a rough calculation I just made the top ten meters of the ocean contains more heat than is contained in the entire atmosphere. I just can’t see how you can transfer enough heat from the air to the sea to make a measurable difference under these circumstances.

      So let me propose a modification to your theory. Heat is removed from the upper layers of the ocean dominantly by evaporation. Heat is added to the ocean not by transfer from the air but by solar radiation in the high visible and UV ranges, which penetrates the ocean to considerable depths (IR does not). The SST-SAT oscillations we see arise from a complex balancing act between solar radiation, ocean thermal inertia, the air/sea temperature differential and probably a bunch of other contributors such as wind speed, cloud cover, ocean currents and ENSO events as well.

      Regardless of the mechanism, however, the fact remains that by averaging SATs and SSTs into a one-size-fits-all variable like HadCRUT4, by doing the same thing with tos and tas in the CMIP5 models, and then by trying to explain everything in terms of increasing CO2, the IPCC is grossly oversimplifying the complexity of the Earth’s climate. I think that’s the take-home message here.

      • Craig Crosby says:

        In your last reply to Vaughan, Roger, I think you are correct. I am not certain that the IPCC is grossly understating complexity, though. Maybe they are ‘dumbing down’ public releases? In any event, that is pretty much what I have thought for quite a while. The complexities are huge and varied, and past data is so restricted that we are, or should be, creating the science as we go along. The real problem is that the media either overlooks the scientific hedging that is always done, or else they act as though that is all that matters. Science should say, “We can say X with a high/medium/low degree of certainty.” And, IPCC does do that. When that language is reported or commented on by the media, it largely is taken out of context to try to say that it is all climate science is a guess. When it is ignored, blatantly alarmist proclamations result. Neither is conducive to intelligent debate or scientific discussion.

        Perhaps it is an endemic problem with reporting on science. Science is constantly adjusting for new data; news people look for “HEADLINES!!” And, when last month’s headline is rejected or adjusted, that is not newsworthy. And we are left with many/most people simply in the dark, with assumptions and misinformation. I am more alarmed by pseudo science and propaganda spin than by the underlying science. Which is what I expect from fossil fuel industries that fear (rightfully, might I add) limiting regulation and negative publicity.

        I am accused by climate extremists of being a denier, and by deniers of some sort of quasi-religious adherence to the “great climate hoax.” Point of fact, there is no hoax. The science is uncertain due to lack of clear data, and scientists are constantly reviewing new data, adjusting models and reformulating theories in order to a better job of prediction. Of necessity, that means better theories explaining past events, and based on gradually improving data bases, they may create better models and heightened predictability. This is exactly what I expect from science.

        I do not have any reason to believe that the body of climate scientists are aware of what you posted. Nor do I have any reason to believe that they are not looking for better ways to represent input into their models. And, finally, I have no reason to believe that when they realize better data, revise their theories, or improve their models, they will not share them worldwide, whether those models and observations show increased global warming, or decreased warming. That, again, is the nature of science.

        Thank you again for your input. Like you, I certainly wish that the topic was not so maddeningly complex and uncertain.


      • Vaughan Pratt says:

        Roger, your own model of ocean-atmosphere heat transport is too simplistic to give correct results. However I’m finding it more work than is worth my time to organize my replies to get them past your “invalid security token” message. If you google that message you’ll see what’s likely to be causing it. This seems to be an ongoing WordPress problem that they still haven’t fixed—I suggest bringing it up with WordPress.

      • [I’m down in Pacific Grove for the weekend and posting this from a different operating system (Win8.1 instead of Win7) on a different computer (AMD instead of Intel) via a different ISP (AT&T instead of Comcast). Maybe one of these changes will be enough to avoid the Invalid Security Token problem. Also I’ve worked on shortening my reply to the bare minimum.]

        Roger, as you’ve presumably calculated yourself, the heat capacity of the atmosphere is 5.14E18 (mass of atmosphere in kg) * 1010 (specific heat of air in J/kg/K)= 5.2E21 joules per degree, while that of the top 3.6 m of the Earth’s oceans is 3.6E14 (area) * 3.6 (depth) * 1025 (density of seawater) * 3850 (specific heat of seawater) = 5.1E21 joules per degree, about the same. (All in SI units.) This equivalence is well known and has been pointed out by many authors.

        What’s simplistic about this analysis is that it neglects heat transport via the atmosphere. The heat capacity of the rain that fell into the ocean during 1970-2000 is 3.98E14 (annual ocean precipitation in m^3) * 1000 (density of rainwater in kg/m3) * 4181 (specific heat of rain) * 30 (years) = 5E22 joules per degree.

        This is an order of magnitude greater than the heat capacity of the atmosphere, and equivalent to the top 36 m of ocean.

        Warming of the atmosphere results in warming of precipitation, which during 1970-2000 is therefore sufficient to warm those 35 meters. This shows that the heat capacity of the atmosphere by itself has no bearing on whether the atmosphere can warm the ocean, because far more heat than it can hold statically can travel via it over the period during which recent global warming occurred.

        • Roger Andrews says:

          Vaughan: Glad you were finally able to get through with a different computer and operating system. (I too am on a different computer and operating system, my other computer having succumbed to the dreaded blue screen of death yesterday.)

          I’m getting outside my fields of expertise here, such as they are, so you will have to excuse me if I say anything dumb. Your point on rainfall is a good one and one I frankly hadn’t thought about. But shouldn’t there be a balance between heat introduced by rainfall into the ocean and heat removed by evaporation from the ocean, which is what generates the rainfall? And if not, how great might the imbalance be?

        • Euan Mearns says:

          Vaughan, I hope the posting problems resolve. Whatever you do, don’t give up. My first suggestion would be to buy a Mac;-) I’m just following this conversation out of the corner of my eye. I’m not a physicist, but did read physics for 1 year at university. Got a merit certificate. I believe you are saying that the top 3.6 m of the oceans has the same heat capacity as the atmosphere. That for me is an interesting statistic. The atmosphere has got tiny mass. And while I believe it is the case that many global warming observers believe that the atmosphere is warming by gaining cumulative heat I believe it is more of an instantaneous effect where more GHG results in increasing amounts of outgoing IR being trapped with the passage of time. Whilst bearing in mind that most of the IR that CO2 can trap is already trapped at pre-industrial levels of CO2.

          You say:

          Warming of the atmosphere results in warming of precipitation, which during 1970-2000 is therefore sufficient to warm those 35 meters.

          This is said with authority and would sound convincing to the layman. But is there any empirical evidence to support this statement? That rainfall has on average warmed? And what is the physical basis? The physical processes that go on in clouds are dominated by water vapour not CO2.

          One burning question I have is the popular anecdote “wait till all the heat comes out of the oceans”. By what process might that occur? It strikes me that one candidate might be a cooling atmosphere.

        • Euan Mearns says:

          Vaughan, I find this interesting. So increasing global rainfall would cool the atmosphere and vice versa?

          Quantitatively, how would this rainfall “heat pump” compare in energy budget to the total GH effect.

          So the pause might mean that global rainfall has been stable since 1998?

          I know I’m may be twisting your argument a bit 😉

          • Euan Mearns says:

            And then on the other hand, more evaporation would cool the oceans, perhaps the precipitation energy balance all cancels out?

          • Euan. In the “clouds” post that never made it to publication there are graphs showing a close positive correlation between ocean clouds and SST for a least the last 60 years. This correlation suggests that the rain was induced by a warming ocean rather than that the ocean was warmed by the rain.

      • Vaughan Pratt says:

        I’m not a physicist, but did read physics for 1 year at university.

        I’m not a physicist either, Euan. My main claim to any insight into physics is that, with no study at all (I am a dreadful procrastinator) I miraculously came 8th in the state of NSW (out of a field of some 15,000) in the final year high school exam in physics. This encouraged me to take maths and physics at Sydney, graduating in 1966 with double honours in those subjects. Computers were just then appearing in Australia and I fell under their spell, without which I would most likely have gone on to a career in physics.

  15. Am I the only one encountering WordPress’s notorious “Invalid security token” problem on this blog?

  16. Craig and Todd:

    This post addresses the inappropriateness of mixing SSTs with air temperatures and the validity of the bias corrections applied to the raw ICOADS SST series before 1950. The Cowtan and Way paper addresses “Coverage bias in the HadCRUT4 temperature series and its impact on recent (i.e. relative to the late 1990s) temperature trends”. It has no bearing on the conclusions of the post.

    Neither has it caused HadCRUT4 to be “discarded”.

    Future comments on this thread will be moderated for content and relevance to the topic.

  17. Glen Mcmillian says:

    My comment is not directly related to the article but nevertheless of considerable relevance especially to people in Scotland.

    It seems some information has been dug up about the English lying about the oil reserves prior to the last independence referendum and that the people of Scotland may actually vote for independence.This could be the straw that breaks the camel’s back.

    Any body who has had time to investigate this matter should post his findings.

  18. Ok, I give up. I ‘ve tried again and again to point out the fatal errors in your arguments, but WordPress continues to bounce my explanations of why you’re wrong with “Invalid security token” errors. I suggest that if you want your erroneous arguments to remain intact then don’t fix this idiotic WordPress problem. That way you win.

    • Euan Mearns says:

      I suggest that if you want your erroneous arguments to remain intact then don’t fix this idiotic WordPress problem.

      Vaughan, as far as I’m aware you are the only person in the World experiencing this problem. Asking me to fix this is like asking me to hack into the SEE I A computers.

      At the weekend, as you pointed out, you posted from a different IP address, using same email address but posted via Gravatar. That all seemed to work. Perhaps the security token problem is at your end? Why don’t you try posting via Gravatar (I’m not even sure how that works, but a lot of people use it).

      Meanwhile I have updated platform to WP4. I suggest you avoid making any form of insinuation that we are somehow trying to prevent you from making your arguments.

  19. Euan, sorry for losing my cool – actually it was my fault for not making a backup copy of my explanation about rain temperature before hitting “Post Comment”. My explanation, which took some time to write, was replaced by the Invalid Security Token message. I was in no mood at the time to start from scratch. Will do so now. Hopefully WP4 won’t have that problem.

  20. is there any empirical evidence to support this statement? That rainfall has on average warmed? And what is the physical basis? The physical processes that go on in clouds are dominated by water vapour not CO2.

    Euan, I don’t know whether global warming has any influence on the temperature of clouds. However, all else save temperature being equal, I would expect not on the ground that water vapour should always condense at the same temperature. Global warming should merely raise the altitude at which the atmosphere cools to that temperature. It would follow that the initial temperature of rain would likewise be independent of global warming.

    However the temperature of rain at the surface is a different matter because it passes through increasingly warmer air as it falls. In 1951 Kinzer and Gunn rigorously analyzed the situation and arrived at the beautiful result that, to within measurement error, the temperature of rain at any point during its fall is exactly the wet-bulb temperature at that point, that is, the temperature of a wet-bulb thermometer there.

    For fixed relative humidity, RH, wet-bulb temperature tracks air temperature, albeit a certain amount below it depending on RH. Hence global warming raises the temperature of rain at the surface.

  21. Doug Proctor says:

    The higher amount of temperature changes over land relative to over the oceans is of not surprise; this is why the oceans are considered to have a “moderating” influence on climate, after all.

    What might be worthy of a simple graph would be the ratio of land/SST anomalies vs time: the ratio should stay the same. But I already semi-know that it will not: the SST changes in the last 10 years don’t seem to match the land surface temp changes.

    Non-equal AND changing (goalpost) treatment of sand and sea surface temperatures should show up with the above plot. Just an Excel spreadsheet.

  22. Hi Doug

    Is this what you’re looking for?

Comments are closed.