hadcrut1

hadcrut1
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15 thoughts on “hadcrut1

  1. Shub
    The point really is that “global warming is accelerating” is a totally meaningless statement.
    A look at your graph shows that the rate of increase during the late 20th century was substantially the same as during both the 1920-1940 warming and the 1880-1900 warming.
    I had this argument with BBD some time ago when he accused me of being unable to read a graph.
    Yes, both 20th century warming periods have started from a higher base than the previous one but the rate is much the same and BBD’s answer was to compare the latest increase with the entire 1880-200? (I can’t remember off-hand what the cut-off was) record which obviously distorts the result. He couldn’t see it!

  2. Shub

    Let’s look at some more data.

    I’m limited here by what is available – and so transparently checkable – on WfT. I’ve used GISTEMP as the other global gridded reconstruction and CRUTEM3 and BEST for global land surface data.

    I have striven to be fair. Early C20th warming is about 1910 – 1945. Late century warming begins around 1975.

    Obviously we can change the start and end points but I want to be clear that I have not attempted to cherry-pick. In fact most people seem to treat the early C20th warming as ~1910 – 1940, but this is perhaps to omit the peak.

    Decadal trends (degrees C) for the three periods compared*:

    HADCRUT3
    1900 – present: 0.07
    1910 – 1945: 0.16
    1975 – present: 0.16

    HADCRUT3

    GISTEMP
    1900 – present: 0.06
    1910 – 1945: 0.12
    1975 – present: 0.16

    GISTEMP

    CRUTEM3
    1900 – present: 0.08
    1910 – 1945: 0.11
    1975 – present: 0.22

    CRUTEM3

    BEST
    1900 – present: 0.09
    1910 – 1945: 0.14
    1975 – present: 0.24

    BEST

    What do we see?

    - HADCRUT has the highest trend for 1910 – 1945

    - Only HADCRUT has equivalent trends for 1910 – 1945 and 1975 – present

    - Both land-only data sets show a substantial increase in trend for the period 1975 – present compared to 1910 – 1945

    We all know that surface (land) temperatures are projected to rise more rapidly than SSTs because of the far greater heat capacity of the oceans compared to land. The land-only reconstructions are based on far more data than SST reconstructions and are more reliable indicators of actual change.

    The decadal warming trend 1975 – present indicated by CRUTEM3 has doubled compared to the trend for 1910 – 1945.

    The decadal trend in BEST almost doubles from 0.14C to 0.24C.

    The IPCC claim is not falsified.

    *To check the trend, click the green ‘Raw Data’ link below the graph. Scroll to the end of the series and look for the value:

    #Least squares trend line; slope = 0.xxxx per year

  3. BBD

    [1] Firstly, thanks for coming around to a reasonable, and correct, method of answering the question posed by the IPCC’s statement: ‘Is the global temperature rise really accelerating?’ This is more important than the results themselves

    [2] Please note that the IPCC arrives at their conclusion of accelerating warming, by a method dissimilar to, and wrong, compared to our mutually acceptable one used above. This automatically falsifies their claim

    [3] GISTEMP and CRUTEM are in the hands of untrustworthy fiddlers, whose actions with the temperature record, especially with the ’1940s blip’ are suspect. GISS’ methodology of extrapolation is scientifically suspect. Why are you wheeling in these cripples?

    [4] In any case, even if you include them, the range for acceleration is 0-11(C/episode). This only confirms the null hypothesis in question rather than refuting it. Secondly, it simply makes the point, that a claim of accelerating warming is dependent on the data series used, rather than CO2.

    [5] Questions about warming over land etc are irrelevant to the question of the method of arriving at a conclusion about acceleration of global temperature rise.

  4. If BBD had read the IPCC pages in question (p 253) he would have seen that their claim is based on HADCRUT3. So their claim of accelerated warming is falsified, by the data BBD has kindly provided.

    He might also have noticed the IPCC’s claim that
    “Instrumental observations over the past 157 years show that temperatures at the surface have risen globally, with important regional variations. For the global average, warming in the last century has occurred in two phases, from the 1910s to the 1940s (0.35°C), and more strongly from the 1970s to the present (0.55°C).”
    This claim is also falsified by the IPCC’s own graph and the numbers given by BBD.

    I think Shub is a bit too polite with “you are making a mistake”!

  5. Shub

    Your point (3) is both unsupported and libellous (‘untrustworthy fiddlers… suspect’). I did also state at the outset that I was limited by which data sets we can compare together – transparently – using WfT. Not an encouraging start.

    Your point at (4) is incomprehensible.

    Your point at (5) is incorrect. Surface temperature data are the best we have for the full century. SST data sets are much sparser and less reliable. Of the two components synthesised into global gridded temperature reconstructions, the surface data is by far the most useful for examining C20th temperature change. I thought you might try to dismiss the surface data. You can’t.

    Since you tried to throw it out, I am going to repeat it:

    CRUTEM3
    1900 – present: 0.08
    1910 – 1945: 0.11
    1975 – present: 0.22

    CRUTEM3

    BEST
    1900 – present: 0.09
    1910 – 1945: 0.14
    1975 – present: 0.24

    Both land-only data sets show a substantial increase in trend for the period 1975 – present compared to 1910 – 1945

    The decadal warming trend 1975 – present indicated by CRUTEM3 has doubled compared to the trend for 1910 – 1945. The decadal trend in BEST almost doubles from 0.14C to 0.24C.

    It’s… undeniable.

  6. BBD,
    How can you come up with data, ex post facto, to support a claim that was made using data, that refutes what you say?

    Paul,
    I ended up being polite because I really don’t know what to say about contortionists such as the IPCC.

  7. Stop trying to dismiss the surface temperature data. Stop trying to pretend that I give a stuff about the IPCC. Start admitting that the rate of warming in the late C20th was nearly double that of the early C20th. Then we might get somewhere.

    And how can you claim that HADCRUT3 supports your contention and also say this:

    [3] GISTEMP and CRUTEM are in the hands of untrustworthy fiddlers, whose actions with the temperature record, especially with the ’1940s blip’ are suspect. GISS’ methodology of extrapolation is scientifically suspect. Why are you wheeling in these cripples?

    Such contradictions. Such muddle.

  8. “Stop trying to pretend that I give a stuff about the IPCC.”

    I don’t think you are very good with sticking to a line of argument through a length of time.

    This does go back to the 500 plus comment discussion thread at Bishop Hill where people tried to educate you on the matter.The same popped up again with the IPCC’s acceleration graph in the “Cherrypicking” post.

    Of course, you don’t ‘give a stuff’ about the IPCC, since you saw the error of their ways. But it took months of persistence on my part, and Paul’s, and others, for us to get here.

    What you do to prevent the bottom falling out from your sympathies for the IPCC is none of my business. But wrong method+wrong data=right answer, is probably not the best bet.

  9. I don’t think you are very good with sticking to a line of argument through a length of time.

    My position is and was simple: find out what is actually happening. Looking at the data as we did above, it is clear that the rate of surface warming has increased over the C20th.

    Do you accept this?

    The shortcomings of the IPCC presentation are far less important than the evidence, which to an extent, we can examine ourselves.

    For example look at CRUTEM3 and HADSST2 – the component parts of HADCRUT3.

    Trends compared:

    CRUTEM3
    1900 – present: 0.08
    1910 – 1945: 0.11
    1975 – present: 0.22

    HADSST2
    1900 – present: 0.07
    1910 – 1945: 0.17
    1975 – present: 0.14

    Whatever caused the 1910 – 1945 warming, it was SSTs that exhibited the strongest upward trend. Modern warming is the opposite: surface warming is dominant. The two episodes are qualitatively different. That’s one reason why simplistic comparison is invalid. The other is that such a comparison does not itself explain why surface and SST have risen since the mid-1970s.

    This does go back to the 500 plus comment discussion thread at Bishop Hill where people tried to educate you on the matter.

    I have not received much ‘education’ from commenters at BH.

  10. Shub

    While I think about it, the AR4 SPM surface temperature graphs are very much worth revisiting. The overview (and the range of model hindcasts both with and without anthropogenic forcings) is revealing.

  11. What are you talking about mate?

    One of the main pillars of anthropogenic CO2 driven warming is the purported uniform global warming by the globally present CO2 in the atmosphere. Anytime, we start acknowledging differences in trends between periods of warming, it is hurting your position.

    In other words, it the IPCC and you, who insist on calculating a global average temperature as though it has some special meaning.

  12. Shub

    You ask:

    What are you talking about mate?

    One of the main pillars of anthropogenic CO2 driven warming is the purported uniform global warming by the globally present CO2 in the atmosphere.

    Let’s look at regional warming on a global scale. Scroll down to ‘Global Surface Temperature’ and look below GISTEMP for the ‘Time Series 1884 – 2010′ box. Use the slider to compare the regional components of the 1910 – 1945 warming with modern warming. The regional extent of warming (SAT and SST) has increased.

    You say:

    Anytime, we start acknowledging differences in trends between periods of warming, it is hurting your position.

    Why? Modern warming is mainly CO2 forced. The early C20th warming was (?) solar variation (which was slight, suggesting that the climate system is sensitive to changes in radiative forcing). Surface air temperatures are rising at about double the rate of the period 1910 – 1945.

    In other words, it the IPCC and you, who insist on calculating a global average temperature as though it has some special meaning.

    Again, see the NASA link above. GAT does have meaning but I agree entirely that an overview of regional change is essential. It shows the increase in extent of regional warming.

  13. BBD said: …Your point (3) is both unsupported and libellous (‘untrustworthy fiddlers… suspect’)…

    The point made here about these datasets, particularly GISS, is that they are ‘fiddled’. This is not a new point. It has now, with supporting data, been spread widely across the web, by many people.

    I believe that a charge of libel can be refuted by proving that what has been said is the truth. That being the case, the fact that there has been no sign of a libel charge is, I submit, very telling…

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