Realclimate.org continues with its same line of attack. Wishfulclimate.org writers try again and again to concoct what appears to be deep critiques against skeptic arguments, but end up doing a very shallow job. All in the name of saving the world. How gallant of them.
A recap. According to realclimate.org, everything my "skeptic" friends and I say about the effect of cosmic rays and climate is wrong. In particular, all the evidence summarized in the box below is, well, a figment in the wild imagination of my colleagues and I. The truth is that the many arguments trying to discredit this evidence simply don't hold water. The main motivation of these attacks is simply to oppose the theory which would remove the gist out of the arguments of the greenhouse gas global warming protagonists. Since there is no evidence which proves that 20th century warming is human in origin, the only logically possible way to convict humanity is to prove that there is no alternative explanation to the warming (e.g., see here). My motivation (as is the motivation of my serious colleagues) is simply to do the science as good as I can.
Anyway, the last slur says that my astronomical analysis is wrong. Well, I've got news. The argument raised by Jahnke and Benestad is irrelevant. It has two grave flaws to it.
First, the Milky way is not a typical two spiraled armed galaxy. It has four spiral arms. You can see them in a CO doppler map here. (Well, at least 3 arms separated by 90°. And unless the Milky Way is an amputee, a 4th should be behind the center of the galaxy). J & B also failed to tell their readers that all the 5 galaxies in the work they cited have a very dominant 2 armed structure. I wonder why they kept this detail to themselves. Thus, the conclusions of Kranz et al. 2003, as interesting as they are, are simply not applicable for the Milky Way.
Fig. 1: The Co-Rotation radii for the 5 galaxies analyzed by Kranz et al. 2003.
Second point. Spirial arms can exist between the inner and outer Lindblad resonances (e.g., the galactic dynamics bible of Binney and Tremaine). If you force the 4 armed pattern to have a co-rotation radius near us (as J & S do), it will imply that the outer extent of the 4-armed pattern should be at roughly rout ~ 11 kpc. However, the patten is seen to extend out to about twice the solar-galactic radius (Shaviv, 2003 and references therein). Clearly, this would counter our theoretical understanding of spiral density waves.
Thus, B & J were wrong in their claims. Nevertheless, it turns out that surprisingly, they were not totally incorrect. Sounds strange? Well, it appear that the Milky Way has at least two independent sets of spiral arms, with two different pattern speeds. One is the above four spiral arms, which we traverse every 145 Myr on average. The second set is probably a two armed set which has a co-rotation radius near us (and hence we pass through it very rarely). This can be seen by carrying out a birth-place analysis of open clusters, as Naoz and Shaviv (2006) did. This result explains why over the years, different researchers tended to find two different pattern speeds, or evidence that we're located near the co-rotation radius. We are, but not for the 4-armed spiral structure which we pass every 145 Myrs on average!
Incidentally, this is not the first time Jahnke tried to discredit my results. The previous time was when he unsuccessfully tried to debunk my meteoritic analysis. I wonder if this time was too prompted by a request from Stefan Rahmstorf.
To summarize, using the final paragraph of Jahnke and Benestad, we can say that
Trends in cosmic rays
I genuinely think you've got a decent hypothesis here, and I think that you may have rebuffed Benestad's and Janhke's arguments regarding the 145 My cycle, but non of this shows that CRF could have had any influence on the climate beyond the 11 year solar cycle in recent times. I am still to see any convincing evidence available from measurement groups or in the literature which shows that CRF has changed to the required extent that would explain any of the climatic changes seen in the last 35 years. Given the lack of this basic correlation it seems very difficult to make bold claims regarding CRF's influence on the current climate warming episode. I know that you've cited the ocean lagging effect as an explanation for this, but there are several problems with this argument: it is at odds with the current understanding of ocean lags and the oceans are still warming. Surely if the effect of added heat from decreased CRF fluxes had been removed we would see a halt in the temperature rise in the oceans and land temperatures would remain constant or continue to rise for a short while. With the warming CRF gone the oceans have nothing to heat them; the atmosphere doesn't have the heat capacity to retain heat long enough to cause the oceans to warm after the added heat source has been removed; and neither are the oceans like a kettle with a heating element that remains warm after the power is turned off. So, why would the oceans continue to warm in the absence of the warming CRF effect? The ocean temperatures have been rising consistently throughout the last 35 years.
I'm all in favour of trying to explain paleoclimate with this hypothesis. I really think it is a nice idea, but there seems a constant refusal to acknowledge the point I have raised regarding the trends in CRF fluxes since the 70s.
The ocean is cold!
I've also been troubled by the lack of correlation between rising temperatures and changes in CRF. However one has to realize there are many factors in play here. For one thing the ocean on average is cold! I believe if I'm not mistaken that its average temperature is under 4 degrees so it will tend to continue to warm up on an ongoing basis regardless of what the CRs are doing at any given time. We then have the impact of changes in ocean currents such as the PDO which could account for much of the jump in temperatures over the last 30 years. The reality is that after volcanic factors are taken into account, there has been little or no warming of the surface temperature since the late 70's when the PDO had a major shift. There are indications that the PDO may now be experiencing a shift the other way. The next couple of years will be telling! Likelihood is that ocean currents, solar factors, aerosols/volcanoes and maybe even CO2 are all factors in what has happened to the climate over the past century. Won't be easy untangling the mess but a swing in the PDO could go a long way in trying to figure the puzzle out.
Well, the full answer is complicated
Dear anonymous,
Unlike the devout climatologists of realclimate.org, who deny the any natural effect, I will be the last to claim that solar-activity explains everything. In fact, my best estimate for climate sensitivity implies that anthropogenic radiative forcing explain about 1/3 of the 20th century warming, in particular over the past few decades. So, when you consider that only the last solar cycle was weaker, the fact that some of the warming is anthropogenic, that the oceans have a finite heat capacity, etc, there is no real discrepancy. A student of mine is in the midst of showing this rigorously.
As for your particular question. It is not unreasonable that you can have a decreasing radiative forcing with an increasing ocean temperature, in fact, you see it every year. Between the end of June and August, the solar radiative forcing is decreasing (over the northern hemisphere), however, the ocean temperature is increasing. (Here in Israel, the Mediterranean can reach 30°C, at the end of August). The reason is that even after the solar irradiance started to decrease (i.e., during July), the ocean is still cooler than the equilibrium temperature it should have with the lowered yet still high forcing. So the ocean continues to heat. The heating stops only after the ocean heated enough and the forcing decreased enough such that the heated ocean reached an equilibrium with the decreased irradiance. Beyond August, the irradiance decreases enough for the ocean to be warmer than the equilibrium and it starts cooling.
Similarly, even if solar forcing was the only one affecting 20th century temperature change (and it isn't), then the fact that the last solar cycle was weaker than the previous two, doesn't imply that the ocean should have started cooling immediately. The oceans cannot cool until solar activity (+ the other forcings) would decrease to below the average forcing over the latter half of the 20th century. If it ever happens (it might not because of the anthropogenic contributions).
currents
Currents may also move the heat to places where it is not measured. I believe this is part of what leads to low surface temperatures such as we are experiencing now with la nina. The warm waters are pushed into localized areas and below the surface. The warmth returns to the surface during el nino.
To try to simplify what Nir said: Just because solar irradience is lower than the last cycle wouldn't mean cooling, it would mean slower warming since the activity is still higher than normal. The slower warming could also be washed out by heat already in the system, but not yet measured.
aaron
Thanks for your response
Thank you for your reply to my comments. I acknowledge that the sea does continue to warm in the manner that you have described ie. through the early autumn after summer. Thank you for correcting my false assumption that you are unwilling to ascribe any of the warming to GHGs. I see too that you have acknowledged that real climate don't assume GHGs are the sole contributor to climate change. Seeing that I've made a similar mistake to you it appears that the deabte has become rather polarised. I attribute a few factors to this: your post is titled with the word slurs, which implies personal insult or defamation; your post did contain a slight edge to it that implied bitterness; I found your post via Lubos Motl and I am sorry to say that I don't find Lubos an objective commentator on these issues - as a result I guess I falsely labelled you, again, I was wrong.
Back to some science. So what you are saying is that 1950s-present solar and CRF forcing has been consistently higher than 1850 levels and therefore much of the warming since the 1950s is due to the lag effect. Without any numbers your suggestion is certainly plausible. I am going to see detailed numbers relating to the heat flow into and out of the oceans in order to verify that explanation. This is going to be very difficult in the absence of a CRF forcing. Do you have a proposed figure for the CRF forcing since 1850? Without these numbers it is very difficult to place any great certainty on your hypothesis; do you agree? This is what you need to do if you are going to start convincing the wider community.
Given that AGW theory has already reconciled itself with the oceans, has largely determined the relevant forcings to a satisfactory precision and this has been coupled with our understanding of climate sensitivity to yield fairly accurate reconstructions of past and present climate I am more inclined to place much greater certainty in its validity. Do you agree?
Of course, if you do accurately determine a significant CRF forcing and this can be repeated by other groups then AGW will have accomodate this.
Rebuttal
You state "and the oceans are still warming"
No they are not. In fact that are slightly cooling over the last four years. Look here:
http://www.npr.org/templates/story/story.php?storyId=88520025
In fact, it seems that the AGW guys are scrambling to find some new bogus man made explanation for their data...it the data doesn't support our claims we'll tweak the data!
The aim of realclimate is
The aim of realclimate is not to engage a sincere scientific debate. Their aim is post a reply full of straw man so their supporters can claim that your point "has been refuted by real scientists at reaclimate".
Demesure,
I think that to a large extent you're correct, which is why having debates with them is rather futile.
Debates
How can one have a debate, when the editors at realclimate routinely refuse to post any comments that refute the points they wish to prove?
The aim of realclimate is
The aim of realclimate is not to engage a sincere scientific debate. Their aim is post a reply full of straw man so their supporters can claim that your point "has been refuted by real scientists at reaclimate".
This is what is wrong with the UN conducting the science debate and the UN collecting the taxes. If science is to rescue itself from the politics, the debate needs to be open and in public. There can be no more hiding in scientific back-rooms.
Forums like this are invaluable for OPEN DEBATE. All points of view should be allowed ...
thanks nir
Very nice. You are too kind to them.
It's unfortunate that the posters on realclimate are uninterested in finding out what is really happening. If they were, they could have written a much better piece in less time by contacting you first.
Being that you were such a presence in their writing, I'd expect that to have been the first thing they did.
aaron
I was just thinking about a way you may further evaluate CRF-cooling affects. By looking at periods of high and low flux during different seasons, you might be able to get a better picture of what's happening. My thinking is that during winter the earth is closer to the sun and the SH has more ocean recieving direct sunlight and less land mass in general, so high energy CRF anomalies should have a greater impact on global temps. Sea surface temps should respond very quickly to clear skies during low CRF periods.
Agreed on Realclimate
I really don't even read their stuff anymore. It's one guy making up one strawman and red herring after another followed by 350 posts of back-slapping and high-fives. Sad, really.
Nir, you are among a handful of scientists really thinking outside the box on this. Keep it up.
Aaron
I am not sure that you're suggestion is possible. Even if the ellipticity of Earth's orbit was large, the otherwise large asymmetries between the winter and summer, northern hemisphere and southern, etc. would make it virtually impossible to single out a CRF effect this way.
yes
I understand your points that there probably isn't enough data to draw any real conclusions and the that differences in solar flux through the disc of the earth over a year probably aren't very large, but I thought a quick look might provide some insights.
I'm not sure if I made myself clear or that I fully understand your reply though.
My idea was to take advantage of the differences in the northern and southern hemisphere. I was thinking that the more immediate cloud CRF effects would likely be amplified during the SH summer. I thought if you look at cloud cover, CRF, and temps during just those months, you might see a more clear relationship.
aaron
Cloud cover
Interesting point. The temp anomaly usually peaks early in the year, about the same time the low level could cover reaches minimum. http://isccp.giss.nasa.gov/climanal7.html
Less GCR because the earth is closer to the sun could explain that. What is the "established" explanation of the timing of cloud cover minimum?
Alexander
I don't know how affecting the low altitude clouds will affect the stratosphere. If there is any effect, it is going to be an indirect one.
Cosmic Rays
While I am certain that there is something more then CO2 in driving climate change, I am not convinced that cosmic radation is it, however I am happy to see people deeply engaged in understanding the full impact of ALL the different inputs to our climate. Is nice to know that there are people looking past the 'science is settled' closed minded thought process of a really biased camp at this time. They call skeptics 'flat earthers' which strikes me as funny because only the 'skeptics' are trying to look past the horizon of what is obvious ( the obvious correlation being CO2 ). Just as it was obvious to the flat earth camp that the earth was flat because the earth around them was flat. Oh well thanks for giving me more information anyway, not convinced yet that Cosmic rays are a driving force but it is interesting to read on how they may be effecting the earth.
Seeing galaxy arms
Prof Shaviv
I went to the site with the doppler survey.
http://cfa-www.harvard.edu/mmw/MilkyWayinMolClouds.html
And I'm not able to understand it! Could you maybe give a post some time about how to understand this information? It looks pretty cool but I don't understnad what I'm looking at when I look at those graphs.
Mapping the Galactic Spiral Arms
To understand this method, look for example here.
Basically, you see that different elements on the same line-of-sight (i.e., the same longitude) will have different relative velocities relative to the solar system. Thus, in a doppler map, they'll appear with different velocities because of the rotation around the galaxy. This implies that the 2D plane of the galaxy is folded into the 2D plane of the longitude-doppler.
Moreover, molecular gas (and these maps are sensitive to CO which resides in cold molecular gas) will be concentrated on the spirals, so the map will trace the spiral arms.
The catch, however, is that it is hard to map this way the structure within our galacto-centric radius. The reason is that within our radius, there is a redundancy. In the above linked figure, you see that both elements B and C will have the same doppler relative to the solar system. This means that the spiral arms at smaller galactic radii will be folded upon each other, giving rise to an ambiguity. Thus, this method is excellent for seeing the spirals at large galactic radii, and 4 are apparent.
If you go to the link you quoted, then the 2nd figure has the following inset:
prompted by a request from Stefan Rahmstorf?
If Jahnke was indeed prompted by Stefan Rahmstof to discredit your results, then maybe Jahnke should try taking a close look at some of Rahmstorf's own work.
Please see the the critique of Rahmstorf's "A Semi-Empirical Approach to Projecting Future Sea-Level Rise” from Science, January 9th, 2007 at
http://climatesanity.wordpress.com/critique-of-a-semi-empirical-approach-to-projecting-future-sea-level-rise-by-rahmstorf/
Links at the bottom of this page go to subsequent posts that show:
1) Rahmstorf presents sea level rise rate vs. temperature in a way that deceptively implies that it is well fit to a line.
2) Rahmstorf's assumption that the time required to arrive at the new equilibrium is “on the order or millennia” is not borne out by his own data.
3)Rahmstorf hypothesizes gigantic sea level rise in the 21st century by preposterously extrapolating out more than five times the measured temperature domain of his data.
Please be advised that the page referred to above is recently imported from another location (tom-moriarty@blogspot.com) and is under construction, so it may be a little bumpy.
Lubos, thank you for the always interesting blog.
Tom Moriarty
ClimateSanity.wordpress.com
Tom,
I think the best example for why extrapolations can be dangerous is the London manure problem. In 1894, the Times of London estimated that by 1950 every street in the city would be buried nine feet deep in horse manure.
Anyway, if a paper appeared in Science, it must be correct, mustn't it?
-- Nir
p.s. Lubos always has interesting blog entries, but why are you thanking him here?
Why am I thanking Lubos
Nir,
Sorry. That was a consequence of cutting and pasting.
Let me formally thank you also, Nir, I do enjoy your work.
Tom
http://climatesanity.wordpress.com/critique-of-a-semi-empirical-approach-to-projecting-future-sea-level-rise-by-rahmstorf/
Reply
You are wrong about the motivation about our critisism, Shaviv; we are primarily interested in doing good sicence. We want to unravel the facts behind climate variability. In science, one challenge other views if one finds them strange or not credible. This is what we habve done. You make claims based on your own subjective belief og based on far-fetched speculations. The fact is that the claim that the recent global warming is due to GCR is not supported be any real evidence; there is no credible trend in the solar activity or GCR in the last ~50 years.
Rasmus
Rasmus you state that the motivation behind your criticism is in the interest of good science.
Could you answer some of the following question:
Why does Realclimate.org edit comments from other known scientist: Roger Pielke jr, Steve McIntire, Nir Shaviv, etc all have had some trouble with that. It is understandable that layman comments that are either false or do nothing to advance the debate may be deleted. But to edit other fellow scientist comment is simply dishonest and lead people to believe that you are not interested by good science but only by your personnal agenda, whatever it is (from the outside it looks to be the same as Al Gore).
Why are you affraid to link to other blog like climateaudit.org for example (I must admit that I was very surprised that you posted the link to this blog, must have been an over sight) while promoting laymen's blog that have nothing scientific like Coby Beck's, how to talk to a skeptics.
Why do you keep defending Micheal Mann's work even though it is flawed to the point that it should be considered fraud.
Rasmus,
Perhaps you're right. But if so, then it means you should have the integrity to add at the end of your post (and not buried in the discussion below), an addendum saying that this particular critique turned out to be wrong, as Kranz et al. is not applicable to the Milky Way. I for my part would add a similar addendum to my response, specifying that my comments about motives was wrong.
Second, over all, there was a large increase in the solar activity over the 20th century, even if you discard the Yakutsk data (used in the Ahluwalia plot), and this increase explains a large fraction of the 20th century temperature increase if the CRF/climate link is real. As for the temperature increase over the 1990's, see my response above. Some of the warming is due to the fact that although there was a decrease in the indirect solar forcing over the last cycle, it is still notably above the current forcing/temperature equilibrium (and therefore causes warming), and of course, some of the warming is anthropogenic.
-- Nir
p.s. Sylvain. I personally never had my comments on realclimate edited per se, though I did notice from the time stamps of other posts that mine took longer than they should to get approved and then when the guys I debated with couldn't address my comments, simply cut the debate.
Ridiculing RealClimate
Nir,
You are misquoting (or deliberately ridiculing?) realclimate’s position when stating that they deny any natural effect (third comment/response). I’ve read multiple times on realclimate that climate change is a response to a mixture of forcings, both natural and anthropogenic. Your characterization of their motives does not add anything to proper debate; rather it seems to serve the needs of the “skeptic’s” followers to question and ridicule climate scientists’ motives.
In one reply you say that you (amongst others) had your comments edited; in your next reply you say that your comments were never edited. Rather you noticed some juggling with the timing of some of your comments. Hey, that’s funny, I noticed the same here: you appear to post some (critical) comments with a substantial delay (a day or more), and then it appears simultaneously with your response. That’s an effective way of enticing other readers to immediately digest your response, lowering the chance of them thinking for themselves about what the outside poster had written. But you know what? That’s your perogative. This is your blog, and it is not a formal scientific venue such as a conference or a journal. You set the rules in your own house, and others play by your rules when in your house. But accusing others of what you do yourself as well (be it a very minor issue anyway) is a bit petty.
So too can realclimate’s contributors chose which websites they provide links to. I am not surprised that they prefer to link to a non climate scientist’s blog that they feel represents the science properly (eg Coby Beck) than to a non climate scientist’s blog that they feel does not represent the science properly and fairly (eg Steve McIntyre). They do provide links to blogs that put forward different viewpoints than their own (eg Roger Pielke Sr and Jr), provided they feel the scientific quality and integrity is up to par. Of course I’m just guessing as to their motives here (but it’s probably a better guess than yours, or at least a more respectful one).
Regarding Michael Mann: Many newer temperature reconstructions arrived at pretty much the same result as Mann et al did. Moreover, McIntyre and McKitrick’s critique contained a very basic flaw in their application of principal component analysis (PCA): they retained too few components, thereby causing the result to deviate from the underlying data (which resemble the shape of a hockey-stick). Tamino.wordpress.com has an informative series on PCA.
There are accusations that some of the cosmic ray - sun - climate studies are flawed to the point of being fraud that have in my opinion stronger arguments behind them than your claim regarding Mann et al. By this I personally don’t mean to accuse you or anybody else of fraud; I am quite willing to give you the benefit of the doubt that you are sincerely in search of the truth. But for your claims regarding recent climate change to be correct (e.g. it being caused predominantly by cosmic rays, and low climate sensitivity), you would have to push a whole lot of observations, evidence and basic physics aside. Perhaps not impossible, but not very likely to be true either.
Advancement in science these days occurs mainly by small increments, from the efforts of many over a long time. Sudden paradigm shifts, that completely overturn current thinking, were probably more common in the times when a religiously influenced worldview was slowly being replaced by a scientific worldview than now. Any new theory will still have to be consistent with the existing evidence, observations and basic physics. Of course it does not have to be consistent with the existing philosophy or worldview. Good luck.
correction
I mistakenly took both replies to (and entitled) Rasmus as coming from Nir Shaviv. As such my comment is a reply to both Shaviv and Sylvain, and I was mistaken in stating that Shaviv said two different things regarding his comments being edited at RC. My apologies.
accpeted
After I submitted the reply just below, I saw your new one waiting for approval and then I realized that you were mistaking Sylvain for myself. I on my part, thought I was starting to get senile, because I really didn't remember myself accusing realclimate of editing MY comments!
account
Barth, if you register an account, your comments will appear much faster.
Rasmus, while I realize I shouldn't purport to know what realclimate's motivations are, I feel justified is speculating that they are not entirely honest. As I stated before, especially with the tenor and focus on Nir, realclimate should have contacted him before posting it. It may have made for a much better post. Nir seems to me very amenable and interested in exploring the weaknesses of his hypothesis. It seems likely to me that if you did so, you could have ended up with a much more concrete criticism and avoided some of your more specious suppositions (the suposed inadequacy of iron metorite samples and the application of priciples of 2 arm spirals to a more complicated 4). A more balanced consideration would have at least lended credibility to your criticism.
I also realize that it's not practical to always think of or pursue such approaches [always trying to be so considerate would result in an inability to focus and get much done], but it may be something to consider in the future. It doesn't hurt to ask.
aaron
Barth,
Please validate your allegations before writing them.
First, I never said that my posts where edited by realclimate. Check to see who did so. Moreover, if I didn't care about being accurate, I wouldn't have made the point to correct Sylvain, but I did.
Second, I cannot allow for unregistered users to post unmoderated posts. This way I'll get too many Viagra links. This means that either you register as I user, and then I approve you, or, you will have to wait until I can approve the comments. Like most homo sapiens, I have to sleep at night. Mind you, I live in GMT+2hrs, so, some people might post posts which I cannot approve until the morning, or until I have time again to visit my site, during the evening. I NEVER wait with approving a legitimate posts, even those I don't like. The only occasions a post has to wait longer than a day is when I am traveling.
Anyway, this last accusation of procrastinating with approving the posts and then approving them with a reply is EXACTLY what realclimate.org does. In fact, realclimate.org writers did not even try to hide it. They approved my posts with the response in separate color as part of the same comment. See comments #37, #49, #54, #57, #125 here
As for other allegations, I never complained about realclimate not linking other sites. Why should I complain about something I really don't expect them, given their agenda?
As for your comments about Michael Mann, I never made any comment about his work. Enough other people did. We even had once a very pleasant conversation while happening to sit by each other on a flight. It is not in my habit to attack people who did not attack me or my work personally. Jahnke and Benestad did, so they got this post.
Anyway, to the best of my knowledge no idea I support contradicts known observations.
Have a nice weekend.
-- Nir