In an earlier post, we discussed a review article by Frohlich et al. on solar activity and its relationship with our climate. We thought that paper was quite sound. This September saw a new article in the Geophysical Research Letters with the title «Phenomenological solar signature in 400 years of reconstructed Northern Hemisphere temperature record» by Scafetta & West (henceforth referred to as SW). This article has now been cited by US Senator James Inhofe in a senate hearing that took place on 25 September 2006 . SW find that solar forcing accounts for ~50% of 20C warming, but this conclusion relies on some rather primitive correlations and is sensitive to assumptions (see recent post by Gavin on attribution). We said before that peer review is a necessary but not sufficient condition. So what wrong with it…?
The greatest flaw, I think, lies in how their novel scale-by-scale transfer sensitivity model (they call it “SbS-TCSM”) is constructed. Coefficients, that they call transfer functions, are estimated by taking the difference between the mean temperature of the 18th and 17th centuries, and then dividing this by the difference in the averages of the total solar irradiances for the corresponding centuries. Thus:
Z = [ T(18th C.) – T(17th C.) ] / [ I(18th C.) – I(17th C.) ]
Here T(.) is the temperature average for the century while I(.) is the irradiance average. If the two terms, I(18th C.) & I(17th C.), in the denominator have very similar values, then the problem is ill-conditioned: small variations in the input values lead to large changes in the answers; which implies very large
error bounds. In my physics undergraduate course, we learned that one should stay away from analyses based on the difference between two large but almost equal numbers, especially when their accuracy is not exceptional. And using differences of two large and similar figures in a denominator is asking for trouble.
So when SW repeated the exercise for the differences between the 19th and 17th centuries, and for three different estimates of the total solar irradiance, the results gave a wide range of different values for the transfer functions: from 0.20 to 0.57! The problem is really that SW assume that all climatic fluctuations in the 17th to the 19th centuries to solar activity, and hence neglect factors (natural forcings) such as landscape changes (that the North America and Europe underwent large-scale de-forestation), volcanism (see IPCC TAR Fig 6-8), and internal variations due to chaotic dynamics. It is, however, possible to select two intervals over which the average total solar irradiance is the same but not so for the temperature. When the difference in the denominator of their equation is small (the changes in the total solar irradiance are small), then the model blows up because other factors also affect the temperature (i.e. the difference in temperature is not zero). Thus their model is likely to exaggerate the importance the solar activity.
To show that the equation is close to blowing up (being “ill-defined”) their exercise can be repeated for the differences between 19th and 18th centuries (which was not done in the SW paper). A simple calculation for the 19th and 18th centuries is quickly and easily done using results from their table 1 and figures 1-2: A back-of-the envelope calculation based on the 19th and 18th centuries suggests that the transfer functions now would yield an increase of almost 1K for the period 1900-2000, most of which should have been realized by 1980! One problem seems to be that now the reconstruction based on solar activity increases faster than the actual temperature proxy. That would be difficult to explain physically (without invoking a negative forcing).
The SW paper does discuss effects of changes in land-use, but only to argue that the recently observed warming in the Northern Hemisphere may be over-estimated due to e.g. heat-island effects. SW fails to mention effects that may counter-act warming trends, such as irrigation, better shielding of the thermometers, and increased aerosol loadings, in addition to forgetting the fact that forests were cut down on a large scale in both Europe and North America in the earlier centuries. Another weakness is that the SW analysis relies on just one paleoclimatic temperature reconstruction, but using other reconstructions is likely to yield other results.
Looking at the SW curves in more detail (their Fig. 2), one of the most pronounced changes in their solar-based temperature predictions is a cooling at the beginning of the record (before 1650), but a corresponding drop is not seen in the temperature curve before 1650. It is of roughly similar magnitude as the increase between 1900 and 1950, but it is not discussed in the paper. As in their earlier papers, the solar-based reconstructions are not in phase with the proxy data. However, SW argue that by using different data for the solar irradiance, the peaks in 1940 (SW claim it is in 1950) and 1960 would be in better agreement. So why not show it then? Why use lesser data?
The curves in Figure 2 (Fig. 2 here shows the essential details of their figure) of the SW paper suggests that their reconstruction increases from -0.4 to 0K between 1900 and 2000, whereas the the proxy data for the temperature from Moberg et al. (2005) changes from -0.4 to more than +0.6K (by rough eye-balling). One statement made both in the abstract of the SW paper and the Discussion and Conclusions (and cited in the senate hearing) is that «the sun might have contributed to approximately 50% of the total global surface since 1900 [Scafetta and West, 2006 – an earlier paper this year])». But the figure in the SW paper would suggest at the most 40%! So why quote another figure? The older Scafetta and West (2006) paper which they cite is discussed here (also published in Geophysical Research Letters), and I’m not convinced that the figures from that paper are correct either.
There are some reasons to think that solar activity may have played some role in the past (at least before 1940), but I must admit, I’m far from convinced by this paper because of the method adopted. It is no coincidende why regression is a more widely used approach, especially in cases where many factors may play a role. The proper way to address this question, I think, would be to identify all the physical relationships, and if possible set up the equation with right dimensions and with all appropriate non-linear terms, and then apply a regression analysis (eg. used in “finger print” methods). Last week, we discussed the importance of a physical model in making attributions because statistical correlations are incapable of distinguishing between forcings with similar trends. Here is an example of a paper that has exactly that problem.
There is also a new paper out on the relationship between galactic cosmic rays and low clouds by Svensmark. We will write a post on this paper shortly.
A question, only slightly off topic:
I’ve been looking for the solar cycle response in the global temperature time series. Haven’t found it yet.
I know of two papers giving an estimate of response to the solar cycle: 1. Scafetta & West 2005, GRL 32, L18713, and 2. Douglass & Clader 2002, GRL 29, 1786. Both give a sensitivity to solar-cycle forcing of about 0.1 K/(W/m^2) (about twice what would be expected from radiative calculations alone). The Scafetta & West paper is just plain rubbish; they take the total signal power in an entire *octave* of the spectrum and attribute it entirely to 11-yr solar cycle variation, with no account for other forcings or for noise.
The Douglass & Clader article seems, on the face of it, to be basically sound, but I have three misgivings: 1. the total time span of the temperature time series is a scant 23yr or so — very short for study of an 11-yr periodicity; 2. the error bars they give for their coefficients seem unrealistically small; 3. their analysis is based on MSU tempererature time series, which I know has some serious problems.
So my question is: are there any other papers I should look at for a realistic estimate of the sensitivity of global temperature to the solar cycle? Urs, you’ve mentioned that the solar cycle is detectable if one detrends, and removes the effects of volcanos and ENSO. Is your statement based on Douglass & Clader, or some other paper, or your own investigation? Is the temperature data on which this is based MSU, HADCRU, GISS, or other?
Gavin? Urs? Anybody?
[Response:There is one:
http://adsabs.harvard.edu/abs/2005JCli…18..996C
-rasmus]
Re #92: . . . reconstructions based only on tree rings may overestimate the influence of volcanic eruptions, as not only the temperature is reduced, but there is also a change in direct and diffuse incoming sunlight . . .
Iâ??m not sure this is well understood. The Gu et al. 2003 Science paper found increased photosynthetic activity after Pinatubo as a response to increases in diffuse sunlight in a deciduous forest, typically not the type of tree rings used in temperature reconstructions. More importantly, a post-eruption increase in photosynthesis would lead to positive growth anomalies and, all other things being equal, an underestimation of the influence of eruptions on temperature.
[Response: Yes, as usual Ferdinand doesn’t quite understand what he’s talking about. In this case, he has it 180 degrees wrong, as you suggest. See the paper by Robock (2004) on this. – mike]
Re 100 (comment):
Gavin, you forget the Hadcm3 model tests with 10 x solar and 5 x volcanic, which found that the model probably underestimates solar variations with a factor 2…
Btw, the largest changes in the ocean heat content are found in the (sub)tropics, where insolation differences are at their maximum. See Levitus, Fig. 2.
[Response: Completely different thing. The question was whether, for the same forcing, there was much evidence for different responses in temperature. As far as I can tell, the answer is no (i.e. the efficacy of solar is near 1). The Haldey centre experiments were related to pattern matching with observations where they deduce a stronger pattern for solar in the obs than they produce in the model given a prescribed forcing. That says nothing about efficacy, since the real world forcing might have been bigger. However, there are other reasons to hold back from accepting that result wholeheartedly. First off, the patterns of solar response seem to be affected by the mechanisms incorporated. At least when you allow the strat ozone feedbacks to occur, you get a different spatial signature of warming due to interactions with the annular modes. Further new mechanisms might change that again (conceivably). And with different spatial patterns, the fit to the spatial pattern in the obs. might change. I don’t know how important that might be, but it’s something that needs consideration. -gavin]
Re #102,
I have not the slightest problem to admit that I am wrong (if the arguments are good…). Indeed, trees growth with less direct sunlight can be (over)compensated by enhanced diffuse light.
In this case I did look at the slide (of Robock in #92) in which he didn’t find any influence on climate over 20-year periods, after correction for the diffuse light effect on tree growth, except after quite strong eruptions (of we had only 9 in the past 600 years + Tambora, which was an order of magnitude larger). This is confirmed in the Robock article (in comment #102) if you have a look at Fig.4, where dendro in general have less pronounced variations (even with opposite sign in some non-volcanic periods) on short-term scale. After huge eruptions, the cooling is more pronounced for non-dendro than dendro (even some warming in the latter).
If we may believe what Robock says in #92, then, after correction for the diffuse light in dendro, a back-of-the-envelope calculation of volcanic cooling over the past 600 years (9 eruptions of Pinatubo strength x 3 K x 3 yrs + unknown/Tambora x 6 K x 10 yrs + 24 smaller ones x 0.3 K x 1 yr) is some 0.036 K, based on dendro and non-dendro proxy reconstructions…
Some longer-term effects may remain after several consecutive eruptions, but even then, the 0.1 K cooling by volcanic eruptions over the past 600 years (0.3 K modeled over the past 100 years, see fig.1 on this page) seems rather high…
Thank you Gavin, for answer #100. So :
1) There’s no physical reasons (on the contrary) to expect the same kind of feedbacks, and climate sensitivity, for solar and GHG’s forcings.
2) But, models give a similar sensitivity.
So my next (basic) question is : which models for which parametrizations ? (e.g. : Empirical models from temperature reconstructions ? Energy balance models ? AOGCM models for 21st prediction and 20th retrovalidation ? In each case and in relation to 1), do we deduce from “independant” datas that solar and GHGs sentivities are similar, or do we parametrize a priori a similar sensitivity ? Or in each case, what is the methodology to exclude an “ad hoc” attribution to each forcing / feedback, not so different from Nicola’s method you seem to strongly criticize here ? By advance, thanks.
Re 101
Grant, I did some calculations myself. I looked at the period after 1970. I used the detrended CRU global temperature dataset and the MEI-Index for ENSO, one-year running mean for both. The ENSO signal is clearly visible in the temperature. Now I compensated for the ENSO signal in the temperature data (empirically: CRU temp minus the MEI-Index with a scaling factor 0.11 and a 5-month time lag). Now if you look at the residual you will see the volcano signals (El Chichon and Pinatubo) together with an oscillation which corresponds more or less to the 11y solar cycle (hardly any time-lag), with 0.1K per W per m2 TSI change (about the same as Douglass and Clader). It is difficult to compensate mathematically for the volcano signal, since the global forcing signal is not so easy to establish (as the discussions above show ..). But the picture seems rather evident. Of course, it s still only less than 3 TSI cycles (I looked at the PMOD data). I can send you the graphs if you like.
However, I cannot find any 22-year signal, neither in TSI nor in temperature . At least it will be much weaker than the 11-year signal.
It is obvious that there are strong ENSO and volcanic signals in the frequency bands Scafetta and West 2005 are using. That is the reason why they find a 9-year instead of an 11-year signal in the temperature. Thus as you stated their results are meaningless. For the 11-year cycle they get probably the right result by chance, but for the 22-year cycle their signal is much too strong.
Re #100: Gavin, when you say “the effects of equivalent GHG and solar forcings are…within about 10%”, do you mean global average or within any region (eg. the Arctic)?
The IPCC 2001 report states “Several recent reconstructions estimate that variations in solar irradiance give rise to a forcing at the Earth’s surface of about 0.6 to 0.7 Wm-2 since the Maunder Minimum and about half this over the 20th century… All reconstructions indicate that the direct effect of variations in solar forcing over the 20th century was about 20 to 25% of the change in forcing due to increases in the well-mixed greenhouse gases.”
Depending on from where you measure, the warming in the first half of the 20th century is about one third to one half of the total, so that suggests 40 to 50% of the warming in the first half of the century was caused by solar (which is a lot less than Scafetta is claiming).
But according to the data in this 2000 Delworth and Knutson in Science the warming in the first part of the 20th century was strongly concentrated in the Arctic region. That does not fit well with the expectation that solar warming would be relatively stronger in the tropics. The paper seems to discount solar warming, and attributes it to a combination of greenhouse gases and internal variability. I notice they use a climate sensitivity of 3.4K, much higher than the 2.7K James Hansen is currently using, so they may be overstating the GHG contribution.
Is the climate science community backing away from earlier views of solar forcing in the early 20th century? If not, how do you account for the fact that most of the warming occured in the Arctic, and what value would you assign for the solar contribution to 20th century warming? I am sure that is rather less than 50%.
Re: #106
Thanks! It was easy to find the MEI ENSO data on the web.
So, I’ve just done a *preliminary* (only!) analysis. I fit the CRU temperature time series to volcanic and ENSO signals, a la Douglass & Clader. For ENSO I used the MEI index, for volcanic forcing I used data from Ammann et al. 2003, GRL 30, 1657. No smoothing was applied to any of the data. The time period is from 1950 (start of MEI index) to 2000 (end of volcanic data from Ammann et al.). I determined coefficients by least-squares fit (but with no time lag!). The results are a bit puzzling.
The residuals don’t seem to show the solar cycle. There is a strong response at P=9.3 yr, but this doesn’t really match. During the period 1950-2000, the average length of the solar cycle is 10.7 yr (using either the sunspot numbers, or the TSI reconstruction of Lean 2000, GRL 27, 2425). During the 50-yr interval, this leads to a phase differential of 0.7 cycles.
Some of the difference may be due to the different time interval, starting at 1950 rather than 1970. But most of it is probably due to my lack of application of a time lag for ENSO and volcanic signals. I’ll do that next (by nonlinear least squares, it’ll take me a few days). For one thing, the need for a lag is evident from visual inspection of the data-vs-fit graph. For another thing, the coefficient I get for ENSO is only 0.07, well below your value 0.11 (almost certainly due to mismatch from my lack of time lag). So, I’ll compute the fit with time lags computed, and report the results some time this week.
BTW, I’d love to see your graphs.
Re: solar cycle response
Well, I couldn’t help myself; I stayed up late to do some more analysis. I applied nonlinear least-squares to fit the MEI index for ENSO, and volcanic signal, to the CRU temperature time series from 1950 to 2000. The best fit is for a lag of 9 mon. for the volcanic signal, 5 mon. for the ENSO signal.
The residuals don’t show the solar cycle. There is a periodicity at 9.54 yr, of amplitude 0.07 K — but a 9.54-yr period doesn’t match the solar cycle period 10.7 yr (over the same time interval); the difference in periods leads to a phase differential over the 50-yr span of 0.57 cycles.
Even if I assume the 9.54-yr period *is* a solar cycle response, its amplitude is smaller than expected from the computations of Scafetta & West or Douglass & Clader. They quote a response (to the 11-year cycle) of 0.11 K/(W/m^2), I get 0.08 K/(W/m^2). And this is a more generous response level than is realistic; the 9.54-yr period really doesn’t fit the solar cycle.
So, I’m beginning to think that the response of global average surface temperature to solar variations for the 11-yr solar cycle is *not* amplified (by feedbacks). I suspect that it’s very near the 0.05 K/(W/m^2) from radiative calculations alone. It could even be less, due to the inertia of the climate system. But, the noise level of the data and the brevity of the time span prevent a more accurate determination.
Re #107:
Blair, the influence of direct insolation changes over the solar cycle is mainly in the tropics (~0.2 K amplitude in ocean surface temperature, in average 0.1 K global, see White ea.), while the indirect effect is via relative larger changes in the stratosphere. This is caused by changes of up to 10% in UV radiation, which influences the ozone concentration and stratospheric temperatures (up to 1 K), mainly in the tropics. This causes changes in the jetstream position, rain patterns and the Arctic Oscillation (AO).
See for stratospheric/tropospheric interactions up to the Arctic:
http://www.nwra.com/resumes/dunkerton/pubs/jastp.xx.xx.xx.pdf
One sun-cycle influences:
http://folk.uio.no/jegill/papers/2002GL015646.pdf (fig.1, low cloud cover, global)
http://www.gsfc.nasa.gov/topstory/20010712cloudcover.html (cloud cover, USA)
http://www.cig.ensmp.fr/~iahs/hsj/453/45310.htm (discharge Po river, Italy)
http://www.agu.org/pubs/crossref/2005/2005GL023787.shtml (rainfall, Portugal)
http://ks.water.usgs.gov/Kansas/pubs/reports/paclim99.html (rainfall, upper Mississippi basin)
http://ks.water.usgs.gov/Kansas/waterdata/climate/ (same)
For longer-term cycles on climate:
http://www.sciencedaily.com/releases/2003/09/030926070112.htm
http://www.knmi.nl/~weber/abstracts/Weber2004ClimDyn.pdf
The difference in climate reaction between GHGs and solar variation in the troposphere and even more in the stratosphere may be that the GHG warming(troposphere)/cooling(stratosphere) is more evenly distributed over the latitudes, while the solar heating/cooling is mainly in the tropics, which changes temperature(/pressure) differences between the tropics and higher latitudes, thus increasing/decreasing wind speeds and patterns…
Further, the current circumpolar temperatures were not higher than in the 1930-1940’s, a few years ago I checked all stations over 67N, some 30 % were higher than in the 1940’s (mainly West Canada/Alaska/East Siberia), 70% didn’t reach or just reached the 1940’s temperatures, but this may have changed in the past few years. The same for Greenland: updated (2005) summer (melting) temperatures still seems below the 1930-1945 period, while yearly temperatures are rather equal.
Grant,
there are two possible reasons for the difference: I’ve only looked at the data since 1975. It is possible on the one hand that the period before 1975 shows more a 9.5y period in the temperature (the raw temp. data does not, apart from the small oscillation in the early 50ies). The second possibility is that you did not eliminate all of the volcano signal, since the forcing is regionally different and the global response is not easy to determine. The volcanoes have a strong 9y signal which might influence the period length. I would use the data until 2005 since there is no volcanic signal after 2000. this might also alter the result somewhat.
What is the period length before 1980? Or maybe it’s possible to do the analysis excluding somehow the years 1983-1985 and 1992-1995 which have the volcano disturbance. Because I fear that it’s very difficult to correct realistically for the volcano signal.
Proposition: Use the data until 2005 and then look at the temperature curve, if the mismatch might not be only due to the small peak in 1952 (or test the sensitivity to that peak by starting in 1955), and if there might still be a volcano signal (e.g. negative peaks around 1983/84 and 1992/94).
Anyway, it s really not easy to find a solar signal, but I try hard… (besides: to find the 22y cycle seems hopeless).
Nicola
sorry, I have missed your comment in 91.
However, your argumentaion goes in illogic circles.
I have argued that the match of the long-term trend is only a result of your assumption. Then you answered that there additionally is a match of the patterns (Maunder and Dalton Minimum).
However, I have found that these patterns match better with half of the sensitivity (I can not see any other distinct patterns besides Maunder and Dalton minimum and the long-term trend) So you are just left again with only the match of the long-term trend … which is only based on your assumption…
Urs,
I am sorry, but you should read better my paper.
You are auguing about a short pattern during the Dalton Minimum where the solar effect seems larger than the observed temperature pattern that is consistent with a scale of 30/40 year cycle.
In the paper, if you read it carefully, I clearly say (a lot of times) that the climate sensitivity to solar changes is “frequency” dependent. Larger is the frequency and smaller is the sensitivity.
In the paper I did the calculations having in mind the secular sensitivity, not a 30/40 year cycle sensitivity that would be significantly smaller than the secular one.
Your finding is perfectly consistent with the hypothesys of my paper (if you read it carefully)!
On a secular scale your estimate is too small, but on a 30/40 year cycle scale it might be realistic.
In other words, you cannot criticize my finding by stating something like:”your estimates for the climate sensitivity to secular solar changes is too large because I find that on a 30 years scale the sensitity is lower”!
By stating this you simply prove that you have not understood the principal hypothesys of my paper and of the previous ones that the sensitivity is “frequency” dependent because of the thermal inertia of the ocean, a fact confirmed by theoretical studies too (Wigley, Foukal, etc).
Ref# 112
Hey Urs;
Just a quick question, last year Dr. Scafetta presented his 9/2005 paper at our University. At the time I was curious that the data did not seem to match logic. He was indicating that the solar to terrestrial energy coupling was “capacitive” instead of “inductive”, meaning that it appeared as rapidly rising energy content until it reached a plateau peak and discharged. Where as the satellites indicated in the TOA measurements that over the solar cycle, input from Sol appeared clearly to demonstrate an inductive input of slowly rising energy until the load was saturated and the energy rose rapidly to finally discharge.
In looking at the solar cycle neither the 11 or 22 year reversals appeared to play into the 20th century temperature pattern. However, if I look at 2(two) 22 year periods things begin to become interesting. If you consider a 22 year cycle and an inductive load the low build up to saturation and discharge rebuilding towards saturation becomes apparent. Is this mearly a coincidence of multiple forcings and feedbacks or does this merit solar influence?
Dave Cooke
Re: #111
I intend to try all those suggestions (thanks!). But, I’m giving a paper at a conference this weekend (on an entirely different topic) so it’ll be a week or so before I can get around to it. But rest assured, I’m gonna get around to it.
Re: response to #101
Thanks, Rasmus, for the lead. At first glance it looks like a very thorough and rigorous analysis.
Nicola
So you agree, that only the secular trend matches. My original argument was, that this is not a finding but your assumption. It was you who then argued that other patterns match. But they do not. So your finding only consists of your assumption (that the secular trend has to fit). That s all. And it does not help to read your paper ten times more.
Hey Dave
The problem is that it does not make sense to compare global temperature to the solar cycle without considering the other forcing factors. Volcanic eruptions and ENSO have a strong frequency component with a similar response amplitude in the same frequency bands, especially the 7-14year band. In Figure 4 of Scafetta and West 2005 you clearly can see that the temperature signal can not be a sole response of the solar cycle, since the frequency of the signals is significantly different. Especially for the 22year cycle you see 16 cycles for the temperature while there are less than 14 solar cycles over the same period. So it’s impossible that one signal is the response of the other. Of course it is possible that there is a solar component in the temperature signal, but there are certainly other signals of comparable strength. Thus the temperature signal certainly shows features of other factors. Neither inductive nor capacitive imaginations can wipe that off. Additionally I have not been able to find any 22 year signal neither in temperature nor in TSI.
If you look e.g. at the temperature of the last few decades, the clearest signals are the response to the El Chichon and Pinatubo eruptions in 1983/4 and 1992/94, respectively (cooling) and the El Nino in 1998 (warming). These events are crucial for the decadal frequency of the temperature at that time and produce something like a 9year oscillation. To pretend that this signal might be of solar origin, because the frequency is in a similar range is nonsense. This is mere coincidence. If you really want to see a solar signal you have to remove the other influences which is difficult for the volcano signal (see my discussion with Grant). I think there is some signal of the solar cycle in global temperature if you account for the other factors, but it looks different than what was presented by Scafetta and West.
Besides, I have not been able to find any 22 year signal neither in temperature nor in TSI. There is a 22-year signal in Cosmic rays, which is a result of the cycle of the magnetic field (you can see it e.g. in the 11-year running mean curve of the Climax CRF). If there is a response of the temperature to the 11year TSI cycle, but not to the 22year cosmic rays cycle (which is not seen in TSI), that would suggest that the temperature is influenced rather by TSI than by Cosmic Rays.
Dave
sorry, there is a mistake in my answer above. It is the 11-year cycle which shows 16 and less than 14 cycles, respectively, not the 22year cycle.
Urs,
I never pretended that the match was “perfect” in the minimal details!
If you extend the same methodology to catch shorter pattern with 30/50 year time scale the match would be better, of course. But this was not the purpose of that work.
However, even in this simple form the match is much much better that what you would get with a GCM like GISS or a EBM like the one adopted by Foukal, whose simulations are at odd with the secular data and even from 1880 to 1970 when there are instrumental data, as I proved above in #94.
Hey Urs;
Thanks for the clarification, pretty much the pattern I saw that seemed to point up the 22 year cycle was the incoming satellite TOA measurements. Granted the distributed less then 7 watts/meter^2 would be eaten up as noise, it still elevates the noise and I believe that is the point the Dr. Scafetta may have been attempting to point out.
Primarily what we saw was a unique approach of applying electrical engineering wave form analysis to the issue and attempting to ascertain it’s impact. The approach is unique in that it provides an insight in a format that helps folk like me better grasp the variables and the possibility of concidental peaks of noise forcing a real effect. Not that I consider supporting the proposed conclusion; however, the approach if applied to all the known periodic contributors in a given period may make for some interesting model derivations. Now if we can only use a reverse Forier Transform analysis to try to extract the signals from the noise like we did in cryptology…
Dave Cooke
I don’t understand how #94 proves what you claim, when read in the light of the inline comments about Moberg. #94 claims what you claim, but the basis seems unreliable. Why do you consider Moberg more reliable than those who comment? Is this a statistical argument?
dear all,
I believe we have discussed this topic enough, at least for me. Of course the issue remains open to future research and debates.
I do not believe the criticism of Rasmus to my paper is correct, as also #21 has easily discovered after a cerefull reading of my paper.
However, I would like to kindly thank Rasmus for having given to us all the possibility to discuss my research and this interesting and important topic.
I would like also to thank Gavin and Ferdinand for their interesting comments and auguments.
Well, perhaps I will see somebody of you at the AGU meeting in December. I am organizing one section there dedicated to solar variability and global change with Dr Willson (that is, Mr. ACRIM).
You all are invited to attend, if you like.
I am really busy in doing a lot of different things, I cannot continue to write here and probably there is no need any more.
This experience has been very interesting.
well,
ciao ciao
nicola
Re #110: Ferdinand, thanks for the response. The papers you linked to suggest the solar cycle feeds into the internal variability of the climate due to wind and ocean current patterns. But I am having trouble understanding an effect that is mostly felt in the tropics is entirely concentrated in the Arctic. If you could not access the Delworth and Knutson Science paper I referenced, here is the diagram I am referring to. It shows that the high Arctic was warmer in the 1940’s than today, as you state, but the rest of the world warmed very little. This is in contrast to the greenhouse warming since 1980, which is truly global in extent. The Medieval Warm Period has a a similar pattern.
The information I have seen make me think that solar changes, or the response to them, is less than commonly stated. Factors like the Atlantic Oscillation seem more important, with solar changes mainly acting as a trigger. This does not fit will with the Scafetta claim that solar is responsible for half of the warming in the 20th century. Rather, I am wondering if the IPCC 2001 report overstated solar effects.
Re #123: Blair, the effect is not only in the Arctic, but is more pronounced in the Arctic. It has something to do with the amount of energy which is absorbed in the tropics and via evaporation, ocean and air flows gets into the high latitudes.
Models don’t capture the real (regional) world that good. See the difference between observations and model estimates in Johanessen, Fig. 1. The real temperatures were increased in all latitudes for the period 1930-1940, but more in the Arctic. The same happens now, but the increase is also pronounced in the mid-latitudes. The Echam4 model overestimates temperatures with GHGs alone, and gives too much cooling when including aerosols. For the whole 1930-1940 period, the temperature is underestimated in both cases. The model described in Science does a better job for one of the simulations, but with an unrealistic “internal variation”…
Further, there are fortifying mechanisms for solar like cloud cover (inversely correlated to solar radiance at the TOA). And indeed, solar may trigger some of the internal variations, which may include the AMO/NAO/AO… If the rather uniform warming by GHGs triggers similar internal modes (and cloud cover), that is another question.
Re #124: Hi, Ferdinand. I agree that while models may give a good picture of the overall trend, they are not ready yet to give accurate regional forecasts. As you say, this is apparent in the Johanessen paper. However, they also state:
It seems to me that solar forcing is not as significant as I used to think. Indeed, as you state, its main effect may be as a trigger for internal variations.
Thank you Gavin & Nicola et al for an interesting exchange. Sounded just like baseball fans arguing over the world series statistics. But now a question:
WHY isn’t there both a “convective and conductive feedback” to the internally generated RADIATIVE forcings (ie GHGs, volcanoes etc in Hansen et al 2005 – all except solar) such that the net result is that only external solar can raise or lower the temperature of the world?
Certainly any increase in air temperature from radiative forcings (apparently reasonably well modeled in the GCMs) is going to increase the temperature differential from ground to space, which will increase the vertical air velocity (ie increased hurricane strength) and DECREASE the residence time of energy in the air in the same manner that GHGs increase the residence time. Just WHY won’t convection/conduction increase to compensate for the decreased (slowed) radiative transport? Is it even in the Radiative GSMs?
IF conduction & convection increase, then we no longer have a problem with GHGs violating conservation of energy, Wien’s Law, the Ideal Gas law, and a violation of the second law of thermodynamics or Entropy. These all occur in the GCMs when GHGs etc create a higher air temperature without an external energy source. How can Wien’s law require more energy-out be generated but the only source of energy for global warming (except the solar) is by reducing the energy-out to create an energy imbalance to create the radiative warming. There can’t be an Earth energy imbalance in the air because the daily 10-20 degree warming/cooling cycle would very quickly reestablish the balance. How can the ideal gas law predict a trivial change in temperature (due to the change in air density by substituting CO2 for oxygen) when the GCMs predict global warming of 4 to 11 degrees? How can a GHG internally generate enough heat to cause global warming with out an external source of energy? (violates Entropy). IF there is a convective and conductive feedback, then all these problems go away.
Just think of convection, conduction and radiation being 3 parallel heat transport processes. If one decreases (eg GHG radiative heat trapping) then the others increase to compensate.
Solar is the only source of external energy added to the globe (identified so far), and capable of causing global warming and cooling. In fact since solar insolation changes add ~4 w/m2 out of 1364 w/m2 (since ~1700) or ~0.3% of 288Absolute or K ( http://www.grida.no/climate/ipcc_tar/wg1/245.htm), which equals a rise of 0.84K, it already accounts for ALL the observed global warming in the hockey stick. This means GHG caused warming doesn’t exist. There is no greenhouse effect. There is no need for carbon taxes or exchanges or carbon sequestration or the Kyoto treaty or IPCC. The only problems excess CO2 cause are less oxygen to breathe, and a higher ocean PH.which could be solved by dumping chemicals there.
Unfortunately there is also the problem of unemployed climatologists, environmentalists, politicians and bureaucrats.
John Dodds
[Response:I think virtually nobody denies the existence of the greenhouse effect. There is a natural greenhouse effect without, which surface temperatures would be too low (~256K) for presently known life forms. I don’t think that is a ‘violating conservation of energy’, but that you have misunderstood the concept. -rasmus]
RE # 126
John Dodds, your simple view of ocean acidification either mocks your inteligence or is your ironic humor at work. If ocean acidification requires, as you say, [ dumping chemicals there ] why would that be necessary since increasing CO2 atmospheric concentrations are not an AGW problem rather a consequence of increased ocean acidification.
Can you not find something more rewarding to do with your free time than to waste electricity spouting nonsense. Move on!
I’ve been discussing this global warming issue on a couple of other sites, but I have a problem; whenever I ask climate change denialists for the emperical evidence that they base their views on, they change the subject or run away, I am beginning to think that maybe there is not mathematical evidence that supports the view that increases in greenhouse gases doesn’t result in a stronger greenhouse effect, and that, just maybe, denialism is simply an allergic reaction to Kyoto.
I guess what I’m trying to say is, why is it that the flat Earthers are never asked to prove that the Earth is flat? If the pressure went on them to do so, maybe some of them would be forced to accept that their views are more a result of their politics, rather than being built on good science. Why are those that support the IPCC always on the defensive rather than attacking to exploit, what appear to me at least, to be glaring weaknesses?
If we are approaching dangerous tipping points (I make
Re 126
By analogy, you seem to be arguing that if the water level (heat) in a lake goes up because rain increases the inflow (insolation) everything is fine, but if the water level goes up because building a dam (GHGs) reduces the outflow the laws of the universe have been violated.
The feedback fallacy at work here is that somehow convection and conduction will increase without any attendant increase in temperature. But since it’s temperature gradients that drive conduction and convection, that can’t be. So really it’s the gain of the temperature-convection feedback that’s at stake, and if it were high enough to fully offset all radiative effects on temperature, there’d be some obvious symptoms – low natural variability and glacial cycles perfectly correlated with insolation perhaps.
And who ever said that GCMs don’t include conduction and convection?
Can’t tell from outside if the John Dodds who asked the questions at 10:07 am is someone new, or is the engineer named John Dodds whose previous questions have been asked and answered, but in general, it’s worth reading and using the search tool for the really basic questions about physics. Reading that engineer’s questions and the inline answers say starting at the link below in the water vapor thread, you’ll see a pretty good review of the basic science, I think.
https://www.realclimate.org/index.php/archives/2005/04/water-vapour-feedback-or-forcing/#comment-1816
#110 Ferdinand, Must disagree with your statement about North of 67 Polar stations, although you hinted that the latest data may not be the same as during the 1940’s. As always I use recent examples to
disprove solar impact. A large swat of the Canadian Arctic has experienced above average temperatures which are astounding: +10 to +15C above average during the last 10 consecutive days or so.
The sun is about to set for the long night, it is not a solar effect, especially since we are right in the middle of the solar minima cycle. The answers lie elsewhere, advection from the Pacific and Atlantic, widespread cloud coverage, shrinkage of Arctic Ocean ice, and above all a prevailing warmer atmosphere which in this case has very little to do with the sun.
Re #132,
Wayne, one never should use what happens on a few days/weeks or even months as evidence of warming/cooling or whatever may happen for the next years…
As far as I have seen on TV here, New York State had a lot of snow in a only one day last week, because of the polar front going very deeply southward. That is no sign of a continuous cooling trend at all.
Solar effects are mainly in the tropics, but the result of that is more pronounced in the Arctic (as good as temperature variations are much smaller in the tropics than at higher latitudes), due to air/sea flows (including in the stratosphere), going from warm(er) places to cold(er) places… Thus at higher latitudes, the energy transport from the equator is the important item which governs much of the temperature variations, besides direct insolation, of course…
Re 130 & 131:
Same John Dodds, STILL a sceptic, but a better educated one. Thanks for the reference to previous posts. You saved me from doing it. The previous posts suffer from one big deficiency: the responses usually are not addressing all the questions. Eg See Rasmus above in 126 who says the greenhouse effect does exist, but fails to address my question of IF the GCMs take into account Convective forcing/feedback, and consevation of energy etc, etc
ie I find the answers to be NOT very convincing BUT as you pointed out a very good education sometimes.
As to the lake analogy: If the lake has 3 sluice gates over a dam, one called convection, one conduction & one called radiation. If I continuously add rain (solar insolation) all three increase output until in equals a new higher out & the lake level is higher, or if the rain stops the lake level goes back to its original level old in equals old out.
NOw if the rain stops to establish the old equilibrium, AND I build the radiation gate higher (add GHGs) then the reduced radiation flow (some? all?) goes out the convection and conduction gates, instead of the radiation gate. BUT OLD IN still equals OLD OUT. ie the higher GHGs did NOT raise the lake level/temperature, because no one added any water. The decrease in radiation flow (ie what the GHGs cause) is the driver of the increased convection which is actually a convection feedback that will revert the entire system to its old equilibrium state. SO the question is where is the convection feedback in the GCMs What size is it? As long as there is ANY increased temperature from the GHGs, then there will be a driver to cause increased convection etc. And the other question how did raising the GHG gate add any water to the system? – ie conservation of energy.
Note also that if the rain/solar increases, then some of the “out” goes out the convection gate. IS this accounted for in the GCMs? ie The total solar in is partly a convective forcing. Where is this? As far as I can see only radiative is addressed.
If you look at IPCC there is an entire chapter on Radiative forcing, but only that convection equals a fixed number. I want to know that convection forcing is addressed, that convective feedback is addressed, just like radiative forcingas are addressed. As for conduction, I’ve not seen any mention of conduction forcings/feedback in the GCMs, but a temperature increase (from splar or GHGs) will surely force an increase in conduction and lighting.
Because for the life of me I can’t figure out where the extra energy comes from to allow the GHGs to increase the temperature of the world without adding energy to do it. If adding GHGs reduces the output of radiated energy to space and raised the temperature per the GCMs, then Wien’s law which dictates the energy out, doesn’t work. How can adding rain to the lake, increase the lake level by 5 times (ratio of GHG forcing to solar forcing) what the amount of rain (solar in) is? (see Gavin’s numbers above) THE GCMs violate conservation of energy, entropy, cause Wien’s Law to not work, cause the ideal gas law to not work, So I am left with the conclusion that the GCMs are right and Physics is wrong, OR the GCMs are wrong. (actually not wrong – just incomplete by not addressing ALL the convection implications- according to my current theory.)
Re #134: You are just confusing yourself with water analogies. Let me give you a simple example of how the Earth’s temperature can rise without any change in solar input: Albedo. If the Earth gets a little darker, it will reflect less solar energy, therefore absorb more of it, and get warmer.
Conservation of energy is not violated here. To maintain a constant temperature, the Earth must radiate back into space the same amount of energy it receives from the Sun. If the Earth absorbs more energy, its temperature rises, which causes it to radiate more energy back into space (Stefan-Boltzmann law) until it reaches equilibrium at a higher temperature.
You can think of a greenhouse gas as a form of albedo that operates on the infrared radiation emitted by the Earth. If less energy is radiated into space because of greenhouse gases, the Earth’s temperature must rise until the emission of infrared increases enough that the system returns to equilibrium. No physical law is violated by this model of greenhouse gases.
#133 Ferdinand, This is where I seriously part with the idea that causation effects are only for Climate concerns and not for weather. Nonsense, both Climate and Weather causations are identical,
both are driven by clouds, ocean temperatures, wind patterns, Hadley cells, and yes solar effects. I distinguish climate from weather by its simplicity, recognition of patterns and trends, but a climate prediction is usually much easier than a weather one. The sun warms up your location , when its at zenith temperatures are usually warmer than at midnight on a clear night, this is a solar effect. The leap is then made, the sun is warmer, therefore GW is a solar effect, same as a high sun at noon. Here again I completely part with solar proponents, there are so many instruments about measuring the sun everywhere, from space, from the ocean, even underground (cosmic rays) , there are none as it is often repeated, no solar variation to justify GW present conditions. Now a SGW (Solar Global Warming) proponent, must be able to explain everything warmer as caused from the sun. I just explained, a present condition of a significantly lesser solar input giving a warmer (more than ten days) climate. Where is your solar causation in this Arctic case which is occuring right now during a solar minima (-1 w/m2)? What is happening in New York does not answer my question. I am equally fascinated by the apparent disparity, where the location with less solar input, has a much greater warming anomaly than the location with greater sunlight. The contradiction is delightful, but it points out that something else is warming the Arctic. I would suggest that the continent right now is certainly susceptible to cooling, as it always does, but the Northeast US gets its weather usually from the West, while the Arctic is heated by the Arctic Ocean, advecttion from greater Oceans, persistent cloud base and no or very little sun.
Your analogy’s confusing you, I think.
Look: incoming solar energy, 100 units. What wavelengths?
These, for our particular star’s output and our particular atmosphere:
http://www.noao.edu/image_gallery/html/im0600.html
Distributed something like this by the time it reaches ground level:
http://www.molalla.net/~leeper/sunligh2.jpg
Okay? 100 units of that, coming in.
Now, before people started adding CO2 faster than nature consumes it again, the planet was at radiative equilibrium —- alla same in, alla same out, as far as the planet’s temperature measures it.
Yes, different wavelengths in and out, but the energy balanced. 100 = 100.
Now, add CO2. Mr. Arrhenius noticed that CO2 absorbs across some bands of the infrared.
Why? Wavelength happens to be the right length to be absorbed by the CO2 molecule — it’s absorbed, makes the molecule wiggle as it absorbs energy, then it re-radiates it in a random direction.
How much of the infrared part of the spectrum gets through the atmosphere without being absorbed and re-radiated in some random direction? Well, suppose you had a telescope and used infrared film. Could you take a picture of the stars in infrared?
Sure — through a few narrow wavelengths they call “infrared windows” — otherwise, no, because the sky’s full of molecules that are radiating energy in the infrared. Why? Because they absorbed it from other molecules.
http://www.ipac.caltech.edu/Outreach/Edu/Windows/irwindows.html
So — most of the energy from the sun is blocked, of course. That 100 units is getting through the atmosphere, in the wavelengths shown above. 100 in. Earth proceeds to do some basic arithmetic.
Plus 100 — equals 100.
Ah, but that’s over time. So say that’s 100 units per year. Whatever you like.
Now, Earth’s temperature’s been fairly stable for ten thousand years or so, til these monkeys came along and discovered fire, and coal, and put the two together and made excess CO2. Cue Arrhenius, who noticed, what? That carbon dioxide absorbs infrared light.
So Earth has a math problem. It’s doing addition, and needs to do subtraction, to keep its energy balance — or it’s going to warm up or cool down.
Incoming, though you’ll get arguments on this elsewhere, we say is stable at 100 units.
Earth’s received all that solar energy — you get your conduction, and convection, and fraternization, and conglomeration, and all those other things, stirring around, because of the incoming energy. Doesn’t matter. 100 in, reaches the planet. All we count is the heat energy. Keep it simple, S.
Now, we boosted CO2. Earth’s sitting here, rotating, one side intercepting that 100 units of sunlight. Rotates (and all those other things going on that don’t matter, they just redistribute the heat energy, make waves, make hurricanes — negligible for energy balance calculations).
Warm Earth turns and is under the night sky. Sky’s dark in most wavelengths. Sky’s, however, become a little brighter — in the infrared. Why? That CO2 (and other greenhouse gases, mostly water vapor of course). There was a stable amount of it, for oh, ten thousand years, maybe more.
Incoming 100, outgoing 100, equilibrium.
Carbon dioxide increased with coal burning — increased because it’s showing up in the atmosphere, where it can absorb (in those bands of infrared).
What temperature is the planet? Oh, somewhere in the infrared. Infrared radiated from the planet goes where? Out, til it hits something. Like a greenhouse gas. Then it’s (aside from your conduction and convection, which are just stirring, no addition or subtraction there) going to be absorbed and re-radiated.
The sky’s gotten a little ‘brighter’ (or more opaque) — same thing, if you’re an astronomer interested in infrared objects. The heat isn’t being radiated away as fast as it was.
100 in, still. Same. 99.98 out. There’s your “extra” heat. It’s not addition — it’s failure to subtract.
What’s happened? Outgoing energy is now down to (begin arm waving here, if not sooner) say 99.98 instead of the previous 100.
What’s happened? Why, the planet’s failed its subtraction exam and has a bit of excess heat.
There you are. What’s the heat doing? Short term, conduction, convection, etcetera. Doesn’t matter.
Long term? Atmosphere is — say — stable at 2x the previous level of CO2. As they say, a miracle happens. Incoming energy from the sun is still at 100. Atmosphere’s gotten a bit warmer, and a bit bigger — it’s a slightly taller and wider radiating surface up there at the very top.
Why the top? Remember that CO2 molecule that intercepted an infrared photon and twanged and started wiggling, then emitted another infrared photon in any old random direction. Which way did it go? A few of them went directly into the outer dark, off into space — Earth did a subtraction problem successfully for that photon, and got rid of it.
The rest of the photons the C02 molecules intercepted —- which is most of them in a fairly wide range of infrared energies, see Arrhenius again —- went off in any other direction. What’d they do? Not subtraction. Not addition. They just hit another molecule somewhere in the atmosphere.
So — incoming we have 100 units of sunlight.
Outgoing, we have, oh, 99.98 units of infrared.
Where did that extra energy come from? You can do the math.
Don’t fail to read down in that infrared astronomy page.
Earth viewed in the infrared — this is the radiation going out:
http://www.ipac.caltech.edu/Outreach/Edu/Regions/irearth.jpg
“Planets absorb light from the sun and heat up. They then re-radiate this heat as infrared light. This is different from the visible light that we see from the planets which is reflected sunlight. The planets in our solar system have temperatures ranging from about 53 to 573 degrees Kelvin. Objects in this temperature range emit most of their light in the mid-infrared. For example, the Earth itself radiates most strongly at about 10 microns…..”
Remember, CO2 is a greenhouse gas because the particular wavelengths that carbon dioxide absorbs and re-admits — the ones that are blocked for our infrared astronomers stuck on the ground — are in that 10 micron area, where planets heated by the sun are brightest.
Want to create, say, a heat ray, for your next planetary invasion? — what do you use? Why, carbon dioxide — in a laser:
“Unlike the other lasers producing visible or short near-IR light, the output of a CO2 laser is medium-IR radiation at 10.6 um. It is the classic heat ray of science fiction. I have no doubt that the Martians in H. G. Wells’ “The War of the Worlds” used CO2 lasers…..”
http://www.eio.com/repairfaq/sam/laserco2.htm
re: 134. It is nothing less than an astonishing height of arrogance that a layman who has apparently never published any climate-related research in peer-reviewed journals believes he knows something more than literally thousands of climate scientists engaged in climate modeling and research all over the world.
Re #134 Let’s assume the dam has three outlets each three feet wide. The water pouring out of them is one foot high. If you block the outlet labelled radiation then the water which was flowing through that outlet will flow through the other two labelled convection and conduction. But the water there will now be 1 foot 6 inches high to compensate for the water no longer being radiated. Thus the lake level (temperature) will rise by 6″ (or 1F.)
While the lake is filling up to reach the new height six inches higher, there will be a loss of outflow, and so the total outflow will be less than the rainfall, but only temporarily. It is important to realise that this delay also applies to the atmospheric temperature. Even if we stop adding more CO2 today, (raising the radiation outlet) the atmosphere will continue to warm until the surface is hot enough to produce the extra convection and conduction needed to return the system to balance. Most of the surface of the earth is water, and when it heats up it is soon cooled again by the wind mixing the upper layer. There is an awful lot of water to warm before the system stabilises at the new levels of CO2 we have now set up.
Here is the question that John Dodds brings up, and one which I have been trying to get addressed for months by Dan’s “experts” but have so far failed. If you increase the temperature in the bottom of a column of air, convection will increase. Anybody want to argue that point??? So, *how much* does convection compensate for a, say, 1° C theoretical increase in temperature at the ground due to radiation outflow restriction? That’s the question.
(In the dam analogy, by increasing the height of the radiation weir, you will increase the height of the water behind the dam, but only as relative to the widths of the other weirs. In order for water to increase flow out of the other weirs the height must increase – but not by as much.)
Then we have to consider that the amount of water coming in will decrease because since convection is increasing cumulus cloudiness is increasing. So, for extra credit, how much does cloudiness increase as a result of the increase in convection, and how much does *that* additionally detract from the original 1° C increase due to radiative imbalance?
Re #134 and “fails to address my question of IF the GCMs take into account Convective forcing/feedback, and consevation of energy etc, etc”
I believe Manabe and Strickler were the first to parameterize convection in an atmosphere model, in 1964. They (Manabe and Wetherald) came up with a better model in 1967, and many subsequent models. Conservation of energy is treated by ensuring that the radiation leaving Earth at the top of the atmosphere is the same amount as that coming in. As far as I know, all existing GCMs have addressed both these issues for some 40 years now.
Give him time to do the arithmetic (and the experts time to comment on my attempt to explain it as simple arithmetic — I would have written less, if I’d had more time).
Re #142 Steve,
You have raised a very important point. Increasing the temperature of the air near the surface by one degree will cause convection. But there is an inversion at the tropopause, ie. below the stratosphere. Since the stratosphere is warmer than the troposphere the convection will halt when the parcel of air reaches the tropopause, the top of the troposphere. In other words, the troposphere can warm until its potential temperature is greater than that of the stratosphere. When that happens the global climate will face a major hiatus.
Your second point is also important. The balance in outflow is not completely controlled by the weirs as you point out. The convection weir feeds a water wheel which drives a weir on the river that feeds the lake. As the water in the convection weir increases, more of the feeder river is diverted into a bypass tunnel which feeds directly to below the resevoir dam. So the lake will not rise by the full six inches I predicted. As you say a major control on the global temperature are the clouds, which provide a quick escape route for incoming solar radiation.
However clouds only work in the tropics. In the sub tropics and over polar regions there are very few clouds. Antarctica is one of the world’s great deserts! Global warming will only have a small effect in the tropics provided the cloud forests remain. On the other hand it will have a major effect on the poles, especially the Arctic where the increased temperature will mean that there is continual cloud providing the greenhouse warming to ensure continual cloud.
The sceptics are right that the computer models are wrong, but the sceptics are wrong in arguing that the models are overestimating the effect of anthropogenic greenhouse gases. They are underestimating the effect in the Arctic and in the northern hemisphere continental land masses where we all live!
Alastair, In what sense are the models underestimating the effect in the Northern Hemisphere? Are you thinking only of temperature? Roesch found that most of the AR4 models overestimated precipitation in the temperate regions leading to a delayed snow melt relative to observations and a positive surface albedo bias. Other models had a positive surface albedo bias due to snow cover for other reasons. So some things in the Northern regions are underestimated and some are overestimated. A positive albedo bias would indicate that the effect of the solar forcing is underestimated and possibly compensated for by an overestimate of GHG effects. Furthermore since modelers tweak cloud parameters to match global albedo and achieve energy balance, and because the AR4 models achieve a good match to global average surface temperatures, there are at least partially compensating errors elsewhere in the models for both albedo and temperature. In a non-linear climate system, it would indeed be fortuitious if these compensating errors made the models more useful for projecting out 100 years. Can you convincingly demonstrate that the projections from such models would also be “underestimates”? So, what is being underestimated, and how can you be sure what the effects of the underestimate are on climate sensitivity to GHGs over where we live?
I submit, that if you can know these things, then we don’t need the models, we can just consult you. The whole point of the models is that we need them to understand and project such a non-linear complex system. The models just are not good enough yet, but they are well worth further investment. I can’t be sanguine about the errors.
Roesch A. (2006), Evaluation of surface albedo and snow cover in AR4 coupled climate models, J. Geophys. Res., 111, D15111, doi:10.1029/2005JD006473.
Hey Mr. McDonald;
Just a few quick questions, I too had similar questions regarding the tropopause termperature inversion layer convection related to saturated adiabatic procceses. Upon exploring the available data I came across some interesting set of measurements. On the UCAR site under the COSMIC program appears to be a set of experiments regarding the air temperature associated with the various front movements in range of the Colorado microwave stations.
(Specific URL: http://www.cosmic.ucar.edu/~braunj/front_range/mwrp.html )
When I review the tropopause temperature change in relation to approaching cyclonic fronts it appears the -20 Deg. C isothem layer increases in altitude to around 11 Km. By the same token, if the data I have recently reviewed are correct, the mesopheric “cooling” appears to intrude into the Stratospheric range during anti-cyclonic events. I cannot recall them anymore; however, if I remember correctly there were a number of studies that discussed the apparent wave characteristics of approaching fronts in the early 1990’s regarding the compression of the stratospheric region and the effect it had on the transfer of tropospheric temperatures into space near terrestrial surface features.
Is it possible that just the atmospheric fronts themselves could result in waves or destabilization of the temperature inversion layer? By the same token if I look at polar regions with the concentration of frontal changes there seems to be a rapid rise of tropospheric water vapor invading the stratospheric range. This increased water vapor appears to be participating in the generation of PSCs which also affect the ztratospheric ozone layer with the introduction of denitritification (the formation of NAD and NAT) which reduces both the ozone content and reduces the removal of chlorine in the polar regions.
The initial CloudSat and Calipso images appear to demonstrate in the presence of strong thunderstorms in the US Plains that there appears to be Stratospheric clouds forming above them. (We are not talking about “sprites”, or the expansion of the the normal 5-7 km ice->precipitation transition zone.) This would make me wonder is the thermal inversion as strong as you indicate? If along with the reduction in stratospheric ozone there was also a reduction in the stratospheric temperature there is the possibility of the intrusion of tropospheric temperatures and water vapor laden air intruding in to the stratosphere isn’t there?
If I extend the physics regarding an earlier post by the kind folks here regrading the skin effect of the temperature inversion layer on the calm sea as preventing the transfere of the heat content of the top of the ocean back into space; If I add in the NOAA 0 Deg. C themal barrier rise from about 2300 meters to about 1700 meters; If I consider that the 20 Deg. C isothermic level in the pacific appeared to rise from an average of 400 meters to about 100 meters recently; I find myself wondering then how is it that the oceans heat content is dropping, the solar input appears to be consistant, that one of the GEWEX comitties appears to indicate that the atmospheric water vapor seems to be decreasing. I see much data that is conflicting.
Is the heat simply going into melting the surface ice or is it radiating into space? Granted it would take 2500 Joules of energy to convert each ccm of ice; however, there certainly is a much higher precentage of energy coming in than can be accounted for in the melt rate and is currently attributed to re-radiation. Even if the incoming 1364 watts/meter^2 (roughly +/- 7 watts) is indirect to the earths surface it certainly would be transferable to the atmosphere if the atmosphere contain a high amount of aerosol particles would it not?
My apologoies to the kind folks here. This actually is not a rant nor is it an attempt to deny the physics “everyone” has come to accept. This is simply an attempt to find answers, as it appears not all the experimental data supports the multitude of theoritical hypothesis so far. Regarding the original subject, convection, is it possible that there are multiple laws regarding black body radiation in relation to multiple refraction indexes that are just not documented yet?
Dave Cooke
#144, Alastair, Calculating the rate of GW is a complicated affair, I don’t think that most who have came up
with a trend have claimed absolute certainty. May be in the near future better methods will be used.
I agree that some estimates appear erroneous, I would suggest that the commonest of errors is to make a surface temperature trend, Surface temperatures around the world are not all taken at the same height, I kind of am a bit perplexed when I hear a surface temperature trend, GT’s are useful, but again based
on various temperature heights, sea surface temperature trends are for the most part the ones to analyze.
Going back to the atmosphere, there must be methods devised in calculating the total heat in the system
planet wide, that is the key, I see some efforts in finding Upper Air trends, that is better, but again flawed,
the Upper atmosphere constantly changes tenperatures throughout a vertical profile hour by hour , taking an average at 700 mb, may miss a strong cooling just below, or warming above. Taking the temperature of the entire atmosphere, however weird ithis may sound, is the thing to do.
this is gay
Re Martin’s #145
what is being underestimated is the greenhouse effect from water vapour. However, it is not a constant and it varies itself with temperature. This means that the water vapour greenhouse effect feedback depends on the surface specific heat, latitude and altitude; all of which affect temperature.
The models do give a a reasonable description of the climate as it is today, but that is no guarantee that they are predicting the future correctly.
Most importantly they do not reproduce the rapid climate change events that have happened in the past. Therefore it seems self evident to me that they are unable to predict the rapid climate change events that will happen in the future. Since those are certain to cause more disruption to the economic system than the slow changes presently envisaged, then for me that is a major failing.
Rapid climate changes can be to both warmer and to cooler conditions. The only driver for those types of event that has not already been eliminated by geological evidence is the main greenhouse gas: water vapour. IN FACT IT IS WELL KNOWN THAT DURING GLACIAL PERIODS THE CLIMATE WAS MUCH DRYER, AND DURING WARMER PERIODS MUCH WETTER.
You were right when you wrote “I submit, that if you can know these things, then we don’t need the models, we can just consult you.” But I am afflicted by the Cassandra syndrome. No one wants to believe me :-(
Pehaps it is because I insist in quoting Sergeant Frazer’s catch phrase “Waur all doomed!”
Re #148 and “this is gay”
No no, old fellow, it’s dead solemn.