Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.

Settings

Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup

Settings


All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Donate

Twitter Facebook YouTube Pinterest MeWe

RSS Posts RSS Comments Email Subscribe


Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...



Username
Password
New? Register here
Forgot your password?

Latest Posts

Archives

Astronomical cycles

Posted on 17 June 2010 by Riccardo

Guest post by Riccardo

Recently a new paper by Scafetta came out (a freely downloadable version can be found on arxiv but I don't know if they are exactly the same). In a few words, Scafetta connect the orbital motion of the planets with solar variability and hence on earth climate. He found a dominant 60 years cycle which, he claims, greatly downplay the anthropogenic contribution to the warming after the '70s. I won't go through the details of his analysis and the hypothesis on the yet to be discovered physical mechanism behind. Forget about physics for a moment, as Scafetta does, and think only about cycles and periods.

He does a nice and fascinating analysis of various orbital cycles which cause the motion of the sun around the center of mass of the solar system. It's assumed that in one way or another the gravitational pull affect sun activity. He then compares the power spectra from detrended Hadley's temperature data with that of the orbital cycles and obtains the nice graph reproduced below.


Fig.1: reproduction of fig. 10B in the original paper. It shows the eight years moving average of the temperature anomaly detrended of its quadratic fit (gray); the thin black line is the same curve shifted by 61.5 years.

The data has been detrended assuming an underlying parabolic trend. The main 60 year cycle, due to the alignment of Jupiter and Saturn, shows up very clear, but there are more. In particular, he identifies a total of 10 cycles due to combination of planets motion and one due to the moon (fig. 6B in the paper). Of those cycles, only two more are considered significant, namely those with periods of 20 and 30 years.

Fascinating. But then, a few pages later, Scafetta writes:

However, the meaning of the quadratic fit forecast should not be mistaken: indeed, alternative fitting functions can be adopted, they would equally well fit the data from 1850 to 2009 but may diverge during the 21st century.

His warning is on the problem of extrapolation of the trend in the future, which he nonetheless shows. But this sentence made me think that it's true, once we put physics aside, we're free to use the trend we like; so why parabolic?  I decided to take a closer look, and this turns out to be the begining of the end.

The first and more obvious try is a linear trend and then one with a higher power. I kept the functional form y=a(x-1850)n-b used by Scafetta, but let n be 1,2 or 4. Here's what I got.


Fig.2: HadCRUT3 monthly data (grey) and the fits for n=1 (red), 2 (green) and 4 (blue).

Already by eye inspection it may be noticed that, due to the different curvature of the fitting functions, the behaviour is different between the middle and the extremes of the range. To be quantitative, we need to calculate the residuals, i.e. the difference between the data and the trends.

The fits were performed using the raw monthly data, as shown in fig. 2, but given that we are looking for long term cycles, I smoothed the data before detrending to clean them up a bit, as Scafetta did too. The results are shown in the following figure.


Fig.3: residuals calculated with the trend curve shown with n=1 (red), 2 (green) and 4 (blue).

As noted before, the behaviour at the extremes of the range is opposite with respect to that at the center and the two peaks at year 1880 and 2000 get smaller on increasing n. In particular, for n=1 the curve barely flattens aroud year 2000 while for n=4 only a small short-lasting peak is left. Only with n=2 we get the three nice equal amplitude peaks.

More generally, for n=4 the claimed 60 year cycle seems to vanish after the peak at year 1940. It's not to say that the n=4 trend has more value than the n=2, but in the end we can say that the nice cyclic behaviour seen in fig. 1 depends on the choice of the trend function. It's worth to recall that its choice is arbitrary, no physics behind it.

I tested this findings with the other global surface temperature datasets (GISS and NCDC) and, not unexpectedly, they confirmed. The claim that the anthropogenic contribution to the increase in temperature after the 70s has been overestimated has then to be dismissed, at least until we can make a proper choice of the underlying trend.

Still, small, periodic and short-lasting peaks seem to be real. More accurate and hopefully physics-based studies on decadal variability are required, taking into account all possible internal and external contributions.

0 0

Printable Version  |  Link to this page

Comments

Prev  1  2  3  Next

Comments 51 to 100 out of 141:

  1. Berényi Péter, I do not trust Scafetta exponent 2 nor any other, as clearly stated, so it's not at all my job to play with it. My "job" has been to show that we can not extract valuable informations from this kind of analysis and that the strong conclusions of that paper lack solid bases (euphemism?). P.S. You used a different functional form from Scafetta (and me) and dropped part of the data, no surprise you got different results. This confirms, once more, my point.
    0 0
  2. It strikes me that a lot of the recent activity by skeptics is to perform some "analysis" that looks like science from far away. The fact that real scientists can come in to close range and debunk it does not really matter to the skeptics, because thay are playing to an audience that a) is relatively unsophisticated scientifically and b) does not trust or care what "real" scientists have to say about the original work. This debate is political, not scientific. The skeptics are winning the political debate, because their side is winning converts, even though their science is bunk. I am not sure how to respond, but I think that the present situation demands new tactics, which involve more that just debunking bad skeptic science.
    0 0
  3. Ken Lambert, it might surprise you to know that there are significantly large holes in the fossil record that make it extremely difficult for scientists to show how life evolved from single-cell to the current, wide array of multi-cellular organisms-so are you suggesting we abandon Evolutionary Theory in favor of Creationism? Indeed, the fields of biology, physics & chemistry consist of theories & models which lack some pieces of the puzzle to make our understanding of them complete. If we were to apply your attitude to AGW to the rest of Science, then we'd simply abandon science altogether. Whatever pieces of the AGW might be "missing", the pieces we have paint a very telling picture-we have near-surface & troposphere warming at an accelerated rate-a rate that is strongly correlated (ca. 75%) with the accelerated rate of CO2 emissions into our atmosphere; we have extensive knowledge of the various gases that contribute to the natural-& enhanced-Greenhouse Effect, most especially their ability to absorb & re-emit Long-Wave IR radiation; we have measurements of the Stratosphere showing how it has cooled at almost the same rate as the troposphere has been warming (which wouldn't be happening if the sun were to blame); of the remaining, inter-annual climate variability for the past 60 years, we can explain virtually all of it in terms of either (a) the 11-year solar cycle, (b) changes in Ocean Oscillations (most especially the El Nino/La Nino cycle & (c) changes in the atmospheric concentration of other-more potent-Greenhouse gases (most especially methane, which had been leveling off since the 1990's, but which has started to rise again recently). Now, when the skeptics can come up with a feasible model to explain the observed changes in temperature throughout our atmosphere, then maybe I'll listen to them. Scafetta's paper, though, doesn't even come close. All Scafetta does is engage in some truly Herculean levels of mathematical contortionism to make the trend fit his theory (something that the correlation between CO2 & climate variability doesn't need).
    0 0
  4. #37 Riccardo Obviously the volcanic input is random, short-lived and wouldn't contribute to a regular cycle. Surely they would just add noise to the analysis? Again each ENSO event is random and short-lived and couldn't contribute to a regular 60 year cycle. So we seem to be left with just denying the 60 year cycle exists. Ithink the solar cycle is much shorter and my understanding is that the AGW theory only allows for a very low amplitude, nothing like the amplitude seen in the phases of HADCRUT3. I still see 1850-1880 an upward phase 1880-1920 a downward phase 1920-1940 an upward phase 1940-1970 a downward phase 1970-2000 a upward phase You could even see 2000 onwards as the turning to a downward (it's generally been flat) Obvious the noise caused by ENSO and volcano's is in there (you can see the volcaic activity of the mid-60s causing a blip upwards in the middle of the down stroke). It is a shame that Scaffetta didn't try 'cleaning up' the signal by removing these short-lived affects. I still think you identified short-lived processes that just dirty the analysis, they are not explanations of the longer phases. Just on your analysis. There is either a cycle or there isn't. You seem to wish there isn't. If the cycle exists and it is influenced by the regular movements in our solar system then surely you would expect the amplitude of those cycles to be fairly regular as well. It would seem only right to attempt to detrend to give such regular amplitudes. This may in fact be a self proving process but it seems in appropriate in your example to choose n=1 and n=4 for the very reason these give very irregular amplitudes.
    0 0
  5. HumanityRules, the 60 year cycle in the temperature record should not be taken for granted, it's what we are looking for. So, the choice of the trend cannot be that which shows it; and you can not say that n=1 or 4 are not good choices just because they do not show the cycle. Just for clarity, I do not "wish" there isn't a cycle as you insinuate. My wishes, as well as yours, are (supposed to be) irrelevant here. I just showed that the analisys provided by Scafetta does not allow him or anyone else to claim there is this cycle, let alone that anthropogenic warming after the '70s has been exagerated.
    0 0
  6. HumanityRules at 19:27 PM, even though each individual ENSO event is short lived, the frequency at which they occur, and their magnitude, tends to cycle through periods of greater frequency, and periods of lesser frequency. With the solar cycles, is it the aa geomagnetic index that perhaps should be considered for contribution to a regular cycle?
    0 0
  7. johnd, actually the ENSO periodogram is a bit messy (part B on the right taken from Lean 2009), but it does not show any dominant 60 year cycle. The large peaks beyond beyond 1000 months are spurious, being too similar to the time range of the data. Interestingly, although in Lean 2010 she also finds a peak around 60 years in the temperature periodogram, she is able to reconstruct temperature as a combination of various effects (sun, ENSO, volcanoes and anthropogenic) with no dominant 60 years cycle. Including the known sources of variability and calculating the residuals could be a good way to isolate what's left.
    0 0
  8. 55 Riccardo You may answer this question as you did a similar question with something like "it's not my job to identify cycles" but how would one go about identifying a cycle in the 20th century temperature record in a credible way? Because simply saying Scaffetta's assumption could easily be wrong really doesn't move things forward. Given the complex,chaotic, poorly measured and poorly understood nature of climate I imagine most analyses of data in this field rely on one or two untested or unproven assumptions. We end up with an arguement that you can use statistics to prove anything, not the most enlightening idea. You're still avoiding specifically describing what is going on in the ~30year up and down phases of the HADCRUT3 data. I'm not convinced ENSO, Volcano and solar really address this. 56 johnd From memory earlier articles here about solar cycles, whatever the index, have tended to downplay the potential amplitude of warming that can be caused by these solar changes. Again from memory this was in the region of >0.1oC. Also this website has argued there is no long term trend in ENSO, I think you'll have to look elsewhere for an explanation.
    0 0
  9. >0.1oC should be <0.1oC
    0 0
  10. HumanityRules, I'm not a scientist, you can not ask me to find the solution to a problem that professionals didn't solve yet ;). I agree that pointing to the weakness of Scafetta paper does not move anything forward; this means we have to rely on previous scientific litterature which tells us that other effects influence decadal variability more than the sun's 60 year cycle. You may find more on this, for example, in the Lean 2009 quoted in my previous reply to johnd.
    0 0
  11. Riccardo, I agree with BP on this one. Simply because Scafetta doesn't discuss physical mechanisms doesn't mean that a sixty-year cycle in temperatures(induced by variations in the position of the SSCM) is equally physically plausible to a quartic trend in temperatures. Practically everything we know about physics would say that it would not be possible (for example) for each doubling of the forcing to produce 16 times the temperature increase as the last doubling. Further, even if you accept the quartic trend, you still have the same basic patterns of the last 150 years(that match up reasonably well with changes in the SSCM) as shown by Fig. 3, except that they break down on the most recent timescales for an exponent of n=4. You are then in a position of still having to explain the apparently cyclical changes in temps. Cheers, :)
    0 0
  12. shawnhet, apparently my point was not made clear enough if commenters keep repeating the same criticism: "It's not to say that the n=4 trend has more value than the n=2, but in the end we can say that the nice cyclic behaviour seen in fig. 1 depends on the choice of the trend function." The point here is that being the presence of the cycle dependent on the (arbitrary) choice of the trend, no conclusions can be drawn "at least until we can make a proper choice of the underlying trend.". That's it. If you drop the last cycle, e.g. like with the n=4 trend, i can't see what cycle need to be explained. Would you call for a connection with the 60 years sun cycle when you have less than 2 periods that does not repeat? I think the really hard part would be to explain why the supposed cycle has disappeared.
    0 0
  13. 60 Riccardo But you seem to be finding a solution. The solution being there is no 60yr cycle? From yours and others post on this subject there seems a very simple solution to all this. You take the HADCUT temp record and you subtract the solar cycle effect the enso signals the volcano signals any other signals you think acceptable and you're left with a nice curve that has some simple relationship to the increases in GHG emissions. You then get the equation for your 20th century trend. Why haven't I seen this curve? It seems the consensus around climate science would tell us we know everything necessary to have a reasonably good attempt at this. In fact it doesn't seem too much to demand this of the science.
    0 0
  14. HumanityRules, why are you choosing such arbitrary dates to prove your point about temperature trends? It sounds to me that, like Scafetta, you're desperate to shoehorn the data to fit your extremely weak hypothesis-yet your dates don't even fit his 60 year cycle hypothesis-they're more like 70 years here & 50 years there-hardly very scientific. Also, if you look at the HadCrut3 data, the period from 2000-2009 showed a *warming* of +0.003 degrees per year, not much lower than the warming of 1850-1880, that you're trying to attribute to this magic 60-year cycle (which isn't *really* 60 years at all). So already your hypothesis is looking extremely shaky. Also, if you look at the GISStemp data, your hypothesis takes another battering, because the cooling from 1880-1920 is missing-temperatures remained effectively *flat* during that time period. As I said above, if you look at a *real* set of 60-year cycles (1890-1950 vs 1950-2010), you see that you have half the warming in the first 60 years that you have in the 2nd 60 years-even though the first 60 years is dominated by rising sunspot numbers, wheras the 2nd 60 years is dominated by falling sunspot numbers. This does really shot some massive holes in the 60-year cycle hypothesis, as does the lack of stratospheric warming-which we'd definitely see if the sun was to blame for post 1970's warming. Lastly, the Hue & Cry of the Denialosphere has always been that correlation doesn't equal causation, yet people like yourself, HR, are pretty desperate to cling to correlations based entirely around statistical gymnastics-without any firm rationale with which to back it up. That's not the action of a SKEPTIC, its much more of a FAITH BASED position. I guess though, HR, that you'll cling to any hypothesis, no matter how far fetched, if it will absolve humanity of responsibility for global warming!
    0 0
  15. Ooops you provide a possibly example of what I'm asking for from Lean except what she seems to do is develop a model which has reasonable match to HADCRUT then derive the anthropogenic signal from that model. Unfortunately graph a) isn't the clearest but her model does seem to flatten out the 20th century data. The magnitude of the 1910 low and the 1940 high are reduced. We seem to have a similar problem to Scaffetta. In the case of Lean a model that seems to remove the cyclical nature of the 20th century temperature ends up 'proving' there is no room in the data for a 60year cycle.
    0 0
  16. HR @ 63. There's a very simple test you can do-plot the temperature anomaly for 1950-2010 vs CO2 concentration for 1950-2010. Guess what you get? A linear correlation with an R-squared value of around 0.79. That effectively means that 79% of all climate variability since 1950 can be attributed *solely* to the change in CO2 concentration. In science, that's considered an extremely good fit-good enough for the statement that "CO2 is driving climate variability post-1950" to be valid. Of course correlation alone doesn't prove anything, it's also backed up by things like our knowledge of the IR-absorbtion properties of the various GHG's, the reduction in outgoing IR radiation reaching the outer atmosphere & the cooling of the stratosphere-all of which are consistent with a GHG-induced, not solar induced, warming trend.
    0 0
  17. 60 Marcus I know the human eye likes to see patterns in things but do you not see phases of warming/cooling/warming/cooling/warming with an approximate length of 30years? We can argue about the exact length or whether that pattern in 'dirtied' by other phenomenon but if I see it and you don't then I guess there is no possibility for us to come to any sort of understanding. My comments here don't come from any sort of position other than I see that pattern superimposed on a general warming trend and I'm curious about it. I can accept that pattern may be circumstantial but I've yet to see anything that proves that. I wonder if you'd like to expand on what "people like yourself" are? Or maybe apologize for the unnecessary language in your post. Finally I don't understand who humanity should be seeking absolution from, who's judging us?
    0 0
  18. Ken Lambert wrote:- "this “nice AGW trend” is not looking so nice when the purported energy flux imbalances are not showing up in OHC for the last 6 years and probably not much in the last 16 years." Well, they have been and they are showing up. The Scaffetti paper is similar to the 'cooling trend' distraction - statistical construction artifacts. Mathmagic, if you like. http://www.noaanews.noaa.gov/stories2010/20100615_globalstats.html 1. May 2010 - warmest May in the records, 1st on land, 2nd for SST 2. April 2010 - warmest April in the records, 3rd on land, 1st for SST 3. March 2010 - 2nd warmest March in the records, 1st on land, 13th for SST 4. March-May qtr - warmest in the records, 1st on land, 2nd for SST The cooling 'trend' only lasted as long as the latest La Nina 'event'.
    0 0
  19. #66 Marcus Riccardo's article suggests Scaffetta links this analysis to the motions of the planets. It isn't just some free floating "statistical gymnastics" it does try to base things in a real universe.
    0 0
  20. Something that bothers me about Scafetta's paper is the seemingly combative or biased attitude he drags into the conclusion section of his paper. He makes some statements that are plainly exaggerated or at least factually erroneous as well as citing other, unrelated research in an apparent attempt to bolster his findings with circumstantial evidence that he cannot show as related to his core thesis. For instance, Scafetta claims "...the AGWT promoted by the IPCC [2007], which claims that 100% of the global warming observed since 1970 is anthropogenic, is erroneous." Nowhere in the IPCC 2007 report can such an assertion be found; the remarks on attribution in the IPCC synthesis are heavily nuanced and qualified. Scafetta departs from a straight discussion of the relationship of his research to the IPCC summary to make an unfounded allegation. This harms his credibility for any reasonably informed layperson reading his paper, leading readers to conclude he's pursuing an agenda beyond scientific inquiry. Elsewhere in the discussion Scafetta mentions Solomon's work on stratospheric water vapor. By his own words, we can conclude that he's attempting to establish a conceptual space for unidentified climate forcings: "[Solomon 2010] reinforces that climate change is more complex than just a response to added CO2 and a few other anthropogenic GHGs." That's a plainly obvious fact and adds nothing to his thesis, but it certainly will help lead readers in the "correct" direction. He also makes a curious choice of words to describe Solomon's findings, saying "...stratospheric water vapor has largely contributed both to the warming observed from 1980-2000 (by 30%) and to the slight cooling observed after 2000 (by 25%)." We could agree that Solomon's work describes a significant influence, but largely? That word suggests that water vapor is a dominant effect but it's apparently not. Again, there's a clear tone audible here that goes beyond a simple spirit of curiosity. Further to Solomon, Scafetta goes on to say "Perhaps, stratospheric water vapor is driven by UV solar irradiance variations through ozone modulation, and works as a climate feedback to solar variation [Stuber et al., 2001]. Thus, Solomon’s finding would partially support the findings of this paper..." But Scafetta cannot describe how this might work; he can't establish any factual basis for a relationship between Solomon's findings and his thesis. In fact, he struggles to establish any physical mechanism for how the solar system vibrations might act: "Alternatively, the planets are directly influencing the Earth’s climate by modulating the orbital parameters of the Earth-Moon system and of the Earth. Orbital parameters can modulate the Earth’s angular momentum via gravitational tides and magnetic forces. Then, these orbital oscillations are amplified by the climate system through synchronization of its natural oscillators." Reading that part of Scafetta's discussion makes me better able to understand this notion of "handwaving" scientists speak of. Scafetta presents us finally with this conclusion: "...climate models are missing fundamental mechanisms that have their physical origin and ultimate justification in astronomical phenomena, and in interplanetary and solar-planetary interaction physics." A bold claim based on what appear preliminary results and an incomplete investigation, and when I consider that Scafetta tries to shore up this assertion with incorrect summaries of the IPCC thesis and what appear to be rhetorical artifices I'm left to wonder, is this research, or axe-grinding? I would have thought that before making such a claim Scafetta would have extended this work by further investigating the specific nature of the physical mechanisms that might exert the influences on climate he alludes to but cannot actually identify. Scafetta's leapfrogging of open and unexplored investigative alleys to jump to conclusions about the validity of GCM projections leaves me with the solid impression he's not concerned so much with research but instead is pursuing an agenda not primarily concerned with scientific investigation.
    0 0
  21. Riccardo, I guess I don't really understand what you're up to here. Scafetta is attempting to reconstruct the observed temperature record by combining a cyclical component (initiated by changes in the SSCM) and a given trend. I don't really know if he does a good job of this or not. You, OTOH, seem to be claiming that because your n=4 trend more closely matches the recent temp trend, then apparently it is superior (or at least equal to) Scafetta's, but really this is apples to oranges. Scafetta, purportedly has an explanation for warming for the entire record, you, at best can only explain the last 30-40 years. For periods prior to that you still have essentially the same fluctuations(Fig. 3) in temp that Scafetta tries to explain by referring to SSCM. An effective competitor to Scafetta's hypothesis would need to explain the same data that he did, not simply choose one portion of the data, and calculate a trend on that basis. Cheers, :)
    0 0
  22. HumanityRules, "what she seems to do is develop a model which has reasonable match to HADCRUT then derive the anthropogenic signal from that model." This claim is compleately unfounded. Please stick to what she said in the paper and do not try to make people say what you'd like them say. shawnhet, you assume that: 1) i'm supporting the n=4 versione of the trend; 2) i'm a competitor to Scafetta. Neither is true and nothing i said should let you think they are. I esplcitly stated (several times indeed) that the n=4 has no more value and I nowhere tryed an alternative hypothesis. Insisting on this point is, at best, specious. I'll said it again, maybe sooner or later you'll will accept it. I just showed the weakness of Scafetta paper through its arbitrary choice of the trend. Stop. I understand that it's hard to accept the fault one of the skeptics heros, but you know, sometimes even heros might be wrong. As for the "competitors", aka currently accepted hypothesis, again as said countless time now, there are plenty of papers, one of them quoted before. I'm sure you know many more. There's still something missing? Sure, hardly a breaking news, you will hardly find someone claiming the opposite. It's still a topic of active research for a reason. For sure what is missing is an "alternative" hypothesis and the astronomical cycles theory is not (yet?) up to the task.
    0 0
  23. HumanityRules at 03:41 AM, in addition to the various factors illustrated, perhaps the annual precipitation cycle has a place. Whilst it may be indirectly represented, perhaps by ENSO(?), precipitation is a direct indication of a cooling influence both immediate and longer term as it replenishes and maintains a reservoir of soil moisture that are only significantly depleted by drought. This IPCC chart at the bottom gives an indication of the cycle as observed in the 20th century.
    0 0
  24. These notes apply to the chart posted above. Figure TS.9. (Top) Distribution of linear trends of annual land precipitation amounts over the period 1901 to 2005 (% per century) and (middle) 1979 to 2005 (% per decade). Areas in grey have insufficient data to produce reliable trends. The percentage is based on the 1961 to 1990 period. (Bottom) Time series of annual global land precipitation anomalies with respect to the 1961 to 1990 base period for 1900 to 2005. The smooth curves show decadal variations (see Appendix 3.A) for different data sets. {3.3, Figures 3.12 and 3.13}
    0 0
  25. When this kind of pseudo-statistical reasoning is applies to stock market prices, it is called 'chartism'. I guess it is not just in the stock market that chartism continues to fool many even today, years after it was soundly refuted...
    0 0
  26. Methinks that HumanityRules & John D both need to spend a little time hanging out with the Pastafarians, to see the dangers of the kind of unfounded correlations on which they choose to rely. After all, the Pastas can show a *really* strong inverse correlation between declining number of pirates in the world & the rise in global CO2-it's such a close fit that it *has* to be true! Right? Of course not-not unless you can back it up with (a) a physical explanation of *how* pirates were keeping CO2 levels down; (b) some empirical evidence that backs up this explanation (like showing pirates sucking the CO2 out of the atmosphere) & (c) making sure that the declining number of pirates was the *cause* of rising CO2 levels-instead of the other way around. This is where Scafetta's paper falls apart. With a little statistical gymnastics, he's able to show a correlation between a 60-year alignment of planets & a warming of the climate-what he doesn't give is an explanation of *how* this alignment might be causing the sun to make the Earth warmer or how we might expect these impacts to manifest themselves on the planet's surface. Nor does he try & show how his hypothesis compares to existing paleo-climate data from before 1850 (probably because it increasingly falls apart). The thing is that we already have a very *very* good idea what caused the warming between 1880-1940, & that is the significant rise in sunspot numbers over that period. Now I'm happy to accept the possibility that planetary alignments could be driving this increase in sunspot numbers but, if that were the case, then we should have seen a similar sunspot response during this current PUTATIVE 60-year cycle. Yet we don't see that response from the sun. Indeed, sunspot numbers have been trending downward. The fact is that Scafetta's 60-year "trend" is highly dependent on only focusing on the period from 1850 on, & then only if you rely on HadCRU data, rather than the more reliable GISStemp data (GISStemp shows no cooling trend between 1880 & 1910, the supposed "cooling" trend between 1940-1970 only works because of the relatively big drop off in temperatures around 1943-1945-without it it becomes a warming trend-& 2000-2009 shows a distinct warming of +0.12 degrees for the entire decade-not the cooling that we'd expect if Scafetta was correct). As to John D, a fall in average precipitation is *exactly* what we expect when temperatures warm excessively-the only thing is that you've got CAUSE & EFFECT the wrong way around-just like those who run around claiming that warming is generating the excess CO2 in our atmosphere!
    0 0
  27. Riccardo:"you assume that: 1) i'm supporting the n=4 versione of the trend; 2) i'm a competitor to Scafetta. Neither is true and nothing i said should let you think they are. I esplcitly stated (several times indeed) that the n=4 has no more value and I nowhere tryed an alternative hypothesis. Insisting on this point is, at best, specious. I'll said it again, maybe sooner or later you'll will accept it. I just showed the weakness of Scafetta paper through its arbitrary choice of the trend. Stop. I understand that it's hard to accept the fault one of the skeptics heros, but you know, sometimes even heros might be wrong." Sure he can be wrong and frankly I am quite skeptical of these sorts of linkages, but that doesn't mean that you have demonstrated what you think you have demonstrated. Whether or not Scafetta's choice of exponent is valid or not is dependent on how effective his *complete model* is at reconstructing all the observed temperatures. At this, his model beats your "model" hands down. I am pretty sure that there are many equally effective (to Scafetta's) ways of getting a decent reconstruction of temps. The way to deal with Scafetta's paper would be to show how an alternative reconstruction works just as well or better. Scafetta himself concedes that there are other possible trends to explain the data so I doubt that he considers your objection significant(he mentions it himself). Respectfully, your trend doesn't work, so even if both your and his choice of trends are both *completely* arbitrary, his is *still* better than yours. (I don't want to get into the semantics of the word arbitrary). BTW< just because a choice of parameters may be arbitrary, doesn't mean it won't turn out to be a good predictor of events. Cheers, :)
    0 0
  28. shawnhet, I think you're missing the central point of what Scafetta did. His model model is about the cycles and does not include the trend. Indeed, Scafetta works with separately detrended data, he does not fit trend and cycles together. If, as I showed, his starting point (the detrended data) is biased, his conclusions are biased as well. Does one need to show a better model or measurement to prove that the one shown in a paper is biased? It could be desirable, but not required; if its very premises are untenable one can not add a few bits to correct it. And given that it is Scafetta that is trying to push an alternative view, it's up to him to prove it. We stand where we were if he fails. "your trend doesn't work, so even if both your and his choice of trends are both *completely* arbitrary, his is *still* better than yours." I'll never get tired to repeat it, I do not have a trend of mine. And yes, they're all unjustified. Being them the basis of the subsequent analysis, the latter stands on shaky grounds.
    0 0
  29. 72 Riccardo at 08:28 AM on 20 June, 2010 "HumanityRules, "what she seems to do is develop a model which has reasonable match to HADCRUT then derive the anthropogenic signal from that model." This claim is compleately unfounded. Please stick to what she said in the paper and do not try to make people say what you'd like them say." I can understand your confusion Riccardo, in Lean 2009 the author states the figure I show is derived from the temperature record, the figure is derived from an earlier Lean 2006 paper. In that paper she labels part a) of that graph "an empirical model obtained from multiple regression for the period from 1889 to 2006" If it's my use of the word model that upsets you I'd like to point out that she uses it herself (but not in 2009 I'll admit). You're ignoring the point of my post I think the work Lean does has to be critically assessed for it's ability to identify or dismiss the presence of a 60 year cycle. The overall ability of her empirical model to match the actual temperature record is good but you need to look at the detail when deciding it's usefulness for the 60 year cycle. The features of that possible cycle in the temperature record are the low of 1910 and the high of 1930, I hope you would accept that. You can also see that Leans empirical model (the brown line in a, it's actually clearer in the 2006 paper) fails to match these important time periods. As I stated it flattens out the record. Surely any analysis of this data for the 60 years cycle is going to be comprimised by this?
    0 0
  30. 76 Marcus You'll have to make up your mind on whether you like correlation or not because you we're all over it in post #66. Maybe it's just some correlations? Given your wish to admonish humanity for our ill-deeds I guess it's a shame not more of us aren't pirates.
    0 0
  31. in #79 1930 should read 1940.
    0 0
  32. HumanityRules, no confusion on my part. In presence of a multiple regression, saying that anthropogenic contribution is derived from the model is reductive. What has been found is the relative weight of the various contributions (known a priori) included in the regression. It's not the same thing. As for the 60 years cycle in light of Lean papers, one should have Lean's results and calculate the residuals. You may try to ask her and do it yourself. On my side, I'm not that impressed by the mismatch around 1910 and 1940. To think of a cycle that mismatch should repeat, which apparently it doesn't. A better question would be what is missing (or what is not done appropiately) in Lean's calculations.
    0 0
  33. Riccardo, "I think you're missing the central point of what Scafetta did. His model model is about the cycles and does not include the trend. Indeed, Scafetta works with separately detrended data, he does not fit trend and cycles together. If, as I showed, his starting point (the detrended data) is biased, his conclusions are biased as well." Respectfully, it seems that you are the one who doesn't seem to understand what Scafetta has done here. See here: "If the global temperature continues to rise with the ***same acceleration*** observed during the period 1850-2009, in 2100 the global temperature will be little bit less than 1 oC warmer than in 2009. This estimate is about three times smaller than the average projection of the IPCC [2007]. However, the meaning of the quadratic fit forecast should not be mistaken: indeed, alternative fitting functions can be adopted, they would equally well fit the data from 1850 to 2009 but may diverge during the 21st century. The curve depicted in the figure just suggests that if an underlying warming trend continues for the next few decades, ***the cooling phase of the 60-year cycle*** may balance the underlying upward trend. Consequently, the temperature can remain almost stable until 2030-2040. The underlying warming trend can be due to ***both natural and anthropogenic influences***." The acceleration he is talking about is the quadratic trend(ie increasing anthro temp effect) combined with the 60 year cycle allows him to predict, for example, that temps may be flat until 2030-40. You can also see this of Figs 12A&B of the paper, where he has separate lines for the SSCM effect and the quadratic trend which are then combined to make his Forecast 1 line. ""your trend doesn't work, so even if both your and his choice of trends are both *completely* arbitrary, his is *still* better than yours." I'll never get tired to repeat it, I do not have a trend of mine. And yes, they're all unjustified. Being them the basis of the subsequent analysis, the latter stands on shaky grounds." Well, you're the one who proposed it ;). BTW, have you tried actually assuming that the only thing operating is quadratic curve to see what the predictions for the temp in 2100 is? If you tried comparing that quadratic trend with the one you proposed here, you might find it a bit harder to say they are all equally arbitrary. Cheers, :)
    0 0
  34. 82 Riccardo "I'm not that impressed by the mismatch" Why?
    0 0
  35. shawnhet, thanks for quoting the entire paragraph quoted just in part by me. Though, I do not understand why you refer to the conclusions and not the premises of which i'm talking about. Apparently you continue to shift your attention to something else. True that toward the end Scafetta extrapolated his curves but still the trend comes before his analysis of the cycles. You should not overlook it because his building would collapse without them. And you also persist in claiming i'm proposing a different trend. Maybe I should repeat it once more, I do not propose any. On the contrary, I say that no trend can be used without a reason when the results strongly depends on it, let alone extrapolate it. You fell into the mistake that even Scaffeta warned against. HumanityRules, becaause they're relatively small deviations and because they do not repeat cyclically, thus pointing to something that happened or not properly accounted for in those limited time ranges.
    0 0
  36. Riccardo:"thanks for quoting the entire paragraph quoted just in part by me. Though, I do not understand why you refer to the conclusions and not the premises of which i'm talking about. Apparently you continue to shift your attention to something else. True that toward the end Scafetta extrapolated his curves but still the trend comes before his analysis of the cycles. You should not overlook it because his building would collapse without them." Riccardo, again, respectfully, you are very confused here. I referred to the section I posted last time, because it showed how you were wrong about what Scafetta was doing. You now are moving the goalposts to talk about his premises. It still doesn't mean what you think it means. The fact remains despite the fact that you can (arbitrarily) set n to whatever you want doesn't mean that you will be able to *reproduce* the observed temperature changes of the last 150 years(alone or in combination with some other effect). There is no point IMO with comparing hypothetical trends that do not match the observed records to ones that do (at least potentially). As I have said before, this is apples and oranges. Cheers, :)
    0 0
  37. Is it ironic that Scafetta's hypothetical but unexplained connection between climate and Earth-external ~60 year periodic forcings appears to hinge largely on acceptance of Mann et al's dendrochronology interpretations? See Scafetta's key cite of Long-period Cycles of the Sun's Activity Recorded In Direct Solar Data and Proxies (MG Ogurtsov, YA Nagovitsyn, GE Kocharov, H Jungner - Solar Physics 2002, full-text PDF) If Scafetta had confined himself to making this a review paper and eschewed forming conclusions about actual percentages of attribution it would have been a lot better.
    0 0
  38. shawnhet, maybe i now can see why you are focusing there. As convinient to your position you do not like to see where the bases of his paper are and rather prefer to look at it upside down. As a general rule, the begining is were one should start, not the end. doug_bostrom, several scientists are currently looking at possible sources of decadal variability. I think that the work on the cycles could be valuable in this respect, but his sort of obsession to disprove AGW led him off road.
    0 0
  39. I've had fun rummaging through Scafetta's citations, Riccardo. Indeed he does seem obsessed, makes a perilous leap from tentative indications to firm conclusions, indulging in rhetoric along the way. I suppose in way that's good; I dug into the citations because Scafetta's remarks about the IPCC report are factually wrong and led me to wonder what else he was misinterpreting or exaggerating .
    0 0
  40. "maybe i now can see why you are focusing there. As convinient to your position you do not like to see where the bases of his paper are and rather prefer to look at it upside down. As a general rule, the begining is were one should start, not the end." It doesn't make any difference whether you start at the beginning or the end here. The facts are as I have already laid them out. Scafetta proposes *at the beginning middle and end of his paper* that temperature can be reconstructed using a quadratic trend(to represent AGW) and SSCM cyclical trend. The fact that the choice of AGW trend may be somewhat arbitrary(though less so than n=4) does not mean that his model does not do a good job in reconstructing temperature. Cheers, :)
    0 0
  41. @Marcus - sunspot ... The sun also, for instance through its "active" gravitational effect on Earth's volcanic activity - aerosols - and such as, cause e.g. transferred those to the activity of "direct" (TSI) Sun - LIA ... Please look at this picture: http://www.nature.com/nature/journal/v443/n7108/fig_tab/nature05072_F5.html (with: Variations in solar luminosity and their effect on the Earth's climate, Foukal et al., 2006, Nature). For example, year 1150 - 1300 - is nearly complete lack of direct correlation: sunspots - global temperature. Shifts in time are all too visible - even when compared with the newer (than in this work) temperature reconstructions. Present here the natural pattern of origin of the current warming - an explanation which will be dominated in the forthcoming report NIPCC (not the theory of Svensmark - like now). The increase in solar activity (TSI), is closely correlated with interactions of the planets in our star. Additionally, it causes (parallel - or cyclically delayed in time - the TSI) changes in the gravitational system the Sun - the planet - the Moon. Currently, a number of cycles is the most important series of changes to the layout Millennium - "Millennium" x multiples - it requires also, or the strongest short cycle - 60 years. The gravitational influence of solar system planetary radius of THC changes will affect the NAO, AMO, PDO, ENSO, about AO, etc. (Long-term natural variability and 20th century climate change, Swanson, 2009,: "Variability associated with these latter processes, generally referred to as natural long-term climate variability, arises PRIMARILY FROM CHANGES IN OCEANIC CIRCULATION.") Currently, more energy is put to NH. Warming to NH - particularly the Arctic - is greater than in SH. They will run a strong positive feedback associated only with the NH (not in the SH): - Increases the area of the lower albedo (less sea ice, glaciers are melting); - Increased evaporation - the greenhouse effect (on the NH is more land than the SH, the lands have a lower thermal inertia compared to the oceans ...), greater CO2 emission from the richest soils in carbon ...; Moreover, when such changes in THC - AMO - of ENSO, El Nino often occurs - it is stronger - the ocean gives more (and faster) energy ... In conclusion, in our view, the system planets - the Sun - Earth - Moon - by affecting the atmospheric and oceanic circulation, corresponds to (mostly) for the increased capacity of the Earth's atmosphere to heat accumulations (...). - and with that Marcus (and al.) should discuss. .. and for me is the impact of THC on the MOON seems to be the most important ... P.S. In addition, I recommend the discussion: Dickman, 2006, Short and longer-term planetary effects on Sun and Earth; Mackey, 2009, The Sun's role in regulating the Earth's climate dynamics.
    0 0
  42. Chris#43, Albatros#48 Marcus#53 Owl905#68 You all had better go back and read the "Robust" thread here: http://www.skepticalscience.com/Robust-warming-of-the-global-upper-ocean.html Far from being 'flawed', both BP and I have shown the impossibility of the jumps in the 0-700m OHC charts being TOA imbalances over such short periods which happen to coincide with the change from XBT and the full deployment of Argo in 2003-04. The jump of about 7E22 Joules in a 2 year period is most likely an instrument offset error. Take out the jump and the OHC is pretty flat for the whole 16 year period - and the more accurate Argo data from the 6-7 anlyses starts to converge on a flatter trend over the last 6 years (Fig 2). Dr Tremberth's paper (Aug09) oft quoted here also summarises the sea level story in Table 1. The total land ice melt accounts for about 2.0mm of the total 'observed' 2.5mm rise per year (2004-2008), leaving about 0.4-1.2mm for the ocean thermal expansion. These numbers have wide error bars eg. 0.8mm +/-0.8mm is quoted for steric estimates. Chris and I have debated the TOPEX - Jason satellite transition - and if the two trends are linearized - there is a flattening in the Jason record closer to 2.0mm than 3.2mm per annum often quoted over the combined record. There is also the probably of an offset error in the transition. Lack of steric rise means lack of thermal expansion means lack of take-up of heat in the oceans which means - globally - lack of TOA imbalance - which means lack of global warming over the last 6 years at least. Cop that for reductive thinking. And finally if the current 'lack of warming' over the last 6 years or so is due to Chris' bottoming of the 11 year Solar cycle, there is a the difficult question of scale of forcing imbalance of Solar (0.25W/sq.m)compared with Dr Trenberth's 0.9W/sq.m overall 'observed' imbalance. In other words, if a drop of 0.25W/sq.m (top to bottom) of the 11 year cycle, flattens global warming over the last 6 years or so, then that suggests a similar warming figure was acting at the top of the cycle ie. about 0.25W/sq.m, which is a lot less than the Trenberth TOA imbalance of 0.9W/sq.m.
    0 0
  43. Look, let's cut through the chase. Scaletta clearly states that in the period 1970-2000 that 60% of the warming is due to the 60 & 20 year cycles while 40% is due to human causes. In other words a full 0.3 of 0.5 deg C is attributed solely to Scaletta's cycle. For that claim to have any validity, I would expect to see a 0.3 deg C increase in a 30 year period in relation to that cycle every time in addition to any other forcings. Conversely, I would expect to see a 0.3 deg C. drop at the bottom of that cycle in a 30 year span as well. I don't see it. Anyone?
    0 0
  44. Ken Lambert I know that it's rhetorically important to focus on hypothetical, undemonstrated errors in the XBT-ARGO transition. Putting aside that thesis for a moment, is it your claim that -no- heating has been observed in the ocean over the instrumental record period?
    0 0
  45. Ken #92 You're repeating yourself here. Essentially your argument seems to be about claiming that noise is signal. You appear to be claiming that a poor quality, highly complex measurement model is strong evidence against AGW. For such a complex noisy system, 6 years is a ridiculously short period of time in which to attempt to draw strong conclusions. If you want your argument to appear to have substance you'll have to do much better than fiddle with the minutae of a large coherent data set at the end of the series.
    0 0
  46. DougB #94 and kdkd #95 "The jump of about 7E22 Joules in a 2 year period is most likely an instrument offset error. Take out the jump and the OHC is pretty flat for the whole 16 year period - and the more accurate Argo data from the 6-7 analyses starts to converge on a flatter trend over the last 6 years (Fig 2)." Go and work the numbers for yourselves and show me my error. I also note that most sea level charts show a flattening of SLR from around 2005-2008 eg. see Fig 3 of: http://www.cgd.ucar.edu/cas/Trenberth/trenberth.papers/EnergyDiagnostics09final2.pdf Then they happily report a rise from 2008-2009 to put the SLR back on the 3.2mm/year trend from 1993-2009. Of course 6 years a ridiculously short period according to kdkd when SLR and OHC is flattening and there is a 'lack of warming', but one year is fine to get the SLR back on trend, when the trend fits the AGW theory.
    0 0
  47. Ken, it seems that indeed you believe there's been essentially no significant warming of the ocean over the past 16 years. That's a remarkably bold assertion and leaves you in a vanishingly small minority, on the fringe even in the contrarian camp. You ought to make a case for your belief. It might be better to take further discussion of OHC to the thread you cited, but let me just remark that "The jump of about 7E22 Joules in a 2 year period is most likely an instrument offset error" is not a demonstration of an error, not a useful argument, it's a supposition for which you supply no evidence other than being uncomfortable with the eyeball appearance of a graph. You need to supply a cogent argument to support your assumption. At the very least, to form a conclusion about the 16 year period better than what the instrumental record suggests, you'll need to fill in the period you're worried about with some numbers. Note that the meta-analysis of OHC described here elaborates real methods and forms a conclusion derived from those methods. It's superior to your graphically-inspired supposition, more trustworthy until you do better work.
    0 0
  48. DougB#97 It looks like BP and I have the same eyeballs Doug, and our independent analysis is chock full of numbers if you care to read them VIZ: http://www.skepticalscience.com/Robust-warming-of-the-global-upper-ocean.html KL#24: "Figure 2 shows a huge increase in OHC from roughly a 2 year period 2001 to 2003 in which the OHC rises from the zero axis to about 7E22 Joules or about 700E20 Joules. This is about 350E20 Joules/year heat gain. Dr Trenberth's 0.9W/sq.m TOA energy flux imbalance equalled 145E20 Joules/year. Therefore a rise of 350E20 Joules/year in OHC equals about 2.1W/sq.m TOA imbalance - a seemingly impossible number. Coinciding with the start of full deployment of the Argo buoys around 2003-04 this impossibly steep rise in 2001-03 looks like an offset calibration error. Similar would apply to Fig 3." And a bit later BP shows the satellite year-year data showing flatness in the 2003-04 period ie: BP#30: "Therefore either satellite data are absolutely useless or the 6-8×1022 J heat accumulation in the oceans after 2000 followed by a more or less level plateau from 2004 on is an artifact due to transition to ARGO." So I came up with 7E22 Joules in the 2 year period and BP canme up with 6-8x1022 J - the same number. What you have to explain is how the acknowledged expert on global energy balances (Dr Trenberth) got a TOA imbalance of 0.9W/sq.m globally for the 2004-2008 period which is largely based on Fig2.4 of IPCC AR4, and how the OHC chart for the similar period works out to 2.1W/sq.m. - nearly 2.5 times Trenberth's global TOA imbalance. The most likely explanation is that the OHC chart is wrong and that the later data from Argo being much more extensive is giving a much more accurate result up around the 7E22 Joules AND that it follows that the far less extensive and accurate XBT data prior to 2004 was not measuring enough OHC due to the impossibility of the jump from around zero to 7E22 Joules in 2 years. This is further confirmed by the flatness of the 6-7 analyses when averaged since 2004 around the 7E22 Joule figure, when the OHC should have been showing up a chunk of Dr Trenberth's 145E20 (1.45E22) Joules per year.
    0 0
  49. Ken, so again your argument comes down to "The most likely explanation is that the OHC chart is wrong... and again you don't have the skill to show that. I see your fog of numbers but they're a tautology. Sorry, I'm sticking with the experts on this one.
    0 0
    Moderator Response: There is already a robust discussion available for further exploration of OHC. Please follow up there.
  50. Ken Lambert at 23:44 PM on 21 June, 2010 I know I shouldn't be talking about ocean heat, but I can't let a couple of your comments go unremarked: "Chris and I have debated the TOPEX - Jason satellite transition - and if the two trends are linearized - there is a flattening in the Jason record closer to 2.0mm than 3.2mm per annum often quoted over the combined record. There is also the probably of an offset error in the transition." That's incorrect on two counts Ken. (i) There is no contemporary "flattening" of the Jason sea level record. There was a temporary apparent slow down in the rate of sea level rise during the period around 2006-2008. That may or may not have been real (if so it's quite interesting, yes?). However if you are going to assert that that slow down is of significance (it may well be), then you really should take on board the fact that during the 2.4 year period from 2008 until the present, the Jason sea level rise regresses to a value of 6.5 mm.yr-1; a massive acceleration. More realistically, the sea level rise continues around the trend of the last 17 years near 3.2 mm.yr-1 (it may be accelerating; time will tell). That is simply incompatible with the absence of ocean heat uptake that you are attempting to deduce. (ii) Your insinuation of a "probably of an offset error in the transition" is completely unsubstantiated. We saw in a previous discussion how this was unlikely to be the case. You can't just assert "offset errors" willy-nilly to support a particular viewpoint.
    0 0

Prev  1  2  3  Next

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.



The Consensus Project Website

THE ESCALATOR

(free to republish)


© Copyright 2020 John Cook
Home | Links | Translations | About Us | Privacy | Contact Us