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Comparing past climate change to recent global warming

What the science says...

Statistical analysis of the rate of warming over different periods find that warming from 1970 to 2001 is greater than the warming from both 1860 to 1880 and 1910 to 1940.

Climate Myth...

It warmed just as fast in 1860-1880 and 1910-1940
“In fact, the rate of warming from 1975-2001, at 0.16 °C per decade, was the fastest rate to be sustained for more than a decade in the 160-year record, but exactly the same rate occurred from 1860-1880 and again from 1910-1940, when we could not possibly have had anything to do with it.” (Christopher Monckton)

Let’s have a look at some warming rates of the periods of interest from several different temperature records:


Table 1: Rate of warming for given indices in °C/century.

First we can conclude that Monckton's statement that 1975-2001 was the fastest warming rate for longer than a decade is absolutely wrong as a much higher rate is demonstrated for 1975-2005 in row 5. Secondly, to compare the three periods in Table 2, the only index which covers that period is Hadley, making his 1.6°C per century number wrong for 1975-2001 as it is actually much higher at 1.78°C per century.

 

Based upon the evidence presented here, he cannot support his statement that 1860-1880 had a similar warming rate as it was demonstratively lower than the 1975-2001 warming rate and nearly half the 1975-2005 rate. Finally, regarding the 1910 to 1940 warm period, evidence presented here suggests that only 1 out of the 4 major indices indicates a rate of warming within 0.25°C per century and none within 0.2°C. His claim that the rates are similar is dubious at best.

Last updated on 31 January 2011 by robert way.

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Comments 1 to 50 out of 109:

  1. While Monckton's statement is not precise, is it worth noting that between the three warming rate periods described in the graph, the largest change is between the first two? The warming rate from 1975 to 2005 is 0.34°C higher than the period 1910 to 1940. Maybe we caused that, maybe we didn't. How can we explain the much higher rate increase of 0.55°C between the first and second periods, if not caused by us?
    I'd expect a bigger change between the second and third rates if we'd added something to this experiment, but the biggest change comes between the period we had no influence on...or am I wrong?
  2. expect a bigger change between the second and third rates if we'd added something to this experiment

    Ceteris paribus. ("All other things being equal or held constant.")

    Solar activity was not identical so such a direct comparison is not applicable. Solar activity was decreasing during the period 1975-2005 and increasing during the period 1910-1940, except 1920-1930 (roughly rounded).

    Solar activity & climate: is the sun causing global warming?
  3. Sorry for my bad English, I am french.
    Thank you for your very good blog.

    In your case, without the confidence intervals for the trends, it is difficult to say if all the trends are really statistically significant different.

    For example, in this graph of Tamino, http://tamino.files.wordpress.com/2010/08/rates.jpg, for those trends, http://tamino.files.wordpress.com/2010/08/annual.jpg, there is not statistically significant difference between the trend 2 and 4 (so, no difference significant between the trend 1 and 3)

    Other example in my graphs with the GISS data for the lands only, all the differences between the trends are statistically significant :
    http://meteo.besse83.free.fr/imfix/signifianoterrestrendgiss.png
    http://meteo.besse83.free.fr/imfix/anoterrestrendgiss.png

    Could you give us the confidence intervals ? Thank you.
  4. This is a response to Adam carried over from the Zebras in Greenland thread.

    Adam... Here is a composite graph of Dr Box's work and GISS global data zeroed to the start of the GISS data. Is there no relationship between the two? No signature of AGW? None at all?



    I would contend that there is a clear signal when you compare the two trends. The only thing you can take from the Greenland data is that there is a much larger noise factor but you can clearly see that the overall trend for the 20th century is much greater than the global record, fully consistent with AGW theory.
  5. Rob Honeycutt, I'm not entirely sure what you are trying to show in your comment. Yes, the trend in Greenland throughout the 20th century is slightly greater than the global record, but it still doesn't change the fact that the warming that occurred from 1920-1940 was clearly equal to the 1980-2000 warming. As it clearly says on the graph for 1916-1932 the warming trend was 1.26 C/decade, but for the 1994-2010 warming it was only 0.97C/decade.

    I can't see how what you are saying in your comments, answers any of the points I have made.

    You have also not answered why the Greenland temperature variations don't show any correlation to carbon dioxide emissions.
  6. Once again I suggest that you read Chylek's paper. It explains about the two periods of warming, and why there is nothing unusual about the current one.
  7. Rob @4,

    You are right of course. This graph also demonstrates that the Arctic is currently warmer than it was early in the 20th century:



    And again, for those hard of "hearing", it is not so much where we are now, but where we are heading under BAU.
  8. Adam - "You have also not answered why the Greenland temperature variations don't show any correlation to carbon dioxide emissions."

    You might want to take a step back from CO2 (or a step forward?) and look at the global temperature anomalies.



    The Greenland data tracks the global anomalies reasonably well (mid century rise, drop until ~1970, increasing after that). The reason neither of these directly follow CO2 emissions is because CO2 is not the only driver of climate, as is discussed on that thread.

    The current temperature rise, in particular post-1970, cannot be accounted for without anthropogenic greenhouse warming: factors involved in earlier climate changes are insufficient or of the wrong sign to cause recent temperature rises, rises which we expect to continue for quite some time. We're headed to mid-Pliocene temperatures, where the sea level was ~25m higher due to ice melt.

    The concern is particularly strong since Greenland ice melt is increasing:



    As noted on the previous topic, there are a lot of different kinds of glaciers on Greenland, but many of them are subject to water temperatures in their melt rates, not just air temperatures.

    So:

    - You're mistaken in thinking that CO2 is the only driver of climate.
    - Recent warming could not have happened without AGW; other forcings don't add up.
    - Air temperature is not the only driver of glacial melt; rising sea temperatures (observed) are a huge influence.
    - Current warming is expected to continue for quite some time, based on the science and current policies.
    - This has nasty implications for sea level due to Greenland ice melt.
  9. Albatross, first of all that graph is based on the entire Arctic, which is not what I was referring to. I was referring to the current climate on the Greenland ice sheet. And as shown by Jason boxes graph, apart from the two anomously warm years 2003 and 2010, the current Greenland temperature is matched with the temperature it was 70 years ago.

    Secondly, I suggest that you read this paper

    'Variable solar irradiance as a plausible agent for multidecadal variations in the Arctic-wide surface air temperature record of the past 130 years' by Willie Soon published in 'Geophysical Research Letters' (2005)

    Albatross Arctic temperature changes show a much better correlation with changes in the sun, than changes in CO2 concentration.



    Albatross, the current Arctic climate is very difficult to be explained by co2, and shows a much better link to natural forcings.

    Alabatross, the perfect correlation with changes in the sun, and the lack of any correlation with co2, surely support the argument that the Arctic climate is dominated by natural variability and not CO2.
  10. Adam... My objection here is that you're quoting Dr Box's work as evidence that Greenland shows no signal of AGW which is diametrically opposed to the conclusions of Dr Box himself.

    You keep making the same mistake that every skeptic seems to make when then look at Greenland. You keep trying to assign a global response to a local record.

    The point when you look at the 20th century record of Greenland is that there is an overall trend consistent with the overall global trend.
  11. KR polar regions are especially sensitive, so looking at what they're doing (specifically if there is any correlation to CO2) would indeed be very important in our understanding of climate change and the forces that drive it.

    KR, as for your argument that there is no correlation because 'co2 is not the only driver of climate' I will repeat my questions to you, which I asked Rob.

    Do you agree that the Greenland warming of 1920-1940 was equal to the 1980-2000 Greenland warming?

    If so, do you agree that CO2 is much higher than it was in the 1930's?

    If so, could you please tell me what other forcing caused the previous Greenland warming of 1920-1940?

    And could you also please explain why you don't think it could be that, which is causing the current Greenland warming?

    As for the increasing Greenland ice melt, I will state once again that evidence of warming (i.e. melting greenland ice) tells us nothing about what caused the warming in the first place.
  12. Adam - Blaming Arctic temperatures on the sun should be carried to the appropriate It's the sun thread:



    Soon is not known for his quality of science, and appears to have neglected the last 30 years of data in his graph.

    See again the CO2 is not the only driver of climate thread: by asserting that CO2 (and CO2 forcings only) don't match the temperature record, you're really pushing a Strawman argument. CO2 is part of the picture, not all of it, but it's become the dominant changing forcing causing recent warming.
  13. Adam... I believe those charts from Soon require a bit more research because they definitely don't agree with other data I'm locating...

  14. Rob Honeycutt

    "My objection here is that you're quoting Dr Box's work as evidence that Greenland shows no signal of AGW which is diametrically opposed to the conclusions of Dr Box himself."

    Once again, personal opinions have no relevance to science. Whether or not Jason Box believes in AGW is irrelevant to the fact that his papers and data show that Greenland was equally warm 60 years ago.

    "You keep trying to assign a global response to a local record."

    Rob do you believe that post 1980 Greenland warming is caused by humans?

    If so do you agree that if it was human caused, then there would at least be a correlation between CO2 and Greenland temperatures?

    Rob it is not unreasonable to look at an area's (and not the world's) climate change and see if it fits with CO2 forcing. The mainstream media has constantly cited Greenland's melting ice as evidence of AGW, yet it has provided no evidence for it. Greenland should be reacting to CO2, yet the fact that there is no correlation pretty much shows Greenland climate change is not anthropogenic.
  15. Adam - I'll repeat it again, look at the CO2 is not the only driver of climate thread for other forcings.

    The early century warming appears to have been due to high TSI and a decided lack of volcanic activity. The 1950-1970 cooling ties into sulfur aerosols, which decreased rapidly after the Clean Air act and other (international) attention to that pollution problem.

    Currently the insolation is dropping, we have a fair number of active volcanoes, and we're warming anyway - due to greenhouse gases, much higher CO2. The natural forcings that caused the early century warming are not currently active. Which is fortunate; if they were we would be warming at twice the current rate.
  16. Definitely something fishy with Soon's chart on TSI. I'm finding numerous sources for TSI and none of them agree with Soon's representation.
  17. KR,

    "Soon is not known for his quality of science, and appears to have neglected the last 30 years of data in his graph. "

    If you had actually looked at the graph presented in Soon's paper you would see that he clearly includes the last 20 years. His data goes all the way up to 2005.

    I am not pushing a strawman argument. If there is no correlation, that shows that there is no significant causation. But the strong correlation between Arctic temps and the sun shows that the sun is most likely the Arctic's dominant driver and not CO2.

    And Rob Honeycutt just so you know Willie Soon has written a much more detailed paper on the link between the sun and the climate, which carries on from his 2005 paper.

    'Solar Arctic-Mediated Climate Variation on Multidecadal to Centennial Timescales: Empirical Evidence, Mechanistic Explanation, and Testable Consequences' by Willie Soon published in 'Physical Geography' (2009)
  18. Rob#13: "they definitely don't agree with other data I'm locating..."

    Kelly O'Day shows another TSI/temp comparison that is vastly different from Soon's.

    Adam#14: "it is not unreasonable to look at an area's (and not the world's) climate change and see if it fits with CO2 forcing."

    Some would consider that a cherry-picking approach.

    "Greenland should be reacting to CO2, yet the fact that there is no correlation"

    You keep repeating that despite the correlation shown by Rob#4.

    Skeptics are known for their criticism of temperature records. If you look at the light blue line in the graph in #4, there are two years in the mid 1920's with extremely large upwards jumps. You've suggested filtering out 2003 and 2010 as anomalous: Why haven't those 1920's anomalies caught your attention? Or is it more convenient to be skeptical of things you want to disagree with than things that appear to support your position?
  19. Adam,

    Citing the much discredited Soon (that is but one of many examples) is not helping your case-- also, correlation is not causation. It seems that you have been gleaning papers from the "Prudent path" document which support your beliefs without being skeptical of their validity or credibility.

    As KE has noted,

    "Recent warming could not have happened without AGW; other forcings don't add up. "

    And you continue to misrepresent Dr. Box.

    I'm sorry, but several people now have very patiently explained the errs of your ways to you, yet you are not listening. You may not realize it, but by choosing to go down this road, you are essentially trolling, and not convincing anyone who has an understanding of these matters.
  20. KR oceanic oscilations play a major role in Arctic climate. They most likely brought in warmer waters, which caused the previous Greenland warming and are most likely what caused the most recent Greenland warming. KR natural factors are indeed still present and can explain observed climate changes.
  21. Adam... "Rob it is not unreasonable to look at an area's (and not the world's) climate change and see if it fits with CO2 forcing."

    It is not unreasonable to look at an area to see if it is consistent with CO2 forced warming. But it is not reasonable to locate what you believe to be an inconsistency and dismiss all other information because of it. The appropriate scientific response would be to question why there is an inconsistency or even if your perception of the inconsistency is even accurate.

    That's how scientists get research money. "I found an area of science where we currently lack an understanding of the data or response being measured. Please give me money so we can better understand why this is the case."

    You have gone the other direction and decided because you think there is no correlation that the entire theory of AGW is wrong in spite of the overwhelming other evidence to the contrary. So, you are left with no theory, no explanation, nothing other than your desire for AGW to be wrong.
  22. "You've suggested filtering out 2003 and 2010 as anomalous: Why haven't those 1920's anomalies caught your attention? Or is it more convenient to be skeptical of things you want to disagree with than things that appear to support your position? "

    Muoncounter, the 2003 and 2010 spikes were just one year events, which quickly went back to normal straight after. Could you please explain how it could have been anthropogenic co2, which caused those two spikes, and why it went straight back down. The temperature in Greenland for 1920-1940 didn't have many outlier temp anomalies, it stayed at roughly the same trend over those few decades.
  23. Albatross, blog posts are not published and do not warrant a reply. Of course many pro-AGW websites are going to attack him and say that he is wrong. Only published criticism counts.
  24. Rob et al.,

    There is something horribly wrong with those TSI data in Soon's figure, especially after 1960, where he has increasing TSI and all the reputable data that I am familiar with shows a slow decrease in TSI since the sixties. Note too that in the Soon paper, the TSI the are inferred/estimated.......

    I really have no idea how the reviewers' missed that glaring problem.
  25. Looking at Soon's paper he relies on Hoyt and Schatten [1993] (and update from D. Hoyt, 2005) for his TSI data. I find this data heavily referenced on all the standard denier websites.
  26. "I'm sorry, but several people now have very patiently explained the errs of your ways to you, yet you are not listening."

    No, I have not been answered. You just keep repeating the same arguments over and over again (e.g. that Greenland is not the whole world) and are not giving the issue appropriate thought.
  27. Albatross@19
    I do not think that Adam is "misrepresenting Dr. Box." He is using Dr Box's research to come to a different conclusion than the Dr himself.

    Adam@20
    "KR natural factors are indeed still present and can explain observed climate changes."

    Natural factors are still at work, no one would deny this. There seems to be great disagreement with your second assertion though. One paper by Soon is a good start to supporting your argument, but why is his dissenting opinion more credible than all the others he disagrees with?
  28. "The appropriate scientific response would be to question why there is an inconsistency or even if your perception of the inconsistency is even accurate. "

    So, once again, could you please explain to me why there is no correlation between CO2 and Greenland temperature variations.

    You do agree that there is no correlation with CO2, right?

    So therefore could you please explain to me how it is possible that CO2 is the driver of Greenland's climate despite the fact there is no correlation.
  29. Adam,

    Re blog posts, I concur, but to a point. Please explain why Soon's TSI data after 1960 contradict the reputable (and official TSI ) data. His paper falls to pieces right there.
  30. Adam#20: "the previous Greenland warming"

    In Soon's temperature graph shown by Adam#9, the temperature jumps by more than 1 degree in 1920. In the data available from Polyakov et al, this jump does not occur until the mid 1930s.

    Does this suggest that the surface temperature data for the early 20th century Arctic isn't all that reliable?
  31. "So, you are left with no theory, no explanation, nothing other than your desire for AGW to be wrong. "

    Rob Honeycutt, I have explained why Greenland and Arctic temperature variations are not man made. I do not think that anyone here, has properly answered my points. Yes, Greenland is not the whole world, but polar regions are especially important for detecting any effect caused by anthropogenic greenhouse gases.

    Therefore, seeing that there is no correlation between Greenland temperature and co2, is not 'cherry picking' and is indeed valid as evidence against AGW.
  32. Adam - "...oceanic oscilations play a major role in Arctic climate. They most likely brought in warmer waters, which caused the previous Greenland warming and are most likely what caused the most recent Greenland warming."

    To which I will reply: Evidence? Do you have any evidence of such changes in Arctic circulation showing correlation to temperatures? There's certainly plenty of evidence for the various known forcings driving global temperatures, along with the Arctic amplification - you're asking for an unproven hypothesis with no evidence to supplant a well supported hypothesis that matches the data.

    I believe the term is "wishful thinking". If that's all you have, then you're not even hand-waving. As has been said here before - You're entitled to your own opinion - but not your own facts.

    --

    "You do agree that there is no correlation with CO2, right?"

    Sigh - There's excellent correlation with known forcing factors, including CO2; your strawman argument against CO2 as the only factor is both repetitive and deeply incorrect.

    Your arguments are unsupported, incorrect, and generally empty of data, theory, or (in my opinion) content. Please read some of the references you have been pointed to.
  33. "Please explain why Soon's TSI data after 1960 contradict the reputable (and official TSI ) data. His paper falls to pieces right there."

    Albatross, first of all from 1960 to 1980 the correlation did indeed increase. I think it is fair to say that the correlation between the sun and the climate (supposedly) ends at around 1981, which is the time of the solar maximum.

    However, when you use tropspheric temperature data instead of solar data you can see that the correlation does indeed continue. As shown by the graph below, for the past 20 years there is a perfect correlation between cosmic rays and tropospheric temperature. Albatross, the link between the sun and climate did not end.



    http://icecap.us/images/uploads/SvensmarkPaper.pdf
  34. Adam
    "So, once again, could you please explain to me why there is no correlation between CO2 and Greenland temperature variations.
    You do agree that there is no correlation with CO2, right?"

    and

    "I have explained why Greenland and Arctic temperature variations are not man made."

    I do not believe you have adequately established or supported this position. No. If you are going to take a position contrary to the majority opinion then you have to provide a lot more evidence than you have.
  35. KR read this paper

    http://www.lanl.gov/source/orgs/ees/ees14/pdfs/09Chlylek.pdf

    " the Arctic temperature changes are highly
    correlated with the Atlantic Multi-decadal Oscillation
    (AMO) suggesting the Atlantic Ocean thermohaline
    circulation is linked to the Arctic temperature variability on
    a multi-decadal time scale."

    "The Atlantic
    Ocean thermohaline circulation multi-decadal variability is
    suggested as a major cause of Arctic temperature variation."

    The Arctic multidecadal oscilation can indeed explain the temperature changes observed in the Arctic.

    "Your arguments are unsupported, incorrect, and generally empty of data, theory, or (in my opinion) content. "

    KR I don't think you have actually read my comments. I clearly explained it in detail and provided peer reviewed studies.
  36. Adam#22: "the 2003 and 2010 spikes were just one year events, which quickly went back to normal straight after. Could you please explain how it could have been anthropogenic co2, which caused those two spikes,"

    No one said those one year events were caused by CO2.


    "The temperature in Greenland for 1920-1940 didn't have many outlier temp anomalies, it stayed at roughly the same trend over those few decades. "

    That's just not true. There is in fact a 1.2 degree jump in 1919 (I just plotted the Polyakov data). If that's in error, your rapid 1930s warming is a thing of the past. Wouldn't a real skeptic question an entire conclusion that rests on the validity of a single data point?
  37. Anyway, this is getting pretty tiring.

    I'm leaving now. I'm going out tomorrow, so I probably won't be able to comment again until tomorrow evening.

    So long.
  38. Adam - Thanks for repeating the Chlylek link.

    Looking at their paper, it's quite evident that Arctic (and for that matter Greenland) temperatures follow the global temperature trends. Their statement that Arctic amplification is insufficient to explain the magnitude of such trends is a bit more iffy, however, bordering on odd. I would be interested in the Arctic expert's opinions on this.

    The AMO data is also quite interesting; given that the AMO appears to also track the temperature anomaly record, however, I would consider this a possible correlation to temperature (and changing wind patterns) as a first cause - otherwise you have to argue that the AMO is affecting global temperatures, including the Southern Hemisphere, which I quite frankly would have to see some strong evidence (and a plausible mechanism) for before accepting.

    Have you at least dropped the strawman argument about CO2 being the only driver of climate?
  39. 33, Adam,

    I love that graph, and that paper!!!! I love them!!!

    The caption for the graph, in particular referencing the lower graph where things match so very nicely between cosmic rays and tropospheric temperatures, says this:
    The lower panel shows the match achieved by removing El Niño, the North Atlantic Oscillation, volcanic aerosols, and also a linear trend (0.14 ± 0.4 K/Decade).

    This is great.

    Remove El Niño. Check!

    Remove North Atlantic Oscillation. Check!

    Remove volcanic aerosols. Check!

    Remove global warming. Check!

    Wait! Remove global warming?

    Yes. If you take global warming out of the picture, the match is perfect.

    They have basically proven for us that cosmic rays have nothing whatsoever to do with current warming.

    Does it have an influence on natural short term variations? Apparently (although I'm not so sure that these are people I trust, but since I could care less about short term variations, it doesn't matter much).

    But does it have any influence on global climate? Is there any attribution whatsoever for the current warming trend due to cosmic rays?

    They have proven that this answer is "no."

    [I also despise anyone who puts out a PDF of a paper and tries to make it look like a peer reviewed journal article, which this clearly is not. For shame.]
  40. @ KR

    Not an expert an the Arctic, but my read on Chylek2009 is this:

    The Arctic temps are heavily influenced by the AMO, which makes sense. The problem is, and perhaps Robert Way could provide some insight on this, that (as currently defined), the AMO is not properly detrended for the post-1975 warming. The detrending performed is linear, but the warming itself since 1975 is non-linear. Tamino made that observation here, that (under the linearly detrended AMO definition, the post-1975 increase reflected in the AMO is because of global warming. It is the residue of global warming.

    That being said, Chylek 2009 only says the rates of Arctic Amplification were greater in the earlier time frame than the later. It does not say that the earlier was warmer.

    Tamino also removes the cyclical exogenous factors from the temperature records to show this:



    My two cents. HTH.

    The Yooper
  41. Adam... "I have explained why Greenland and Arctic temperature variations are not man made."

    No, you have explained why you believe there is an inconsistency between the warming period in the early 20th century and the warming in the latter 20th century, making the wrong assumption that both had to be directly correlated with the increased concentrations of atmospheric CO2.
  42. Sphaerica... You also have to look at Fig 3 in Adam's Svensmark/Friis-Christensen PDF and then compare it to the same data at Wood For Trees.
  43. All,

    Re the dubious TSI data from Soon. Here is a graph by Kopp and lean (2011; both (eminent scientists in this field) that shows a distinct downward trend between 1979 and 2010:



    Caption: Contributions to the empirical model of temperature shown in Figure 1 are broken down here: El Niño Southern Oscillation (purple), volcanic eruptions (blue), anthropogenic effects (red), and solar irradiance (green).

    [Source]

    and compare those data with the SAT data:



    Caption: Global surface temperature from 1980 to 2010 has risen by 0.4 degrees Celsius (0.72 degrees Fahrenheit) according to Climate Research Unit measurements (black) and an empirical model (orange). (Courtesy Kopp and Lean), same source as above.

    Not surprisingly, Kopp and Lean conclude that:

    "Using this model, Lean estimates that solar variability produces about 0.1°C global warming during the 11-year solar cycle, but is not the main cause of global warming in the past three decades."
  44. 42, Rob,

    Wow. Okay, so this guy has a really, really deep bag of scientific "tricks." And the deniers are all up in arms about "hide the decline?" Sheesh.

    Adam,

    Sorry, but as a source, that one is downright pathetic. Please check your sources more carefully in the future. If you don't mind taking a bit of advice, usually I find it helpful to be skeptical about these sorts of things, read them carefully, and look into them in some detail. Otherwise you could find yourself falling for some very alarming scientific hoaxes.
  45. Okay I'm back.

    KR I have never claimed that CO2 is the only driver of climate change. Could you please point out where in my comments I said that?

    Sphaerica you are completely misunderstanding what the authors did in the paper I provided. The top graph is of tropspheric temperature compared with changes in cosmic rays.

    The radiosonde data shows a lot less warming over the past 30 years than the surface station data.

    The bottom graph is the removed effects of el nino, volcanoes and the NAO. The removal of the effects caused the slight warming trend to disappear. You completely misunderstood what they did. They didn't get rid of the warming for no reason. The removal of those effects (natural forces) simply effected the total trend after they were removed.

    Daniel Bailey, once again blog posts are not published. Tamino didn't really provide proper evidence that the AMO was the result of the warming. In Chylek's paper they theorised that Arctic temperature was caused by the AMO which makes much more sense.

    Albatross, once again the graph you showed is ignoring Svensmark's cosmic ray theory and using surface data. Cosmic rays can indeed still be the major cause of warming of the past three decades. Read Svensmark and Friis-Christenson's paper. See also here

    Sphaerica I think you're the one who needs to read papers more carefully, since you completely misunderstood what it did.
    Response: [DB] Tamino's graph is based on removing exogenous factors like volcanic eruption effects and cyclical things like the NAO or El Nino or the AMO (since oscillations have no NET effects). Tamino's comments showed that the changes reflected in the AMO IS the global warming signature BECAUSE the warming is non-linear. So a detrended AMO still has the global warming signal in it.
  46. Adam#45: "Cosmic rays can indeed still be the major cause of warming of the past three decades. "

    No, they cannot. See the thread 'Its cosmic rays'.
  47. muoncounter, read the paper and link I provided. The correlation only ends when you use surface station data. Cosmic rays still correlate with radiosonde temp data and ocean temp data.

    Read also the link I provided.
    Response: [Dikran Marsupial] Results that are only valid if you select the "right" dataset is what is known as "cherry picking". Results that hold true regardless of which dataset you use are described as "robust".
  48. Adam @45,

    "The radiosonde data shows a lot less warming over the past 30 years than the surface station data."

    That is incorrect. They in fact show a slightly higher rate of warming than some global SAT products. And the radiosonde data rate 2010 as the warmest year on record, warmer than 1998 even.



    Svensmark has a GCR hypothesis, hardly a fully fledged theory. I doubt very much that the paper you linked to demonstrates "Cosmic rays can indeed still be the major cause of warming of the past three decades". But I'll have a look.

    I do not understand why you insist on repeatedly making demonstrably false statements.
  49. Adam#47: "The correlation only ends when you use surface station data. Cosmic rays still correlate with radiosonde temp data and ocean temp data."

    And in your view, that is somehow valid? A correlation which doesn't fit a significant part of the data is no correlation at all. If you're getting your information from the same site that provided the graph you linked in #33, did you miss the obvious nonsense (see Sphaerica#39)associated with the lower graph?

    Your link in #45 is to motl's blog; that's not a credible source. See the 'its cosmic rays' thread before you go on touting Svensmark.

    Please stop claiming you've proved something simply because you've repeated it several times. One other poster tried that, resulting in a thread of over 800 comments.
  50. "Tamino's graph is based on removing exogenous factors like volcanic eruption effects and cyclical things like the NAO or El Nino or the AMO (since oscillations have no NET effects). "

    But once again Tamino's graph used surface station data. Satellite and Weather balloon data have been shown to be much more reliable.

    Albatross, the dataset you use is from NCDC. That isn't the one used in their paper. The radiosonde data used was HadAt2. Your graph doesn't really present the temperature anomalies clearly, but the graph I showed did.

    You will also see that weather balloon data, also matches up with the satellite data.
    http://img136.imageshack.us/img136/9021/hadat2rsstropics.png
    Response: [Dikran Marsupial] Cherry picking again.

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