Is the causal link between cosmic rays and cloud cover really dead??
Just recently, Sloan and Wolfendale published a paper in Environmental Research Letters, called "Testing the proposed causal link between cosmic rays and cloud cover". In the Institute of Physics Press Release, it said, "New research has deal a blow to the skeptics who argue that climate change is all due to cosmic rays rather than man made greenhouse gases". Did it really?
First, we should note that so called "skeptics" like myself or my serious colleagues never claimed that cosmic rays explain all the climate change, it does however explain most of the solar-climate link and a large fraction (perhaps 2/3's of the temperature increase over the 20th century).
Now for the paper itself.
Sloan and Wolfendale raise three points in their analysis. Although I certainly respect the authors (Arnold Wolfendale is very well known for his contributions to the subjects of cosmic rays and high energy astrophysics, he was even the astronomer royal, and for good reasons), their present critique rests on several faulty assumptions. Here I explain why each of the three arguments raised cannot be used to discredit the cosmic-ray/climate link.
Lack of latitudinal dependence:
According to Sloan and Wolfendale, if clouds are affected by the cosmic ray flux, they should exhibit the same latitudinal dependence as the cosmic ray flux variations. That is to say, because different magnetic latitudes have notably different cosmic ray flux variations, the relative cloud cover variations should similarly have a large dependence on the magnetic latitude. Although at first is sounds logical, this critique misses an important issue, and that is that the CRF variations at the top of the atmosphere are much larger than those at lower altitudes since the latter depends on the variations of much higher energy cosmic rays, those needed to penetrate the atmosphere. Let us look in more detail.
Sloan and Wolfendale compare the latitudinal dependence of solar min to solar max neutron monitor variations to the latitudinal variations of the solar-min to solar-max Low altitude Cloud Cover (LCC) variations. This wrongfully assumes that the ionization rate governing the low atmosphere (and with it the clouds) varies the same way as the neutron monitors.
The neutron monitors have a very weak dependence on the amount of atmosphere above them. The reason is that once neutrons are formed from cosmic ray spallation at the top of the atmosphere, they easily continue to the ground because they are neutral. This implies that the neutron monitor count rate will indeed be nearly proportional to the cosmic ray flux reaching the top of the atmosphere, and the latitudinal dependence will heavily depend on the magnetic cut-off.
On the other hand, the flux of ionizing particles to the lower atmosphere critically depends on the amount of atmosphere above. In fact only primary cosmic ray particles above about 10 GeV can generate showers of which their secondary charged particles can give any atmospheric ionization at an altitude of a few kilometers. The bulk of the low atmosphere ionization is actually generated by primary cosmic rays with energies a few times higher. This implies that the latitudinal dependence of the low altitude ionization rate is very weakly dependent on the magnetic latitude. This is because the magnetic field has an effect only for cosmic ray particles of 0 to 15 GeV, which are anyway blocked by the atmosphere!
Thus, the data to compare with would not have been with neutron monitor data but with ionization chambers which exhibit a much smaller latitudinal dependence. Another option is to calculate the actual latitudinal dependence of the atmospheric ionization variations. This was done by Usoskin et al. (2004), who took the top-of-the-atmosphere variations in the CRF, and using a code to calculate the shower products, calculated the actual latitudinal ionization rate variations.
They found that the relative change in the LCC is the same as the relative change in the ion density (which itself is proportional to the square root of the ionization rate). Both vary by several percent from equator to pole over the solar cycle. This can be seen in fig. 2. In other words, the latitudinal dependence of the cloud cover variations is totally consistent with the CRF/cloud cover mechanism. For comparison, the solar cycle variation in the neutron monitor data is almost 20% at the poles, and 5% at the equator.
Fig 1: (from Sloan and Wolfendale). Top panel: Sloan and Wolfendale expect the solar-min to solar-max variations in the cloud cover to have the same latitudinal dependence (i.e., magnetic cut-off dependence) as that of the neutron monitor variations. This assumption ignores the fact that low atmosphere ionization is generated by CRF particles of relatively high energy, those needed to penetrate the atmosphere. As a consequence, the ionization variations are only of a few percent, and in fact consistent with the observed cloud cover variations (see fig. 2 below). Bottom panel: Sloan and Wolfendale find that the cloud cover variations lead the cosmic ray flux variations by about 3 months, which according to them, is inconsistent with the mechanism. As we show below, this lead is actually consistent given the climate response.
Fig 2: (From Usoskin et al. 2004). The observed latitudinal variation in the cloud cover as a function of the magnetic latitude (right) or as a function of the atmospheric ionization variations (left). The graphs clearly demonstrate that the cloud cover varies as expected from the ionization variations.
Cloud cover CRF lead:
The next criticism Sloan and Wolfendale raise is the fact that when the cloud cover is correlated with the cosmic ray flux over the 11-year solar cycle, it appears that the cloud cover leads the cosmic ray flux variations by about 3 months (see panel 2 of fig. 1 above). If cosmic ray flux affect the cloud cover, such a lead should not be observed.
This would have been the case if all the cloud cover variations arise only from cosmic ray flux variations. However, Sloan and Wolfendale did not consider that the clouds are part of the climate system. The cloud also react, for example, to the varying global temperature, either variations due to the solar cycle, which lag behind the radiative forcing, or altogether unrelated temperature variations.
We can estimate the phase mismatch between the cloud cover variations (arising from the 11-year solar cycle) and the cosmic ray flux. Towards this goal we need to estimate LCC changes arising from the temperature variations. This depends on the cloud feedback in the climate system. We can expect it to be between 1 to 2 (W/m2)/°C if we want the cloud feedback to give a climate sensitivity of 1 to 1.5°C per CO2 doubling, which is the sensitivity consistent with the cosmic ray cloud cover link (see http://www.sciencebits.com/OnClimateSensitivity).
We also know that the global temperature changes by about 0.1°C between solar maximum and solar minimum, with a delay of a 1/8 cycle. (e.g., Nir J. Shaviv, "On Climate Response to Changes in the Cosmic Ray Flux and Radiative Budget", JGR-Space, vol. 110, A08105, and references therein).
The two numbers imply that we should expect a cloud feedback radiative forcing of about [0.1°C] x [1 to 2 (W/m2)/°C] = 0.1 to 0.2 W/m2. Since ERBE shows that low altitude clouds are responsible for a net forcing of 17 W/m2 from their 30% area fraction coverage, if the cloud feedback is through low clouds, then we can expect an area fraction change of about (0.1-0.2) / 17 * 30% ~ 0.17 to 0.35%.
More quantitatively, we see that the LCC changes by about 1.5% over the solar cycle (presumably from the CRF variations). The total LCC will therefore precede the CRF by something like [(0.17-0.35%) / 1.5% / sqrt(2)] / (2π) of a cycle, i.e., about 1.8 to 3.5 months. This of course is consistent with the observations!
No apparent effect during Forbush decreases.
The last point raised by Sloan and Wolfendale is the fact that no effect is observed during Forbush decreases. These are several-day long events during which the CRF reaching Earth can decrease by as much as 10%-20%. Sloan and Wolfendale expect to see a decrease in the cloud cover during the events, but just like with the latitudinal effect, they expect to see an effect which is much larger than should actually be present.
Sloan and Wolfendale plot a graph for the cloud cover reduction vs. the cosmic ray reduction during Forbush events, based on the Oulu neutron monitor data. For the largest event, the Oulu neutron count rate decreased by about 15%. If the cloud reduction during the Forbush decreases should be similar to that over the solar cycle, a 7% reduction in the cloud cover is expected.
Fig 3: (From Sloan & Wolfendale) The reduction in the LCC during Forbush decreases. The straight line is the expectation according to Sloan and Wolfendale. The correct expectation should consider that the cloud data points are either weekly (D2) or monthly (D1) averages. Over these durations, the average CR reduction is smaller than the reduction over 1 day for example. For D2, the slope should be about 3 times smaller, and more than 10 times smaller for the D1 averages.
At face value this might seem like a real inconsistency, but at closer scrutiny it becomes clear where the discrepancy arises from. Fig. 3 plots the CRF reduction following the biggest Forbush event between 1982 and 2002, which took place in 1991. Indeed, one can see that the immediate reduction in the Oulu count is of order 15%, however, the data points for the cloud cover, plotted by Sloan and Wolfendale are either monthly average or weekly averages. Over the week following the 1991 even, the average CRF reduction in Oulu was actually roughly 5%, not 15%. This implies that the expected LCC anomaly is three times smaller, and therefore drowns under noise. The situation is much worse for the monthly data.
Fig: 4: The largest Forbush decrease between 1982 and 2002, from Kudela & Brenkus (2002). Over 1 day, the Oulu neutron monitor decrease is about 15%. However, if averaged over a week or a month, the average reduction is much smaller.
To see effects, one therefore needs to use daily averages of the cloud cover. This was done, for example, by Harrison and Stephenson (2006) who found that there is an apparent Forbush decrease in the cloud cover over Britain.
Fig 5: To see the effects of Forbush decreases, one has to look at daily data, and then, because of the noise, average many Forbush decreases. The graph depicted here demonstrates that during Forbush decreases, there is a statistically significant reduction in the odds for an overcast day. That is, less cosmic rays implies less clouds. The data is from Harrison and Stephenson (2006), for stations located in the UK.
Summary
Sloan and Wolfendale raised three critiques which supposedly discredit the CRF/climate link. A careful check, however, reveals that the arguments are inconsistent with the real expectations from the link. Two arguments are based on the expectation for effects which are much larger than should actually be present. In the third argument, they expect to see no phase lag, where one should actually be present. When carefully considering the link, Sloan and Wolfendale did not raise any argument which bares any implications to the validity or invalidity of the link.
One last point. Although many in the climate community try to do their best to disregard the evidence, there is a large solar-climate link, whether on the 11-year solar cycle (e.g., global temperature variations of 0.1°C), or on longer time scales. Currently, the cosmic-ray climate link is the only known mechanism which can explain the large size of the link, not to mention that independent CRF variations were shown to have climatic effects as well. As James Whitcomb Riley supposedly once said:
References:
- Harrison R.G. & D.B. Stephenson, Proc. Roy. Soc. A, doi:10.1098/rspa.2005.1628, 2006
- Kudela, K. & Brenkus, R., J. Atmos. Sol.-Terr. Phys. 66, 1121, 2004
- Shaviv, N.J., J. Geophys. Res. 110, A08105, 2005
- Sloan T. and A.W. Wolfendale, Environ. Res. Lett. 3 024001, 2008
- Usoskin, I.G., et al., Geophys. Res. Lett., 31, L16109, doi:10.1029/2004GL019507, 2004
Comments (31)
Dear Nir, thank you for this very clear and quantitative analysis in which the real points of those two scholars are meaningfully addressed. Unless there is a subtle error in the input numbers you use - such as the energy range of the ionizing cosmic rays, the duration of the Forbush events, the ratio of the direct cosmic and via-temperature cosmic influences on the cloud cover etc. - your answer seems to settle the questions. And I would even say that the paper by Sloan and Wolfendale was useful at least for me to understand some extra details of the relevant mechanisms (of course after reading your reply only).
Is there a way to write a comprehensive review that would address all these more detailed things in a coherent but concise way? I mean the expected dependence of the processes on the energies of rays, charges, latitude, timescales of lags, special events where the effect can be checked, and so on? Such a basic review could make various new criticisms redundant. Could it be written in a Svensmark-friendly way or are there some major points where two of you disagree? If you do and are trying to hide it, you are doing it very well because I haven't identified the points yet although I feel that they must exist. ;-)
Best wishes
Lubos
THE CENTRAL SUBJECT OF CLIMATOLOGY
In my opinion the researchers in climatology should put aside their work for a moment and focus their attention on the central and decisive subject of climatology. This is the extremely close correlation between the changes in the mean surface temperature and the small changes in the rotational velocity of the Earth in the past 150 years (see Fig. 2.2 of www.fao.org/DOCREP/005/Y2787E/y2787e03.htm), which has been ignored by the mainstream climatologists.
Since temperature cannot influence rotation to the observed degree and vice verca, a third agent must be driving the two. The solution is given in www.icecap.us/images/uploads/Lobert_on_CO2.pdf .
Dear Gerhard Lambert,
Thanks for interesting and different approach about climate change. I have observed that your contributions has been removed on various blogs however, that must be a challenge and I admire that you continue to promote your theory/postulate.
I have one question concerning one sentence in your first reference; "Therefore, the hypothesis that the climatic changes are a consequence of the LOD changes should be rejected (Lambeck 1980)."
Can you please briefly elaborate a bit what this 1980 Lambeck analysis says, as this sentence seems to directly contradict your basic message that LOD influence climate [and hence dT].
Nir
Correction: Dr Loebert didn't write that LOD influences climate. He wrote; "Since temperature cannot influence rotation to the observed degree and vice versa, a third agent must be driving the two." So there is no contradiction. Gerhard describes only correlation, causation is from the unknown third agent.
Nir, a good rebuttal - however the link to the "On Climate Sensitivity and why it is probably small" page has a stray close bracket on the end causing a 'page not found' error that needs fixing.
corrected.
Hi Nir,
Good point!
One more comment. S&W studied either global or longitudinally averaged data. On the other hand, the effect of CR on clouds is shown to exist not everywhere but only in regions with favorable conditions. This is mostly limited to a few climate-defining regions, e.g., North Atlantic/Europe, South Atlantic, Far East. See, e.g., Usoskin et al. (2004), Palle et al. (2004), Marsh & Svensmark (2003), Voiculescu et al. (2006).
The use of global indices, as done by S&W, is misleading and yield unstable results.
Ilya
Hi Ilya:
Wolfendale love to take data from all over the world and combine/analyze in his own way. It happens in the anisotropy of UHECR, GZK cutoffs, etc. After a few years, all his results were disapproved! Main reason is just that he is too smart to know everything! I am not surprised that he mis-interprete your paper and come out with something loud and naive! That's his royal style.
Dear Nir,
an excellent analysis of the paper by Sloan and Wolfendale. I encourage you to submit this as a formal comment on the paper to the Editor of Environmental Research Letters. Otherwise the paper will become the standard reference for people who want to dismiss the CR-Cloud link, even though, as you have shown, the logic of the paper does not stand up to a closer examination.
An excellent idea - we need rebuttals like this in the literature. Though no doubt the BBC and co will not be amending their stories...
I agree - you should try to get it published. However - one should not be surprised if that could be a difficult task.
The editor of Environmental Research Letters is one of the lead author of IPCC.. Daniel M Kammen :)
http://www1.ipcc.ch/ipccreports/sres/tectran/360.htm
Nir, I just happened upon an interesting post at Roger Pielke Sr.'s blog.
http://climatesci.org/2008/04/15/robust-relations-between-ccn-and-the-vertical-evolution-of-cloud-drop-size-distribution-in-deep-convective-clouds-by-freud-et-al-2008/
Increased aerosols from forest fires decrease percipitation.
If this effect also applies to cloud nucleation from CRF, it would mean that the atmospheric cooling during high CRF episodes would be dampened by decreased efficiency of the water cycle.
(my guess would be that more cloud nucleation particles means more and smaller droplets form, raising the threshold conditions for percipitation to occur.)
aaron
Dear Dr. Shaviv,
Excellent analysis, and I agree that you should submit it. You may have seen this already, but Sloan responded to your post on bigcitylib: http://bigcitylib.blogspot.com/2008/04/on-solar-links-sloan-responds-to-shaviv.html#links
-Robert S
Dear Shaviv,
I would like to correct the factual errors in your blog. 1.
Concerning cosmic rays. Muons, neutrons and the soft component of cosmic rays are all produced from the interactions of the primaries in the upper atmosphere. So the thickness of atmosphere above them is irrelevant. This is a factual error in your paper.
Our fit only requires that the ionization rate in the atmosphere is proportional to the neutron monitor rate. The factor kappa in equation 3 is the proportionality constant. We did a close examination of the long term muon data (such as exist) and the neutron data and this proportionality is compatible with the data. Hence what we have done is safe.
You are right. It would have been nice to have compared with ionization chamber data. Unfortunately, no such long term data exist either for shielded ion chambers (only sensitive to muons) or unshielded (sensitive to ionization from both muons and electrons). If such data had existed we would have used them.
The Ususkin et al computations of the solar modulation of the total ionization in cycle 22 are reasonably compatible with our neutron monitor curve.
2. Your fig 2 from the other Usoskin et al paper is for a highly selected data sample with a large correlation coefficient - not the global average with which we compare. Hence your fig 2 has little to do with our analysis using global averages. We stuck to global averages because in the original Marsh and Svensmark work they computed from the globally averaged dip in cycle 22 that the radiative forcing was 1.4 W m^-2 if all the dip was caused by CR. We set out either to confirm whether the dip was due to CR or not and if not to set a limit on the fraction of it which could come from this source. As we could find no corroborative evidence that it was due to ionization we set a limit. Our limit says that the radiative forcing cannot be more than 23% of 1.4 W m^-2.
3. Forbush decreases - the changes in the CR rate were averaged over the same time intervals as the changes in the LCC - so we have done this correctly and not incorrectly as you imply. The Forbush decreases usually take place over times between days to a month.
Regards,
Terry Sloan.
Dear Mr Sloan,
thanks for engaging in the debate.
You say "Muons, neutrons and the soft component of cosmic rays are all produced from the interactions of the primaries in the upper atmosphere. So the thickness of atmosphere above them is irrelevant."
I don't quite follow your logic here. If the atmosphere do indeed stop many particles from reaching the height were GCR byproducts are supposed to ionize particles, then the thickness of the atmosphere is obviously important?
You continue "Our fit only requires that the ionization rate in the atmosphere is proportional to the neutron monitor rate. The factor kappa in equation 3 is the proportionality constant. We did a close examination of the long term muon data (such as exist) and the neutron data and this proportionality is compatible with the data. Hence what we have done is safe."
Disproving somethings statistically requires quite a lot of your data. Disproving something based on an assumption that is itself questionable would yield very wide uncertainty bounds. I wonder what you got when validating your model? And "safe" is not a term to be used when applying statistical tools....
As to your assertion that "New research has dealt a blow to the skeptics who argue that climate change is all due to cosmic rays rather than man made greenhouse gases." I think that climate science has already suffered enough of hyperbolic press releases. Admittedly Svensmarks press releases are just as bad as yours, but please restrain yourselves. You have not disproven the GCR-cloud link even if your paper would stand up complettely to scrutiny.
It turns out that Sloan and Wolfendale have mostly used monthly averaged data for their assessment. Forbush events are counted in days and any averaging over a full month will obviously obscure the signal.
In respect of what Terry Sloan has said regarding the expectation of the effect of Forbush decreases. The CORSIKA calculations that Svensmark produced 2 years ago in 2006 indicate that these solar shock waves generally have much less impact on the key muon-making particles (which are the ones that are predicted to make the lower atmosphere and trigger an increase in cloud condensation nuclei. As such any statistical correlation regarding forbush decreases and cloud cover do not have much weight as a contradiction to Svensmark's theory.
My apologies if you are already familiar with these references:
Cloudiness decreases associated with Forbush-decreases of galactic cosmic rays
M. I. Pudovkin and S. V. Veretenenko
Journal of Atmospheric and Terrestrial Physics
Volume 57, Issue 11, September 1995, Pages 1349-1355
Meteorological characteristic changes in the high-latitudinal atmosphere associated with Forbush decreases of the galactic cosmic rays
M. I. Pudovkin*, S. V. Veretenenko*, R. Pellinen** and E. Kyrö
Advances in Space Research
Volume 20, Issue 6, 1997, Pages 1169-1172
Quote "The CORSIKA calculations that Svensmark produced 2 years ago in 2006 indicate that these solar shock waves generally have much less impact on the key muon-making particles (which are the ones that are predicted to make the lower atmosphere and trigger an increase in cloud condensation nuclei."
This is what I thought too... but now I'm slightly muddled... These CORSIKA calculations referenced in his paper published in A&G (2007) explain that he believes that ionization of the air < 2km altitude is mainly due to high-energy primary cosmic rays, and that the most important particle they create for cloud formation is the muon.
The problem is that Sloan is now quoting Usoskin et al. (2006) CORSIKA results, which he says show that muons are not the biggest producer of ionization at < 2 km. He says that Usoskin shows that "At low cloud forming altitude of 1-3 km there is a finite secondary muon component of the ionization (roughly 30% of the total) with the other 70% coming from secondary hadrons and electrons. There is a small solar modulation of the muons with a larger modulation of the hadrons and electrons."
Usoskin appears to be in conflict with Svensmark & Svensmark (2007), unfortunately S&S (2007) referenced in A&G (2007) does not appear to have been published anywhere... so it can't be checked...
If Sloan is right - that the majority of Ionisation at the low cloud forming altitude is from softer primaries - then he says that Solar modulation of LCC should show a greater effect than they were able to find?
For the record I like Svensmark's theory, and the strong negative correlation of historical Temperature vs Radiocarbon/Radionuclide deposits say's to me that he's on the right path, I just wonder whether his 'Muon'/LCC theory is quite as strong as he initially believed...?
Can anybody explain this...
None sense, all of what you guys analyze is noise and nonsense predictions. The causality of climate change is simply unknown. All of the variables that you plug in your equations are arbitrary. Human responsibility vs. cosmic rays vs. other factors, all of this remains speculation. Why don't you do REAL science and comment on REAL conclusions instead of fighting on suppositions. All I can say is that climate science is the silliest of science and that IPCC (with its unique definition of PROBABILITY) has much to do with this impression. Perhaps, the PUBLIC believes in you, in the purpose of your science aimed at convincing rather than demonstrating, but I object strongly. We need to be told the latest facts, not of the latest “grantable” equations...
Hi!
Nice website!... Anyhow:
NASA posted this article http://www.jpl.nasa.gov/news/news.cfm?release=2008-094 on 3d of June. It says that the milky way have 2 spiral arms and not 4.
Does this have anythinf to do with a "classification" issue, or will this have an impact on your theory?
Keep up the good work!
Do you think the resent boming of the satilite could have something to do with that storm that went across the USA right arter they blew it up? The reports were it had no advers affect on the earth. However they stated there being a toxic cloud the size of a football field. Hmmm no effect I hardly think so. Oh and sorry if this was the wrong place to post this comment. I am new and just learning my way around.http:helpinginchrist.com
Hi folks,
I'm a climate skeptic, but have been doing some reading and was interested to know if Mr Shaviv could respond to the following issues which have come up:
Thanks in advance.
Antony
http://environment.newscientist.com/channel/earth/climate-change/dn11651
* But cloud physicists say it has yet to be shown that such clumping occurs. And even if it does, it seems far-fetched to expect any great effect on the amount of clouds in the atmosphere. Most of the atmosphere, even relatively clean marine air, has plenty of cloud condensation nuclei already.
* But after 1995, the beguiling fit of Svensmark's graph depends on a "correction" of satellite data, and the satellite scientists say this is not justified.
[ There appears to be descrepancies in the data anyway according to one writer ]
* In fact, clouds are one of the greatest uncertainties in climate science. It is not even clear whether the satellite measurements of changes in cloudiness are correct or how these changes have affected temperature, let alone what will happen in the future. Clouds might mitigate global warming or amplify it
* Direct measurements of cosmic ray intensity going back as far as 50 years show no downward trend coinciding with the recent warming.
[ Are these talking about Muons or normal rays?]
* Experiments now underway at the European Laboratory for Particle Physics (CERN) should settle the issue of whether cosmic rays can trigger the formation of cloud condensation nuclei, though this will not reveal whether it matters in the real world.
http://www.realclimate.org/index.php/archives/2006/10/taking-cosmic-rays-for-a-spin/
1) Particles are too small to be form clouds
2) Many CCN's over the ocean already - need separate proof
3) No link between CCN & cloud cover (actually changing)
4) Cloud link with radiative forcing - there doesn't appear to be a link
5) No decreasing trend in Cosmic rays
New paper here. Appears to do a similar analysis to S&W. Have you seen it, and if so do you have a response?
Dear Nir Shaviv,
is there anything you can share with us on your new article (on calorimetric studies of oceans vs TSI)? Or do I need to spend some of my medioker pay to AUG? ;-)
Certainly it's not.
Nir, have you looked at water vapor in the atmosphere and cosmic rays and solar activity?
Cosmic rays have the biggest affect over water, and humidity/water vapor content is primarily driven by light incident on bodies of water.
Also, I read from a paper someone, somewhere linked that there is a correlation with volcanoes and solar activity.
aaron
I have recently had the paper below published and one of the propositions is that the drifting magnetic poles cause the GCRs to move to different climate sensitive areas thus affecting temperature. I would appreciate any inputs.
Thanks
Adrian
Climate Change and the Earth's Magnetic Poles, A Possible Connection
Author: Kerton, Adrian K.
Source: Energy & Environment, Volume 20, Numbers 1-2, January 2009 , pp. 75-83(9)
Publisher: Multi-Science Publishing Co Ltd
Abstract:
Many natural mechanisms have been proposed for climate change during the past millennia, however, none of these appears to have accounted for the change in global temperature seen over the second half of the last century. As such the rise in temperature has been attributed to man made mechanisms. Analysis of the movement of the Earth's magnetic poles over the last 105 years demonstrates strong correlations between the position of the north magnetic, and geomagnetic poles, and both northern hemisphere and global temperatures. Although these correlations are surprising, a statistical analysis shows there is a less than one percent chance they are random, but it is not clear how movements of the poles affect climate. Links between changes in the Earth's magnetic field and climate change, have been proposed previously although the exact mechanism is disputed. These include: The Earth's magnetic field affects the energy transfer rates from the solar wind to the Earth's atmosphere which in turn affects the North Atlantic Oscillation. Movement of the poles changes the geographic distribution of galactic and solar cosmic rays, moving them to particularly climate sensitive areas. Changes in distribution of ultraviolet rays resulting from the movement of the magnetic field, may result in increases in the death rates of carbon sinking oceanic plant life such as phytoplankton.
Keywords: MAGNETIC POLES; DRIFT; CLIMATE; COSMIC RAYS
Document Type: Research article
DOI: 10.1260/095830509787689286
I am interested in your opinion about possible influence on the climat by the fact that our magnetic field is constantly fluctuating (and thus also the Allen Belts) and even changing its polarity from time to time. I heard that last change took place some 780 000 years ago, that the polarity may change even few times during one milion years and that it is possible that we are now just about the next change of planet polarity.
At this moment we know about South Atlantic anomaly and it was also measured that during the last 300 years the average magnitude of our magnetic field deacresed about 10%.
Hello :-)
I study geography at the Tel Aviv University (if you kick out all the ultra-lefts that don't come to study but to turn people from students to political fanatics, it will be a really nice place) and support your views. At our climate lesson our lector criticised you alot! I asked her what can she say about the cosmic rays... and she said: "We havent studied that subject", and I'm like, to myself... dude! Then how can they criticise you if they don't even know what you are talking about? I mean, she just said that what you say is wrong, without even knowing your arguments. It's probably boring for you to have such easy-to-beat opponents at the academic discussions. Anyway, love your blog so thank you! Keep on the good work. People like you bring alot of pride to Israel!
Hello! I've recently become acquainted with Svensmark's and your hypothesis -- does it have a name? -- via the Danish video documentary "The Cloud Mystery." In fact I just linked to that video in a diavlog between John Horgan & George Johnson over at Bloggingheads.tv I hope I haven't represented the gist of it.
In the interests of full disclosure, I am just a feeble old man with fond memories of science from my college days. By now I can only judge the quality of an argument on the basis of style: by its tone, logic, demeanor, clarity of prose, etc. In other words, if it walks like physics and talks like physics then maybe it really is physics! By that criterion I expect to see your ideas discussed, tested, and refined by the world's leading physicists in the years ahead.
Best of luck,
Luke Lea
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