More slurs from realclimate.org

12 Mar 2008

More slurs from realclimate.org

By shaviv 38 Comments

Blog topic:

cosmic rays, global warming, personal research, weather & climate

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 20^th 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.

A brief summary of the evidence for a cosmic ray climate link.

Svensmark (1998) finds that there is a clear correlation between cosmic rays and cloud cover. Since the time he first discovered it, the correlation continued as it should (Svensmark, 2007). Here is all the other evidence which demonstrates that the observed solar/cloud cover correlation is based upon a real physical link.

1) Empirical Solar / CRF / Cloud Cover correlation: In principle, correlations between CRF variations and climate does not necessarily prove causality. However, the correlations include telltale signatures of the CRF-climate link, thus pointing to a causal link. In particular, the cloud cover variations exhibit the same 22-year asymmetry that the CRF has, but no other solar activity proxy (Fichtner et al., 2006 and refs. therein). Second, the cloud cover variations have the same latitudinal dependence as the CRF variations (Usoskin et al. 2004). Third, daily variations in the CRF, and which are mostly independent of the large scale activity in the sun appear to correlated with cloud variations as well (Harrison and Stephenson, 2006).

2) CRF variations unrelated to solar activity: In addition to solar induced modulations, the CRF also has solar-independent sources of variability. In particular, Shaviv (2002, 2003a) has shown that long term CRF variations arising from passages through the galactic spiral arms correlate with the almost periodic appearance of ice-age epochs on Earth. On longer time scales, the star formation rate in the Milky Way appears to correlate with glacial activity on Earth (Shaviv, 2003a), while on shorter time scale, there is some correlation between Earth magnetic field variations (which too modulate the CRF) and climate variability (Christl et al. 2004).

3) Experimental Results: Different experimental results (Harrison and Aplin, 2001, Eichkorn et al., 2003, Svensmark et al. 2007) demonstrate that the increase of atmospheric charge increases the formation of small condensation nuclei, thus indicating that atmospheric charge can play an important role (and bottleneck) in the formation of new cloud condensation nuclei.

4) Additional Evidence: Two additional results reveal consistency with the link. Yu (2002), carried out a theoretical analysis and demonstrated that the largest effect is expected on the low altitude clouds (as is observed). Shaviv (2005) empirically derived Earth's climate sensitivity through comparison between the radiative forcing and the actual temperature variations. It was found that if the CRF/cloud cover forcing is included, the half dozen different time scales which otherwise give inconsistent climate sensitivities, suddenly all align with the same relatively low climate sensitivity, of 0.35±0.09°K/(W/m²).

A Summary of why the attacks on the CRF/climate link are toothless

1. The CRF / cloud cover link breaks down after 1994 (e.g., Farrar 2000). This supposed discrepancy arises because of a cross-satellite calibration problem in 1994. The problem is evident when considering for example the high altitude cloud data, which exhibits a jump larger than the variability before or after 1994. When the calibration problem is rectified, the significant CRF / cloud correlation continues unhindered (Marsh & Svensmark, 2003).

2. Large variations Earth’s magnetic field (for example, the Laschamp event and alike) should manifest themselves as climate variations. Their absence contradicts the CRF/cloud-cover link (e.g., Wagner et al. 2001). In principle, terrestrial magnetic field variations should indeed give rise to a temperature change, however, when the effect is quantified, the expected global temperature variations are found to be only of order 1°C (Shaviv 2005). This should be compared with the typically 5°C observed over the relevant time scales, of 10⁴-10⁵ yr. In other words, it is not trivial to find the CRF/climate signatures as is often presumed, but signatures do exist (e.g., Christl et al. 2004).

3. The Cloud cover data over the US (Udelhofen & Cess, 2001) or the cloud data following the Chernobyl accident (Sloan & Wolfendale 2007) does not exhibit variations expected from the CRF/cloud-cover link. These expectations rest on the assumption that the CRF climate link should operate relatively uniformly over the globe. However, the lower troposphere over land is filled with naturally occurring CCNs, such as dust particles. Thus, one would expect the link to operate primarily in the clean marine environments.

4. The secular solar activity is now decreasing, but the temperature is increasing. Hence, solar activity cannot be responsible for the recent temperature increase (Lockwood 2007). Indeed, the last solar cycle was weaker, and the associated CRF decrease was smaller. However, this argument assumes that there must be an instantaneous relation between solar activity and climate. In reality, the large heat capacity of the oceans acts as a “low pass filter” which releases previously absorbed heat. Moreover, heat absorbed over longer durations penetrates deeper into the oceans and thus requires longer durations to leave the system. This implies that some of the temperature increase is due to a previous “commitment”. In any case, some of the warming over the 20th century is certainly human. So having some human contribution does not invalidate a large solar forcing.

5. The work of Shaviv & Veizer (2003) was proven wrong. The work of Shaviv & Veizer attracted two published criticisms (Royer et al. 2004 and Rahmstorf et al. 2004). The first was a real scientific critic, where it was argued that the 18O/16O based temperature reconstructions (of Veizer et al. 2000) has an unaccounted systematic error, due to ocean pH, and hence the atmospheric pCO2 level. Shaviv (2005) considered this effect and showed that instead of an upper limit to the effect of CO2 doubling, of 1°C, Earth's sensitivity increases to 1-1.5°C, but the basic conclusion that CRF appears to be the dominant climate driver remains valid (as later independently confirmed by Wallman 2004). Rahmstorf et al. 2004 published a comment stating that almost all Veizer and I did was wrong. We showed in our response why every comment is irrelevant or invalid. In their response to the rebuttal, Rahmstorf et al. did not address any of our rebuttal comments (I presume because they could not). Instead, they used faulty statistics to demonstrate that our results are statistically insignificant. (Basically, they used Bartlett's formula for the effective number of degrees of freedom in a limit where the original derivation breaks down).

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 4^th 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 r_out ~ 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

Remarkably, the poor scientific basis of the attacks against the galactic cosmic ray hypothesis seems to be inversely related to the amount of media backing it is getting tenacity of the devout global warming protagonists At least 3 documentaries ('The Climate Conflict', the 'Global Warming Swindle', and now 'The Cloud Mystery') have been shown on television – all with a strong thrust of wanting to cast doubt on the human causes of global warming possibility that natural climate drivers may have been important to 20^th century temperature change.

References

- Christl M. et al., J. Atmos. Sol.-Terr. Phys., 66, 313, 2004
- Eichkorn, S., et al., Geophys. Res. Lett., 29, 44, 2003
- Farrar, P. D., Clim. Change, 47, 7, 2000
- Fichtner, H., K. Scherer, & B. Heber, Atmos. Chem. Phys. Discuss., 6, 10811, 2006
- Lockwood, M., & C. Fröhlich, Proc. R. Soc. A doi:10.1098/ rspa.2007.1880; 2007
- Harrison, R. G., and K. L. Aplin, Atmospheric condensation nuclei formation and high energy radiation, J. Atmos. Terr. Phys., 63, 1811–1819, 2001.
- Harrison, R. G. and Stepehnson, D. B., Proc. Roy. Soc. A., doi:10.1098/rspa.2005.1628, 2005
- Marsh, N., and H. Svensmark, J. Geophys. Res., 108, 4195, 2003
- Naoz, S. and N. J. Shaviv, New Astronomy 12, 410, 2007
- Rahmstorf, S. et al., Eos, Trans. AGU, 85(4), 38, 41, 2004. And the rebuttals
- Royer, D. L. et al., GSA Today, 14(3), 4, 2004. And the rebuttals
- Shaviv, N. J., New Astron., 8, 39–77, 2003a.
- Shaviv, N. J., J. Geophys. Res.-Space, 108 (A12), 1437, 2003b
- Shaviv, N. J., J. Geophys. Res., 110, A08105, 2005
- Shaviv, N. J., and J. Veizer, GSA Today, 13(7), 4, 2003
- Sloan, T., and A. W. Wolfendale, in Proceedings of the ICRC 2007 (also arXiv:0706.4294 [astro-ph])
- Udelhofen, P. M., and R. D. Cess, Geophys. Res. Lett., 28, 2617, 2001
- Usoskin, I. G., N. Marsh, G. A. Kovaltsov, K. Mursula and O. G. Gladysheva, Geophys. Res. Lett., 31, L16109, 2004
- Shaviv, N. J., and J. Veizer, GSA Today, 13(7), 4, 2003
- Svensmark, H., Phys. Rev. Lett, 81, 5027, 1998
- Svensmark, H., Astron. Geophys., 58, 1.19-1.24., 2007
- Veizer, J., Y. Godderis, and L. M. Francois, Nature, 408, 698, 2000
- Wagner et al., J. Geophys. Res., 106, 3381, 2001
- Wallman, K., Geochem. Geophys. Geosys, 5, Q06004, 2004
- Yu, F., J. Geophy. Res., 107(A7), 10.1029/2001JA000248, 2002.

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Comments (38)

aaron
At most the ocean temps were flat after 2003. There was a bunch a cooling after 2003, but it was decided there was an artifact that reduced the cooling. Not confirmed.

So temps were slightly cooling or flat. Definitely not warming.

aaron

Mar 18, 2008

Tom (not verified)
I agree that they are not warming anymore, but doomsayers would have everyone think otherwise. Many governments and institutes are exaggerating global warming to encourage people to cut down on waste and become more energy efficient, a form of white lie imo. The commercial sectors are feeding off this to create "buzz" products, like "green" this and "eco friendly" that. Studies also show that the Earth is long over due for an Ice age, which would also support the fact that oceans aren't warming anymore and makes humans less responsible for global warming (if at all responsible).

Oct 24, 2008

Sylvain (not verified)
Prof. Shaviv

Is it possible that there is or should be a link between between GCR and SST's.

What I mean is that more GCR should create more clouds which in turn should decrease SST's by having the oceans receive less direct sun light. And in turn less GCR's should reduce cloud cover and increase the direct sunlight on the oceans leading to increase SST's and global sea temperature.

Is there a way to verify a link between them. I believe that if this can be verified, it would means that oceans have more effect on the athmosphere than the atmosphere on the ocean.

Thanks

Mar 14, 2008

Mike Davis (not verified)
Please don't let the disbelievers get you down and keep up the good work. I believe in natural causes and the work you and others are doing is helping to explain that. There are a lot of natural interactions that explain past climate so I have a hard time believing that only one small item can explain current and possible future climate change. CO2 may have a small affect but I think you may be getting closer to some of the answers. Only time and further observations will answer the big question. Closed minds only distort the truth.

Mar 16, 2008

Alan McIntire (not verified)
I recall reading that earth's magnetic field has been weaking over the last several hundred years, and the magnetic poles may switch in the next few millennia. Would a changing magnetic field on earth have any effect on climate due to changes in cloud formation from cosmic rays? - A. McIntire

Mar 24, 2008

shaviv
Because the primary cosmic ray energy required to reach the troposphere is relatively high (typically greater than 10 to 20 GeV), and since the effect of Earth's magnetic field is simply a cutoff (between 0 to 13 GeV, depending on the magnetic latitude), the effect of the terrestrial field is very small. I estimated that entirely switching off the terrestrial field would correspond to a temperature decrease of about 1°C. So the slow decrease over the past several centuries is an order of magnitude smaller.

For more details, see the appendix of this paper.

Mar 24, 2008

Halliday
Shaviv:

I looked at the appendix of the paper you pointed to in the above post. From Figure 8 it appears the the relative change of cosmic ray induced ions I is more sensitive to the Earth's magnetic field (at least the overall magnetic dipole moment) than it is to the solar modulation parameter. Am I reading that right?

Also, I see that you went from a yield function of Y(E,h) to one of Y(E, theta) (theta being the latitude). Is this done in order to take into some account a different angle of incidence of the cosmic rays into the atmosphere? I thought they came at essentially all angles, so I wouldn't expect such a dependence.

By the way, I assume the C = 1.24×10^6cm^(−2)s^(−1)MeV^(−1) was intended to be the C_p in equation 26, above that. Also, is the 14.8 GV that multiplies the RHS of equation 27 supposed to be 14.8 GeV, or some other energy units? (14.8 GeV is somewhat larger than your 13 GeV stated in the above post. It gets closer to 50% of the 10-20 GeV energy band you state is important for low altitude cloud cover.)

What I'm trying to get a grip on is whether there is expected to be much of a latitude dependence in the low altitude cloud cover (LACC) effect. From the energy band and cutoff you gave in the post, I would expect there to be only minimal change (depending on the energy dependence of the yield and/or the cosmic ray flux), but the great magnetic dipole dependence causes me to wonder (of course I recognize that one is a more local effect while the other extends far out into Earth's surrounding space).

What brought this to the fore is the "Testing the proposed causal link between cosmic rays and cloud cover" paper by T Sloan and A W Wolfendale (of course I see from your references that you are already familiar with their similar earlier work). However, they have now added a temporal issue with so called ground level events (GLE) and Forbush decreases. With these temporal cases, especially since they are being determined via neutron and muon detectors (that only agree on one of three GLEs they looked at) I have to question wether such cosmic ray flux fluctuations are correlated across the entire energy regime, or not.

(Interestingly, the April 3rd, 2008, PhysicsWorld [IOP] post refers to Slaon and Wolfendale as two particle physicists. I would expect that particle physicist might know about how only higher energy cosmic rays would deposit their energy in the lower atmosphere, rather than making such a global claim about how cosmic rays should be modulated less at the geomagnetic equator simply based on the high flux of low energy cosmic rays and the cutoff energy from the geomagnetic field.)

Just wondering.

David

Apr 09, 2008

Puppy Potty (not verified)
To get rid of the effect in a local area by insulating the area against magnetic fields. I assume you mean eliminating the effect globally, though. Current theory states that the magnetic field is generated by the movement of magnetic iron and nickel at a different rate than surrounding layers. Thus, planets which have a solid core have no magnetism, because the entire solid planet rotates together. In order to get rid of the magnetic field, you would have to either cool the outer core to solidity, or somehow regulate it's rotation such that it was equivalent to the rest of the planet.

Apr 27, 2012

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