Nails in the coffin of GCR-Climate Connection?

Question

On possible drivers of Sun-induced climate changes
de Jager C, Usoskin I
J. Atm. Solar-Terr. Phys. 68: 2053-2060 2006
Abs: We tested the validity of two current hypotheses on the dependence of climate change on solar activity. ... Therefore, we can conclude that in so far as the Sun-climate connection is concerned tropospheric temperatures are more likely affected by variations in the UV radiation flux rather than by those in the CR flux.

Aerosol nucleation over oceans and the role of galactic cosmic rays
Kazil J, et al.
Atmos. Chem. Phys. 6: 4905-4924 2006
Abst: We investigate formation of sulfate aerosol in the marine troposphere from neutral and charged nucleation of H2SO4 and H2O. ... the variation of ionization by galactic cosmic rays over the decadal solar cycle does not entail a response in aerosol production and cloud cover via the second indirect aerosol effect that would explain observed variations in global cloud cover.

next!

TC: The point where you make a blanket statement denigrating all models is the point where you cease arguing rationally. This is a study published in ACP, not some no-name website. The authors know that someone will likely check up on their work, they're not going to fiddle the numbers to get a predetermined answer. They're going to put in the best physics and parameterizations.

As for your first comment, all GCR proponents have at this point are some correlations. How come you don't like the ones that don't come out in your favor?

Article discussing ACP:

http://www.nature.com/nature/peerreview/debate/nature04988.html

Often you hear skeptics hollering that "correlation does not imply a causal relationship" when presented with graphs showing the trends in global mean temperature and atmospheric CO2 concentration. However, in this case, the skeptics are quick to accept an observed correlation (which is thin at best, and works only for certain types of clouds at certain latitudes) as proof of a causal link. The two references above suggest that the causal link is less certain (and Usoskin has a few other papers out there showing correlations of CR flux with cloud cover).

I have no problem accepting that CRs and TSI have an effect on climate that might be observed in the absence of the large increase in radiative forcing due to anthropogenic greenhouse gases, but to claim solar/CR changes are largely responsible for the observed recent temperature increase, when there has been relatively little change in TSI or CR flux over the same period, seems a bit hopeful to me.

Larry:

We're limiting this to peer-reviewed studies from reputable journals, and also, in keeping with the skeptic's bias against inferring causation from correlation, a preference to mechanistic studies would be preferred.

Answer 1

Interesting. Here is an article summarizing the second paper which will be easier for the layperson to understand.

http://www.innovations-report.com/html/reports/earth_sciences/report-75458.html

Its conclusion:

"This finding indicates only a weak effect of galactic cosmic rays on clouds due to aerosol formation from ions, and hence on the Earth's climate. These results, however, do not preclude the possibility that other mechanisms connect solar variability and climate."

The full paper can be downloaded here:

http://www.atmos-chem-phys.net/6/4905/2006/acp-6-4905-2006.html

The first paper can be downloaded from here (paper #12):

http://cc.oulu.fi/~usoskin/personal/List.html

It concludes that changes in solar irradiance have more of an effect on climate than cosmic rays and their related cloud formation. Both papers are from 2006, but they certainly appear to refute Svensmark's cosmic ray theory.

Answer 2

The first paper is based on cross co relation of two different proxies, but TSI, Sunspot's and Solar Magnetic Field Strength while are modulated by the 11 and 22 year cycle are still decoupled.

The second paper, well, computer models are great aren't they? they can be made to simulate nails of many various shapes, sizes and materials.

EDIT:

The facts are there is a causal link between directly observed GCR data and low level cloud cover changes. While you may be able to dig up some research that highlights some theoretical issues with the understood mechanism via atmospheric chemistry, the phenomena has been demonstrated in the lab. Unless Svensmark has falsified his research.

EDIT :

Paul H

Take for instance the paper below, which indicates an anti correlation after 1993, but is this paper very objective? I do not believe so, because they assume that PMOD is the correct and only choice for TSI. PMOD makes everything real simple, TSI, the Solar Magnetic Field and Sunspots all have a direct linear and predictable relationship. But ACRIM would tell a different story if it were implemented in this study. While magnetic field strength and TSI rise and fall by the modulation of the 11 year cycle, to assume that TSI or magnetic field strength should always fall to the same level as the pervious cycle, is a bit naive.
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http://stephenschneider.stanford.edu/Publications/PDF_Papers/Kristjansson_etal_2002.pdf

I asked a question on this forum not to long ago, about the validity of PMOD, and as usuall I was bombarded with the predicable rhetoric about how neither would make a big difference.

EDIT:

There should not be any large trend in GCR data, just a simple acknowledgement that GCR data modulates cloud cover changes based on the 11 year cycle, is all that is needed to explain a much larger percentage of the warming observed over the last 30 years. Svensmarks theory only adds an amplification to TSI, it does not independantly explain global warming. The ACRIM composite shows an increase in TSI over the last thirty years. The paper does not show a decrease in GCR however; from 1985 - 1988 GCR rates are over 1700, however from 1994 - 1999 GCR rates are over 1700. Looking at peak amplitudes in a cyclical time series and estimating trends is a tricky business, and one should not draw conclusions without doing spectral analysis. If I showed GCR / cloud relationship from Svensmark's paper you probably would have labeled me a hopeless denier, and we would not be having this debate, that is the point for the paper, to lend some credability to the casual relationship of GCR/Cloud connection.

EDIT:

I don't really get it Paul, if you look at the plot and you do not see cloud cover changes that are proportional to the changes in GCR with the exception of the 98 El-Nino, I don't see that this discussion can go any further, because the correlation is pretty obvious to me.
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Paul:

Just look at the last link Larry provided, and you should be able to see the correlation assocated with GCR flux and cloud cover, I hope.
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Answer 3

Aside from these articles there are a few problems with any attempt to link GCR to recent climate (ie. the last 30 years):

* A rather fundamental flaw, to which I haven't even seen a mention of a refutation, is that there is simply no trend in cosmic rays that might support the hypothesis:

http://www.realclimate.org/images/TheChillingStars.jpg

http://ulysses.sr.unh.edu/NeutronMonitor/Misc/neutron2.html

I'm eager to see this point being addressed by proponents of this theory. Tomcat, perhaps you could do this?

* The much hyped link between cloud cover and GCR in Svensmark's earlier work as yet hasn't been reproduced by anyone, but not for lack of trying. Analysis of the global cloud cover trend using ISCCP cloud data shows no such trend. If other scientists were reproducing these observations I would have a lot more faith, but quite the opposite, the other studies simply refute such a trend or connection. Thus, rhetorically stating that such a connection between the two is alive and well is both perplexing and blind to the apparent truth.

* Despite the laboratory studies showing that GCRs can form charged particles which could form clouds there has still been no discussion (by Svensmark and co.) of how this might work in the real atmosphere i.e. where, as a far as our best info shows, sulfate aersols, and not charged particles from GCRs, dominate the process of aerosol formation and cloud seeding. TC, can you see my point? If you have high concentrations of sulfate aerosol in a particular location, the influence of charged particles is minimal because their concentration never exceeds about ~1x10^6 x particles cm-3. Sulfate aerosol is present in concentrations magnitudes many orders higher. Sulfate aersol has been proven to be highly effective at cloud seeding, yet you expect us to believe that something present in far smaller quantities with no quantified assessment of its potential to seed clouds is more important? It would be easier to understand if we were furnished by some quantified estimates, but that hasn't happened yet. Instead we get bombarded with bold claims about how great the GCR-climate link is. I'd much rather discuss the fundamentals of what's going on rather than leaping to conclusions (see the rhetorical press statements from Danish space agency).

EDIT:

TC, my question to you referred to whether or not you believe that GCRs have affected the climate during the last 30 years. This is the really important question, I think. GCRs may have affected the climate in the past, though the lack of any concrete mechanism and the difficulty in separating its effects from those of TSI will be difficult. Considering the possible impact of GCRs on the climate during th last 30 years has to start from a position where we examine the trend in GCRs and compare that to the trend in surface temperatures. As I pointed out, there is no compelling trend in GCRs during the last 30 years, so how can they have influenced the climate. A mechanism may exist, but how can climate change be attributed to GCRs given the lack of a trend. This is really the point that I would like to see addressed by anyone proposing that AGW is not AGW, but is instead GCR-GW.

TC, can you clarify, are you suggesting that your cited paper shows GCR data with a requisite downward trend to explain GW?

EDIT:

You say that there shouldn't be any trend in GCR? But then how can GCRs have affected the climate of the last 30 years if there isn't a trend? I only asking because this doesn't appear to make sense. I've read the paper you linked to, thanks for posting it. However, why are you holding this up in support of the GCR-cloud-climate link? Have you even read this this paper? I quote from the conclusions section where it relates to GCR cloud correlations:

"We have presented a re-evaluation of the hypothesis
of possible links between solar activity and low clouds. Due
to a falling correlation between IR-low cloud cover and
cosmic rays after 1993, we conclude that even though the
two series are rather well correlated, the statistical significance is low. For the more reliable daytime low cloud cover data, the correlations are significantly lower than for the IRdata. Furthermore, we find a negative correlation between
high pass filtered cloud cover data and cosmic rays. We
conclude that this new analysis significantly weakens the
evidence for the cosmic ray-cloud coupling suggested by
Svensmark [1998]."

Can I emphasise this:

"Furthermore, we find a negative correlation between
high pass filtered cloud cover data and cosmic rays. We
conclude that this new analysis significantly weakens the
evidence for the cosmic ray-cloud coupling suggested by
Svensmark [1998]."

Why does this study support Svensmark's calls for a correlation between GCR and clouds? If you read the rest of the paper it will explain more about this.

ACRIMS vs. PMOD, an aside, if you want to discuss this start a new thread, but this won't change what the underlying numbers show.

The paper does point out that a positive correlation exists between TSI and cloud cover and a mechanism for this is proposed, again, exactly the opposite of what Svensmark suggested.....

Without an obvious correlation between clouds and GCRs (according to your own link), without a fully identifed mechanism and in the absence of a trend in GCRs how can you say that GCRs have affected the climate in the last 30 years. If you answer these questions my opinion of this hypothesis will change.

Answer 4

Interesting papers aren't they? Yet people will argue you're wrong or arguing against their stand without even knowing what you are talking about.

I guess some just don't understand you are providing the reason the AGW cannot possibly be linked to solar / cosmic radiation or any effect of cosmic rays on cloud formation. I thought it was pretty clear.

Answer 5

Now look at real world evidence that supports the GCR cloud modulation theory instead of numbers plugged into a computer model.

http://wattsupwiththat.wordpress.com/2007/10/17/earths-albedo-tells-a-interesting-story/

http://www.canada.com/nationalpost/financialpost/comment/story.html?id=597d0677-2a05-47b4-b34f-b84068db11f4&p=4

The correlation is pretty outstanding.

http://www.spacecenter.dk/research/sun-climate/cosmoclimatology/a-brief-summary-on-cosmoclimatology

Answer 6

Not surprised. The whole idea seemed a bit "out there" to me ... but it's nice to see good confirmation. And it's also nice to see science working the way it should: creative people proposing creative hypotheses, and others working to confirm them, or not.

Answer 7

I'm sure that you fully understand these articles and can explain in layman's English why you think they refute global warming. If you can, e-Mail me at [e-mail] with your explanation.