UPDATE: Lead author Ben Laken responds in comments below.
I’ve reported several times at WUWT on the galactic cosmic ray theory proposed by Henrik Svensmark which suggests that changes in the sun’s magnetic field modulate the density of Galactic Cosmic Rays (GCRs) which in turn seed cloud formation on Earth, which changes the albedo/reflectivity to affect Earth’s energy balance and hence global climate.
A new paper published today in Atmospheric Chemistry and Physics suggests that the relationship has been established.
Figure 1 below shows a correlation, read it with the top and bottom graph combined vertically.
As the authors write in the abstract:
These results provide perhaps the most compelling evidence presented thus far of a GCR-climate relationship.
Dr. Roy Spencer has mentioned that it doesn’t take much in the way of cloud cover changes to add up to the “global warming signal” that has been observed. He writes in The Great Global Warming Blunder:
The most obvious way for warming to be caused naturally is for small, natural fluctuations in the circulation patterns of the atmosphere and ocean to result in a 1% or 2% decrease in global cloud cover. Clouds are the Earth’s sunshade, and if cloud cover changes for any reason, you have global warming — or global cooling.
Well, it seems that Laken, Kniveton, and Frogley have found just such a small effect. Here’s the abstract and select passages from the paper, along with a link to the full paper:
Atmos. Chem. Phys., 10, 10941-10948, 2010
doi:10.5194/acp-10-10941-2010
Cosmic rays linked to rapid mid-latitude cloud changes
B. A. Laken , D. R. Kniveton, and M. R. Frogley
Abstract. The effect of the Galactic Cosmic Ray (GCR) flux on Earth’s climate is highly uncertain. Using a novel sampling approach based around observing periods of significant cloud changes, a statistically robust relationship is identified between short-term GCR flux changes and the most rapid mid-latitude (60°–30° N/S) cloud decreases operating over daily timescales; this signal is verified in surface level air temperature (SLAT) reanalysis data. A General Circulation Model (GCM) experiment is used to test the causal relationship of the observed cloud changes to the detected SLAT anomalies. Results indicate that the anomalous cloud changes were responsible for producing the observed SLAT changes, implying that if there is a causal relationship between significant decreases in the rate of GCR flux (~0.79 GU, where GU denotes a change of 1% of the 11-year solar cycle amplitude in four days) and decreases in cloud cover (~1.9 CU, where CU denotes a change of 1% cloud cover in four days), an increase in SLAT (~0.05 KU, where KU denotes a temperature change of 1 K in four days) can be expected. The influence of GCRs is clearly distinguishable from changes in solar irradiance and the interplanetary magnetic field. However, the results of the GCM experiment are found to be somewhat limited by the ability of the model to successfully reproduce observed cloud cover. These results provide perhaps the most compelling evidence presented thus far of a GCR-climate relationship. From this analysis we conclude that a GCR-climate relationship is governed by both short-term GCR changes and internal atmospheric precursor conditions.
I found this portion interesting related to the figure above:
The composite sample shows a positive correlation between statistically significant cloud changes and variations in the short-term GCR flux (Fig. 1): increases in the GCR flux
occur around day −5 of the composite, and correspond to significant localised mid-latitude increases in cloud change. After this time, the GCR flux undergoes a statistically significant decrease (1.2 GU) centred on the key date of the composite; these changes correspond to widespread statistically significant decreases in cloud change (3.5 CU, 1.9 CU globallyaveraged) over mid-latitude regions.
and this…
The strong and statistically robust connection identified here between the most rapid cloud decreases over mid-latitude regions and short-term changes in the GCR flux is clearly distinguishable from the effects of solar irradiance and IMF variations. The observed anomalous changes show a strong latitudinal symmetry around the equator; alone, this pattern
gives a good indication of an external forcing agent, as
there is no known mode of internal climate variability at the
timescale of analysis, which could account for this distinctive
response. It is also important to note that these anomalous
changes are detected over regions where the quality of
satellite-based cloud retrievals is relatively robust; results of
past studies concerned with high-latitude anomalous cloud
changes have been subject to scrutiny due to a low confidence
in polar cloud retrievals (Laken and Kniveton, 2010;
Todd and Kniveton, 2001) but the same limitations do not
apply here.
Although mid-latitude cloud detections are more robust
than those over high latitudes, Sun and Bradley (2002) identified
a distinctive pattern of high significance between GCRs
and the ISCCP dataset over the Atlantic Ocean that corresponded
to the METEOSAT footprint. This bias does not
appear to influence the results presented in this work: Fig. 6 shows the rates of anomalous IR-detected cloud change occurring over Atlantic, Pacific and land regions of the midlatitudes during the composite period, and a comparable pattern of cloud change is observed over all regions, indicating no significant bias is present.
Conclusions
This work has demonstrated the presence of a small but statistically significant influence of GCRs on Earth’s atmosphere over mid-latitude regions. This effect is present in
both ISCCP satellite data and NCEP/NCAR reanalysis data for at least the last 20 years suggesting that small fluctuations in solar activity may be linked to changes in the Earth’s atmosphere via a relationship between the GCR flux and cloud cover; such a connection may amplify small changes in solar activity. In addition, a GCR – cloud relationship may also act in conjunction with other likely solar – terrestrial relationships concerning variations in solar UV (Haigh, 1996) and total solar irradiance (Meehl et al., 2009). The climatic forcings resulting from such solar – terrestrial links may have had a significant impact on climate prior to the onset of anthropogenic warming, accounting for the presence of solar cycle relationships detectable in palaeoclimatic records (e.g.,Bond et al., 2001; Neff et al., 2001; Mauas et al., 2008).
Further detailed investigation is required to better understand GCR – atmosphere relationships. Specifically, the use of both ground-based and satellite-based cloud/atmospheric monitoring over high-resolution timescales for extended periods of time is required. In addition, information regarding potentially important microphysical properties such as aerosols, cloud droplet size, and atmospheric electricity must also be considered. Through such monitoring efforts, in addition to both computational modelling (such as that of Zhou and Tinsley, 2010) and experimental efforts (such as that of Duplissy et al., 2010) we may hope to better understand the effects described here.
It seems they have found the signal. This is a compelling finding because it now opens a pathway and roadmap on where and how to look. Expect more to come.
The full paper is here: Final Revised Paper (PDF, 2.2 MB)
h/t to The Hockey Schtick
Enneagram says:
November 25, 2010 at 9:23 am
electricity is better, and to make magnetism too
You have that backwards. In Nature [except very rare places, like our non-conducting air] it takes magnetism to make electricity.
It’s good that others are finding the same thing Svensmark had painstakingly taken years to find. Others are catching up to where he is.
eadler says:
November 25, 2010 at 8:43 am
There is no overall increasing trend in Cosmic Rays to match the trend of increasing temperatures.
http://www.realclimate.org/images/TheChillingStars.jpg
Probably the blue line on the graph is due to the UHI effect.
This report demonstrates Association NOT Causative connection.
Solar particle emission flux, the suns general magnetic field and cosmic rays reversed all move together – they are proxies for each other; so don’t confuse association and causation. Straightforward examination of EVIDENCE shows the CR agency theory to link solar activity (11yr) to earth’s weather does not work (or it might have up to 0.3% effect) . The link is directly solar particles which are magnetically linked (22yr cycle) please see “World cooling has…. and comments therein – http://climaterealists.com/index.php?id=3307&linkbox=true&position=4
Thanks Piers Corbyn WeatherAction
Roy W. Spencer says:
November 25, 2010 at 9:11 am
…waiting to see if Hansen will claim that it’s actually the cloud changes causing the changes in cosmic ray activity
Funny. 🙂
Richard S Courtney says:
November 25, 2010 at 8:03 am
“SWAG…..
“Firstly, your finding and the finding by Lakis et al. each needs to be confirmed.”
I listed the logical progression from that point to my final one.
Speculating on what a research study could lead to is good because it gives reason and incentive to conduct the research. But, very importantly, one needs to first determine
(a) whether the effect(s) to be studied is (are) known to exist with significant certainty
and
(b) if the magnitudes of the effect(s) is (are) significant or trivial.
Concentrating on what the research may provide can induce a false confidence in the importance of the effect…..
_________________________________________________________
Richard,
I certainly agree this information needs to be verified, validated and repeated. That is why I called it a Silly Wild A… Guess. I doubt very much we will have a really good idea of all the factors effecting climate, much less how they interact in my lifetime so it is fun to speculate a bit and hope we see some of our speculations proved true or false.
Ben Laken commented, “From the research I got the impression that any Cosmic ray – cloud link is strongly dependent on not only variations in Cosmic rays themselves, but also on the state of the atmosphere. I.e. if cosmic rays are enhancing microphysical processes connected to clouds, then it is very likely be governed by the cloud conditions.”
Not inconsistent with what Karin Labitzke has been saying:
http://strat-www.met.fu-berlin.de/labitzke/
Since ClimateGate there seems to be a growing consensus that the Science is un-settled (as exhibited by this post) !
vukcevic & ninderthana,
Interesting exchange. A few years ago when I studied relationships between geomagnetic aa index and a variety of terrestrial indices, I found nonrandom seasonal variations (weak or no winter correlations; moderately strong summer correlations). I am left not with conclusions, but questions…
vukcevic, could the coupling sign-switches you note be related to spatial pressure & circulation patterns? (e.g. eddies on opposite sides of a jet…)
What timetochooseagain said.
vukcevic November 25, 2010 at 1:04 am says:
There is a strong correlation between the Arctic temperature and the Earth magnetic field. However the correlation is negative, weaker field higher temperature. If the Svensmark’s effect is at work it is in reverse; …
This reverse correlation actually might make sense, recognizing that clouds also can trap heat underneath them. As the main cause of melting is from warm air and water from lower latitudes, more cloud cover would decrease the rate of heat loss to space, facilitating melting.
Ben Laken, “If we discarded any dataset with issues there would be nothing left to use! As scientist, we can only work with best guess and attempt to minimise uncertainty.”
If this is really true, then a “statistical robust relationship” between the model and NCEP reanalysis data only means significance with respect to the mean of an estimated trend.
That in turn means the uncertainty of the relationship must be convolved with the uncertainty in the trend to get the true total uncertainty in the result.
How certain does the relationship look when one does that?
Looking at Figure 4 of the paper, I note that the 95% confidence interval bands vary with the value of the data, becoming zero when the data pass through zero. This shows that the 95% confidence interval was calculated as a percent relative to some reference, which was then scaled by the relative magnitude of each data point.
True statistical confidence intervals of empirical data are not scaled by the magnitude of the measurement, but are an interval of resolution determined by the instrument and the noise in the measurement including systematic error.
One can also note that GCMs have never demonstrated predictive capacity, so it’s hard to see how correspondence with a GCM output implies physical causality.
Paul Vaughan says:
November 25, 2010 at 10:23 am
…………
Paul, thanks for the links.
Re: sign-switches you note be related to spatial pressure & circulation patterns? (e.g. eddies on opposite sides of a jet…)
Would not be able to comment with any degree of confidence on that particular aspect.
The abstract contains one important mis-statement:
Not by a country mile. The GCR-climate relationship has already been firmly established by the many statistical studies that find a .5 to .8 degree of correlation between solar-magnetic activity and global temperature change over thousands and millions of years. The only thing lacking has been clear evidence of the mechanism involved (although some of Svensmark’s previous evidence was pretty clear). THIS is what the current study provides: perhaps the most compelling evidence presented thus far that it is Svensmark’s hypothesized GCR-cloud mechanism that explains the already well established GCR-climate relationship.
Quotes from two of the many studies that have already firmly established that relationship:
In other words, GCR (and the solar activity that modulates it) “explains” in the statistical sense, 50-80% of past temperature change, making it THE dominant climate driver.
Such a high degree of correlation over such long periods of time can only be causal, and since it is certainly not global temperature that is causing solar activity, we know that it is solar activity that is driving global temperature. Thus the GCR-climate relationship has already been well established.
Jim D says:
November 25, 2010 at 8:55 am
“when we look at the 11-year cycle, at a stretch we only see 0.2 C oscillations in global temperature. So, I suspect that while these short-term fluctuations are interesting, they are not saying anything about climate even at the decadal scale”.
I’m no scientist, so my view may be wrong, but I think that thermal delay is the answer. How do temperature change in a kitchen owen it’s switched on and off, e g when the thermostat switches it on and off?
The 0.2 C variation in a sunspot cycle is a great signal, too large to explain by variation in solar irradiance. GCR-low level cloud cover co-variation is shown by e g Palle et al, in the Earthshine Project.
If this mechanism affects low level cloud cover over decades it should also, I think, have an effect over decades.
The GCR change I think is larger than 1-2 percent. Solar irradiance variation I think is about 0.1 percent, and GCR seems to change more like …10-15 percent?
http://wattsupwiththat.files.wordpress.com/2009/01/oulu-neutron-graph-123108.png?w=520&h=323
vukcevic, the sign of temperature-precipitation relations flips near the freezing point of water. Could it be that during a warm period, when heavy rains melt sea ice, the sign of the correlation discussed by you & ninderthana reverses? I base this question in part on many years spent working & travelling on frozen rivers and snowy mountain slopes. When the warm rains come, the change is discrete, not continous. Once the ice is gone, the clouds reflect more than the surface… (Note for those trying to follow my earlier comments: I work with absolutes, not anomalies.)
Using Harrison Ford’s voice:
“Robust… why did it have to be the word ROBUST?!?”
If this gets out they will lose their funding and any posts at real research units like UEA.
Keep it up. James
My first language is not English , but I am still able to notice that several people, whose first language it seems to be, are mixing up the meanings of “effect” and “affect” both in nominal and verbal positions. See Gail Combs, timetochooseagain, and SWAG, in their comments.
Paul Vaughan says:
November 25, 2010 at 10:53 am
………………
It certainly makes lot of sense, the Arctic winters are strait forward: ice or snow, high albedo, but not much insulation, so the extent of the cloud blanket ‘must’ be the main factor.
The summer months are far more complicated:
– vegetation/soil
– water (ice free surface)
– ice surface
3 different variables to be considered, with the relative ratios continuously changing, certainly complicates the issue, but albedo is possibly more relevant.
So you are correct, certain conditions could make whole system flip from negative to positive correlation.
Not that I would like to draw direct comparison (but I can think of a good reason) while similar flip in correlation happens here, where correlation is not necessarily causation.
http://www.vukcevic.talktalk.net/LL.htm
But in the Arctic case the flip may happen, even if there is a causation, which would makes Dr. Svalgaard’s statement :
Now, Vuk says that the correlation is negative except at times when it is positive. In my book that means ‘no correlation’.
very questionable !
Interesting note:
-Earth’s magnetic field is fading. Today it is about 10 percent weaker than it was when German mathematician Carl Friedrich Gauss started keeping tabs on it in 1845, scientists say:
http://news.nationalgeographic.com/news/2004/09/0909_040909_earthmagfield.html
This looks like a clue (or clew) to what is happening in the atmosphere, but doesn’t put the cuffs (or darbies) on the perpetrator (or villain.) More research is definitely warranted in this particular area, and there are other significant, solar-cycle-related variables of this magnitude or greater that should be looked at, in my opinion. We still don’t know everything about climate. The more complicated the model, the greater the likelihood that it’s wrong.
Congratulations to Drs. Laken, Kniveton, and Frogley.
Ben – I should have appended a smiley face behind my comment for you took my comment verbatim. It was just a jab at the colsed minds.
Enjoyed reading of your work. See if you can also find the tie through some real observations and data for I feel you will find some there. Look at cloud formation variances over the inner-continental land masses away from large bodies of water as the oceans. That seems where GCM/cloud signiture should maximize, and as you seemed to show, in the temperate bands.
Oh, it’s Wayne, not Wane.
How about “closed”, not “colsed”. Seems the last moment changes always get you.
Gamma rays are emitted by some rocks. These can travel 10s to thousands of meters through air. I assume that gamma radiation over the ocean should be a good bit less. Does this influence the relative occurrence of clouds over land vs. ocean?