Guest post by Alec Rawls
My first post on this subject remarked on the number of scientists who assert that late 20th century global warming cannot have been driven by the sun because solar activity was not trending upwards at the time, even though it remained at peak levels. To follow up, I asked a dozen of these scientists whether solar activity has to KEEP going up to cause warming?
Wouldn’t that be like saying you can’t heat a pot of water by turning the flame to maximum and leaving it there, that you have to turn the heat up gradually to get warming?
My email suggested that these scientists (more than half of whom are solar scientists) must be implicitly assuming that by 1980 or so, ocean temperatures had already equilibrated to the 20th century’s high level of solar activity. Then they would be right. Continued forcing at the same average level would not cause any additional warming and any fall off in forcing would have a cooling effect. But without this assumption—if equilibrium had not yet been reached—then continued high levels of solar activity would cause continued warming.
Pretty basic, but none of these folks had even mentioned equilibration. If they were indeed assuming that equilibrium had been reached, and this was the grounds on which they were dismissing a solar explanation for late 20th century warming, then I urged that this assumption needed to be made explicit, and the arguments for it laid out.
I have received a half dozen responses so far, all of them very gracious and quite interesting. The short answer is yes, respondents are for the most part defending (and hence at least implicitly acknowledging) the assumption that equilibration is rapid and should have been reached prior to the most recent warming. So that’s good. We can start talking about the actual grounds on which so many scientists are dismissing a solar explanation.
Do their arguments for rapid equilibration hold up? Here the short answer is no, and you might be surprised to learn who pulled out all the stops to demolish the rapid equilibration theory.
From “almost immediately” to “20 years”
That is the range of estimates I have been getting for the time it takes the ocean temperature gradient to equilibrate in response to a change in forcing. Prima facie, this seems awfully fast, given how the planet spent the last 300+ years emerging from the Little Ice Age. Even in the bottom of the little freezer there were never more than 20 years of “stored cold”? What is their evidence?
First up is Mike Lockwood, Professor of Space Environment Physics at the University of Reading. Here is the quote from Mike Lockwood and Claus Fröhlich that I was responding to (from their 2007 paper, “Recent oppositely directed trends in solar climate forcings and the global mean surface air temperature”):
There is considerable evidence for solar influence on the Earth’s pre-industrial climate and the Sun may well have been a factor in post-industrial climate change in the first half of the last century. Here we show that over the past 20 years, all the trends in the Sun that could have had an influence on the Earth’s climate have been in the opposite direction to that required to explain the observed rise in global mean temperatures.
The estimate in this paper is that solar activity peaked in 1985. Would that really mean the next decade of near-peak solar activity couldn’t cause warming? Surely they were assuming that equilibrium temperatures had already been reached. Here is the main part of Mike’s response:
Hi Alec,
Thank you for your e-mail and you raise what I agree is a very interesting and complex point. In the case of myself and Claus Froehlich, we did address this issue in a follow-up to the paper of ours that you cite, and I attach that paper.
One has to remember that two parts of the same body can be in good thermal contact but not had time to reach an equilibrium. For example I could take a blow torch to one panel of the hull of a ship and make it glow red hot but I don’t have to make the whole ship glow red hot to get the one panel hot. The point is that the time constant to heat something up depends on its thermal heat capacity and that of one panel is much less than that of the whole ship so I can heat it up and cool it down without an detectable effect on the rest of the ship. Global warming is rather like this. We are concerned with the temperature of the Earth’s surface air temperature which is a layer with a tiny thermal heat capacity and time constant compared to the deep oceans. So the surface can heat up without the deep oceans responding. So no we don’t assume Earth surface is in an equilibrium with its oceans (because it isn’t).
So the deep oceans are not taking part in global warming and are not relevant but obviously the surface layer of the oceans is. The right question to ask is, “how deep into the oceans do centennial temperature variations penetrate so that we have to consider them to be part of the thermal time constant of the surface?” That sets the ‘effective’ heat capacity and time constant of the surface layer we are concerned about. We know there are phenomena like El-Nino/La Nina where deeper water upwells to influence the surface temperature. So what depth of ocean is relevant to century scale changes in GMAST [Global Mean Air Surface Temperature] and what smoothing time constant does this correspond to?
Jim Hansen has looked at ocean temperature profile changes and found that about a global average of 1Wm-2 is going into warming the oceans (compared to 235 Wm-2 of infrared (longwave) radiated by the top of Earth’s atmosphere back into space and (342-106) = 236 Wm-2 supplied by the solar shortwave (342 W is the daily mean supplied by the sun to every m2 of the top the atmosphere an 106 m-2 is reflected back into space (making the global albedo 106/342 = 0.31). This is why in climate model predictions even if you turn greenhouse emissions to zero the climate continues to rise for up to about 10 years (as the relevant part of the ocean that has warmed gives back the heat that it has stored) – its called the “temperature commitment”. (So climate models are given the relevant time constant is up to about 10 years).
In the attached paper, we cite a paper by Schwartz (2007) that discusses and quantifies the heat capacity of the oceans relevant to GMAST changes and so what the relevant response time constant is. It is a paper that has attracted some criticism but I think it is a good statement of the issues even if the numbers may not always be right. In a subsequent reply to comments he arrives at a time constant of 10 years. Almost all estimates have been in the 1-10 year range.
In the attached paper we looked at the effect of response time constants between 1-10 years and showed that they cannot be used to fit the solar data to the observed GMAST rise. Put simply. The peak solar activity in 1985 would have caused peak GMAST before 1995 if the solar change was the cause of the GMAST rise before 1985.
This is a significant update on Lockwood and Fröhlich’s 2007 paper, where it was suggested that temperatures should have peaked when solar activity peaked. Now the lagged temperature response of the oceans is front and center, and Professor Lockwood is claiming that equilibrium comes quickly. When there is a change in forcing, the part of the ocean that does significant warming should be close to done with its temperature response within 10 years.
Peak GMAST by 1995?
One thing to note here is how little Mike’s position is actually at odds with a solar explanation for late 20th century warming. Suppose the solar activity peak was not in 85, but several years later, as a straightforward reading of the data suggests. (As documented in Part 1, solar cycle 22, which began in 1986, was more active than cycle 21 by pretty much every measure.) If the solar activity peak shifts five years then Mike’s temperature response formula says peak GMAST should have occurred by 2000, which is pretty close to when it did occur.
Then there is the lack of warming since 2000, which is fully compatible with a solar explanation for late 20th century warming but is seriously at odds with the CO2 theory. Of course 10 or 15 years is not enough data to prove or disprove either theory, but the episode that is held to require a CO2 explanation is even slighter. The post 1970’s warming that is said to be incompatible with a solar explanation didn’t show a clear temperature signal until 97 or 98:
By this standard, the subsequent decade of no warming should be seen as even stronger evidence that climate is being driven by the sun, and the quicker the oceans equilibrate, the less room there is for CO2 driven warming to be hidden by ocean damping. Maybe it is time for another update: “Recent samely directed solar climate forcings and global temperature.”
Not samely directed trends, because the equilibration mechanism has to be accounted, but a leveling off of surface temperatures is just what a solar-driven climate should display when solar activity plummets. This most recent data is a big deal. It’s hard to justify reading so much into the very late 20th century step-up in temperature while ignoring the 21st century’s lack of warming.
The Team springs into action, … on the side of a slow adjustment to equilibrium?
Professor Lockwood cites the short “time constant” estimated by Stephen Schwartz, adding that “almost all estimates have been in the 1-10 year range,” and indeed, it seems that rapid equilibration was a pretty popular view just a couple of years ago, until Schwartz came along and tied equilibration time to climate sensitivity. WUWT readers are going to like this part of the story. Schwartz 2007 is actually the beginning of the end for the rapid equilibration view. Behold the awesome number-crunching, theory-constructing power of The Team when their agenda is at stake.
The CO2 explanation for late 20th century warming depends on climate being highly sensitive to changes in radiative forcing. The direct warming effect of CO2 is known to be small, so it must be multiplied up by feedback effects (climate sensitivity) if it is to account for any significant temperature change. Schwartz shows that in a simple energy balance model, rapid equilibration implies a low climate sensitivity. Thus his estimate of a very short time constant was dangerously contrarian, prompting a mini-Manhattan Project from the consensus scientists, with the result that Schwartz’ short time constant estimate has now been quite thoroughly shredded, all on the basis of what appears to be perfectly good science.
Too bad nobody told our solar scientists that the rapid equilibrium theory has been hunted and sunk like the Bismarck. (“Good times, good times,” as Phil Hartman would say.)
Schwartz’ model
Schwartz’ 2007 paper introduced new way of estimating climate sensitivity. He showed that when the climate system is represented by the simplest possible energy balance model, the following relationship should hold:
τ = Cλ-1 where
τ is the time constant of the climate system (a measure of time to equilibrium); C is the heat capacity of the system; and λ-1 is climate sensitivity
The intuition here is pretty simple (via Kirk-Davidoff 2009, section 1.1 ). A high climate sensitivity results when there are system feedbacks that block heat from escaping. This escape-blocking lengthens the time to equilibrium. Suppose there is a step-up in solar insolation. The more the heat inside the system is blocked from escaping, the more the heat content of the system has to rise before the outgoing longwave radiation will come into energy balance with the incoming shortwave, and this additional heat increase takes time.
Time to equilibrium will also be longer the larger the heat capacity of the system. The surface of the planet has to get hot enough to push enough longwave radiation through the atmosphere to balance the increase in sunlight. The more energy gets absorbed into the oceans, the longer it takes for the surface to reach that necessary temperature.
τ = Cλ-1 can be rewritten as λ-1 = τ /C, so all Schwartz needs are estimates for τ and C and he has an estimate for climate sensitivity.
Here too Schwartz keeps things as simple as possible. In estimating C, he treats the oceans as a single heat reservoir. Deeper ocean depths participate less in the absorbing and releasing of heat than shallower layers, but all are assumed to move directly together. There is no time-consuming process of heat transfer from upper layers to lower layers.
For the time constant, Schwartz assumes that changes in GMAST (the Global Mean Atmospheric Surface Temperature) can be regarded as Brownian motion, subject to Einstein’s Fluctuation Dissipation Theorem. In other words, he is assuming that GMAST is “subject to random perturbations,” but otherwise “behaves as a first-order Markov or autoregressive process, for which a quantity is assumed to decay to its mean value with time constant τ.”
To find τ, Schwartz examines the autocorrelation of the temperature time series and looks to see how long a lag there is before the autocorrelation stops being positive. This time to decorrelation is the time constant.
Forcings are random?
So what to make of this scheme? Start with the assumption that forcings are random. Not only does solar activity follow a semi-regular 11 year cycle, but Schwartz only looks at GMAST going back to 1880, a period over which solar activity was semi-steadily rising, as was CO2. Certainly the CO2 increase has been systematic, and solar fluctuations may well be too, so the forcings are not all that random it seems.
I’m not a physicist so I can’t say how critical the randomness assumption is to Schwartz’ model, but I have a more general problem with the randomness assumption. My background is economics, which is all about not throwing away information, and the randomness assumption throws away information in spades.
By assuming that perturbations are random Schwartz is setting aside everything we can say about the actual time-sequence of forcings. We know, for instance, that the 1991-93 temperature dip coincided with a powerful forcing: the Mount Pinatubo eruption. This allows us to distinguish at least most of this dip as a perturbation rather than a lapse to equilibrium, and this can be done systematically. By estimating how volcanism has affected temperature over the historical record, we can with some effectiveness control for its effects over the entire record. Similarly with other possible forcings. To the extent that their effects are discernable in the temperature record they can be controlled for.
Making use of this partial ability to distinguish perturbations from lapses would give a better picture of the lapse to equilibrium and a better estimate of the lapse rate. Thus even if Schwartz’s estimation scheme could be legitimate (maybe given a long enough GMAST record?) the way that it throws away information means that it certainly cannot be efficient. Schwartz’s un-economic scheme cannot produce a “best estimate,” and probably should not be referenced as such.
The Team’s critique
Given Schwartz’ time constant estimate of 4-6 years:
The resultant equilibrium climate sensitivity, 0.30 ± 0.14 K/(W m-2), corresponds to an equilibrium temperature increase for doubled CO2 of 1.1 ± 0.5 K. …
In contrast:
The present [IPCC 2007] estimate of Earth’s equilibrium climate sensitivity, expressed as the increase in global mean surface temperature for doubled CO2, is [2 to 4.5].
These results get critiqued by Foster, Annan, Schmidt and Mann on a variety of theoretical grounds (like the iffyness of the randomness assumption), but their main response is to apply Schwartz’ estimation scheme to runs of their own AR4 model under a variety of different forcing assumptions. Their model has a known climate sensitivity of 2.4, yet the sensitivity estimates produced by Schwartz’ scheme average well below even the low estimate that he got from the actual GMAST data, suggesting that an actual sensitivity substantially above 2.4 would still be consistent with Schwartz’ results.
Part of the discrepancy could be from Schwartz’ use of a lower heat capacity estimate than is used in the AR4 model, but Foster et al. judge that:
… the estimated time constants appear to be the greater problem with this analysis.
The AR4 model has known equilibration properties and “takes a number of decades to equilibrate after a change in external forcing,” yet when Schwartz’ method for estimating speed of equilibration is applied to model-generated data, it estimates the same minimal time constant as it does for GMAST:
Hence this time scale analysis method does not appear to correctly diagnose the properties of the model.
There’s more, but you get the gist. It’s not that Schwartz’ basic approach isn’t sensible. It’s just the hyper-simplification of his model that makes this first attempt unrealistic. Others have since made significant progress in adding realism, in particular, by treating the different ocean levels as separate heat reservoirs with a process of energy transport between them.
Daniel Kirk-Davidoff’s two heat-reservoir model
This is interesting stuff. Kirk-Davidoff finds that adding a second weakly coupled heat reservoir changes the behavior of the energy balance model dramatically. The first layer of the ocean responds quickly to any forcing, then over a much longer time period, this upper layer warms the next ocean layer until equilibrium is reached. This elaboration seems necessary as a matter of realism and it could well be taken further (by including further ocean depths, and by breaking the layers down into sub-layers).
K-D shows that when Schwartz’ method for estimating the time constant is applied to data generated by a two heat-reservoir model it latches onto the rapid temperature response of the upper ocean layer (at least when used with such a short time series as Schwartz employs). As a result, it shows a short time constant even when the coupled equilibration process takes many decades:
Thus, the low heat capacity of the surface layer, which would [be] quite irrelevant to the response of the model to slowly increasing climate forcing, tricks the analysis method into predicting a small decorrelation time scale, and a small climate sensitivity, because of the short length of the observed time series. Only with a longer time series would the long memory of the system be revealed.
K-D says the time series would have to be:
[S]everal times longer than a model would require to come to equilibrium with a step-change in forcing.
And how long is that? Here K-D graphs temperature equilibration in response to a step-up in solar insolation for a couple different model assumptions:
“Weak coupling” here refers to the two heat reservoir model. “Strong coupling” is the one reservoir model.
The initial jump up in surface temperatures in the two reservoir model corresponds to the rapid warming of the upper ocean layer, which in the particular model depicted here then warms the next ocean layer for another hundred plus years, with surface temperatures eventually settling down to a temperature increase more than twice the size of the initial spike.
This bit of realism changes everything. Consider the implications of the two heat reservoir model for the main item of correlative evidence that Schwartz put forward in support of his short time constant finding.
The short recovery time from volcanic cooling
Here is Schwartz’ summary of the volcanic evidence:
The view of a short time constant for climate change gains support also from records of widespread change in surface temperature following major volcanic eruptions. Such eruptions abruptly enhance planetary reflectance as a consequence of injection of light-scattering aerosol particles into the stratosphere. A cooling of global proportions in 1816 and 1817 followed the April, 1815, eruption of Mount Tambora in Indonesia. Snow fell in Maine, New Hampshire, Vermont and portions of Massachusetts and New York in June, 1816, and hard frosts were reported in July and August, and crop failures were widespread in North America and Europe – the so-called “year without a summer” (Stommel and Stommel, 1983). More importantly from the perspective of inferring the time constant of the system, recovery ensued in just a few years. From an analysis of the rate of recovery of global mean temperature to baseline conditions between a series of closely spaced volcanic eruptions between 1880 and 1920 Lindzen and Giannitsis [1998] argued that the time constant characterizing this recovery must be short; the range of time constants consistent with the observations was 2 to 7 years, with values at the lower end of the range being more compatible with the observations. A time constant of about 2.6 years is inferred from the transient climate sensitivity and system heat capacity determined by Boer et al. [2007] in coupled climate model simulations of GMST following the Mount Pinatubo eruption. Comparable estimates of the time constant have been inferred in similar analyses by others [e.g., Santer et al., 2001; Wigley et al., 2005].
All of which is just what one would expect from the two heat reservoir model. The top ocean layer responds quickly, first to the cooling effect of volcanic aerosols, then to the warming effect of the sun once the aerosols clear. But in the weakly coupled model, this rapid upper-layer response reveals very little about how quickly the full system equilibrates.
Gavin Schmidt weighs in
Gavin Schmidt recently had occasion to comment on the time to equilibrium:
Oceans have such a large heat capacity that it takes decades to hundreds of years for them to equilibrate to a new forcing.
This is not an unconsidered remark. Schmidt was one of co-authors of The Team’s response to Schwartz. Thus Mike Lockwood’s suggestion that “[a]lmost all estimates have been in the 1-10 year range,” is at the very least passé. The clearly increased realism of the two reservoir model makes it perfectly plausible that the actual speed of equilibration—especially in response to a long period forcing—could be quite slow.
Eventually, good total ocean heat content data will reveal near exact timing and magnitude for energy flows in and out of the oceans, allowing us to resolve which candidate forcings actually force, and how strongly. We can also look forward to enough sounding data to directly observe energy transfer between different ocean depths over time, revealing exactly how equilibration proceeds in response to forcing. But for now, time to equilibration would seem to be a wide open question.
That also leaves climate sensitivity as an open question, at least as estimated by heat capacity and equilibration speed. Roy Spencer noted this in support of his more direct method of estimating climate sensitivity, holding that the utility of the fluctuation dissipation approach:
… is limited by sensitivity to the assumed heat capacity of the system [e.g., Kirk‐Davidoff, 2009].
The simpler method we analyze here is to regress the TOA [Top Of Atmosphere] radiative variations against the temperature variations.
For solar warming theory, the implications of equilibration speed being an open question are clear. We have a host of climatologists and solar scientists who have been dismissing a solar explanation for late 20th century warming on the strength of a short-time-to-equilibrium assumption that is not supported by the evidence. Thus a solar explanation remains viable and should be given much more attention, including much more weight in predictions of where global temperatures are headed.
If 20th century warming was caused primarily the 20th century’s 80 year grand maximum of solar activity then it was not caused by CO2, which must be relatively powerless: little able either to cause future warming, or to mitigate the global cooling that the present fall off in solar activity portends. The planet likely sits on the cusp of another Little Ice Age. If we unplug the modern world in an unscientific war against CO2 our grandchildren will not thank us.
Addenda
There is more to Lockwood’s response, and more that I want to say about it, but this post is already quite long, so for anyone who wants to comment, please don’t feel that due diligence requires reading this additional material.
Addendum 1: A slow equilibration process does not necessarily support solar-warming theory and a fast equilibrium process does not necessarily support the CO2-warming theory
In my enthusiasm to pitch the importance of being explicit about the role of equilibrium, my email suggested that it could provide a test of which theory is right. If these scientists could show that the temperature gradient of the oceans had reached equilibrium by 1970, or 1986, then their grounds for dismissing a solar explanation for late-20th century warming would be upheld. If equilibrium was not reached, that would support the solar warming theory.
Well, to some extent maybe, but equilibrium alone doesn’t really resolve the issue. This was the second topic of Professor Lockwood’s response:
Incidentally, one thing I cannot agree on in your e-mail is that the response time is the only thing separating solar and anthropogenic “theories”. Our understanding of greenhouse trapping (by water vapour, CO2, methane etc) predicts the right level of GMAST (without it the GMAST would be -21 degrees) and it also predicts that changing from 280 ppm by volume of CO2 to 360 (which has happened since pre-industrial times) will have caused a GMAST change by a sizeable fraction of a degree – the science of the radiative properties of CO2 are too well understood and verified for that not to be true. (There are utterly false and unscientific statements around on the blogosphere that adding CO2 doesn’t add to the greenhouse trapping – this is completely wrong. It is true of some CO2 absorption lines but not of them all so if you integrate over the spectrum (rather than selecting bits of it!) one finds a radiative forcing rise that matches the observed GMAST rise very well indeed. Our best estimates of the corresponding radiative forcing by solar change are smaller by a factor of at least 10. So solar change is too small to have caused the rise we have seen, greenhouse trapping by extra CO2 is not.
I hope that helps
Mike Lockwood
I would just disagree with Mike’s conclusion. The reason the IPCC fixes the radiative forcing effect of solar variation at less than 1/10th the effect of CO2 (0.12 vs 1.66 W/m^2) is because the only solar effect that the IPCC takes into account is the tiny variation in Total Solar Insolation. TSI, or “the solar constant,” varies by one or two tenths of a percent over the solar cycle while other measures of solar activity can vary by an order of magnitude. If 20th century warming was driven by the sun, it pretty much has to have been driven by something other than TSI.
Maybe the spectrum shift that accompanies solar magnetic activity has a climate-impacting effect on atmospheric chemistry, or it could be the solar wind, deflecting Galactic Cosmic Radiation from seeding cloud formation. That is Svensmark’s GCR-cloud theory. Noting that TSI alone could not have caused 20th century warming does nothing to rebut these solar warming theories.
Where I think Svensmark would agree with Lockwood is in rejecting my suggestion that knowing the state of equilibrium in 1970 or 1980 would tell us which theory is right. His own reply to Lockwood claims that if ocean surface temperature oscillations are controlled for, then the surface temperature tracks the ups and downs in the solar cycle to a tee. I asked Doctor Svensmark if he wanted to chime in and did not get a reply, but there’s a good chance he would fall in the short-path-to-equilibrium camp. As the two heat-reservoir model shows, rapid surface temperature responses to forcing does not imply rapid equilibration, but a lot of people are reading it that way.
Also, it is possible that time to equilibrium is slow, but that the 300 year climb out of the Little Ice Age just did happen to reach equilibrium in the late 20th century. Thus I have to agree with Mike that time-to-equilibrium is not in itself determinative. It is one piece of the puzzle. What makes equilibrium particularly needful of attention is how it has been neglected, with so many scientists making crucial assumptions about equilibrium without being explicit about it, or making any argument for those assumptions.
Addendum 2: collection of quotes from scientists
Below is a list of the dozen scientists I emailed, together with quotes where they dismiss a solar explanation for recent warming on grounds that solar activity was not rising, with no qualification about whether equilibrium had been reached. These are just the one’s I happened to bookmark over the last few years. Undoubtedly there are many more. It’s epidemic!
Most of these folks have responded, so I’ll be posting at least 3 more follow-ups as I can get to them.
Professors Usoskin, Schuessler, Solanki and Mursula (2005):
The long term trends in solar data and in northern hemisphere temperatures have a correlation coefficient of about 0.7 — .8 at a 94% — 98% confidence level. …
Note that the most recent warming, since around 1975, has not been considered in the above correlations. During these last 30 years the total solar irradiance, solar UV irradiance and cosmic ray flux has not shown any significant secular trend, so that at least this most warming episode must have another source.
Solanki (2007):
“Since 1970, the cosmic ray flux has not changed markedly while the global temperature has shown a rapid rise,” [Solanki] says. “And that lack of correlation is proof that the Sun doesn’t cause the warming we are seeing now.”
Solanki and Krivova (2003):
Clearly, correlation coefficients provide an indication that the influence of the Sun has been smaller in recent years but cannot be taken on their own to decide whether the Sun could have significantly affected climate, although from Figure 2 it is quite obvious that since roughly 1970 the Earth has warmed rapidly, while the Sun has remained relatively constant.
Professors Lockwood and Fröhlich (2007):
There is considerable evidence for solar influence on the Earth’s pre-industrial climate and the Sun may well have been a factor in post-industrial climate change in the first half of the last century. Here we show that over the past 20 years, all the trends in the Sun that could have had an influence on the Earth’s climate have been in the opposite direction to that required to explain the observed rise in global mean temperatures.
Professor Benestad (2004):
Svensmark and others have also argued that recent global warming has been a result of solar activity and reduced cloud cover. Damon and Laut have criticized their hypothesis and argue that the work by both Friis-Christensen and Lassen and Svensmark contain serious flaws. For one thing, it is clear that the GCR does not contain any clear and significant long-term trend (e.g. Fig. 1, but also in papers by Svensmark).
And 2005:
A further comparison with the monthly sunspot number, cosmic galactic rays and 10.7 cm absolute radio flux since 1950 gives no indication of a systematic trend in the level of solar activity that can explain the most recent global warming.
Professor Phil Jones (interview with the BBC, February 2010):
Natural influences (from volcanoes and the Sun) over this period [1975-1998] could have contributed to the change over this period. Volcanic influences from the two large eruptions (El Chichon in 1982 and Pinatubo in 1991) would exert a negative influence. Solar influence was about flat over this period. Combining only these two natural influences, therefore, we might have expected some cooling over this period.
Dr. Piers Forster (quoted by the BBC, October 2009):
The scientists’ main approach was simple: to look at solar output and cosmic ray intensity over the last 30-40 years, and compare those trends with the graph for global average surface temperature.
And the results were clear. “Warming in the last 20 to 40 years can’t have been caused by solar activity,” said Dr Piers Forster from Leeds University, a leading contributor to this year’s Intergovernmental Panel on Climate Change (IPCC).
Professor Johannes Feddema (quoted in the Topeka Capital-Journal, September 2009):
Feddema said the warming trend earlier in the century could be attributed to anything from solar activity to El Ninos. But since the mid 1980s he believes data doesn’t correlate well with solar activity, but does correlate well with rising CO2 levels.
Professor Kristjánsson (quotede) by Science Daily in 2009):
Kristjansson also points out that most research shows no reduction in cosmic rays during the last decades, and that an astronomic explanation of today’s global warming therefore seems very unlikely.
Plus here’s a new one I just found. Ramanathan is paraphrased in India’s Frontline magazine this month as saying:
GCR trends (as seen in Graph 2) underwent monotonic decrease from 1900 to 1970 and then levelled off. The trends do not seem to reflect the large warming trend during 1970-2010.
I’ll see if he wants to weigh in too. If anyone finds more, feel free to send them to alec-at-rawls-dot-org.
Addendum 3: Errant dicta from Lockwood and Fröhlich
Professor Lockwood says that his updated paper with Claus Fröhlich (“Recent Samely Directed Trends II”) addresses the issue of equilibrium. Here is the second paragraph of their updated paper:
In paper 1 [the original Lockwood and Fröhlich article that I cited in my email], we completely removed the solar cycle variations to reveal the long-term trends. The actual response of the climate system may not have as long a time constant as the procedure adopted in paper 1. Indeed, as discussed in §3 of the present paper and in paper 3, the fact that solar cycle variations are not completely damped out tells us that this is not the whole story. The key unknown is how deeply into the Earth’s oceans a given variation penetrates. If it penetrates sufficiently deeply, the large thermal capacity of the part of the ocean involved would mean that the time constant was extremely long (Wigley & Raper 1990); in such a case, the analysis of long-term trends given in paper 1 would be adequate to fully describe the Earth’s response to solar variations [emphasis added]. However, the recent studies suggest that the sunspot cycle variations in solar forcing, in particular, do not penetrate very deeply into the oceans and so the time constant is smaller; this means that solar cycle variations are not completely suppressed. For example, Douglass et al. (2004) report a response time to solar variations of τ ˂ 1 year and, recently, Schwartz (2007) reports an overall time constant (for all forcings and responses) of τ = 5 ± 1 years. In §3, we show that this uncertainty in the response time constant does not influence our conclusion in paper 1 that the upward trend in global mean air surface temperature cannot be ascribed to solar variations.
In the bolded sentence above, Lockwood and Fröhlich are making the same mistake that they made in their first paper. A long time-to-equilibrium would most certainly NOT leave the conclusions of paper 1 unchanged. There it was assumed that as soon as solar activity passed its peak, this passage should tend to create global cooling, which would only be the case if the oceans had already equilibrated to the peak level of forcing. In effect, paper 1 assumes that equilibrium is immediate. If equilibrium instead takes a long time, then equilibrium would not have been reached in 1985, in which case the continued near-peak levels of solar activity over cycle 22 would have continued to cause substantial warming.
Still, this is only what a lawyer would call “dicta”: the parts of an opinion that don’t carry the weight of the decision, but simply comment on roads not taken. Lockwood and Fröhlich proceed to argue that time-to-equilibrium is short, so their assertions about the case where time-to-equilibrium is long are dicta, but it does raise the question of whether they grasp the implications that time-to-equilibrium actually has for their argument.
One question is; Have we had any warming outside of urban areas and other areas that have had their environment changed over the past 70 years? I would answer that it appears that after taking out the AMO and PDO, it is doubtful.
Second question is: Why would solar activity matter. D’Aleo found that putting the TSI into his model for North America did not get him a lot. I would think that GCR would be a better candidate for the forcing. If so, the sun is still very magnetically quiet. The present sunspot maximum has cosmic ray counts that equal earlier minimums. After the lag effect of increased clouds, we may get colder even if the TSI is ok.
Plenty of room to do good science. Sadly, a lot of bad science will also be done.
If the equilibration is fast there is no warming in the pipeline and no worries.
If the equilibration is slow then the recent warming happened with no increase in solar output as it was equilibraing.
It is tough to be a Climate hysteric.
The waters off Sarasota FL can change temperature by a few degrees within days depending on weather conditions. They have about a 30 degree F range over the course of a year. It would seem that SSTs are in the rapid response column, no?
Here we show that over the past 20 years, all the trends in the Sun that could have had an influence on the Earth’s climate have been in the opposite direction to that required to explain the observed rise in global mean temperatures.
Modest, is he not? ALL the trends, really, is there absolutey nothing we don’t know about the Sun? e.g. strength of Solar Cycles, being able to clearly predict this without fail. Wait a minute. We did fail, big time! This is the guy who not so long ago claimed that the unusual lull in Solar Activity was not significant, & that if it was we would have seen some cooling by now! Perhaps it’s just me but the last thhree northern hemisphere winters, & last years southern hemisphere was pretty cold I was led to believe!
“Our understanding of greenhouse trapping (by water vapour, CO2, methane etc) predicts the right level of GMAST…”
Whenever I see the word “trapping” used I shunt to ground any further comments by the user.
I see I am among the first to comment; scary since I am not in the know. An enjoyable inquiry, Alec Rawls. The argument appears eminently reasonable since the oceans — 70% of Earth’s surface with the unusual qualities of the H2O molecule — and their heat content is (are) the huge unknown in all theories of global warming and cooling. Plus, it seems that knowing about the oceans should be one of the first elements to get right. Yes, I like time-to-equilibrium; seems an essential measurement. Can we know this? Not an easy matter with today’s technology, seems to me. More than half of those questioned are solar scientists. Mike Lockwood’s title, “Professor of Space Environment Physics”, suggests he looks “outward”. I wonder what scientists/physicists of the oceans have to say? Are many included in this group? And how can they know?
O/T, that image of the sun is astounding O___O
GSA Bulletin; November 2010; v. 122; no. 11-12; p. 1981-1988; DOI: 10.1130/B30088.1
Samuli Helama, Marc Macias Fauria, Kari Mielikäinen, Mauri Timonen and Matti Eronen
Sub-Milankovitch solar forcing of past climates: Mid and late Holocene perspectives
“A comparison was performed of solar activity and terrestrial temperature records, both derived from tree rings (i.e., without dating uncertainties), with identification of detailed and highly quantified time- and timescale-dependent characteristics of solar forcing on climate through the current interglacial in the context of oceanic variability. The tree-ring–derived temperature record from high latitudes of Europe (Lapland) exhibits persistent annual-to-millennial–scale variations, with multidecadal to multicentennial periodicities reminiscent of the Sun’s periodicities. At millennial scales, cool temperatures coincided with large-scale glacial maxima. Moreover, millennial and bimillennial modes of climate variability were correlative with variations in sunspot numbers on similar scales, with near-century and near-zero lags, respectively. Although they were subtle in amplitude, the sub-Milankovitch–scale changes in the reception of the Sun’s energy could thus suffice to noticeably modulate interglacial climate variations. The relative significance of timescale-dependent, Sun-climate linkages has likely varied during the mid and late Holocene times, respectively. Thus, the warmer and cooler paleotemperatures during the Medieval Climate Anomaly and Little Ice Age were better explained by solar variations on a millennial rather than bimillennial scale. The observed variations may have occurred in association with internal climate amplification (likely, thermohaline circulation and El Niño–Southern Oscillation activity). The near-centennial delay in climate in responding to sunspots indicates that the Sun’s influence on climate arising from the current episode of high sunspot numbers may not yet have manifested itself fully in climate trends. If neglected in climate models, this lag could cause an underestimation of twenty-first–century warming trends.”
http://bulletin.geoscienceworld.org/cgi/content/full/122/11-12/1981?ijkey=KLzji3EBmzw9k&keytype=ref&siteid=gsabull
I find it almost incredible to believe such short time constants. I’ve been investigating soil temperature change with changes in sub-surface heat flow, and 10years is only enough to heat the upper 12m or so of rock. 12m of rock!!! Even after 100,000 years, the heat is still flowing into the top few kms of earth!
Where there are deep ocean currents flowing in the opposite direction of the current in the upper layer (which happens all over the world), you have to deal with Kelvin-Helmholtz instability. Wikipedia has a nice animation.
So the rate of mixing between the two heat resevoirs in the Kirk-Davidoff model is not constant. If one current changes velocity relative to the other, the rate of mixing changes. That means either a change in speed, or a change in relative direction and the degree of contact between the currents.
For example, the Pacific Ocean has a deep current flowing generally north, beneath an upper layer flowing generally west. ENSO not only changes the rate of mixing due to increased/decreased upwelling, it changes the rate of mixing due to a change in turbulence at the boundary between the upper and lower currents.
And to think if we understood clouds they could account for virtually all warming and cooling….
Given a noisy system with oscillators operating at many frequencies, it is nonsense to try to tease out the effect on the overall system of an input whose magnitude is less than the amplitudes of most of the other signals in the system.
The temperature rise in the late twentieth century is as easily explained by natural cycles as it is by solar influence or CO2. Until the natural cycles are completely understood, we really can’t say which of the three explanations is correct. A naive model with one or two time constants really doesn’t cut the mustard here.
There appears to be a close correlation between the solar activity, temperature and the North Atlantic Ocean’s currents.
Solar output may or may not control larger temperature deviations.
Solar output may or more likely may not control the N. Atlantic currents.
N. Atlantic currents definitely control regions temperature.
http://www.vukcevic.talktalk.net/NTS.htm
Result:
Major positive/negative forcing – the North Atlantic currents
Minor positive forcing – Solar activity (SSN & UV – direct and possibly GCR – indirect)
Occasional strong negative forcing – volcanic eruptions.
None of the above are part of any feedback loop.
CO2 positive feedback is probably minor factor, with far less forcing than any of the above.
Paging Dr. Svalgaard ?
Well consider the premise:-
“”””” Does solar activity have to KEEP going up to cause warming? “””””
So what the hell is “solar activity” ?
Well we seem to have pretty good satellite data covering about three sunspot cycles (11 year) that suggest that TSI changes cyclically by about 0.1% p-p. Sadly not all continuously from any single satellite; so offsets between satellites; but pretty convincing for the cycle itself, if not for the absolute level. And I’m not a believer that the long time 60s era value for TSI of 1353 W/m^2 is fairly comparable to today’s value of 1362. xxx; simply measuremnt and instrumentation advances.
Now I don’t hear anything from WUWT honorary solar scientist Leif Svalgaard to the effect that TSI shows any long term shifts that are of any similar order of magnitude to the clear 11 year signal. My gut feel is that it is flat compared to that 0.1%. I suppose one can make arguments that something as large as the sun, can’t change very fast; but I’m just arm waving there.
So bottom line, is I see evidence which I believe, that the solar TSI cycles about 0.1%, and simple BB equilibrium theory says that could account for about 1/40 % Earth temperature change or about 72 millidegrees C.
If I understand statements that Leif has (I believe) made in the past; there isn’t any evidence (data) of any 11 year 72 mdeg C Temperature cycle on earth. So then why would any other change on the sun of similar or less magnitude (in TSI) show up at all.
So basically I reject the notion that changes in “solar activity” that simply change TSI have any effect on earth climate. I think it takes major (like orbital shifts) system changes to cause significant effects (like maybe ice ages).
So why doesn’t the 72 mdeg C TSI 11 year cycle show up.
Well as I have said on many occasions; I think the whole damn thing is feedback regulated by cloud cover modulation; “IT’S THE WATER !!”
And in making that assertion (at least I believe it), I am opening the door for OTHER SOLAR CHANGES to shift the balance. And among those effects, the Svensmark thesis, of cosmic ray variation in cloud formation, is one well discussed (possible) mechanism.
So I do think the system has a natural variability, that releates to the ease or difficulty of cloud nucleation, that can be varied by “solar acticvity” whatever that is; presumably magnetic (shield) field changes, and also solar charged particle changes. Now I know nothing about measurments of any solar charged particle fluxes on earth, over long periods of (recent) history; so I am just opining that such changes might affect earth climate.
Given that most of the sea level incident solar energy goes right into the deep oceans, and that most cloud generation seems to start over tropical oceans, I think that cloud modulation is inevitable; which is why I think the whole CO2 argument is quite overblown and largely irrelevent.
And I don’t think I read that any of these dozen solar scientists stepped outside the party line box of “forcings” and similar hocus pocus.
Mother Gaia doesn’t do averages; she notes only real time actual values of weather/energy/climate variables; in particular she doesn’t do forcings.
So I don’t think these 12 solar scientists are throwing much light on the subject.
But that is just my opinion.
“all the trends in the Sun that could have had an influence on the Earth’s climate have been in the opposite direction to that required to explain the observed rise in global mean temperatures.”
Provably False.
Global brightening has occurred since the 1990s, and dimming and brightening have occurred in the past as well.
“Direct surface radiation measurements started to become available on a widespread basis in the late 1950s, with the establishment of numerous radiation sites during the International Geophysical Year (IGY) 1957/58. Based on these records, several studies pointed to a widespread decrease of surface solar radiation from the early 1960s to the late 1980s (“global dimming”). Only data prior to 1990 were available at the time these studies were completed. More recent studies used data records updated for the 1990s and show that the decline in surface solar radiation faded during the 1980s and, to a large extent, reversed during the 1990s (“brightening”).”
https://www.arm.gov/science/highlights/RMTky/view
Obviously without the solar activity data prior to and since 1985, which this article lacks, no sceptic should treat the theory that the warming since 1985 is due to equilibration an credibility whatsoever.
This isn’t simple to show that solar activity did indeed peak in 1985 but without knowing how solar activity got to that peak it’s impossible to know how long it would take to equilibrate. Using the analogy of turning up the flame on a stove. It’s more likely the case that every minute or so someone increased the heat by a minute amount until you’d got to the maximum. In this case the time to reach equilibrium is significantly different compared to suddenly turning up the temperature. There appears to be no evidence to suggest or even any reason to believe the sun would suddenly increase in solar activity in 1985 and then stay at that level.
Even if that were the case there would be other signatures. You’d expect large land masses to have lower warming trends than oceans as they should respond very much quicker to the increased solar activity and, although not in equilibrium, they would show a shallower warming trend. In fact the opposite is true as you’d expect when the forcing was currently increasing. Also the observed higher warming trend in night time is something you’d expect from an increased greenhouse affect and wouldn’t be evident if it was caused because the world was equilibrating with increased solar activity.
While hypothetically this could be the case you appear to have no evidence to support it is the case.
For the ocean to reach equibrium temperature it must take thousands of years. While the upper tenth can approach equilibrium more quickly the lower 90% is all at a constant temperature of 3C and reaches equilibrium with surface water very slowly. Presumably the nearly constant temperature of 3C at depth is the average surface temperature over a 100,000 year glacial/interglacial interval which is sufficient time for conduction and convection to equalize temperature at depth with average surface temperature.
And before anyone makes the common mistake of telling me the deep ocean is 3C because that’t the maximum density temperature of water they need to look up the temperature/density relationship of saltwater. Seawater keeps on rising in density all the way down to its sub-zero freezing point. I can find no other explanation for the temperature of the deep ocean other than it reflects the surface temperature averaged over an entire glacial/interglacial cycle.
With respect to the determination of time constants for the Globe’s response to a thermal forcing there is a tendency to get a value that corresponds to the length of the experiment.
If one looks at short term phenomena one gets short time constants and if one looks at long term phenomena one gets long time constants, This is a state of affairs long known and well understood in the study of the thermal properties of matter.
There is nothing inconsistent in the notion that a system should respond quickly to short term stimulations and slowly to long term ones. The only issue seems to be that the mathematics are a tad more complex than the exponential approach to equilibrium model, which is the case for a single time constant approach.
I think it is likely that the apparent fondness with time constants will continue to blight the debate as long as people keep submitting papers based on highly simplified thermal models and journals keep publishing them.
To me it seems odd that using such a simplified approach one can get a paper published that claims to elucidate the thermal properties of the globe when such a simple approach would be found to be risible if it claimed to describe the thermal properies of a house.
It all seems to have become an inderminable debate about whether it be 1 year, 4 years, 20 years, 100 years, or 1000 years. Consideration that it be all and any of these does not seem to occur. It is almost as if the only decay function known to science is the exponential one. We do know better than this and we can do better than this yet strangely we don’t often do better than this. For what it is worth a house doesn’t have a time constant, in a thermal sense it consists of many diverse thermal pathways coupling its thermal masses together and also coupling them to the ground it stands on and the heavens above. It doesn’t have a time constant that you can write down so why-o-why should the globe.
Alex
In short the warm ocean surface (which drives air temperature) we have been enjoying for the past 10,000 years is but a thin veneer floating on the surface of a gigantic bucket of nearly freezing water. Anything that comes along to increase the mix rate between shallow and deep water will cause surface air temperature to plummet. The ocean isn’t a reservior of heat. It’s a reservior of cold waiting to put a quick ending on the Holocene interglacial period.
What about the global dimming the was alleviated in the late 80’s and early 90’s? As the skies cleared, wouldn’t that be akin to an increase in solar output? — John M Reynolds
Speaking as an engineer, if you don’t know the time constants involved it is extremely foolish to attempt to ‘control’ anything.
I’d say 12 years 🙂
http://virakkraft.com/Mann08-NH-solar.png
I am still interested in changes in spectral distribution of the energy.
Even if TSI remains the same, if the energy distribution across the spectrum changes, I believe it might cause some major changes.
It’s more than a bit disingenuous for Lockwood to say that “Our understanding of greenhouse trapping (by water vapour, CO2, methane etc) predicts the right level of GMAST”. While predicted and observed global temperatures match, that appears to be a byproduct of a combination of faulty modeling and climate sensitivity tweaking. There are large, known systematic differences between the warming predicted by the models and the actual measured warming as a function of latitude. Chelyk et. al. show that the current (alarmist) models all match global observations but they all ignore the heat transport by the ADO in the ocean circulation models which requires increasing the climate sensitivity parameter. A much better match to both the global temperature rise AND the warming by latitude profile can be achieved by including the current heat transport by the ADO in the northerly direction and decreasing climate sensitivity by a factor of 2 to 3. A good test of which model works best will happen when the ADO switches modes.
and I thought the science was settled…
About 10 years. Are they saying that the full effect of the recent modern record solar minimum won’t kick in until later this decade?
Thanks to J for that GSA Bulletin link.
http://bulletin.geoscienceworld.org/cgi/content/full/122/11-12/1981?ijkey=KLzji3EBmzw9k&keytype=ref&siteid=gsabull
Previous cosmogenic isotope studies did not manage to resolve influences on multiple time scales. They just noticed that the maximum correlation to temperature occured very quickly, suggesting they have only been capturing the rapid response of the upper ocean, just as Schwartz’ time constant estimate does. So very good to see that someone has figured out how to analyze longer period responses as well.
When someone wants to claim warming is in the pipeline, the time constant for the ocean is long, but when they want to claim that the sun is not correlated with temperature, they assume instant equilibrium. mad debating skilz there doods
I think that people are looking at the solar cycle the wrong way. The peaks and valleys of TSI don’t have to change as long as the period of the solar cycle keeps changing. It will change the heating. (This is known in electrical engineering as pulse-width-modulation.) Fancy gas stoves have an ultra low heating option for making fine sauces. The burner will turn on for a few seconds to the normal low setting and then turn off. The heat is controlled by varying the amount of time the flame is off, longer times equal cooler temperatures.
The varying solar cycle does exactly the same thing but the modulation is on top of a base output. If I remember correctly, there have been papers that noted the correlation between warmth and rapid solar cycles and cooling and slow solar cycles.
Of course there are other things going on with the sun like a 6% change in UV between high and low…
There are utterly false and unscientific statements around on the blogosphere that adding CO2 doesn’t add to the greenhouse trapping – this is completely wrong. It is true of some CO2 absorption lines but not of them all so if you integrate over the spectrum (rather than selecting bits of it!) one finds a radiative forcing rise that matches the observed GMAST rise very well indeed.
Ok, this is one I’ve not heard before. Perhaps someone could explain. There are different kinds of CO2 that have different types of radiative forcing? That the “type” of CO2 human activity is adding to the atmosphere is the “bad” kind?
I understand the CO2 “blocks” very specific wavelengths (or, more accurately that oxygen and carbon have a specific spectral signature – that’s how spectral analysis works, right?). So is he saying the oxygen bit is Ok, but the carbon bit is not? But that doesn’t sound like what the quoted statement means.
I recall a video of Dr. Lindzen where he equates the radiative forcing of CO2 to painting a pane of glass. A single coat of paint blocks most of the light. Subsequent coats of paint do block additional light, but only the little bit that “leaked through” the first coat.
Which of them is right? Or both? I’m getting confused.
Nice work Alec but one can take a logical step further.
We see that the change in the level of solar activity between LIA and the present is spread over more than 400 years.
Maybe the 11 year sunspot cycle impact as regards energy transfer to the deeper oceans is negligible but it does not follow that the impact over a constant 500 year trend in one direction is negligible.
Elsewhere I have proposed that a more active sun alters the balance of chemical reactions in the atmosphere to alter the vertical temperature profile, effect pressure redistribution at the surface, alter the air circulation systems and allow more solar energy into the oceans.
If that goes on for 500 years as either a rising or falling trend then I anticipate that we would see a temperature discontinuity arising along the length of the thermohaline circulation (1000 years or more).
So we would then have thermohaline waters resurfacing over 1000 years later carrying the temperature signal from 1000 years or more previously.
Now the solar and ocean cycles are not always in phase so it would be somewhat of a lottery as to whether at any given time the resurfacing waters were to be offsetting or supplementing the then current solar effects.
Such a lengthy cycling of ocean heat content would also have interesting implications for CO2 levels in the air due to the oceans changing their ability to absorb CO2 from the air as those long ocean cycles work through the system.
I agree that is almost impossible to measure the phenomenon (time – to – equilibrium) with this kind of technology we have today. We are supposed to be in Holocene period which is one part between two Ice periods, so what if we are getting to the end of warm period (the evidence could be not significant warming activity of the ocean´s depth together with increased seismic activity)?
Tallbloke’s forum has a few of Threads that fit well with this thread.
See
http://tallbloke.wordpress.com/2011/03/03/tallbloke-back-radiation-oceans-and-energy-exchange/
http://tallbloke.wordpress.com/2011/03/05/patrick-geryl-the-sun%E2%80%99s-eleven-year-magnetic-reversal/
http://tallbloke.wordpress.com/2011/03/14/tim-channon-modeling-the-solar-polar-fields-and-barycentric-motion/
http://tallbloke.wordpress.com/2011/03/22/cosmic-rays-be10-and-ice-cores/
The comments on those Tallbloke threads reveal some very interesting Scientific work being done by those guys.
In answer to TomB’s question about “CO2 absorption lines”: that is a reference to different segments of electromagnetic radiation. Some “lines” of radiation that are absorbed by CO2 are also absorbed by water vapor, which is much more plentiful, so a CO2 increase can have little additional heat-absorbing effect. Some absorption lines do not overlap, so CO2 can have a significant effect there.
Craig Loehle (March 22, 2011 at 11:19 am)
…but when they want to claim that the sun is not correlated with temperature, they assume instant equilibrium.
I noticed that too. When I pointed out that the cooling (from the solar minimum) was in the pipeline, they got angry (apparently pipelines only hold heat)
“”””” Alec Rawls says:
March 22, 2011 at 12:02 pm
In answer to TomB’s question about “CO2 absorption lines”: that is a reference to different segments of electromagnetic radiation. Some “lines” of radiation that are absorbed by CO2 are also absorbed by water vapor, which is much more plentiful, so a CO2 increase can have little additional heat-absorbing effect. Some absorption lines do not overlap, so CO2 can have a significant effect there. “””””
All depends. As Phil has pointed out on several occasions, the actual high resolution narrow line spectra of CO2 and H2O do not necessarily overlap, so they can easily be additive in spectral energy interception.
Now I don’t have a good feel for the actual line broadening that takes place in the real atmosphere. You would have to take the probably mean molecular velocity at whatever Temperature, as a fraction of (c) to compute a Doppler line broadening; but then there is also a collision broadening that depends on molecular density (atmospheric pressure). I don’t know for sure (somebody youg can do the math) but based on things I’ve read here the pressure3 broadening may dominate over Doppler. I’ve never done the calculation; but it should be duck soup for any of you PhDs out there.
So don’t assume from the low resolution “band” spectra of CO2 and H2O, that they are in competition; although I don’t dispute that H2O has a big effect; it supposedly is even capable of making puny CO2 look good.
“”””” Paul Linsay says:
March 22, 2011 at 11:29 am
I think that people are looking at the solar cycle the wrong way. The peaks and valleys of TSI don’t have to change as long as the period of the solar cycle keeps changing. It will change the heating. (This is known in electrical engineering as pulse-width-modulation.) Fancy gas stoves have an ultra low heating option for making fine sauces. The burner will turn on for a few seconds to the normal low setting and then turn off. The heat is controlled by varying the amount of time the flame is off, longer times equal cooler temperatures.
The varying solar cycle does exactly the same thing but the modulation is on top of a base output. If I remember correctly, there have been papers that noted the correlation between warmth and rapid solar cycles and cooling and slow solar cycles.
Of course there are other things going on with the sun like a 6% change in UV between high and low… “””””
Paul, if the expected equilibrium Temperature change for a permanent TSI shift of 0.1% is a mere 72 mdeg C; and no such 11 year cyclical oscillation (in Temperature) is detectable; how on earth could a duty cycle modulation of that 11 year cycle have any observable effect whatsoever ? Isn’t your duty cycle effect like the proverbial butterfly beating it’s wings in a Brazillian jungle ?
Prof Lockwood’s heating-a-ship-with-a-blowtorch analogy doesn’t strike me as a very good one. Surely what is going on with the ship is more to do with heat transfer considerations rather than being a simple matter of heat capacity: heat is conducted away from the point of application radially, so exposing a greater surface area for heat loss to the atmosphere by radiation and convection.
But there was a high solar activity in the years leading up to the Dalton Minimum. Did it carry on warming during the Dalton period? There was cooling after ~1940 – but no drop in solar activity. The most intense solar cycle (SC19) peaked in ~1960 – how does that fit with the 20+ years equilibrium time. What about all the supposed correlations which show solar activity and temperature moving in synch (e.g. Lassen & F-C).
The most likely explanation is that solar activity has very little effect on global temperature. Though it may influence regional climate patterns.
Alec, Nice work and the crux of the matter IMHO. To me, the well-accepted energy balance equations for the climate system show, like boiling a pot, that the system responds to constant heat with an slow approach to equilibrium. The comments by scientists that lack of correlation over the last 15 years proves lack of solar influence are the height of ignorance, ignoring the thermal inertia of the system.
The response time would have short and long components, due to different heat sinks, but the overall behaviour will be determined by the largest sink, and has been estimated in different ways, and multi-tau models (eg Scafetta). In the longer tau around half of the response occurs in 5 years. So we are only just now seeing the effect of the recent solar slow-down, and will see the full effect in about 8 years.
Alec Rawls says:
March 22, 2011 at 12:02 pm
“Some “lines” of radiation that are absorbed by CO2 are also absorbed by water vapor, which is much more plentiful, so a CO2 increase can have little additional heat-absorbing effect.”
Not necessarily true. Water vapor is a condensing greenhouse gas and unlike CO2 its distribution varies greatly in 3 dimensions. It gets squeezed out by condensation and freezing as altitude increases. Deserts are exceedingly dry usually because the air there has been lifted over the top of a mountain range which squeezes out most of the water and the dry air falls down the other side into the desert basin. And of course at any altitude where the temperature has dropped enough to fall below the dewpoint or freezing (adiabatic lapse rate is about -1C per 100 meters higher) there’s no water vapor left between that point and outer space but non-condensing greenhouse gases like CO2 on the other hand remain available at relatively constant concentration everywhere at all times.
Both CAGW supporters and sceptics have stated that it does not matter where the forcing comes from the feedback mechanism is the same and the thus the impact is the same. Quite obviously this is true thus if the time constant for for response to soalr changes is short it is also short for resonse to CO2. Now in 1900 CO2 levels were about 280pm. IN 1978 they were about 335 PPM and at present they are about 392 ppm. Thus we have had very close to 0.5 doublings since 1900 of which 1/4 doubling was between 1900 and 1978 and the other quarter since 1978.
The satellite data shows about 0.35C rise since 1978. The NASA plot shows about 0.8C since 1900. Even if we accept this data as correct and attribute all of it to CO2 (which is extremely questionable) then the NASA data suggests a sensitivity of 1.6C per doubling. The satellite data suggests 0.7C per doubling. The prediction of a business as usual model is a rise to 560 ppm by 2070 or a further half doubling from the present. Based on both the satellite and NASA data that would mean a further rise of 0.7 or 0.8C by 2070. Far from the claimed 3C and far below the claimed dangerous level of 2C.
As Alec Rawls has pointed out, the argument that dismisses solar influences as the cause also inherently dismisses CO2 as a dangerous warming agent. One can’t really have it both ways.
What I find ridiculous is the assertion that feedbacks will cause runaway warming. If that were the case, any rise in temps would cause runaway warming. It obviously does not, so it must be a false assumption. To then claim that solar warming does not case runaway warming, and CO2 warming does is just blatantly facile.
I love that the team have been hoisted on their own petard on this one!
An adequate understanding of deep ocean currents and upwelling and downwelling would result in being able to firstly explain, and then predict, how the various atmosphere/ocean systems behave and interact.
For instance, why have on occasion multiple La-Nina years occurred and can anyone say how many La-Nina years this present cycle will bring?
What has caused the coinciding of this current La-Nina with a negative IOD, the last occurrence being 1975, and irregularly prior to that?
I don’t know anyone who can offer anything more than a guess about ocean equilibrium without being able to explain such examples.
The example of the heating of a ships hull as given by Mike Lockwood immediately identified a lack of understanding on his behalf of what was being asked.
The correct analogy of course is whether a constant heat source being applied to one side of the ship has to increase in order for that heat to eventually warm the hull on the opposite side.
Tom in Florida says:
As happens with the North Sea 7°C to 17°C from March to September. The Mediteranean 12° to 28 March to Sept. This is of course sea Surface temperature.
In my looking at the historical records and seeing minimums (Little Ice Age ) and maximums (Roman Warm Period) just when was the climate ever in equilibrium.
Jeroen B. says:
March 22, 2011 at 9:59 am
Paging Dr. Svalgaard ?
My views are well known.
Perhaps of interest for the time constant problem is the strong possibility that solar activity in the past was not much lower than now. See e.g. http://www.leif.org/research/Eddy-Symp-Poster-1.pdf
If so, the time constant must either be very large [many centuries] or solar activity has no effect [so the time constant is irrelevant]
George E. Smith says:
March 22, 2011 at 10:08 am
that TSI shows any long term shifts that are of any similar order of magnitude to the clear 11 year signal. My gut feel is that it is flat compared to that 0.1%. I suppose one can make arguments that something as large as the sun, can’t change very fast; but I’m just arm waving there.
But waving pretty good.
there isn’t any evidence (data) of any 11 year 72 mdeg C Temperature cycle on earth. So then why would any other change on the sun of similar or less magnitude (in TSI) show up at all.
some people claim that there is an 11-yr signal of up to twice that, but even that is trifeling.
BillyBob says:
March 22, 2011 at 10:09 am
“all the trends in the Sun that could have had an influence on the Earth’s climate have been in the opposite direction to that required to explain the observed rise in global mean temperatures.”
Provably False.
Global brightening has occurred since the 1990s, and dimming and brightening have occurred in the past as well.
The global brigtening is not ‘solar activity related’
Paul Linsay says:
March 22, 2011 at 11:29 am
I think that people are looking at the solar cycle the wrong way. The peaks and valleys of TSI don’t have to change as long as the period of the solar cycle keeps changing. It will change the heating. (This is known in electrical engineering as pulse-width-modulation.)
The problem with that idea is that often low cycles are long and high cycles are short, to the integral over the cycle does not vary much
Equilibration is a real world process but seems to play the role of a fudge factor in the science. While it remains uncertain you can choose whichever value you wish to make your just so story work. It’s often said that the strength of AGW theory is the multiple lines of evidence that support it. It seems that’s true as long as you don’t look to closely at the detail.
It would be great to look at the list of papers supporting the lastest IPCC document to see just how much these fudge factors, like equilibration time, vary in support of different lines of evidence.
Alec Rawls wrote, “Then there is the lack of warming since 2000, which is fully compatible with a solar explanation for late 20th century warming but is seriously at odds with the CO2 theory.”
What lack of warming? All estimates of global surface and lower troposphere temperatures show an increase in temperature anomalies since 2000, including HADCRUT, GISS LOTI, NCDC Land+Ocean, UAH TLT, RSS TLT, GCHN/CAMS T2m LST.
http://i54.tinypic.com/z8flu.jpg
The linear trends since 2000 range from 0.45 deg C per Century for HADCRUT to 2.8 deg C per Century for GCHN/CAMS T2m Land Surface Temperatures.
Here is the response I got when I asked the same question in 2006:
http://www.skepticalscience.com/solar-activity-sunspots-global-warming-advanced.htm#307
Response: If solar activity increases then plateaus, the climate will then be in energy imbalance with more energy coming in than radiating back out to space. The earth will immediately start warming. As it warms, the energy radiated back to space gradually increases until the climate reaches radiative equilibrium. Then warming stops. This period it takes to reach equilibrium is refered to as climate time lag.
However, this is not what is observed over the 20th century. Solar activity levels out in the 1950’s. However, the modern global warming trend began in the mid 1970s. If the sun was the cause of global warming, the planet would’ve been at its highest energy imbalance in the 1950s. Then the planet would gradually have approached equilibrium over the next few decades.
The opposite has occured. The energy imbalance has in fact increased over the past 3 decades and is still increasing. Of course, we now know why the planet is in radiative imbalance – due to an enhanced greenhouse effect caused by increasing greenhouse gases such as CO2 and methane.
To continue along the lines of my earlier (March 22, 2011 at 3:43 pm) comment:
Alec Rawls wrote, “The post 1970′s warming that is said to be incompatible with a solar explanation didn’t show a clear temperature signal until 97 or 98”
Actually, it shows a “clear temperature signal”. It even shows a clear warming signal. Again, all estimates of global surface and lower troposphere temperatures show an increase in temperature anomalies from 1979 to 1996, including HADCRUT, GISS LOTI, NCDC Land+Ocean, UAH TLT, RSS TLT, GCHN/CAMS T2m LST.
http://i52.tinypic.com/2ijrwar.jpg
The linear trends from 1979 to 1996 range from 0.33 deg C per Century for UAH TLT to 2.2 deg C per Century for GCHN/CAMS T2m Land Surface Temperatures.
You wrote, “By this standard, the subsequent decade of no warming should be seen as even stronger evidence that climate is being driven by the sun, and the quicker the oceans equilibrate, the less room there is for CO2 driven warming to be hidden by ocean damping. Maybe it is time for another update: ‘Recent samely directed solar climate forcings and global temperature.’”
Since you failed to examine the data and made claims that are not supported by it, would your proposed update be as flawed as this portion of your post?
it isn’t that difficult is it?
if those idiots I mean warmers had a clue then how do they explain how it gets cold in winter and warm in summer.
do they need that explained to them too.
duuuh
As Leif says this warming is not about the ‘solar constant’ at all. Its just too constant.
As George E. Smith says: Well as I have said on many occasions; I think the whole damn thing is feedback regulated by cloud cover modulation; “IT’S THE WATER !!”
And that is what I say too. Here is the argument in the rough, and if you want to give me some feedback that will help improve the exposition I will/would/must be/ totally delighted.
http://www.happs.com.au/climatic-research.html
The change in cloud cover ultimately depends firstly upon the flux in ionizing short wave radiation from the sun that determines plasma density in the lower atmosphere and secondly the ability of the solar wind to change the electromagnetic fields in the lower atmosphere (geomagnetism) directly impacting the activity of the night jet at the poles.
The night jet impacts stratospheric ozone levels.
A coupling of the stratosphere and the troposphere at the poles brings stratospheric ozone into the troposphere impacting surface pressure, the temperature and relative humidity of the troposphere all the way from the pole into the opposite hemisphere.
Its not as simple as the idea that the sun varies in its output or that the atmosphere acts as a greenhouse but, as a former Australian Prime Minister famously remarked : ‘Life was not meant to be easy’.
The data tells the story.
As some are pointing out, do not make the mistake of putting all your eggs in one basket. Climate is mainly controlled by ocean oscillations and solar activity. Trying to separate the main players is bad science.
Usoskin has a paper where he analyses average T lag time for the last thousand years or so between solar proxies and earth T proxies, and concludes this averages about 20 years, mainly due to ocean heat lag.
However this figure is averaged from fluctuations pre 1750 in solar activity which are more variable and shorter than the solar increase in activity from ~1750-1950. Few/none of the earlier solar trends pre 1750 compare in length to the 200 year increase in solar activity from 1750-1950, which also implies a longer lag time for the period from 1750-1950.
There are at least 2 real-world examples where one can calculate earth heat lag times and solar activity.
Eg 1. Seasonal. The constant (average) warming trend from June 21 to Dec 21 (ie towards summer in the southern hemisphere) does not produce a T max on Dec 21, but average T peaks around mid February- about 2 months late, or about 25% of the total warming trend.
EG 2. Diurnal-from about 6am to 12pm solar incidence increases, but average max T occurs around 3pm, again about 25% of the total warming trend. In both these cases, solar activity actually declines after the peak, yet there is still a 25% lag time in max T. (Note also clouds and other factors can obviously severely affect T trends here). In the case of solar activity from 1750-1950, solar activity didn’t decrease much after 1950, so again, this would increase the lag time.
Using the 25% figure form the 2 examples, the increase in solar output from 1750-1950 would give 25% x 200 years or about 50 years, meaning a peak would be expected around year 2000, which is what is observed. It might be even be a little later, since in this case, solar activity didn’t decline very much after 1950. Earth T figures since 1950 are consistent with this, with variability since 1950 (eg more warming from 1978-1998) a funciion of superimposed PDO, but the overall linear trend is consistent with solar heat lag effects calculated above.
This would all also mean that the earth should be approaching ‘equilibrium’ ie –heat in = heat out. Hansen and others have looked at this in recent years and concluded that earth equilibrium is actually decreasing using ‘constants’ and mathematical equations I feel are contrivances. They claim disequilibrium is actually increasing from the greenhouse effect, but I find their analyses rely heavily on assumptions of greenhouse gas warming to begin with.
I can reference their papers if you wish (they are available on the net), including the Usoskin paper.
I’ve never seen one academic paper address the issues above, that real world examples show 25% heat lag times, at both seasonal and daily scales; the same might well apply to century scales, meaning a key AGW argument that warming since 1950 can’t be explained by solar effects/trends is in serious trouble.
Geoff Sharp says:
March 22, 2011 at 7:25 pm
Climate is mainly controlled by ocean oscillations and solar activity. Trying to separate the main players is bad science.
No, it is necessary science. If the ocean contribution is X and the sun is Y and the rest [your ‘mainly’] is Z, where X+Y+Z = 1, then it is of interest and necessary to separate the causes to figure out how large each component is, unless you are like Scafetta and others who say that Y is the overwhelming part, or like Gavin who says that Z is.
thingadonta says:
March 22, 2011 at 7:59 pm
the increase in solar output from 1750-1950 would give 25% x 200 years or about 50 years, meaning a peak would be …>/i>
The problem with this is that there has been no such increase. Cycle 3 [max1778] was likely just as active as cycle 19 [max in 1957].
thingadonta says:
March 22, 2011 at 7:59 pm
the increase in solar output from 1750-1950 would give 25% x 200 years or about 50 years, meaning a peak would be …
The problem with this is that there has been no such increase. Cycle 3 [max 1778] was likely just as active as cycle 19 [max in 1957].
A further comparison with the monthly sunspot number, cosmic galactic rays and 10.7 cm absolute radio flux since 1950 gives no indication of a systematic trend in the level of solar activity that can explain the most recent global warming.
I don’t see anything in the GCR record to support the above. I do see a length of time indication (lag) of about 4-5 years in 1971-78 at elevated levels, and the latest episode in the 2006-2011 that marked the onset of the severest winters.
In the real world, hysterisis abounds. It’s simply the way nature works, and you don’t have to look too hard to find examples.
Eichler etals. paper on the Altai glacier reconstruction of atmospheric temperatures vs solar proxys for the past 750 years indicates a twenty year lag between solar forcing (group sunspot number) and atmospheric temps derived from the core.
http://lch.web.psi.ch/files/Publikationen/analytic/Eichleretal_GRL2009.pdf
1985 may have been the solar peak but the decline began in 1990 and twenty years later is 2010. I believe the decline is just beginning. It is interesting that Eichlers paper points out that in the late twentieth century only half of the temperature rise at the ice core can be attributed to solar forcing but that the temperature at the core was twice the global temperature. In other words solar forcing predicted the late twentieth century warming exactly with the twenty year lag.
[Dave Springer says:
March 22, 2011 at 10:30 am
In short the warm ocean surface (which drives air temperature) we have been enjoying for the past 10,000 years is but a thin veneer floating on the surface of a gigantic bucket of nearly freezing water. Anything that comes along to increase the mix rate between shallow and deep water will cause surface air temperature to plummet. The ocean isn’t a reservior of heat. It’s a reservior of cold waiting to put a quick ending on the Holocene interglacial period.]
Dave, just a thought that jumped into my head as i read your comment. A couple of days after the tsunami hit Japan, the winter cold returned. coincedence more then likely, but maybe something to do with the shock mixing the deeper layer of cold ocean water in a regional way.
Refreshing sign of enlightenment:
Paul Linsay wrote, “I think that people are looking at the solar cycle the wrong way. The peaks and valleys […] don’t have to change as long as the period of the solar cycle keeps changing. […] This is known in electrical engineering as pulse-width-modulation. […]” (Note: I’ve left out the parts “[…]” which are potentially seriously misleading.)
Paul Linsay wrote, “If I remember correctly, there have been papers that noted the correlation between warmth and rapid solar cycles and cooling and slow solar cycles.”
Suggestion: Be careful here. Take a look at rate of change of solar cycle length (i.e. solar cycle acceleration). Since there are other cycles at play (e.g. diurnal, annual, semi-annual, lunar, etc.), there are beats. Even without knowing what other cycles are relevant, one knows that the rate of change of the beats is a function of the rate of change of solar cycle length.
Paul Linsay wrote, “Of course there are other things going on with the sun […]”
Again, the key here is rate of change. For example, compare rates of change of neutron count rate (proxy for cosmic ray flux), solar wind speed, & HMF B with interannual variations of NPI, AO, & NAO (& their rates of change).
I have audited many claims about cycles and pursued many explorations which have arisen as curiosities along the road. The cleanest relations I have yet found are those which I mention in this comment. Cautionary note: The strong spatiotemporal coherence will be vehemently denied by those lacking conceptual understanding of the spatiotemporal version of Simpson’s Paradox. It is possible that it will be decades before the mainstream is in a position to appreciate these natural relations.
Strongly recommended to all serious climate investigators who are genuinely interested in developing intuition about the nature of terrestrial climate oscillations:
Multiscale exploration of terrestrial length of day and its rate of change.
Best Regards to All.
Bob Tisdale,
Some how you must be off a decimal point. Roy Spencer shows no change in UAH since 2002.
http://www.drroyspencer.com/
sorry Bob
I see that you were talking pre 1996.
Leif Svalgaard says:
March 22, 2011 at 8:01 pm
No, it is necessary science. If the ocean contribution is X and the sun is Y and the rest [your ‘mainly’] is Z, where X+Y+Z = 1, then it is of interest and necessary to separate the causes to figure out how large each component is, unless you are like Scafetta and others who say that Y is the overwhelming part, or like Gavin who says that Z is.
You are missing the point again. Trying to calculate a lag in ocean equilibrium using the temperature record and then matching with solar activity will not show the picture unless ocean cycles (PDO etc) are factored in. This does not seem to be happening in the article. There is also no mention of the atmospheric cycles.
With both cycles missing the temperature record is useless and will not follow the solar record as seen during the 50’s. The exercise cannot be performed without all the factors in play, a bit like the useless climate models we see today.
Bob Tisdale asks: “What lack of warming” since 2000? I refer him to… Bob Tisdale:
http://i54.tinypic.com/5c0svt.jpg
If I were to say “no warming since 98” it seems he would have no problem, but somehow it is inappropriate to say there has been a lack of 21st century warming? That’s a cavil.
Similarly for the 1979-96 stretch. Of course HadCRUT, GISS, etc. show big temperature gains here, but nobody knows the provenance of those records. I invoked UAH, which as Bob helpfully calculates, shows only a miniscule gain, as does RSS.
I was actually going to cite Tisdale for this part of the post, but since the point was discursive, I limited myself to a rough comparison of 20th century vs. 21st century.
Looking the post over, my criticism is that it is still too discursive. Should have left out the part about Schwartz’ estimation scheme throwing away information.
Apologies Correction.
The direct link to the article referred to above is
http://www.happs.com.au/images/stories/PDFarticles/TheCommonSenseOfClimateChange.pdf
Rather than play the futures game these scientists of solar ilk and others could perhaps explain the causes of the MWP and the LIA. These are historic, documented and time framed. It was obviously not CO2, therefore they must have a cause, unrelated to man made climate catastrophy. These times are not long past and evidence should abound on our world, as by their reasoning, the sun is not the cause.
I will start to take notice and believe these people when they have plausible and falsifiable reasons for these dramatic periods in our recent history.
Specialisation in all branches of science, engineering, chemistry, physics and even humble trades, destroy the inventive processes and free thought needed to break the nexus of group thought. Hence we are caught with people stuck in groove unable to see the forest for the trees.
richcar that 1225 says:
March 22, 2011 at 9:33 pm
Eichler etals. paper on the Altai glacier reconstruction of atmospheric temperatures vs solar proxys for the past 750 years indicates a twenty year lag between solar forcing (group sunspot number) and atmospheric temps derived from the core.
http://lch.web.psi.ch/files/Publikationen/analytic/Eichleretal_GRL2009.pdf
Have you actually read this paper. This is from the Conclusions section:
There is an increasing divergence between temperature and solar forcing since ~1850 (see Fig 2).
denihilist
It’s an interesting thought, but I suspect that the sea temperature off northern Japan in late winter is not that much different from the ~3 deg C of the deep water, so the effect would be minimised by the time of year and location. However, the inundation of the land (i.e. putting a large volume of water in a location where it can evaporate)together with turbulence from the wave movement could have resulted in a lot more cloud development and consequent reduction in temperature and increase in precipitation.
From reading the rest of the thread, and my recollection of ocean current behaviour (back in undergraduate geology), my suspicion is that the concept of equilibration between the surface temperature (+/- solar activity changes) and the ocean overall is a red herring. Equilibrium will never be reached, because of the different time scales involved in heating of near-surface water, deeper water generally and deep water warm and cool currents (iirc, the circulation of these currents is on the scale of decades or in some cases centuries); at best some sort of pseudo-equilibrium will occur.
Dave Springer says:
March 22, 2011 at 10:30 am
That may just be the most insightful thing you’ve posted here.
Now to figure out what causes mixing of the deep oceans with the surface water and atmosphere now and again
Asteroid strikes in the ocean?.
Alec Rawls says: “Bob Tisdale asks: “What lack of warming” since 2000? I refer him to… Bob Tisdale:
“http://i54.tinypic.com/5c0svt.jpg”
The graph you linked is RSS TLT anomalies north of 20N, not global UAH data. The red line is average temperature anomalies for the periods shown, which is clearly discussed in the post, not linear trends. I made no representations about trends during the discussion of Figure 8 in that post:
http://bobtisdale.blogspot.com/2011/03/rss-msu-tlt-anomalies-february-2011.html
Alec Rawls says: “If I were to say ‘no warming since 98’ it seems he would have no problem, but somehow it is inappropriate to say there has been a lack of 21st century warming? That’s a cavil.”
Bad assumption about my having no problem, because you’re wrong again. Your original statement was wrong and this one, “no warming since 98”, is wrong. And they are not trivial matters. The linear trend of global UAH TLT anomalies (the dataset you chose to illustrate) from January 1998 to present is positive at 0.6 deg C per Century.
http://i52.tinypic.com/rri2hx.jpg
Using the former version of UAH TLT anomalies (Version 5.3), the argument that global temperatures haven’t risen since 1998 was valid as late as December 2009.
http://i51.tinypic.com/119z3b6.jpg
It’s no longer a valid argument. Since then, Global TLT anomalies responded a strong El Niño, and UAH updated their dataset.
Alec Rawls says: “Similarly for the 1979-96 stretch. Of course HadCRUT, GISS, etc. show big temperature gains here, but nobody knows the provenance of those records. I invoked UAH, which as Bob helpfully calculates, shows only a miniscule gain, as does RSS.”
The RSS TLT anomaly linear trend in the graph you referred to is 0.71 deg C per Century. That’s not miniscule. The whole discussion of global warming over the 20th Century is based on a rise of that magnitude.
Alec Rawls says, “I was actually going to cite Tisdale for this part of the post, but since the point was discursive, I limited myself to a rough comparison of 20th century vs. 21st century.”
Your “rough comparison of 20th century vs. 21st century” was wrong. The UAH TLT anomaly trend (Version 5.4) from 1979 to 1996 is less than the trend from 2000 to present. The data presents exactly the opposite of the points you were trying to make.
On the basis of the way the earth behaves I would suggest a three level ocean model. The reason is that there seems to be three natural cycles:
a) a sub decadal cycle which includes El Nino and La Nina oscillations
b) a multi decadal cycle that includes PDO and AMO oscillations
c) an 800 year cycle that is needed to explain the delay in CO2 outgassing after the onset of an interglacial warming.
Furthermore I would like to propose a mechanism by which these varying delays might be generated.
Others have suggested that TSI is not the best measure of the way the sun affects the earth given that this is pretty constant. What does change significantly is the level of UV hitting the oceans. UV increases as a direct result of the sun’s cycles and is also correlated with sun spots which correlates with temperature. It is also likely to increase during the warming part of the Milankovitch cycles as a result of the reduced interaction with the atmosphere when the southern oceans, in particular, enjoy a larger proportion of near overhead sunlight as a result of tilt and orbit changes.
I believe the key missing variable is the depth at which the sun’s radiation is absorbed by the oceans.
Wavelengths longer than 3 micron are not significant in the sun’s spectrum but are measured at the surface. This is due to back radiation from the atmospheric greenhouse gases. This part of the spectrum is absorbed within a few millimetres of the surface so will lead to an immediate increase in surface temperature and a consequential increase in evaporation and radiation upwards and ultimately both will lead to a relatively fast restoration of the earth’s radiation balance. So there is no surprise in having a short delay between greenhouse forcing and temperature, albeit tempered by the action of wind and surface currents which create El Nino and La Nina effects.
However direct sunlight, which dominates in the tropics, peaks in the visible spectrum. The majority of the energy is in the longer wavelengths which is absorbed within a few metres of the surface. My hypothesis is that it is this energy that dominates the multidecadal cycles. Because it does not immediately increase the surface temperature it can build up to form the warm pools that we know exist and wait for deep ocean currents to generate the mixing which brings it to the surface and allow the heat loss which eventually restores the energy balance. My proposition is that this occurs on a multi decadal timescale.
However one only has to look to the bottom of a “blue lagoon” to see that blue light and UV can penetrate to many tens of metres. When one sees the bottom of such a deep pool one is picking up light that has penetrated this far and made it back to the surface. Clearly UV must heat the oceans down to a significant depth. When the proportion of UV is high this might be very significant. It is all the more so because this warming might take place over centuries without any significant increase in the surface temperature. The corrolary is also true that cooling of the ocean depths might also occur over centuries without any significant surface affect. One could also hypothesise a sudden surface change in either direction as deep warming or cooling finally affects the deep ocean conveyor systems. This would explain the sudden appearance of massive temperature swings in the long term climate record, These are synchronised to the Milankovitch cycles but are far greater in amplitude than can be accounted for by direct forcing without some very large capacitive effect. Incidentally the idea that CO2 positive feedback amplifies the changes is just nonsense. The temperature waveform and correlation with CO2 is completely contrary to what one would see in a system with positive feedback.
Something like this?
http://rantingstan.blogspot.com/2008/10/global-warming-experiment-you-can-try.html
cal said:
“I believe the key missing variable is the depth at which the sun’s radiation is absorbed by the oceans.”
I would support that as useful extension of my suggestion that changing solar input over centuries would lead to a temperature discontinuity along the horizontal track of the thermohaline circulation.
Alec,
There is far more happening than what is observed. The time frame to the creation of the sun is so small to what we have recorded.
A sunspot or flare can only effect this planet if it is traveling through the area. The vacuum of space precludes dispersement of energy as it moves away from the sun. The closest point of the sun is the equator of the sun due to distance and the size. All other points are smaller and further from this planet.
Next the distant past. The sun was more compacted and rotating faster. The planets were also more compacted and rotating faster and much closer to the sun.
One planet “pealed off” the sun at creation due to it’s backward rotation. This backward rotation generates far more friction due to the planet not in sequence with the rotation and electromagnetic manipulation.
This planet has to be considered where it is to the equator of the sun as the closest point. This would be slightly warmer than the drift at any other point.
Bob Tisdale said:
“The linear trend of global UAH TLT anomalies (the dataset you chose to illustrate) from January 1998 to present is positive at 0.6 deg C per Century.
http://i52.tinypic.com/rri2hx.jpg
Using the former version of UAH TLT anomalies (Version 5.3), the argument that global temperatures haven’t risen since 1998 was valid as late as December 2009.
http://i51.tinypic.com/119z3b6.jpg”
Although perfectly correct I think those two charts are not being correctly interpreted. During a period of little or no temperature change it would be normal for the chart to show a warming trend after an El Nino and a cooling trend after a La Nina until the new trend becomes established.
thingadonta says: (March 22, 2011 at 7:59 pm)
“There are at least 2 real-world examples where one can calculate earth heat lag times and solar activity.
Eg 1. Seasonal. The constant (average) warming trend from June 21 to Dec 21 (ie towards summer in the southern hemisphere) does not produce a T max on Dec 21, but average T peaks around mid February- about 2 months late, or about 25% of the total warming trend.
EG 2. Diurnal-from about 6am to 12pm solar incidence increases, but average max T occurs around 3pm, again about 25% of the total warming trend. In both these cases, solar activity actually declines after the peak, yet there is still a 25% lag time in max T. ”
I do not believe you have explained this correctly. In Eg 1, on Dec 21 it is only the rate of warming that is Max. After Dec 21 the rate of warming decreases but continued warming still occurs until the date in Feb when more energy is outgoing than incoming so that warming stops and cooling begins. Max T will occur at this point. There is no lag time or “lateness”. The same can be applied to your Eg 2.
Stephen Wilde says: “Although perfectly correct I think those two charts are not being correctly interpreted. During a period of little or no temperature change it would be normal for the chart to show a warming trend after an El Nino and a cooling trend after a La Nina until the new trend becomes established.”
They are being interpreted correctly. The trend over such a short term is established by the response to ENSO, as you noted, but Alec made the claim that global temperatures have been flat since 1998 (originally 2000), and as of this month, they have not. The “no rise in temperature” argument may have been correct a few years ago when it was based on the use of the 2007/08 La Nina to pull down the trend, but it’s not correct now.
Paul Vaughan says:
March 22, 2011 at 9:43 pm
The strong spatiotemporal coherence will be vehemently denied by those lacking conceptual understanding of the spatiotemporal version of Simpson’s Paradox.
Then let me here deny the relevance of this. When dealing with time series [as is mostly what people do] there are no spatial aspects. What is the spatiotemporal coherence of TSI?
Geoff Sharp says:
March 22, 2011 at 10:26 pm
“No, it is necessary science. ”
You are missing the point again.
Your point was that one should not try to separate the causes, but that is necessary in order to ascertain the relative relevance. I’m quite happy with missing your point.
Ice cores record a temperature history in which a subsurface layer may be warmer than the surface. This warm layer will migrate downward with time, so that a subsurface layer can remain warmer after surface cooling commences. Can this subsurface warm region now migrate upward? It can, but there must be a driving force to draw the heat wave back upward which must come from surface temperatures reduced below that at the peak of the heat wave, and surface temperatures cannot again exceed that peak temperature.
But that is ice cores, where convection is eliminated. Can convection change this picture? If convection has been keeping the surface cool and now convection stops, can the surface temperature increase above a recent peak temperature? If deep convection has been present but is now removed, the answer is yes, because the system time constant has changed. The time constant has gone from a long one characteristic of deep convection (La Niña), where the response to a radiative forcing is slow, to a short one characteristic of shallow (or no) convection (El Niño) with a rapid response to radiative forcing.
There are two points here. First, there is no single time constant here on earth. For each process you examine, do not expect to encounter a “standard” time constant. Expect a time constant unique to the specific situation, perhaps measured in centuries, perhaps in minutes. Second, if temperatures continue to rise after a decrease in radiative forcing, attribute it to a change in convective patterns such as an El Niño.
I am still of the persuasion that linear global temperature trends lead to false positives and negatives. Such extreme “averaging and smoothing” hides important details that could better uncover natural warming and cooling as well as anthropogenic trends. That warmists don’t advocate for such data handling is a real mystery to me. I am also of the persuasion that by working with cyclic temperature data instead of linear trends, solar influence can be better described in terms of its teleconnections (or lack of) to temperature data.
John Finn,
As I mentioned before the Eichler paper states that the temperature gain at the Altai ice core site was approximately twice that of the global temperature increase (polar amplification). In otherwords, the predicted increase in temperature for the twentieth century based on solar proxys did match the increase in global temperature which was 50 % of the temperature increase at the site.
http://lch.web.psi.ch/files/Publikationen/analytic/Eichleretal_GRL2009.pdf
Bob Tisdale said:
“The “no rise in temperature” argument may have been correct a few years ago when it was based on the use of the 2007/08 La Nina to pull down the trend, but it’s not correct now.”
Quite so, but I’m expecting it to be correct again shortly when the full effect of the current La Nina has fed into the atmosphere.
“Does solar activity have to KEEP going up to cause warming?”
Not on a water world with a N&O atmosphere. TSI is rather constant. Must be something else.
Re Bob Tisdale: Sorry, but .6-.7 degrees C of temperature rise per century IS miniscule. This rate of temperature change pre and post 97 is not what the alarmists use as the basis for their claim that recent warming cannot have been caused by the sun and hence must have been caused by CO2. They are exercised by the .3 to .4 degree step up in temperature that seems to have ocurred in 97 and 98.
My post acknowledges the step up and points out that the lack of warming since (minuscule warming if you insist) is just as strong evidence against the CO2 theory, especially if one assumes that ocean equilibration is very rapid, as Lockwood et al. are assuming.
Here’s a test for a single box vs multi-box model. At the mid-lattitudes, the daily solar irradiance follows a near perfect sinusoidal pattern for the yearly cycle. Given a lag between the solar forcing and SST of about 79 days, this gives a time constant of about 0.75 years using a single box model. Since this is at odds with Schwartz’s value of 5 years, there appear to be the need to expand the number of boxes.
I propose measuring the temperature lag and amplitude changes at various ocean depths at mid-lattitudes. From this, I will hazard that one should be able to test the multi-box (continuous?) models.
“Then there is the lack of warming since 2000…”
2001-2007 is the longest sustained warm period on the satellite record, and really shows a lack of cooling, apart from the notch in mid 2004.
Alec Rawls, regarding your March 23, 2011 at 11:25 am reply: No matter how you try to justify it, downplay it, or redirect it, what you’ve written in the post is wrong. The rise in UAH TLT anomalies (your choice of dataset) from 1979 to 1996 is less than the rise after January 2000, and that contradicts what you’ve written. I’m not sure why you’re arguing about this.
Alec, I have been impressed with Jasper Kirky’s graphs showing northern hemisphere temperature proxies and graphs of galactic cosmic rays, page 3.
http://aps.arxiv.org/PS_cache/arxiv/pdf/0804/0804.1938v1.pdf
There was generally good eyeball correlation between the two, suggesting roughly simultaneous equilibrium – although how could one really tell with 1000 years on a 2 1/2″ graph. What always troubled me was the big drop in GCR about year 1400 for more than 100 years without low temperatures. So today I found that with a lag of about 120 year, the largest drop in GCR fit the coldest part of the LIA. (hooray!) But then, other parts of the curves didn’t correlate very well. (too bad) I guess 120 years isn’t the proper lag time.
How old is deep seawater and under what circumstances does deep downwelling occur? We get some idea from at least two lines of evidence: CO2/T lag in ice cores, and C14 content in deep water. Analyses have lately been complicated by the discovery of organic microbes living in sea floor rock within a carbon community three times as old as deep sea CO2, causing a bias interpretation older than actual (http://news.ucsc.edu/2010/12/deep-biosphere.html). This discovery might bring the C14 evidence more in line with the ice core data.
Seal kills with meat dated at 1300 years old off McMurdo Sound give at least a qualititive indication of upwelling deep water in the area–both downwelling and upwelling of deep water occur near the poles. An an insulating arctic ice cap goes far to prevent downwelling, as does melting ice, which floats on the surface. Ultimately upwelling is forced by downwelling, which best occurs in an ice free Arctic, and would be expected to cause an ENSO, i.e., the less ice in the Arctic, the more downwelling and the more upwelling in the Antarctic. But I’m just guessing.
richcar that 1225 says:
March 23, 2011 at 9:41 am
John Finn,
As I mentioned before the Eichler paper states that the temperature gain at the Altai ice core site was approximately twice that of the global temperature increase (polar amplification). In otherwords, the predicted increase in temperature for the twentieth century based on solar proxys did match the increase in global temperature which was 50 % of the temperature increase at the site.
http://lch.web.psi.ch/files/Publikationen/analytic/Eichleretal_GRL2009.pdf
Before you start extrapolating over the rest of the globe. It might be worth looking at what has caused the divergence at the Altai site. How come solar forcing and temperature were apparently in lock step up until ~1850 – but began to diverge after then.
What evidence is there for solar forcing correlations (with 20 year lags) with other regions of the world. Why cherry- pick one region and assume the rest of the world responds the same (without the Altai divergence).
The Eichler paper states
That is – since 1850 the CO2 correlation is dominant.
They go on to say
Note the “only up to …..50%” of global warming which can be explained by the sun. 50% is likely to be a significant over-estimation.
NH temperature reconstructions [Scafetta and West, 2007]
revealing that only up to approximately 50%
There’s a strange thing missing from all this talk about how a long time constant would allow for magically- and selectively-amplified solar activity to assume responsibility for the current warming…and that is any actual quantitative analysis. There’s lots of waving of hands and imagining, but I would like to see someone actually take data on solar activity and demonstrate how when you put some simple decay model with some longish time constant on it, you are able to do a good job reproducing the temperature record.
In a past thread by Alec, we were begging him to do this…but all we got was hand-waving arguments of how it is clearly obvious that this would be the case. If it is so clearly obvious, it should not be hard to demonstrate! Folks around here like to denigrate models a lot and claim that they just spit out whatever assumptions you put into them…But in fact, mathematical models, particularly if constrained by mechanistic understanding, are quite constraining, especially as compared to arguments based on gesticulating wildly.
And, on another note regarding solar mechanisms in general: I probably can’t count the times how commenters here on this website have asked, “Why do climate scientists automatically assume that CO2 forcings get amplified by positive feedbacks while other forcings do not?” I have explained time and again that, in fact, the same feedbacks apply to warming produced by all climate forcing mechanisms in the climate models.
However, for those folks who want solar to explain the current warming, they really would have to come up with a mechanism that selectively amplifies solar forcing in a climate system dominated by strong negative feedbacks (because otherwise the known radiative forcing from rising greenhouse gases would be responsible for the warming). I am not saying that it is out-of-the-question that there could be some funky mechanism like the sun modulating the cosmic rays which in turn effect the nucleation of clouds and all that groovy stuff that does this…but it certainly takes a good bit of “good fortune” for this to be the case…and so far the evidence for any such mechanism has fallen well short of convincing, to put it mildly.
And, it is important to note that it is not mainstream climate science that is relying on the selective amplification of certain “preferred” forcing mechanisms!
Leif Svalgaard wrote, “When dealing with time series [as is mostly what people do] there are no spatial aspects.”
Absolutely & categorically untrue.
John finn,
The divergence at the Altai site may have been due to the persisant positve NAO that has characterized the latter half of the twentieth century or it could be the so called ‘polar amplification effect of AGW’ . Never the less the predicted temperature response at the site based on solar proxys did in fact match the global increase with a 20 year lag.
Low solar periods have been correlated with negative NAO like we are experiencing now. High solar periods have been correlated with posite NAO. This is the positive feed back we are looking for. When the NAO is negative the jet stream heads south bringing cold air masses that collide with tropical air masses creating clouds and precipitation. It also appears that ENSO becomes La Nina dominated when the NAO is negative.
The correlation of negative NAO and low solar is seen in this paper which correleates auroral observations (solar proxy) and the Nile River level based on observations over 1500 years. The authors suggest that variations UV/ozone levels control the NAM phase.
https://www.cfa.harvard.edu/~wsoon/BinWang07-d/Ruzmaikinetal07-Nile_06.pdf
The important concept is that this is a top down forcing as opposed to a bottom up forcing one would expect from TSI variations.
This is Lockwood etal summary of their understanding of top down solar forcing.
http://iopscience.iop.org/1748-9326/5/3/034008/fulltext
We shall see if AGW or the sun wins. If the sun is the primary forcing agent we should see a long decline in global temps. The 1998 to 2010 temperature max and flattening would nicely fit a twenty year delay (equilibrium) from the 1985 max as observed in the past from the Altai ice core.
Paul Vaughan says:
March 23, 2011 at 7:37 pm
Leif Svalgaard wrote, “When dealing with time series [as is mostly what people do] there are no spatial aspects.”
Absolutely & categorically untrue.
What are the spatial aspects of a point measure like TSI?
richcar that 1225 says:
March 23, 2011 at 7:48 pm
We shall see if AGW or the sun wins. If the sun is the primary forcing agent we should see a long decline in global temps.
This is under the [unwarranted] assumption that only AGW or the Sun are in play. There could be internal fluctuations of t complex system that have nothing to do with either.
By significant orders of magnitude over other known external sources of earth’s energy, the sun is the earth’s only crucial (to life) external energy source.
The sun is known to provide energy to the earth predominately by electromagnetic radiation; however, there are orders of magnitude lower amounts of magnetic energy and energy from ions and particles. The sun-earth gravitational dynamic also contains the (potential) energy to keep the earth fairly well within its generous life sustaining orbital parameters (except for some life challenging deep glacial periods). Did I miss any sun sourced energy that earth receives?
A lot of critical thinking continues about the sun’s energy supply and how that energy relates to the behavior of earth’s total system. [ The earth surface temp lags versus changes in solar energy input being one of those areas; thanks Alec Rawls for bringing that topic for discussion.]
Note: by ‘total earth system’ I mean, in addition to the climate, also the other parts of the earth system that are not climate related in any close-coupled sense.
Here is some of the solar & earth system related critical thinking that intrigues me:
Solar/Earth 1 – The variation of TSI on any timescale is interesting. Particularly of interest are the variations of TSI related to the all the documented ~11 year solar cycles [ actually they are ~22 year solar cycles :^) ]. Those TSI variations, if on the order of magnitude of ~0.01%, I think have not been shown by consistent correlations or large enough physical mechanisms to be the driver for earth’s historical temperature excursions such as MWP, LIA, RWP, or any of the so-called 20th Century WPs, etc, etc, etc.
Solar/Earth 2 – The study of variation of SSI (Solar Spectral Irradiance) over the satellite observed ~11 year solar cycles appears to be getting more focus as a potential vehicle for illuminating [ nice word that :^) ] if the sun could be the driver for earth’s historical temperature excursions such as MWP, LIA, RWP, or any of the so-called 20th Century WPs, etc, etc, etc.
Solar/Earth 3 – Is there a wind change in science now? One where there is more focus on creation of new scientific knowledge about detailed time dependent (with lags too) mechanisms of how all aspects of the sun’s energy interacts with the total earth system. I can only think that if the focus of our current scientific body is not so overwhelmed by the positing of all things being caused by CAGW then solar/earth system science would gain.
John
I made a roughly stated point that is perfectly legitimate. Bob keeps insisting that what I have written is wrong. If what he means is that I should admit that the point was roughly stated, I already acknowledged that. If what he means is that the point is not correct, I disagree.
Bob asks why I bother to argue. Maybe because I don’t think much of his cavilling. Obviously either of us could pick endpoints that make temperatures on either side of the 98 El Nino slope however we want. I find it more reasonable to speak in rough terms. Until the El Nino, there was no clear warming signal in the satellite record. Early 97 was the same temperature as early 79, with nothing in between to indicate any kind of trend. Bob takes the end of 97 as his endpoint and calls it a warming trend, which completely misses the point, or maybe makes the point. So by the end of 97 there was a clear warming signal? How does that contradict my suggestion that there wasn’t a clear temperature signal until 97?
Really, I don’t even have a problem with the cavilling. Bob’s attention to detail is a valuable asset. I just object to the pretense that these miniscule little gotchas vitiate the point that is being made.
Not sure what to say to Joel. He doesn’t seem to understand what I am reporting on here. I emailed a bunch of scientists who seemed to be assuming that the oceans were in equilibrium by say 1980. I asked them if they were indeed assuming this and if so, could they justify it? Several have written back in support of a rapid equilibrium assumption.
I had no idea that was going to be the upshot. In fact it surprised me quite a bit. I thought they would argue that the asymptotic approach to equilibrium had already been seen in the flat temperatures between 1945-75. A couple did say that. Substance for a future post. But more made a rapid equilibrium argument, claiming essentially that the climate system is always in equilibrium, or very close to it.
So I looked into this odd idea and found that it is actually dead and gone. But that doesn’t interest Joel. He wants me to go do something entirely different. I should go and try to estimate the equilibration properties of the climate system for myself. I find that all these prominent scientists are dismissing a solar explanation for late 20th century warming on the basis of a completely failed assumption, and Joel says: “hey look, a squirrel.”
It isn’t even a squirrel worth chasing. The findings in the current post say there is no point in trying to estimate the equilibration process. Until we have enough sounding data to observe the ocean equilibration process directly, all that any estimation scheme will be able to observe is the rapid temperature adjustment of the upper ocean layer. Doesn’t matter how long it takes further ocean depths to equilibrate. None of that is discernable without a much longer surface temperature record than we have.
What we can say now is that the rapidly adjusting surface temperatures and upper ocean temperatures track solar activity to a tee. That is in Svensmark’s reply to Lockwood and Frohlich. (See his figures 1 and 2.) There is also the lagged solar cycle length correlation to temperature that I pointed out before (with no begging necessary).
John finn,
The divergence at the Altai site may have been due to the persisant positve NAO that has characterized the latter half of the twentieth century or it could be the so called ‘polar amplification effect of AGW’
The divergence is not evident in the 600 years before 1850. What’s so special about the 20th century?
Mike Borgelt says:
March 23, 2011 at 3:15 am
Convection currents driven by differential heating between equator and pole. These currents are called the oceanic conveyor belt.
The arrangment of the continents effects conveyor belt in a big way. The south pole currently has a continent over it so warm equatorial waters can’t get there to cool off which presumably slows down the oceanic conveyor belt. The north pole is open which speeds the belt but it’s choked off to some extent by continental boundaries which are in close proximity.
Other than that I haven’t a clue.
Mike Borgelt says:
March 23, 2011 at 3:15 am
“Now to figure out what causes mixing of the deep oceans with the surface water and atmosphere now and again. Asteroid strikes in the ocean?”
The interglacials come and go with consistent periodicity. Presumably asteroid strikes are random (although they needn’t be if something perturbs them with regularity). Milankovich cycles are the usual suspect. The change in axial tilt lessens or increases the winter/summer temperature differential. The usual effect claimed from that is the milder summers allow more snow cover to survive which raises albedo which is a positive feedback for even colder summers and the glaciers advance. The change in axial tilt will however also change where and when the ocean is heated and cooled. There’s also apogee and perigee min/max in the earth’s orbital mechanics that is on a different periodicity than axial tilt. When these periodic things align in a peak or are in perfect opposition that’s where you get your pefect storm so to speak.
I don’t think TSI can be dismissed so easily for being responsible for temperature trends during the 20thC:
http://www.rocketscientistsjournal.com/2010/03/sgw.html
http://www.grida.no/publications/other/ipcc_tar/?src=/climate/ipcc_tar/wg1/fig6-5.htm
http://www.mps.mpg.de/projects/sun-climate/papers/uvmm-2col.pdf
Alec Rawls: Your entire March 23, 2011 at 11:53 pm reply avoids the points of my first and last comments to you on this thread. And based on the content of your reply, the readers here might conclude you are attempting to redirect the discussion from the blatant error in your post, one that I have discussed twice quite clearly. You elected the dataset and time periods for your discussion, not me. And it is those UAH TLT anomalies and those time periods that contradict your post. Let me try to illustrate this once again for you.
First I’ll confirm one of the points you were trying to make. It was that the 1997/98 El Niño raised the trend in the UAH TLT anomalies. There’s no argument from me there, but they need to be illustrated before I present of the period in which you claim there has been no warming. The following graph illustrates the UAH TLT anomalies and the trends for two periods. Both start in December 1978. The one trend period ends in 1996, before the 1997/98 El Niño, while the other includes data through December 1998. Again, this graph confirms that portion of your post. The period that includes the effects of the 1997/98 El Niño clearly has a higher trend, and it’s quite significant.
http://i53.tinypic.com/33olbo5.jpg
But your repeated claims that there has been no warming since 2000 are obviously wrong. In the post you wrote, “Then there is the lack of warming since 2000, which is fully compatible with a solar explanation for late 20th century warming but is seriously at odds with the CO2 theory.” You then repeated your claim in the next paragraph, “By this standard, the subsequent decade of no warming should be seen as even stronger evidence that climate is being driven by the sun…”
Again, as noted in my March 22, 2011 at 3:43 pm and in my March 23, 2011 at 1:55 pm comments, there is a significant trend in the UAH TLT anomalies from January 2000 to present. To illustrate this, I’ve added a third period and trend to the UAH TLT anomaly graph. It runs from January 2000 to February 2011. In fact, its trend is higher than the trend of the UAH TLT anomalies from December 1978 to December 1998.
http://i54.tinypic.com/2n0se44.jpg
The UAH TLT anomaly dataset and time periods you elected to use clearly contradict your statement that read, “Then there is the lack of warming since 2000, which is fully compatible with a solar explanation for late 20th century warming but is seriously at odds with the CO2 theory.”
I asked in my last comment why you were arguing about this, but, of course, I knew the answer, as do those who are reading this thread. The considerable warming since 2000 also contradicts your statement that read, “By this standard, the subsequent decade of no warming should be seen as even stronger evidence that climate is being driven by the sun…”
Leif Svalgaard wrote, “What are the spatial aspects of a point measure like TSI?”
This is the 2nd time you have unsuccessfully attempted to deflect attention away from key variables.
Alec Rawls says:
March 24, 2011 at 1:25 am
– – – – – – –
Alex Rawls,
Regarding your discussion of the ideas that solar activity levels and variations may be a significant cause of average earth surface temperature levels and variation, here is a relevant presentation (Dec 2010) by Prof. Vincent Courtillot. He touches on several aspects of solar variations versus climate. I found his talk to have some merit.
Commenters ‘Lord Beaverbrook’ and ‘ZT’ over at Bishop Hill’s blog pointed to his presentation.
What are your views on his ideas?
John
Bob Tisdale says:
March 24, 2011 at 5:16 pm
“Again, as noted in my March 22, 2011 at 3:43 pm and in my March 23, 2011 at 1:55 pm comments, there is a significant trend in the UAH TLT anomalies from January 2000 to present. To illustrate this, I’ve added a third period and trend to the UAH TLT anomaly graph. It runs from January 2000 to February 2011. In fact, its trend is higher than the trend of the UAH TLT anomalies from December 1978 to December 1998.
http://i54.tinypic.com/2n0se44.jpg
”
Bob, you’re cherry pickin’. You regress your data from the depths of the 2000 La Niña. Start from January of 2001 and the slope goes from your 0.0154 ℃ /yr to 0.006 ℃ /yr which certainly does not justify your claim of “higher than ’78 to ’98.”
For the last ten years the slope is an astounding 0.002 ℃ per year.
Paul Vaughan says:
March 24, 2011 at 9:06 pm
This is the 2nd time you have unsuccessfully attempted to deflect attention away from key variables.
Instead of being cryptic, perhaps you could explain what is spatial about the key variables [whatever they might be – and why are they key?].
pochas says: “Bob, you’re cherry pickin’.”
Not me. The start year was picked by the author of the post.
Thanks to richcar and John Finn for pointing out that Eichler article:
http://lch.web.psi.ch/files/Publikationen/analytic/Eichleretal_GRL2009.pdf
John suggests that:
The cause of the “divergence” is right there in figure 2. Eichler compares the temperature record at the Altai site to CHANGES in solar activity and finds that they track very closely until 1850, after which solar activity goes down and up, while temperature climbs and then levels.
But remember the subject of this post. The hypothesis that it is changes in the level of solar activity that cause warming (rather than the level itself) entails an implicit assumption that the climate system is always in equilibrium. Lockwood’s reply confirms this. He is assuming very rapid equilibration, so that the oceans are always very close to equilibrated to the level of forcing. Then indeed it will take a change in the level of solar activity to create temperature change.
But the rapid equilibrium assumption is a failure. There is no reason to think the climate system equilibrates rapidly. The studies that show rapid equilibration, like Schwartz, are using estimation schemes that only pick up the rapid response of the upper ocean level, leaving full equilibration time a wide open question.
I submit that the only divergence in the Eichler paper is a divergence between reality and his implicit assumption that the climate system is in constant near equilibrium. Without that assumption, the high average post-1850 levels of solar activity would continue to cause warming, just as the Altai temperature record shows.
Eichler’s paper is such a clear illustration of the implicit equilibrium assumption, and how it is screwing up these scientists’ analyses, that I am definitely going to have to do a post on it. Good find.
Just continuing the Eichler thought:
Eichler does estimate a lag. About 20 years? But that is going to capture mostly the surface layer fluctuation. Only with an extended forcing will equilibration of the deeper ocean layers get involved and take additional time, which is just what Eichler is faced with.
His 750 year temp and solar activity comparison has one extended low period and one extended high period. I wonder if his extended low acts the same way the extended high did, continuing to cause cooling even though the level at the bottom of the Maunder Minimum did not change for 50 years. I’ll check when I get a chance.
Alec Rawls says:
That graph is questionable in a number of ways, one being that they have chosen to plot only North American temperatures rather than global temperatures. With global temperatures, the divergence between solar cycle length would be quite apparent, as it is when discussed here: http://files.klimaskeptik.cz/200000435-7940b7a3ae/Laut2003.pdf and even acknowledged by one of the previous authors of the paper that originally tried to make this connection: http://mthwww.uwc.edu/academics/departments/geography/globcat/globwarm/solar-00.htm
Sorry, I misread Eichler’s figure 2. I mistook the flattened C14 data in 2b for differences. That’s what I get for commenting while I’m heading out the door. Having some time to take a look, I see that they shifted to variance units, and the C14 record peaks before 1800 (!), so the whole thing looks a bit flat. What misled me, I now realize, was the dropping of the Be10 data, which rises much higher in the 20th century, AND which tracks post-1850 temperatures a lot better than the C14 data does. That’s what really makes the 2b data look flat: the steeply rising measure of solar activity is gone.
This omission raises a whole different set of questions. It is the Be10 record that Eichler et al. discuss as having a significant correlation to temperature (r2 = 0.66, p < 0.001). In the text, the C14 record is discussed mainly as support for the validity of the Be10 record of solar activity. Yet the only cosmogenic isotope they graph in comparison to temperature is C14. Very strange.
One is forced to wonder whether the post-1850 fall off in correlation that they describe in the conclusion to their paper is a fall off in correlation between C14 and temperature, not between Be10 and temperature. They are not explicit, but this is what is done in the figure 2b graph that shows the fall off in correlation. Be10 is mysteriously dropped. Are they hiding a contrarian result?
We all know the powerful incentive to do this, with Jones et al. making systematic efforts to destroy journals that publish a single contrarian paper. Can anybody see another explanation for the dropping of the Be10 data from figure 2b? It is just so at odds with the text.
Okay, I read Eichler wrong again. It is the sunspot number (SN) that gets dropped from figure 2b. That is legitimate, as it is only a partial record. What did Emily Litella say? Never mind.
I still think the divergence is probably due to the longer equilibrium time that would go with a longer forcing, as deeper ocean layers get involved, but I obviously need to look at this more carefully.