Israeli Astrophysicist Dr. Nir Shaviv posted a guest essay at Luboš Motl The Reference Frame titled: The CLOUD is clearing
In a nutshell he’s saying that cosmic ray flux modulated by solar variability has a strong place right alongside CO2, and may in fact be a larger forcing.
He writes:
The results are very beautiful and they demonstrate, yet again, how cosmic rays (which govern the amount of atmospheric ionization) can in principle have an effect on climate.
What do I mean? First, it is well known that solar variability has a large effect on climate. In fact, the effect can be quantified and shown to be 6 to 7 times larger than one could naively expect from just changes in the total solar irradiance. This was shown by using the oceans as a huge calorimeter (e.g., as described here). Namely, an amplification mechanism must be operating.
…
As a consequence, anyone trying to understand past (and future) climate change must consider the whole effect that the sun has on climate, not just the relatively small variations in the total irradiance (which is the only solar influence most modelers consider). This in turn implies, that some of the 20th century warming should be attributed to the sun, and that the climate sensitivity is on the low side (around 1 deg increase per CO2 doubling)
Read the entire essay here
h/t to Dr. Indur Goklany
Also, William Briggs has an excellent summary as well.
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Leif,
I suspect there is an apples and oranges issue here. You are talking about total CR flux. But the CRs of interest in the solar moderated climate model are only the high energy ones – above 15 GeV – which are capable of penetrating and causing ionisation in the lower atmosphere. The Earth’s magnetic field has a huge impact on the total CR flux, but it has its predominant impact on the low energy flux (below 15GeV), and these CRs don’t penetrate to the lower atmosphere anyway and therefore couldn’t seed clouds.
As Shaviv himself says “On the time scale of tens of thousands of years, Earth’s magnetic field varies and with it the flux of cosmic rays which can penetrate the atmosphere. Because however the magnetic field can only prevent the penetration of cosmic rays which are anyway severely attenuated by the atmosphere, changing the magnetic field, and even altogether switching it off is not expected to give rise to significant climate effects.” He goes on to quantify the size of the expected effect – small but observable – looks for an effect of this size in the observational data – and finds it. So he hasn’t ignored the effect of variation in the Earth’s magnetic field as you seem to think.
C_14 levels provide a measure of TOTAL CR flux. But most of the C_14 is produced by low energy CRs very high in the atmosphere – above the altitude where cloud seeding effects are expected. So C_14 levels are not directly measuring the CR flux of interest. In fact they have an inverse relationship! Low energy CRs come mostly from the sun. High energy CRs come mostly from outside the solar system. When solar activity is high the number of low energy CRs from the sun (and therefore the total CR flux) goes UP. However the solar wind is more active which means that the number of high energy CRs reaching us from outside the solar system goes DOWN!
C_14 levels are not used by Shaviv to directly measure the flux of high energy CRs of interest. They can however be used after adjustment for the much slower variation in the earth’s magnetic field, to infer solar activity levels, and this is the use Shaviv makes of them. His preferred instrument for deducing high energy CR levels is evidence from the rate of degradation of iron meteorites.
Leif Svalgaard says:
September 1, 2011 at 9:27 pm
Beer explains how the modulation of the cosmic rays depends on solar activity and on the geomagnetic field [slide 12 ff] http://www.leif.org/EOS/Beer-GCRs.pdf As you can see the geomagnetic modulation is by far the largest.
So given geomagnetic variation, which has been considerable on Geological and shorter timescales, your argument about insufficient variation is moot.
tallbloke says:
September 1, 2011 at 8:33 pm
The duty of a scientist is to bend over backwards to show the public how he may be wrong; as Feynman said in his treatise on integrity. The scientists who made the study Leif linked discharged that responsibility honorably and responsibly.
Leif: In stark contrast to what Svensmark did.
In stark contrast to what you did with your one word negative answer and selective quote too…
anna v says:
September 1, 2011 at 9:45 pm
CERN has been preparing the Large Hadron Collider and the experiments around it for all these years. The cost of CERN , and of ITER, and of any other large collaborative research site, is comparable and no more than the cost of an airplane carrier .
Tesla achieved more on a shoestring.
tallbloke says:
September 1, 2011 at 11:04 pm
So given geomagnetic variation, which has been considerable on Geological and shorter timescales, your argument about insufficient variation is moot.
My argument is not of insufficient variation but about the temperature variation not being the same as the cosmic ray variation and that therefore cosmic rays not being a major factor in climate. This should be clear to you by now.
In stark contrast to what you did with your one word negative answer and selective quote too…
Still in the insulting business, eh? When there are conflicting papers it usually means that the case is not established.
Dr. S. has a point, the geomagnetic field is far stronger modulator, so if GCRs are suppose to control climate her is a good correlation I found about a year ago:
http://www.vukcevic.talktalk.net/LL.htm
which is far better than anything Shaviv, Kirkby or Svensmark have come up.
So why I do not subscribe to the GCR hypothesis ?
My answer ‘where is the beef’ ?, certainly not in the GCR, CO2 or any other ‘parts per million / billion’ entity.
Back to the drawing board.
Ian H says:
September 1, 2011 at 10:52 pm
But the CRs of interest in the solar moderated climate model are only the high energy ones – above 15 GeV – which are capable of penetrating and causing ionisation in the lower atmosphere. The Earth’s magnetic field has a huge impact on the total CR flux, but it has its predominant impact on the low energy flux (below 15GeV), and these CRs don’t penetrate to the lower atmosphere anyway and therefore couldn’t seed clouds.
These high energy CRs are also not modulated very much by the Sun. And are also much rarer. See slide 11 of http://www.leif.org/EOS/Beer-GCRs.pdf
And Shaviv forgot the tell Kirkby about this, c.f. Kirkby’s plot of GRs [derived from 14C]: http://www.leif.org/research/INTCAL-Jasper.png
14C is produced mostly in the lower atmosphere at about 5000 m altitude where the density of the atmosphere is high enough.
Low energy CRs come mostly from the sun.
No, very little of the CRs come from the sun.
Leif Svalgaard says:
September 1, 2011 at 11:15 pm
When there are conflicting papers it usually means that the case is not established.
When discoveries are in conflict with the AGW meme, the publication of the paper is delayed and the rebuttal paper frequently appears in the same issue of the journal…
Leif Svalgaard says:
September 1, 2011 at 2:17 pm
David Corcoran says:
September 1, 2011 at 1:21 pm
Leif, hasn’t the effect of Forbush events on cloud cover already been clearly demonstrated?
No: http://www.atmos-chem-phys-discuss.net/8/13265/2008/acpd-8-13265-2008.html
In the case of the paper you cited, the authors also say:
“By focusing on pristine Southern Hemisphere ocean regions we examine areas where we believe that a cosmic ray signal should be easier to detect than elsewhere.”
In fact, it has been discovered that the southern ocean is an area of high primary production for phtyoplankton, which generate large amounts of CCN generating aerosols. Furthermore, the nearest neutron monitoring station, in South Africa, has an amplitude of GCR incidence only half that of Oulu in Finland. Furthermore, their study area went right to the Equator in a large swath of the Pacific, where GCR incidence is weakest of all. In Fig1 of the paper the projection of the globe used masks the fact that by far the majority of their areas of study lie within the region of the earth where GCR incidence is weakest. In summary, The deck was stacked in favour of a negative or at best weak result.
Since most of the climate change (warming) we have seen is in the Northern Hemisphere, it is questionable whether they were looking in the right place anyway. Hardly surprising then, that their result, although positive, wasn’t as strong as those obtained by Svensmark.
A competent and impartial scientist carrying out his duty to give the public a balanced understanding (especially one who spends a lot of time on blogs) would highlight these facts rather than giving a one word negative answer to someone asking if the correlation of low cloud cover reduction and GCR incidence reduction had been established.
It has, multiple times, by Svensmark and others.
tallbloke says:
September 2, 2011 at 12:02 am
Furthermore, they note that the nearest neutron monitoring station, in South Africa, has an amplitude of GCR incidence only half that of Oulu in Finland.
For the high energy GCRs that Shaviv and Svensmark claim are involved there is no difference between the stations and the latitude difference only affects the low energy GCRs. All those special pleading things are just signs that the effect is not established and that was my point.
tallbloke says:
September 2, 2011 at 12:02 am
Since most of the climate change (warming) we have seen is in the Northern Hemisphere, it is questionable whether they were looking in the right place at all.
Absolutely.
Northern Hemisphere.
North Atlantic and the Nordic seas !
http://www.ipcc.ch/ipccreports/tar/slides/large/04.18.jpg
There is the beef, hundreds of W/m2 of heat released, moving back and forth the polar jet-stream. Forget about the CO2, GCR. LOD and such like ‘parts/million’ real but insignificant entities.
One criticism The authors of the paper Leif cites is this:
http://www.atmos-chem-phys.net/8/7373/2008/acp-8-7373-2008.pdf
“They also pointed out that a version of the ISCCP low
cloud cover, which combines infrared and visible channels,
is more accurate and reliable than the IR-only version used
by Marsh and Svensmark (2000), and that using the more
accurate version yields much poorer correlations with GCR
and TSI than the IR-only version does.”
Is anyone aware of Svensmark’s response to this criticism?
tallbloke says:
September 2, 2011 at 12:02 am
A competent and impartial scientist carrying out his duty to give the public a balanced understanding (especially one who spends a lot of time on blogs) would highlight these facts rather than giving a one word negative answer to someone asking if the correlation of low cloud cover reduction and GCR incidence reduction had been established.
the question was if the correlation had not already been clearly established [implying that it had]. The simple answer is ‘No’. I backed that up with a reference. No need to cite dubious claims either way. Your moral indignation is ill founded and unbecoming.
Leif Svalgaard says:
September 2, 2011 at 12:10 am
tallbloke says:
September 2, 2011 at 12:02 am
Furthermore, they note that the nearest neutron monitoring station, in South Africa, has an amplitude of GCR incidence only half that of Oulu in Finland.
For the high energy GCRs that Shaviv and Svensmark claim are involved there is no difference between the stations and the latitude difference only affects the low energy GCRs.
Thanks for your response. I can see why they would use high energy events as clear exemplars of the effect, but I doubt they believe lower energy events have no effect, because lower energy events are far more prevalent and will have a bigger cumulative effect than rarer high energy events.
Please can you point me to a link where I can see Svensmark or Shaviv saying that only high energy GCR’s are involved.
Thanks
M.A.Vukcevic says:
September 2, 2011 at 12:23 am
There is the beef, hundreds of W/m2 of heat released, moving back and forth the polar jet-stream. Forget about the CO2, GCR. LOD and such like ‘parts/million’ real but insignificant entities.
Vuk, the question is, what external factors if any directly or indirectly affect the changes in those flows?
Tb see here
http://rivernet.ncsu.edu/courselocker/PaleoClimate/Marsh%20Svensmark%202000%20Cosmic%20Rays%20Clouds%20and%20Climate.pdf
fig.11 page 13/16
and table III on the next page:
Estimated Solar Max-Min 30-year trend Century trend
Relative Change (%) in: 1983–1987 1964–1995 1901–1995
Cosmic Ray (>12.91GeV) 3.5 3.5 11.2
Solar Source Magnetic Flux 41 131
Global Low Cloud Fraction (ISCCP) 6.1 3.5 8.6
Shaviv himself:
‘ The energies stopped by Earth’s magnetic field are typically up to 10 GeV, in equatorial regions. At polar regions, Earth’s field can stop only lower energies.’
Look Svensmark’s research and the people at CERN have put forth an idea, there is not enough evidence to say that it is the main, or even one of the main, regulating factors in the earths temperature. While it is an interesting discovery it may have less to do with the current earth climate as it may be for understanding future or previous climactic events. I do not know how much of the particle actually can reach the earths surface but from what I have seen bandied about it is not enough to matter.
Look if CO2 is ultimately causing catastrophic global warming I will one day be humbled and have to admit it but let us not fall into the same dogmatic response and grab hold of new news as though it is a way to fight the dogmatic response of AGW belief. We know and understand that CO2 hangs onto heat for longer than a world without it. How much of a temperature increase that will occur is really the only science that is being debated. No one disagrees that CO2 increases temperature, it is more a question of whether the feedback effect amplifies the CO2 to ever higher levels. I would also add that a warmer more Carbon rich planet may well be preferable to what we have now, but of course this a heresy.
Lief, thanks for taking the time to converse with people here and for answering questions with fact rather than hyperbole, which is unfortunately what my post is.
1 degree C increase with doubling of CO2.
Still the mantra. So please explain how, during the Ordovician period with CO2 atmospheric content of 8000ppmv, we had an ice age? And a severe and prolonged one at that.
tallbloke says:
September 2, 2011 at 12:45 am
Thanks for your response. Please can you point me to a link where I can see Svensmark or Shaviv saying that only high energy GCR’s are involved.
Refer to Ian above:
Ian H says:
September 1, 2011 at 10:52 pm
You should be able to use Google to good effect on this.
Vuk, thanks.
That data in Fig 11 and table III is:
” with a neutron counter at Huancayo (cut-off rigidity 12.91 GeV).”
Huancayo is latitude 12S, so only stronger more energetic GCR’s make it through to the near surface. Up inthe arctic region where the biggest climate changes have been happening, the energy required is much lower.
There is too much defence of entrenched positions in this discussion and too little room for wonderment.
It’s entirely reasonable to build apparatus to test an idea that seems plausible on paper. So let’s do full gamut of CLOUD experiments before doing too much prediction.
We know that clouds form and go away, but we are less successful in controlling them. This is because we lack knowledge of mechanisms. Let’s increase that knowledge with open minds.
As to wonderment, I come back to that 35 pptv of ammonia introduced into the chamber. As DocMartyn above speculates, at that concentration it is likely to be catalytic – but the wonderment is, who selected it as a possible catalyst? Who took the trouble to cleanse the chamber of higher ambient quantities of natural ammonia, and then introduced this trace of ammonia, and why? Are there prior publications, or did serendipity work? I guess that it is no accident that 35 is twice the molecular weight of ammonia, in round figures.
We’ve seem ammonia have a significant effect on cluster nucleation. I don’t know the nature of the next set of chemistries to be tested, but would be fascinated to be working wiith a team of people with such original thoughts. Maybe the next paper will report larger clusters. Maybe there will be an experiment that starts with clouds and helps understand their induced rate of growth/shrinkage.
Give it a chance, guys, it’s early days.
tallbloke says:
September 2, 2011 at 1:35 am
Huancayo is latitude 12S, so only stronger more energetic GCR’s make it through to the near surface. Up inthe arctic region where the biggest climate changes have been happening, the energy required is much lower.
But both Svensmark and Shaviv maintain that on;y the high energy one [greater that 10-15 Gev] penetrate deep enough to have effect. One cannot have it both ways.
tb
Yes, but here is the big BUT
the CR impact is strongest at the poles (due to shape of the magnetosphere) and if the CRs form clouds, that is the area to look at, but in the polar regions they have positive (warming) effect on the global temperatures:
– Albedo there is high (ice and snow) so effect is only on the open ocean surface (none in the Antarctica) which is significant only during 2-3 of the summer months.
– For the most of the year insolation is very low and in the winter nonexistent, the area is covered with even more ice and snow, so cloud albedo is irrelevant, but clouds act as a blanket, preventing heat escaping, so winter temperatures would be somewhat higher than in a case of the cloudless skies.
Hence: falling intensity of the Earth’s magnetic field, more CRs at the poles, more clouds, less cold winters, less ice formed in the winter, larger ice-free areas in the summers, and possibly higher global temperatures; exactly the current scenario, but opposite to what is suggested by Svensmark, Kirby and Shaviv.
Even so, the GCRs count is so low that any of the above hardly makes any difference.
Leif Svalgaard says:
September 2, 2011 at 12:44 am
tallbloke says:
September 2, 2011 at 12:02 am
A competent and impartial scientist carrying out his duty to give the public a balanced understanding (especially one who spends a lot of time on blogs) would highlight these facts rather than giving a one word negative answer to someone asking if the correlation of low cloud cover reduction and GCR incidence reduction had been established.
the question was if the correlation had not already been clearly established [implying that it had]. The simple answer is ‘No’. I backed that up with a reference.
Your simple answer is simply wrong. The study you cite did find the correlation, despite the choices of locations and methods, albeit not as strong a correlation as was observed by Svensmark.
No need to cite dubious claims either way. Your moral indignation is ill founded and unbecoming.
Just saying it as I see it Leif. Your reply was incorrect, and the selective quote from the paper compounded the inadequacy of your response. Your imputation of what the questioner was implying is an assumption.
Here’s a couple more quotes from the conclusions in that paper:
– Cloud droplet size has a rather large negative correlation
with GCR, in agreement with a possible GCR-CCNcloud
coupling. In one of the domains studied (off the
coast of SW Africa), that correlation was statistically
significant.
– The six Forbush decrease events with the largest amplitude
show on average slightly stronger indications of a
cosmic ray signal in the cloud parameters than the average
of the other cases, with 16 out of 24 explored correlations
having the expected sign, but only 4 of these
have correlations above 0.5 in absolute value. Due to
the limited number of cases studied, the significance of
this result is difficult to evaluate.
– One of the domains studied (mid-Atlantic) showed correlations
which for all four cloud parameters have signs
that are consistent with a cosmic ray induced CCN formation.
In this rather small domain cloud susceptibility
is large, implying a potentially large impact on cloud
albedo. A more detailed analysis of this domain revealed
high correlations between GCR and the properties
of high clouds in general and low clouds of intermediate
optical depth.
I stand by my assessment that your one word negative reply and your selective quote was highly misleading.
The full paper is available for free a couple of clicks further on from the abstract you linked to:
http://www.atmos-chem-phys.net/8/7373/2008/acp-8-7373-2008.pdf
People can decide for themselves whether your selected quote was representative of the rest of the study.
tallbloke says:
September 2, 2011 at 1:51 am
I stand by my assessment that your one word negative reply and your selective quote was highly misleading.
The authors’s own conclusion:
“In conclusion, no response to variations in cosmic rays associated with Forbush decrease events was found in marine low clouds in remote regions using MODIS data.”
Go tell them that their conclusion was highly misleading.