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Global trends and ENSO

Filed under: — gavin @ 4 July 2008 - (Español)

It’s long been known that El Niño variability affects the global mean temperature anomalies. 1998 was so warm in part because of the big El Niño event over the winter of 1997-1998 which directly warmed a large part of the Pacific, and indirectly warmed (via the large increase in water vapour) an even larger region. The opposite effect was seen with the La Niña event this last winter. Since the variability associated with these events is large compared to expected global warming trends over a short number of years, the underlying trends might be more clearly seen if the El Niño events (more generally, the El Niño – Southern Oscillation (ENSO)) were taken out of the way. There is no perfect way to do this – but there are a couple of reasonable approaches.

In particular, the Thompson et al (2008) paper (discussed here), used a neat way to extract the ENSO signal from the SST data, by building a simple physical model for how the tropical Pacific anomalies affect the mean. He kindly used the same approach for the HadCRUT3v data (pictured below) and I adapted it for the GISTEMP data as well. This might not be ideal, but it’s not too bad:



(Each line has been re-adjusted so that it has a mean of zero over the period 1961-1990).

The basic picture over the long term doesn’t change. The trends over the last 30 years remain though the interannual variability is slightly reduced (as you’d expect). The magnitude of the adjustment varies between +/-0.25ºC. You can more clearly see the impacts of the volcanoes (Agung: 1963, El Chichon: 1982, Pinatubo: 1991). Over the short term though, it does make a difference. Notably, the extreme warmth in 1998 is somewhat subdued, as is last winter’s coolness. The warmest year designation (now in the absence of a strong El Niño) is more clearly seen to be 2005 (in GISTEMP) or either 2005 or 2001 (in HadCRUT3v). This last decade is still the warmest decade in the record, and the top 8 or 10 years (depending on the data source) are all in the last 10 years!

Despite our advice, people are still insisting that short term trends are meaningful, and so to keep them happy, standard linear regression trends in the ENSO-corrected annual means are all positive since 1998 (though not significantly so). These are slightly more meaningful than for the non-ENSO corrected versions, but not by much – as usual, corrections for auto-correlation would expand the error bars further.

The differences in the two products (HadCRUT3v and GISTEMP) are mostly a function of coverage and extrapolation procedures where there is an absence of data. Since one of those areas with no station coverage is the Arctic Ocean, (which as you know has been warming up somewhat), that puts in a growing difference between the products. HadCRUT3v does not extrapolate past the coast, while GISTEMP extrapolates from the circum-Arctic stations – the former implies that the Arctic is warming at the same rate as the rest of the globe, while the latter assumes that the Arctic is warming as fast as the highest measured latitudes. Both assumptions might be wrong of course, but a good test will be from the Arctic Buoy data once they have been processed up to the present and a specific Arctic Ocean product is made. There are some seasonal issues as well (spring Arctic trends are much stronger the summer trends since it is very hard to go significantly above 0ºC while there is any ice left).

Update: A similar analysis (with similar conclusions) was published by Fawcett (2008) (p141).

The ENSO-corrected data can be downloaded here. Note that because the correction is not necessarily zero for the respective baselines, each each time series needs to be independently normalised to get a common baseline.


245 Responses to “Global trends and ENSO”

  1. 151

    In re 138:

    #129 Furrycatherder

    Here’s a mantra for you. Correlation does not equal causation (neither does no correlation equal causation).

    You may wish to try that mantra on someone else. While correlation does not imply causation, there is only so much one can ascribe to chance, and proposing alternate explanations allows one to test those proposed explanations retrospectively. For example, exiting any of the minima whose entrance and exit corresponds to the aa index, but not to changes in CO2 concentration rules out their being caused by man-made CO2. Their short term rules out orbital forcing. The lack of CFCs rules out ozone depletion, etc. Occam’s Razor eventually demands that the most obvious cause — and the one that has the only significant correlation — is the correct cause. Namely, short term changes in temperature, such as seen during Dalton, Maunder, Spoerer, etc. minima are related to changes in total solar output.

    Some things are coincidental and some complimentary in effect. Getting climate models to work right needs positive forces and negative forces of the existing elements that impose forcing. Solar variance is just one piece of the puzzle.

    Right, and based on past observations (see Dalton, Maunder, Spoerer, etc. minima), the relationship of planetary orbits to periods of increased or decreased solar output, and the recent geometry of the various planets, and the solar barycenter, odds are pretty good that we’re due for a decade or more period of reduced solar output.

    The biggest problem people have in understanding this global warming event is narrowly scoped data and improper context of that data when weighed with the big picture of global climate.

    I’d argue that the biggest problem is “All or Nothing” thinking, a logical fallacy in which one argues that singular causes are responsible for all observations.

    Narrowly scoped, the present situation is either strictly caused by solar variations (in which case I believe the “solar variation” crowd will inappropriately gain credibility over the next 10 to 20 years as we work through the next below average solar cycle or two), or strictly caused by CO2 concentrations (in which case I believe the “CO2 concentrations” crowd will inappropriately lose credibility as the non-linear relationship (sensitivity is based on doublings, not linear increases) between increased CO2 concentrations, and forecasts for below average solar cycles reduces the longer term upward trend in global temperatures).

    More broadly scoped, a variety of factors are present, some of which are widely used by skeptics of global warming, and others which are used by proponents. The truth, suggests our dear friend Occam, is likely somewhere in between.

    Also, reread, my post to you #59 above. Further warming is in the pipeline. Heck, we’re doing such a great job at warming the planet, we don’t even need sunspots to do it. Aren’t we industrious! Who needs that extra .3 W/m2 anyway…

    Why? My re-reading it isn’t going to change your all-or-nothing approach and my belief that it is going to result in a diminished response to the problem. How about you actually read my posts for comprehension, rather than as something to knee-jerk rebut?

  2. 152

    Pardon me for being somewhat hypothetic (or pathetic as the case may be). I am still trying to figure out relationships.

    The SOI interacts with ENSO and deep ocean temperature is a strong driver. I don’t understand the lag times of influence yet, but am still reading.

    I am hypothesizing that the El Nino/La Nina oscillation is kinda like the Milankovitch cycles, where you have some big players (EOP) dancing through time.

    – Thermohaline Circulation
    – Schwabe Cycle
    – Seasonal SST Variation

    and that these

    are playing upon the SOI, NAO, PDO, AMO, ENSO

    Anyone want to play in my thought pool? Is anyone modeling this sort of relationship already? What other players may be strongly influencing here?

  3. 153
    cce says:

    On the topic of temperature series in general, can anyone point me to an archived copy of the 5.1 version of the UAH lower troposphere data? i.e. The version before the diurnal correction?

  4. 154
    Mark says:

    Allen (#150)

    Problem is you’re not just sitting on the fence. You’re, um, “fertilizing the field”. And people trying to work in it keep stepping in it.

  5. 155
    Doug Bostrom says:

    #127 Allen:

    Thanks. I suspected as much. That would be Steve McIntyre, still coasting on the momentum of “Hockey Stick Histrionics” as produced and directed by impresario Joe Barton, a costly production which in spite of heavy promotion and vast expense proved a flop with the critics. McIntyre’s more recent poetry (“Ode to Defamation of Jim Hansen”) can also be experienced as dramatic interpretations, performed in a workmanlike manner by such authors as the discredited “Steve Goddard”.

  6. 156

    #150 Allen

    My own ignorance aside, I am an objectivist in many ways. In fact, my uncle worked with Any Rand and wrote the book CAPITALISM (he likes it spelled in big letters). I am a huge fan of Ayn Rand, but I disagree with the way most people interpret her message in the ‘Fountainhead’ and ‘Atlas Shrugged’. She was talking about value in my read, not profit without attachment to value outside of an objective market. In fact I disagree with my uncle in many of his assumptions in his book as they are short sighted and mechanistic, whereas I am more confident that prescience rather that reactivity as a better rule for calculating economic policy considerate of sort/long term economic system health, but that is another discussion.

    I can only agree that being objective, to the extent possible is always important. But that is why I stressed relevance and context. This is a clean argument inside the science that is well known understood. And it is very dirty in the represented science that is out of context and less relevant, but held and proclaimed by some as science. That is confusing a lot of people unfortunately.

    Yes, there are many questions still, but not about what is already known. I assure you personally, you will discover this to be true as well. This part of the argument is pretty much done. GHG’s are the key to the models to explain this global warming event.

    The only possible argument against what is known is we don’t know what we don’t know. It sounds like a good argument until you realize that we know what the forcing components are in the atmospheric composition and we know how much forcing they provide, and we know the source of those components and how many ppm or ppt of those components exist as a result of human industrial process. That is quantifiable.

    I welcome all objective people to the debate :)

    Best,
    John

  7. 157
    Mark says:

    #149:

    So you understand it to be option 3, too complex, yet you still know it will work in one particular way.

    Try skepticism on that idea for a change.

  8. 158
    Timothy Chase says:

    John P. Reisman (#156) wrote:

    My own ignorance aside, I am an objectivist in many ways. In fact, my uncle worked with Any Rand and wrote the book CAPITALISM (he likes it spelled in big letters). I am a huge fan of Ayn Rand, but I disagree with the way most people interpret her message in the ‘Fountainhead’ and ‘Atlas Shrugged’…

    John,

    Your uncle’s name is George, married to Edith. George, Alan Greenspan and Frederick A. Hayek had Ludwig von Mises as at a teacher at one point. Wow… I believe I offered to install a search engine for your uncle at one point. Can’t remember whether or not he accepted. A few people did — a certain dialectician you might know as well as a fellow who has been described as the Tom Brokaw of New Zealand.

    I should have guessed.

    As I see it, for the objective soul, no value or loyality can ever be placed before one’s adherence to reality, and objectivity demands that we recognize reality for what it is irrespective of ideology. It would appear that you see things the same way.

  9. 159
    SecularAnimist says:

    I will resist the temptation to discourse off-topically about Ayn Rand, except to note that her use of the term “objectivism” was ironic given that, as John Reisman notes, her philosophy emphasized values, and the capacity to value is the essence of subjectivity.

    As I understand the terms, “objective” refers to that which is accessible to multiple observers, while “subjective” refers to that which is accessible only to one observer. The scientific method, with its emphasis on replicable, quantifiable empirical observations, is powerfully suited to the investigation of objective phenomena, but has a more difficult time with the investigation of subjective phenomena. This does not mean that subjective phenomena are less “real” than objective phenomena, only that they are less readily accessible to traditional scientific methods of investigation.

    When discussing various observers’ attitudes towards some body of objective data, such as the data underlying the science of climate change, those who evaluate the data without undue ideological bias might better be described as “impartial” rather than as “objective”.

  10. 160
  11. 161
    sod says:

    The first thing that we can see is that there is very little divergence between the two. 0.0163 C for the 125 month period. The unadjusted HadCrut3v data fell by .00375 C over that interval and the adjusted data rose by 0.0125 C.

    this is Tilo Reber at his best. when he started doing his “analysis” he still didn t understand how a trend line is calculated. (see the discussion on deltoid)
    now his useless stuff is repeated all over the denialist blogosphere. (see watts up)

    so, what is/went wrong?
    Tilo started by loking at a 10 year period. (yes, he was told that this is stupid) he tried to show, that the choice of start and end date (yes, he was told that he is cherry picking) does not influence the result.
    he came up with a pretty bizarre method: calculating different trends for the nino/nina phases during those years and summing them up. (yes he was told that this was dubious)
    he came to the conclusion, that ENSO does actually make the temperature trend over the last decade look POSITIVE. (yes, people told him that they had doubts) so he followed that the declining temperature (sic) was in spite of Enso events, not (partly) because of it.

    you don t believe me? well, it is online here:
    http://reallyrealclimate.blogspot.com/2008/05/ten-year-hadcrut3-enso-effects.html

    so now real scientists do a real analysis. they come to the OPPOSIT conclusion:

    when compensated for ENSO, temperature DOES increase.

    but instead of being all humble, Tilo seems to believe, that this result supports his ideas.

    he also is proud, that the difference between his “method” (the one showing that ENSO effect gave a positive trend over the last 10 years, 1998!) only shows a difference of 0.029°C over ten years to the real one. (in a century, that is just 0.3°….)

    (pretty tired, so stopping here…)

  12. 162
    Tilo Reber says:

    “so now real scientists do a real analysis. they come to the OPPOSIT conclusion:”

    That’s a truely pitiful conclusion Sod. My result showed a very slight up trend contributed by the ENSO. The Thompson result showed a very slight down trend contributed by ENSO. Tiny differences around zero do not constitue an “opposite conclusion”.

    In Gavin’s words about the Thompson method:
    “There is no perfect way to do this – but there are a couple of reasonable approaches.”

    So implying that Thompson’s results are perfect and that mine are suspect when there is such a small difference between the two is truely absurd. By the way, you have yet to show any reason why my approach is not reasonable.

    But with all of the squabling aside, the conclusion that I reached remains true. We have a decadal flat trend and ENSO has not caused it. As you can clearly see, the Thompson ENSO corrected warming trend since 1998 is +0.0125 C. You can call that a positive trend if you like, but I call it flat. One century of such a trend would give you less than .125 C. That is flat.

    So wave your hands all you like Sod. My conclusions on Deltoid were correct. We have a missing .187 C of C02 forced warming for the decade and no way to account for it.

    By the way Sod, you are now more than half a million square kilometers behind in the Arctic sea ice race.

  13. 163

    #151 Furrycatherder

    First, that mantra applies to all involved in science (along with many others), and for that matter all involved in reason; which is the purpose of this site (science and reason), if it does not appeal to you, maybe you are here for a different purpose?. I don’t actually like ascribing anything to chance, but between chaos theory, quantum theory, Newtonian physics and the shear number of causal relationships in the universe, I can’t explain everything in detail. So at a certain level of mathematic probability, we must deal with the numbers we have and look forward to the numbers we will get.

    At the same time, if you know what the numbers you have mean and that explains things pretty well, then that is what you work with. In other words, you go to war with the numbers you have, not the numbers you want.

    Please show me your valid, relevant, explanation in context with the forcing level that you are talking about. I don’t know your references so you might want to share them, unless they are a secret and you just want me to guess why you think solar is the cause of our current global warming event. Cycle 22 and 23 just don’t have enough energy to support the known forcing. In fact, none of the solar cycles since Galileo first started looking around 1611 had enough energy to increase forcing by 1.9 W/m2.

    As to Sir William of Ockham, you’ve been watching too many movies. Ockham’s Razor (from Ockham, England) is, Entia non sunt mulltiplicinda praetor nesectita tatum, by my recollection. And that means entities should not be multiplied more than necessary. The Jodie foster interpretation was, I would say, a loose interpretation, but not too uncommon. The idea of all things being equal the best solution is the most simple does not apply to your argument; simply because all things are not equal.

    It is fairly obvious you are trying to state that solar is the main driver of our current climate change. Am I wrong in this ‘comprehension’? My own interpretation of Ockham’s razor is don’t make a Rube Goldberg out of it if you don’t have too, or don’t split hairs when the issue is the whole head and the hairs are not the relevant problem. Einstein countered/complimented by saying make things as simple as possible, but not any simpler.

    I don’t think that Sir Ockham intended you to only examine a narrowly scoped data set in a wide array of complexity and try to build a conclusion on it, especially since other relevant information is known to be influential and changes the overall result and understanding. And while I may be wrong about my interpretation of your incorrect use of the Razor, I don’t think so. Nevertheless, you are trying to match something that simply does not match.

    I comprehend from your posts, that you are asserting that this global warming event can be attributed merely to solar forcing. If that is not your position, then why didn’t you say I don’t think solar is driving this global warming event? If that is your position, there just isn’t enough of ‘it’ (solar forcing) to support your point when weighed against the actual known forcing. (see my previous post #59… oh, that’s right, you don’t want to read that again).

    I would love to look at the data you are referring too that proves your point. Please direct me with some links.

    I’ve read your posts and rather than copying each statement of yours, I will address them generally. Your posts indicate a fundamental misunderstanding of the known understanding on the matter of the relevant science of this global warming event.

    I think the drunk driving analogy explains the natural variation on a different road pretty well. natural is not overriding human caused global warming, it is merely causing swerves on a different, path while we are warming. So yes, solar is influencing the climate in its natural cycle, but on a different trendline than the expected path without the GHG forcing. Again, you need to look at this in long term trends (id est, 30 years or more) and include ‘all’ relevant forcing components. Or are you only speaking about changes outside of the aggregate forcing?.

    Maybe you are not being clear enough in your posts. Your response indicates I ruffled your fur. Maybe I don’t understand your posts, maybe they are not that comprehensible, maybe you wrote words you did not intend to write. How precisely, do I not comprehend your posts? I think you are trying to say that this global warming event is caused by solar influence. Please correct me if that is wrong on my part.

    Proposing alternate explanations is one thing, proposing relevant alternate explanations is another. How precisely do you attribute the amount of forcing in the system of 1.9 W/m2 to a solar forcing of .3 W/m2. In what universe does .3 = 1.9 or 1.6?

    On what are you basing your solar assumptions on show me relevant work, peer review, peer response, show me reason, show me data that is contextually relevant to your assertion. I can offer an alternate explanation but that does not mean it will have any relevance at all. I’m kinda creative, I could make something up that sounded convincing to those that did not understand the components involved. But that would be arrogant of me, and in context of what this all means downright unethical.

    I’m not telling you anything that is not in the data that is currently understood so where am I wrong? I’m not afraid to say I’m the biggest idiot on the planet, knowing only the tinniest fraction of knowledge that exists and trying to understand complex things? But where am I wrong and where is the data that proves it.

    So when I come across a bunch of scientists doing empirical work that is comprehensive in nature and those scientists come to a consensus view about a particular subject, and the data supports the view, and the models support the view, and I’ve investigated it pretty thoroughly and came to similar conclusions of the basic science, I must admit I find that credible. Especially in the face of no reasonable contravening arguments that can hold water, such as ‘it’s solar’.

    I actually agree with your statement of “all-or-nothing” to a degree but again what is the relevant context, really? As I stated in the sentence to which you are responding with that statement, big picture is more important that all or nothing in this context, so why are you arguing that point?

    I’m not sure your consideration of non linear is in context either. The non linear nature of forcing is related more to positive feedbacks and changes that are still being studied, such as cyclic changes in moisture content and regional dispersion, the methane cycles in the ocean or the potential of methane clathrate/hydrate release , and of course the race to feed more people on a planet which will inevitably add more nitrous oxide to the atmosphere and create more dead zones in the oceans, droughts, floods, fires, dogs and cats living together, mass hysteria…. oops, different movie.

    You are maybe trying to be fair to the argument or you are fence sitting or you’re here for some other reason. Either way, you are missing the fundamentals of climate forcing and seemingly cherry picking your data to support your argument.

    I do not have an all or nothing approach, I examine the data and the models and the context and the relevance. It’s pretty simple stuff when you get to the aggregate fundamentals.

    You are obviously intelligent but intelligence does not equal understanding if pieces of the puzzle are either missing or ignored. You don’t want t re read my previous post, so I will say it again.

    Just for fun, let’s postulate what would happen to our warming trend if the sunspot activity died. Please for give my gross oversimplification.
    If we have no sunspot activity we lose .3 W/m2 of forcing.
    The current forcing is calculated around 1.9 W/m2
    1.9 – .3 = 1.6 W/m2
    Well, looks like we will still warm. As mentioned previously, there is a lot of extra forcing in the system and it will take time for the ocean to absorb the energy and give us a new equilibrium to forcing ration/balance.
    Why don’t we call the next extended solar minimum the ‘I wish it were cooler minimum’. That might be more appropriate.

    Unless I am wrong in my ‘comprehension’ of your posts. you are trying to say that solar is the main driver of this global warming event (please do correct me if I am wrong). The simple fact is that humans put some extra greenhouse gasses into the atmosphere and that is causing us to warm outside of the natural climate path. What am I missing here?

    I’ve read a bit on your blog and I’m very happy that you have installed an energy efficient AC unit. But that still does not mean that solar is the cause of this global warming event. Now, if I have this all wrong and that is not what you are saying, I apologize in advance. I try to understand things, but I have to admit that I’m not perfect either. hey maybe I’m just some moron and you should ignore me entirely?

    On the other hand, I should also compliment you that as far as I’ve seen, you have not pulled the hey, we don’t know what we don’t know argument. It may benefit your comprehension of this global warming event if you examine it from a perspective of forcing components and influences, rather than merely hey some data fits some other data.

    Okay, I changed my mind, I will place some of your statements in this post for context.

    “I know there is a strong tendency of most pro-global-warming posters here to ignore that giant ball of fire and its cyclical behavior, but on what planet does ignoring the Dalton and Maunder Minimums make sense? And when the Gore Minimum brings another short term cooling trend, how do you propose explaining that so people understand the difference between short term cooling, long term warming, and the need to do something?”

    – No one is ignoring the giant ball of fire and its behavior; no one is ignoring the Daulton and Maunder minimums. The Gore minimum statement is downright immature.

    “My particular form of denialism isn’t dangerous because it advocates a massive shift to renewable energy forms to avert an economic disaster which will also avert an environmental one. Based on that, I’m a relatively harmless crackpot.”

    – I’m not sure how to ‘comprehend’ what you are saying in what seems to be an obtuse convolution of I’m a denialist that thinks we need to save the environment from??? what the evil economics like the Keynesian model… or just a general break down because of peak oil? And don’t worry, I don’t believe you are “a relatively harmless crackpot”.

    fly in the face of what I understand to be well-established science. What are you going to say when the sun stays spot free for a while longer and the well-established relationship between a spot-free sun and lower global temperatures begins to contradict your remarks? When year after year, there are no new global high records, what do you say?

    – What are you going to say when the sun spots don’t return and the thermal system continues to absorb the existing forcing and raises global temperatures and we get new global high records? Lest we forget that 2007 tied as second warmest year in modern history while solar was in minimum phase and we were in la nina.

    If, as folks like myself argue, the puck-hitting-part is dominated by strong solar cycles 22 and 23, you still have to deal with the rise in global temperatures from before that. And if cycles 24 and possibly 25 are below normal, someone has to explain “natural variability” so that declines in either absolute temperature or rate of increase don’t serve to discredit the overall “increases in CO2 level cause increases in global temperature”.

    You are an absolute expert at misdirection in my opinion. I think if you work a little harder at it you can make it even more confusing for ‘folks’. You are indicating that 22 and 23 were ‘strong’ which caused the hockey stick part that hits the puck, but 18 and 19 were stronger while GMT was cooling, hmmm….

    I guess I’m confused because I have looked at the correlation between the aa index and global temperatures and there does appear to be one. So other than say “Hogwash!” or something similar, how about pointing me at something which explains why there is no correlation.

    – First, the aa index you are referring to http://www.realclimate.org/index.php?p=42 breaks any obvious correlation in 1990. You seem to be falling into the same trap that the great global warming swindle movie fell into. . this is a good time to mention again that correlation is not causation, especially when the correlation breaks but the other rules still apply. you really need to understand forcing levels to get this in context. How about you go reread my post #59… oh dang it, I forgot you don’t reread.

    Why? My re-reading it isn’t going to change your all-or-nothing approach and my belief that it is going to result in a diminished response to the problem. How about you actually read my posts for comprehension, rather than as something to knee-jerk rebut?

    – What on earth does your rereading my post have to do with me changing anything. First I don’t have an “all or nothing approach”. The statement itself is extremely odd. I actually believe there are positive and negative forces, but based on the data models and observations the positives are outweighing the negatives. If something changed and suddenly a bunch of negative forces came into play, enough to knock down the forcing say 2 W/m2, then my perspective would change based on the data to the new information. The problem is that negative forcing does not exist at this time, so there is no reason to believe we are going to start cooling in the foreseeable future.

    – If you are actually only talking about diminished responses to the problem??? then try to present a less confusing argument and specify with clarity and precision what you are trying to say. If you really want to use Ockham’s Razor properly, this is where you should apply it. But your arguments all over the place! From what you have written in this thread, it is very difficult to discern with precision where you stand on your understanding. if you really are on the fence or a denialist that isn’t dangerous, whatever that means… I cant tell what you are trying to say. maybe try not multiplying your entities beyond what is necessary to present your argument and then ‘folks’ like me can comprehend you better.

    And why not use your real name, real people do? What it seems you are trying to do is confuse things. I absolutely may be wrong about that, but that seems the net effect even if it is not intentional. if it’s not intentional then reconstruct your argument so it makes sense to ‘folks’. Your fence riding gymnastics are only good, in my opinion, for distracting ‘folks’ from the real issue, that of the science, the models, and the observations. You distract from the context, and you distract from the relevance of one data set over another, you distract from the relevant argument, your distracting…

    What you clearly don’t seem to understand, in my opinion, is that 2007 was a solar cycle minimum year and a la nina year, and it still tied for 2nd warmest year in modern history. You simple don’t understand GHG forcing in its current context and relevance?

    Good night and good luck,
    John

  14. 164

    Fred Staples posts:

    If you look carefully you will see that the UAH monthly data from June 2001 to date shows a significant negative trend.

    It shows a significant negative trend, Fred, because you’ve artificially inflated the number of points by using monthly rather than yearly data. The characteristic time scale for climate or climate change is 30 years. What you did is equivalent to me saying the temperature has gone up significantly from 5:40 AM to 7:40 AM, dividing it into 121 minutely temperature readings, and using the “significant” results to prove that the oceans will boil tomorrow.

  15. 165
    John Finn says:

    Re: #134

    BPL says

    This is, in fact, something he posts on every climate-related blog he can get to. He simply doesn’t understand the facts that A) the trend is not flat, and B) you can’t tell the trend from ten or eleven years of data, as I showed above.

    But the trends from 1988 to around 1994 that you calculated were all significantly affected by the Pinatubo eruption in 1991. Check out the graphs in Gavin’s post – particularly the second one (ENSO corrected). The huge dip due to Pinatubo is obvious.

    For what it’s worth I don’t think a 30-year trend is adequate. It should be at least 70 years to account for PDO cycles etc. I know there are issues with data accuracy the further back you go, but these are being resolved (e.g. 1940s SSTs). Anyway, here’s something to think about. It’s not very scientific and it does cherry pick (sort of), but I like it because it agrees with my own ‘estimate’ of sensitivity to CO2.

    I was looking at Gavin’s data and trying to find a year when conditions were the same (or as near as possible) as the past 12 months (June 2007 to May 2008), i.e. La Nina, solar minimum, seasonal etc. The best I could find was June 1943 to May 1944. According to the ENSO-corrected data, the ENSO effect, averaged over the 12 month period, for 1943/44 was ~ -0.06 deg C. For 2007/2008 it was ~ -0.05 deg C. We had a solar minimum in 1944. We have (or should have) a solar minimum in 2008. The PDO shifted to a negative phase in 1943/44. There are indications that the PDO may have gone negative recently.
    Average temperature anomaly for June 1943 to May 1944 is 0.18 (0.24 ENSO-corrected). Average temperature anomaly for June 2007 to May 2008 is 0.44 (0.49 ENSO-corrected)

    A difference of around 0.26 deg C (0.25 ENSO-corrected) – call it 0.3.With a change of forcing of around 1 w/m2 since 1944 that gives us a sensitivity of 0.3 K/w/m2 or slightly more than a 1 degree increase for CO2 doubling.

  16. 166
    Brian Klappstein says:

    “…The characteristic time scale for climate or climate change is 30 years….”

    (Barton Paul Levenson)

    Says who? Is the definition based on the PDO cycle length or what? We’ve gotten into the absurd world of semantics, not science, when we say if it’s a short term trend, I guess 10 years or less, it can’t be climate change. Or maybe the definition is “..if we don’t understand the reason for the variability, it is just noise, not climate change…”

    How about this: if I could point to a state change in the radiative balance of the earth that started 6 years ago, would you say unless that state change lasts 24 more years it’s not climate change?

    Regards, BRK

  17. 167
    Ray Ladbury says:

    Brian, Actually, the definition is not arbitrary at all. We are looking to differentiate a positive, monotonic trend from background noise oscillating around it. Thirty years is merely where the trends due to the signal emerge with high confidence from the noise. So, yes, six years would be weather–solar or otherwise–unless we have good physical reasons to presume that it will persist on climatic timescales.

    Given that you don’t understand this, ever wonder what else you don’t understand about climate science?

    John Finn, Other than the fact that you are cherry-picking two years and that we don’t have a comparison of the relative strengths of the La Ninas, etc., I’d merely amend your derivation to say
    Sensitivity>1 degree per doubling, as there are long-term feedbacks the measurement does not include.

  18. 168
    sod says:

    That’s a truely pitiful conclusion Sod. My result showed a very slight up trend contributed by the ENSO. The Thompson result showed a very slight down trend contributed by ENSO. Tiny differences around zero do not constitute an “opposite conclusion”.

    that one is funny. so the person who challenged the scientific consensus, that ENSO had a DOWNWARD effect on the trend over the last decade now believes, that whether it is up or down doesn t really matter.

    In Gavin’s words about the Thompson method:
    “There is no perfect way to do this – but there are a couple of reasonable approaches.”

    what gavin said is very sensible. but there are obvious IMPERFECT ways of doing it. like yours.

    and even choosing an imperfect way is not bad in itself.
    but choosing an imperfect way, getting a false result and spreading it all over the internet IS bad.

    So implying that Thompson’s results are perfect and that mine are suspect when there is such a small difference between the two is truely absurd. By the way, you have yet to show any reason why my approach is not reasonable.

    i told you that i have doubts about adding the results together. you were told a better (standard!) way of doing it as well. you chose to ignore all of it and spread your nonsense.

    But with all of the squabling aside, the conclusion that I reached remains true. We have a decadal flat trend and ENSO has not caused it. As you can clearly see, the Thompson ENSO corrected warming trend since 1998 is +0.0125 C. You can call that a positive trend if you like, but I call it flat. One century of such a trend would give you less than .125 C. That is flat.

    sorry Tilo, but i am slightly sceptical of a person, who denies to look at the STATISTICAL SIGNIFICANCE of his trend lines.

    i guess i don t care, what you define as flat. i am sorry.

    So wave your hands all you like Sod. My conclusions on Deltoid were correct. We have a missing .187 C of C02 forced warming for the decade and no way to account for it.

    that would be right, if we were discussing the claim, that EVERY decade has to show a warming of exactly 0.2°C (or more). unfortunately, we don t discuss such a stupid claim.
    if you had listen to what people told you about the weather noise in short term climate observations or about SIGNIFICANT timescales in this discussion, you wouldn’t be wrong on yet another point. alas, you are.

    By the way Sod, you are now more than half a million square kilometers behind in the Arctic sea ice race.

    far of topic. my position can be found on the web. in short, i don t support a comparison with an outlier. the denialist iceage claim didn’t manifest in arctic sea ice. calling any ice extend above the long term absolute low of 2007 a sign of a reversed trend, is absurd.

    [Response: please can we keep the squabbling to a minimum? – gavin]

  19. 169
    tamino says:

    Temperature noise is not white noise.
    Temperature noise is not white noise.
    Temperature noise is not white noise.
    Temperature noise is not white noise.
    Temperature noise is not white noise.

  20. 170

    In re 162:

    1). Thanks for demonstrating all-or-nothing thinking again.
    2). Enough people here know who I am in real life already. My real name is really none of your business.

    Here’s the argument —

    1). I reject IPCC BAU projections, not because we can’t destroy the environment if we keep burning fossil fuels, but because we’ll destroy the economy long before hand. Have you checked the news lately about recessions, bear markets, food shortages, unemployment, etc? I’d argue the evidence is strongly on my side. I’ve maintained this same position long before oil reached half its current price, so it isn’t a fad or some frantic effort at fence sitting.

    2). I reject all-or-nothing thinking, not because there isn’t an upward trend in temperature caused by rising CO2 levels, but because people understand “weather” more intuitively than “climate”. When the greatly-above-average hurricane seasons of 2006 and 2007 failed to materialize, that fed into the skepticism of people I’ve spoken to regarding AGW. I explained to pro-global-warming people why ’05 was a fluke and was attacked then as a “denialist”. Again, evidence is now firmly on my side as both ’06 and ’07 were less intense than ’05 and now ’08 is looking to be less intense than ’05 as well. That’s the difference between “weather” and “climate”. Using “weather” (hurricane season forecasts, for example) to demonstrate “climate change” can backfire, and I believe it has in this specific instance.

    3). Buzz words aren’t going to convince me that you have a clue what “Correlation Does Not Imply Causation” means. There have been too many “coincidental” climate minima associated with too many solar minima. Not understanding the precise causal relationship between solar minima and climate minima is not the same as there not being a causal relationship. We do know, for example, that strong solar flares dramatically heat and expand the upper atmosphere, and we also know that periods of higher solar output have the same effect. Likewise, we know that periods of reduced solar output don’t have that same effect, so there is definitely a relationship between solar activity — “space weather” — and the upper atmosphere. That the last two climate minima (Dalton and Maunder) were also associated with solar minima is well known, as is the fact that the aa index has increased significantly during the 20th century, and “coincidentally” with changes in the long-term upward trend. Doesn’t mean CO2-related climate change isn’t happening, only that “weather” is the sum of more than one input.

    What does this mean in terms of an overall argument?

    It means I believe we’re due to enter a period of either reduced warming, or moderate cooling, which will be followed by a stronger period of warming as the sun exits the forecast period of low activity for SC24 and possibly SC25 and the effects of increased CO2 levels and increased solar output are combined.

    I also believe that more emphasis should be placed on economic arguments for moving away from non-renewable carbon-based fuels because those impacts are more obvious at present than longer-term environmental impacts. I don’t reject the belief that increased CO2 levels result in global warming, only that the long-term environmental arguments are weaker than the short-term economic ones. Or in other words, my present gasoline bill is about $4,800 per year (yeah, $400 a month), and I can do a gasoline-to-electric conversion for about $10,000 or less than 3 year payback on the entire vehicle.

    As for walking the walk, to the best of my ability to control my own life, I’m carbon negative. I become more carbon negative each day (on average ;) ), and actions this month alone should reduce my CO2 output 3/4 of a ton per year. I’m about 3 or 4 tons a year negative because I was neutral once upon a time. My personal financial investment in renewable energy is north of $30K, and will increase as I invest in renewable technologies to move further away from obscenely expensive motor fuels. In my professional life, I’m actively involved in researching solutions in the areas of renewable energy and power management technologies and currently have approximately 25 patents and/or applications in process. And no, I’m not going to tell you their application numbers either — my name really is none of your business.

    If you think I’m a “denialist”, I think you’re a putz.

  21. 171
    Heikki T says:

    http://junkscience.com/MSU_Temps/Warming_Look.html

    Now we have temperature data up to June 2008, and it looks like 2008 will be as cool as 2000 was. Looking at the Hadley numbers, there has been no global warming since 2000:

    http://junkscience.com/MSU_Temps/HadCRUG.html

    The next couple of years will be very interesting. If global warming does not pick up, then IPCC climate models come under serious doubt.

    If IPCC models turn out to be wrong, that is no big surprise. I looked at the knowledge behind IPCC models. The margin of error in various ‘forcings’ and feedback loop strengths is so big that there is a reasonable probability that global climate will cool in the next decade.

  22. 172
    Brian Klappstein says:

    “…So, yes, six years would be weather–solar or otherwise–unless we have good physical reasons to presume that it will persist on climatic timescales….”

    (Ray Ladbury)

    The 30 years of trend is only required because the signal is weak relative to the noise. A stronger signal would take less time to discern. I think a better definition of climate change would be a recognizable radiative balance state change that appears immune to short term cycles like ENSO and seasonal cycles. Meaning it doesn’t have to be 30 years long, maybe not even 10 years long.

    As for your “if it’s 6 years it must be solar or weather not climate change” statement, isn’t that a kind of circular logic? As in: since we know solar changes can’t force climate, if we see a solar signal in the data, we can reject it as climate change.

    Regards, BRK

  23. 173

    In re #167:

    John Finn, Other than the fact that you are cherry-picking two years and that we don’t have a comparison of the relative strengths of the La Ninas, etc., I’d merely amend your derivation to say Sensitivity>1 degree per doubling, as there are long-term feedbacks the measurement does not include.

    If I read the referenced post correctly, there’s also the issue that one has to include a sufficient period of time to get sufficient CO2 concentration change log base 2.

    This is the point I was trying to make in an earlier post — climate change per increase in PPM CO2 is declining, and will continue to decline (deltaT per PPM is logarithmic, so first derivative is positive and second is negative).

  24. 174
    Jim Eager says:

    Re: BRK @ 166: “Says who? Is the definition based on the PDO cycle length or what?”

    I believe 30 years is the agreed definition for climate used by the World Meteorological Organization. It is also used by both GISS and Hadley Met Centre for calculating temperature anomalies against 30 year base periods.

  25. 175
    Tilo Reber says:

    Sod: #168
    “that would be right, if we were discussing the claim, that EVERY decade has to show a warming of exactly 0.2°C (or more).”

    There is the point that you are missing. If greehouse theory is correct, and if we are getting the expected levels of CO2 increase (which we are), then without any elements of natural variation to change the trend, every decade should show close to .2C increase. Or even if we allow for an error range and say that it is .1C to .3C, then every decade must show that increase within that range unless there are elements of natural variation that take us outside of that range.

    And what have we had in the past ten years to give us a flat trend. ENSO? No. Volcanism? No. Solar? Yes, but it is claimed to be far too small to override CO2 forcing.

    So here is the issue. We are clearly outside of that range. The elements of natural variation that have taken us outside that range are unknown. Therefore it is quite possible that we do not know enough about natural variation to compute climate sensitivity.

    The only other option that you have is to say that 10 year variation is noise that happens without a cause. And I do not believe that.

    [Response: This is nonsense. The idea that ENSO is the only kind of intrinsic variability is silly. Look out of your window – and see planetary waves (of various wavenumber), the Madden-Julien oscillations, the NAO, the PDO, the PNA, the SAM, COWL, baroclinic instability, African waves, Antarctic dipoles etc etc. There is no shortage of variability in short term records. What would meteorologists have to talk about otherwise? – gavin]

  26. 176
    Mark says:

    John Finn states:
    “But the trends from 1988 to around 1994 that you calculated were all significantly affected by the Pinatubo eruption in 1991. ”

    Wee problem. The Pinatubo eruption, powerful though it was, did not release significan tachyon energy. Therefore events before its eruption (say, 1988, 1989 and 1990) can not have been affected by the explosion.

    If the problem is the method by reaching the 1988-91 figures then please elucidate. BPL can’t help you understand without this info.

    PS: tamino, #169, there is no context so I’m assuming this is regarding the “noise goes up less quickly than the signal”.

    And my response is “So?”

    If the base variability is independant of your correlation testing then there’s no (or little) difference between noise and uncorreleated variability.

    E.g. Adult heights vary significantly but also vary closely related to diet.

    So to find out how much diet affects adult heights, you can’t take one person from each dietary group and correlate because inherent variability swamps the individual effect of diet. But if you take 100 from each dietary group, the genetic and other variables are not correlated to diet and so are effectively random within the dietary group. And so the signal is 100 times stronger wrt dietary effects and the internal variability is 10 times stronger because we have 100 more people and therefore some variability within that group.

    And so the signal can be teased out eventually.

    The strength of the signal compared to the noise tells you how much you need to collect together to reduce the variability within the selection group. The smaller the signal or the bigger the noise, the more selections need to be collected within the group.

    And for climatology temperatures, 30 is the minimum that can give any suitable signal for the noise. Adding more years helps increase the signal but you will be hiding information, so you select a period that is the minimum feasible and work with that. If you can add more data without losing information, you can do that with the 30 year means.

  27. 177
    John Finn says:

    Wee problem. The Pinatubo eruption, powerful though it was, did not release significan tachyon energy. Therefore events before its eruption (say, 1988, 1989 and 1990) can not have been affected by the explosion.
    If the problem is the method by reaching the 1988-91 figures then please elucidate. BPL can’t help you understand without this info.

    The Pinatubo eruption would have affected the least squares linear trend for any of the previous 3 years (and before that). BPL, I’m quite sure, understands this.

  28. 178
    Dan says:

    re: 171. “Looking at the Hadley numbers, there has been no global warming since 2000…”

    Gee, a denialist cherry-picking years…again! What a surprise. Not. Cherry-picking data still does not change the hard facts re: AGW trends. Ironically, in this same thread there is a specific discussion regarding the standard 30-year period for climate trend analysis. How conveniently ignored.

  29. 179
    Fred Staples says:

    What a strange comment, Barton (164). It is certainly true that the calculated significance will improve with the number of data observations, but we would expect the precision to improve if we have more measurements.

    In the calculation for F the numerator (the explained variance) depends on the number of observations, while the denominator (the residual variance), does not.

    Whether or not 30 years (167) is sufficient to separate the noise (the residual variance) from the signal (the trend) depends entirely on the size of the trend and the random scatter in the data.

    The UAH data is presented monthly. If we choose to calculate a regression based on longer periods all we will do is lose information.

    Take the 10 years of UAH data from January 1998 to December 2007 – 120 months, 10 years, or 1 decade.
    If we chose to calculate per decade (one data point) we would lose all the information about the trend.
    If we calculate per year we have 10 points, a slope of 0.0057 degrees per year, and a probability of 73% that the slope has arisen by chance.
    If we retrieve the lost monthly information we have 120 points, the slope is 0.0052 degrees per year and the probability of that slope arising by chance falls to 34% (still not significant) because we have more quite legitimate data points.

    To be frank, Barton, you may want to reconsider your comment about the minute temperatures. If you measure the temperature at 5.40 am and 7.40 all you have is 2 data points – not enough to calculate a regression trend.

    Actually, we are not entitled to extrapolate any of these calculated trends unless we have a separately verified physical explanation for the trend to which the data (all of it) conforms. When you look at the UAH mid-troposphere data do you really think, Barton, that we have any such verification?

    Tamino (169) is presumably telling us that temperature data is not random because each value is related (to some extent) to the preceding values. His analysis of the Central England Temperatures is worth a visit. He uses the monthly records.

  30. 180
    Brian Klappstein says:

    “…I believe 30 years is the agreed definition for climate used by the World Meteorological Organization…”

    (Jim Eager)

    I know, I was being somewhat sarcastic. The logic of the 30 year trend is pretty impregnable. “We’ve defined climate change as a trend you can only discern after 30 years. Now sit down and shut up.” Or maybe: “if you think you detect a climate regime change in 2002, call us in 2032 and we’ll check to see if you’re right”

    Regards, BRK

  31. 181

    #170

    1). Thanks for demonstrating all-or-nothing thinking again.

    — Your logic seems quite backward. I’m not-all-or-nothing, I’m show me your data to support your assumptions, and I will believe it when I see it as long as it is in context and has relevance.

    2). Enough people here know who I am in real life already. My real name is really none of your business.

    — Maybe your right? Maybe not. When I here people make claims that are misleading in this argument (AGW) based on assumptions that are either not substantiated, or not substantiable, and knowing that millions if not billions of lives may be at stake. I kinda think those people should not hide behind monikers like furrycatherder and take full responsibility for their unsubstantiated claims and their ramifications. But it is your choice to hide behind your moniker.

    Here’s the argument –

    1). I reject IPCC BAU projections, not because we can’t destroy the environment if we keep burning fossil fuels, but because we’ll destroy the economy long before hand. Have you checked the news lately about recessions, bear markets, food shortages, unemployment, etc? I’d argue the evidence is strongly on my side. I’ve maintained this same position long before oil reached half its current price, so it isn’t a fad or some frantic effort at fence sitting.

    — Show me your data to support your assumptions. Otherwise you are only giving your opinion based on your assumption. You seem be ignoring the fact that we have a lot of coal yet to burn, and coal sands. It does not matter that you have maintained your same position long before oil reached half its current price. You are arguing based on your opinion that the evidence is strongly on your side but you still have not answered a single question of mine to show your data to support your claims, nor have you posted any links to support your claims. You have however made claims that are simply not true such as the correlation of the aa index to global temperature; and you claim this as evidence to support your assumptions; and you still apparently don’t understand forcing.

    2). I reject all-or-nothing thinking, not because there isn’t an upward trend in temperature caused by rising CO2 levels, but because people understand “weather” more intuitively than “climate”. When the greatly-above-average hurricane seasons of 2006 and 2007 failed to materialize, that fed into the skepticism of people I’ve spoken to regarding AGW. I explained to pro-global-warming people why ‘05 was a fluke and was attacked then as a “denialist”. Again, evidence is now firmly on my side as both ‘06 and ‘07 were less intense than ‘05 and now ‘08 is looking to be less intense than ‘05 as well. That’s the difference between “weather” and “climate”. Using “weather” (hurricane season forecasts, for example) to demonstrate “climate change” can backfire, and I believe it has in this specific instance.

    — I’m glad you reject all-or-nothing thinking, so stop thinking that way, or at least stop writing that way. You are confusing people. The above average ‘global’ TC season did materialize, it just didn’t all make the news due to the lack of landfall and proximity. It’s not weather events that you examine in climate, it’s the trend of weather events. You need to explain that to your friends. That is precisely why short term does not override long term trend analysis. maybe it confuses people because you did not explain that to them in an understandable manner? You can’t compare a trend ’06 / ’07 to ’05, and call it climate. Yes people intuitively relate to weather rather than climate but you can explain it to them and as long as you don’t confuse them too much, they will understand. You can use weather to explain climate as long as you explain the relevance and the context. Maybe your not giving good context as is indicated by your posts here in this thread.

    3). Buzz words aren’t going to convince me that you have a clue what “Correlation Does Not Imply Causation” means. There have been too many “coincidental” climate minima associated with too many solar minima. Not understanding the precise causal relationship between solar minima and climate minima is not the same as there not being a causal relationship. We do know, for example, that strong solar flares dramatically heat and expand the upper atmosphere, and we also know that periods of higher solar output have the same effect. Likewise, we know that periods of reduced solar output don’t have that same effect, so there is definitely a relationship between solar activity — “space weather” — and the upper atmosphere. That the last two climate minima (Dalton and Maunder) were also associated with solar minima is well known, as is the fact that the aa index has increased significantly during the 20th century, and “coincidentally” with changes in the long-term upward trend. Doesn’t mean CO2-related climate change isn’t happening, only that “weather” is the sum of more than one input.

    — I’m ONLY using your examples to make my point. You say it is solar yet you reference the aa index as a correlation equals causation example, yet you are wrong, yet you still claim you are right. You are confusing people. Study the forcing levels first, then come back. All the correlation between solar and temperature have validity to the extent of their forcing influence. We are not discussing weather here. we are discussing climate. Show us your data furrycatherder, why should we all have to go chasing your data. Just post the links so we can look at them and see how relevant they are. You keep going back to Daulton and Maunder, but what is your context? There are causal relationships between solar forcing and climate, but what is the degree of relevance? .3 is less than 1.6 and 1.9

    What does this mean in terms of an overall argument?

    It means I believe we’re due to enter a period of either reduced warming, or moderate cooling, which will be followed by a stronger period of warming as the sun exits the forecast period of low activity for SC24 and possibly SC25 and the effects of increased CO2 levels and increased solar output are combined.

    — What is it you still don’t understand about .3 is not equal to 1.6 and 1.9? Substantiate your claims, I’m begging you. Whose forecast? On what basis? Where is the data? Is it peer reviewed? Has it gone through peer response? Did it survive peer response? The ocean will keep absorbing the forcing energy and warming, we don’t need sunspots anymore to warm. The next solar cycle whenever it happens will only add more forcing to the current forcing and give us a bump.

    I also believe that more emphasis should be placed on economic arguments for moving away from non-renewable carbon-based fuels because those impacts are more obvious at present than longer-term environmental impacts. I don’t reject the belief that increased CO2 levels result in global warming, only that the long-term environmental arguments are weaker than the short-term economic ones. Or in other words, my present gasoline bill is about $4,800 per year (yeah, $400 a month), and I can do a gasoline-to-electric conversion for about $10,000 or less than 3 year payback on the entire vehicle.

    — This web site is about the science, not the ecnomics. The economic argument is not a climate science issue, it is a resulting issue, a policy issue, combined with a slew of other issues such as peak oil and industry gone wild that long term has negative return on investment written all over it, due to short term thinking inconsiderate of the ramifications of egregious exploitation of the earths resources for the benefit of a few at the cost of many. The science should certainly drive policy but that is a separate issue. I think it should be discussed too. I don’t ind it being mentioned here, but this web site is about the science not the economy.

    As for walking the walk, to the best of my ability to control my own life, I’m carbon negative. I become more carbon negative each day (on average ;) ), and actions this month alone should reduce my CO2 output 3/4 of a ton per year. I’m about 3 or 4 tons a year negative because I was neutral once upon a time. My personal financial investment in renewable energy is north of $30K, and will increase as I invest in renewable technologies to move further away from obscenely expensive motor fuels. In my professional life, I’m actively involved in researching solutions in the areas of renewable energy and power management technologies and currently have approximately 25 patents and/or applications in process. And no, I’m not going to tell you their application numbers either — my name really is none of your business.

    — I’m very happy you are carbon negative. I’m also not surprised that you have approximately 25 patents and/or applications in process.

    If you think I’m a “denialist”, I think you’re a putz.

    — I don’t know you so I can only go by your own words, “My particular form of denialism isn’t dangerous because it advocates a massive shift to renewable energy forms to avert an economic disaster which will also avert an environmental one. Based on that, I’m a relatively harmless crackpot.” How is it precisely you want me to interpret your own claim that you subscribe to a “particular form of denialism”.

    — Now with this new post of yours you still have not substantiated any of your claims, not one. Please, please, pretty please, with sugar on top, substantiate your claims; otherwise please stop spouting opinion, it confuses people.

    — With kindest regards,
    — John

  32. 182
    Rod B says:

    FurryCatHerder (170), interesting thoughtful post.

  33. 183
    llewelly says:

    ‘John P. Reisman (The Centrist Party)’ #181:

    2). I reject all-or-nothing thinking, not because there isn’t an upward trend in temperature caused by rising CO2 levels, but because people understand “weather” more intuitively than “climate”. When the greatly-above-average hurricane seasons of 2006 and 2007 failed to materialize, that fed into the skepticism of people I’ve spoken to regarding AGW. I explained to pro-global-warming people why ‘05 was a fluke and was attacked then as a “denialist”. Again, evidence is now firmly on my side as both ‘06 and ‘07 were less intense than ‘05 and now ‘08 is looking to be less intense than ‘05 as well.

    What a convenient way to avoid admitting that despite the 2006-7 Atlantic hurricane seasons being less active than 2005 , there is nonetheless a strong upward trend in Atlantic hurricane activity – which, while perhaps not caused by global warming, shows a correlation with rising sea surface temperatures in the Atlantic, and with changing aerosol levels over the Atlantic (See Mann and Emanuel, 2006 )

    Here are some historical facts: The 1950-1999 average Atlantic hurricane activity was about 10 tropical and subtropical storms per year, about 5.9 of those reaching hurricane strength, and about 2.5 of those reaching major hurricane strength. But the averages of the last 20 seasons (1988 – 2007) have been 13 tropical and subtropical storms per year, about 7 reaching hurricane strength, and about 3 reaching major hurricane strength. In the last 10 seasons – 1998-2007 – those averages have been about 15 tropical and subtropical storms per year, about 8.1 reaching hurricane strength, and about 3.7 reaching major hurricane strength. This is an unmistakable upward trend in hurricane activity – the activity of the last 10 seasons is about 150% that of the historical average. Finally – it is not remotely necessary for a season to be as intense as 2005 in order for it to be very intense – after, all, 2004 (15 tropical storms, 9 hurricanes, 6 major hurricanes) had over 150% of the activity of an average season, yet was much less active than 2005 (28 tropical and subtropical storms, 15 hurricanes and 7 major hurricanes.)
    The abnormally high Atlantic hurricane activity of the last 10-15 years may or may not be due to global warming, but the less-than-2005 activity of the 2006-8 Atlantic hurricane seasons does not change the fact that the last 10-15 years have seen extra-ordinary hurricane activity. (In fact, if both 2005 and 2008 numbers are replaced the 1950-99 averages, the 1999-2008 period remains above the 1950-1999 averages on all 3 parameters.)

  34. 184
    Boyle says:

    Re: #178

    How is it cherry picking to point out that the consistent upward trend from 1977 on leveled off around the year 2000? Aside from the Pinatubo interruption in the early 90s, ENSO-corrected temperatures marched steadily upwards until 8-9 years ago. What explanation for this could there be? Simple “decadal variation” doesn’t work for me, because it gives no scientific cause for the halt in warming. If the warming was steady before, why wouldn’t it continue that way?

  35. 185
    Boyle says:

    “This is nonsense. The idea that ENSO is the only kind of intrinsic variability is silly. Look out of your window – and see planetary waves (of various wavenumber), the Madden-Julien oscillations, the NAO, the PDO, the PNA, the SAM, COWL, baroclinic instability, African waves, Antarctic dipoles etc etc. There is no shortage of variability in short term records. What would meteorologists have to talk about otherwise? – gavin”

    So Gavin, what you are saying is that some or all of these natural variables mentioned could have caused the flat trend since 2000? If that is the case, there should be some rationale for how they did so. In addition, what factor could natural variables have played in the warming from 1977-2000?

    [Response: In the long term trend, none of them. While the impacts of the various forcings do give a fit. Currently the expectation is for a trend, but natural variabilty will inevitably cause some periods to have a stronger than expected rise, and others a slower than expected rise. – gavin]

  36. 186

    #183 llewelly

    Thank you and yes, exactly my point, in response to FurryCatHerder.

    For the record, the comment you quoted was from FurryCatHerder, not me. My response to her was more in line with trend over events.

    How do you do that indent thing, I don’t want people thinking I’m saying what she is saying?

    My response as follows to FurryCatHerder (see above in #181):

    — I’m glad you reject all-or-nothing thinking, so stop thinking that way, or at least stop writing that way. You are confusing people. The above average ‘global’ TC season did materialize, it just didn’t all make the news due to the lack of landfall and proximity. It’s not weather events that you examine in climate, it’s the trend of weather events. You need to explain that to your friends. That is precisely why short term does not override long term trend analysis. maybe it confuses people because you did not explain that to them in an understandable manner? You can’t compare a trend ‘06 / ‘07 to ‘05, and call it climate. Yes people intuitively relate to weather rather than climate but you can explain it to them and as long as you don’t confuse them too much…

  37. 187
    llewelly says:

    John P. Reisman (The Centrist Party) #186:

    183 llewelly
    Thank you and yes, exactly my point, in response to FurryCatHerder.
    For the record, the comment you quoted was from FurryCatHerder, not me. My response to her was more in line with trend over events.

    My apologies. Thank you for telling me I had mistaken FurryCatHerder’s words for yours.

    How do you do that indent thing, I don’t want people thinking I’m saying what she is saying?

    I wrap the text in:
    < blockquote >
    < /blockquote >

    This works on wordpress blogs, on scienceblogs, and some other blogs. It does not work on blogger.

  38. 188
    Boyle says:

    Thanks for the response, Gavin. So basically, as long as the overall longterm trend is upward, global warming is still happening. I understand that idea, I just don’t understand how natural variables could have caused 2000-2008 to slow the warming. The PDO, NAO, and ENSO were all mostly positive from 2001-2007…and I’m sure there are other natural variables, but solar is the only one I can think of that has decreased in the past 10 years. Solar Cycle 23 peaked a little lower than the previous two cycles, but that doesn’t seem reason enough to me to cause less warming.

  39. 189
    sidd says:

    Mr. John Reisman wrote at 1619 on the 9th of July in comment # 181:

    “When I here people make claims that are misleading in this argument (AGW) based on assumptions that are either not substantiated, or not substantiable, and knowing that millions if not billions of lives may be at stake. I kinda think those people should not hide behind monikers like furrycatherder and take full responsibility for their unsubstantiated claims and their ramifications. But it is your choice to hide behind your moniker.”

    Sir, I do not agree. There are more things on heaven and earth than are dreamt of in your statement. What if the poster in question is a victim of stalking or domestic violence ?

    More importantly, what does the strength of the argument have to do with the purported identity of the author ? If Prof. Arrhenius were to post here with his CO2 analysis under the name ‘Twirlip of the Mists’ would you dismiss his reasoning ?

  40. 190
    David says:

    I suppose the real worry is whether AGW has influenced the El-Niño recharge/discharge mechanism. ENSO warm episodes have dominated the last twenty years.

    The TAO project allows scientists to monitor warm water volume which tends to lead oceanic Niño indices by around 7 months, however…

    What we really need is real-time sub-surface sea temperature data for the entire planet (not just a slice of the equatorial pacific).

    Until then, I will be using December Antarctic sea-ice area as a surrogate measure of meridional up-welling.
    Decreased sea ice area during December preceded ‘94, ‘97, ‘02 and ‘06 warm episodes.

    The association between Sea ice, Antarctic oscillation, El Niño Southern Oscillation, is poorly understood.
    Indeed, it represents a major scientific challenge.

  41. 191

    In re 183:

    What a convenient way to avoid admitting that despite the 2006-7 Atlantic hurricane seasons being less active than 2005 , there is nonetheless a strong upward trend in Atlantic hurricane activity – which, while perhaps not caused by global warming, shows a correlation with rising sea surface temperatures in the Atlantic, and with changing aerosol levels over the Atlantic (See Mann and Emanuel, 2006 )

    Well, I didn’t address whether or not there was one, I only pointed out that using weather forecasts to explain climate change is a bad idea. I then presented the past two years’ “above average” hurricane season forecasts (which both missed for Atlantic basin storms when compared to ’05) as examples of what not to do if one wants to convince others that climate change is real.

    As regards the uptick in storms, yes, there has been one. And there was one just like it in the 1950’s and another just like it in the 1890’s. Here is a nice chart from NOAA if you’d like to check it out. I’m going to go out on a limb and forecast a period of declining tropical storm intensity in the Atlantic basin over the next few decades, with another peak just in time for me to be dead and buried.

  42. 192
    paulm says:

    Heikki T and others…

    There is proof to more than 99% confidence that HUMAN CO2 emissions are driving the current rise in temperature. The analysis is pretty clear and indisputable. see: (read the comments too)..

    Anthropogenic Global Warming is Absolutely Occurring
    http://autismnaturalvariation.blogspot.com/2008/06/anthropogenic-global-warming-is.html

  43. 193
    paulm says:

    183 llewelly

    And here is the analysis that proves with more than 99% confidence that the frequency of name storms of the Atlantic is linked to surface temperature.

    Hurricanes and Temperature are Indeed Associated
    http://residualanalysis.blogspot.com/2008/06/hurricanes-and-temperature-are-indeed.html

    here

    It is pretty irrefutable!

  44. 194
    Dan says:

    re: 184.

    Sigh. 1. Look at the 30-year trend. At least. 2. There are still natural influences (e.g. La Nina, El Nino) on the short-term trend.

  45. 195

    Brian Klappstein writes:

    “…The characteristic time scale for climate or climate change is 30 years….”

    (Barton Paul Levenson)

    Says who?

    The World Meteorological Organization. Did you actually read what I posted?

  46. 196

    Fred writes:

    The UAH data is presented monthly. If we choose to calculate a regression based on longer periods all we will do is lose information.

    You’re confusing noise with signal.

  47. 197
    Mark says:

    Fred #179

    Yes, the temperature is not random: it depends on many varying factors. However, if we don’t care about those factors they are indistinguishable from noise.

    E.g. the temperature this morning had nothing to do with the temperature three weeks ago.

    The temperature this morning has something to do with the climate (e.g. summer). But the effect of it being summer is very much lower than the variability due to , say, cloud cover. But if we take the temperatures in the morning of the last 30 10th July then the cloud (which doesn’t vary depending on date) will cancel itself out in very much the same manner as “noise”.

    If I use every 10th year, I’m in lock step with the solar constant which varies over that time. If I pick the last six years to add, the changes from cloud cover may still be too long. If I take the last 1,000 years, I’ll miss out any signal that takes

  48. 198
    tamino says:

    Re: #191 (FurryCatHerder)

    As regards the uptick in storms, yes, there has been one. And there was one just like it in the 1950’s and another just like it in the 1890’s. Here is a nice chart from NOAA if you’d like to check it out.

    Are you sure about that? Have you done an analysis of the data, or are you just drawing a conclusion based on visual inspection of the graph?

    I’m a mathematician specializing in time series analysis. To my experienced, professional eye it looks like the most recent period shows a significantly higher level of activity than any previous part of the data record, including the 1950s and 1890s — those time periods were not “just like it” at all. But even though I’m a professional with decades of experience at this, I can’t be sure because I know that visual inspection of a graph can be suggestive but is easily misleading.

    I suggest that it’s folly to draw conclusions such as the one you’ve stated without some analysis to back it up. I further state as fact that conclusions based on visual inspection — even for those of us who are experienced at the analysis of such data — are untrustworthy.

  49. 199
    Rod B says:

    paulm (193) says

    … proves with more than 99% confidence that the frequency of name storms of the Atlantic is linked to surface temperature.

    Yet there is a large respected and credentialed group (including some of RC moderators if memory serves) that says otherwise. Makes your “99% proof” hyperbole at best. (Though a number of the above would claim an increase in intensity of storms.)

    Plus your reference in 192 is prima facie miles away from a universal “99% proof” of AGW.

  50. 200
    Rod B says:

    Tamino (198), you’re being too excessive. To say nobody can rightly look at the chart and reasonably (albeit tentatively) draw a conclusion that the three periods mentioned are roughly similar, is just nonsense. But your take (admittedly very tentative) that one of the periods is significantly greater and the others are not … like it at all is logical (emphasis mostly mine)? Is it your experience (which I am in no way minimizing) that the numerical analysis result will turn an overview completely on its head and make it completely different? If one “calls ‘em as he sees ‘em”, is he highly likely to be 180 degrees wrong?


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