Note: This is my analysis of a new paper by Joe D’Aleo, I’ve tried to simplify and explain certain terms where possible so that it can reach the broadest audience of readers. You can read the entire paper here.
Joe D’Aleo, an AMS Certified Consulting Meteorologist, one of the founders of The Weather Channel and who operates the website ICECAP took it upon himself to do an analysis of the newly released USHCN2 surface temperature data set and compare it against measured trends of CO2, Pacific Decadal Oscillation, and Solar Irradiance. to see which one matched better.
It’s a simple experiment; compare the trends by running an R2 correlation on the different data sets. The result is a coefficient of determination that tells you how well the trend curves match. When the correlation is 1.0, you have a perfect match between two curves. The lower the number, the lower the trend correlation.
|
Understanding R2 correlation |
|
| R2 Coefficient | Match between data trends |
| 1.0 | Perfect |
| .90 | Good |
| .50 | Fair |
| .25 | Poor |
| 0 or negative | no match at all |
If CO2 is the main driver of climate change this last century, it stands to reason that the trend of surface temperatures would follow the trend of CO2, and thus the R2 correlation between the two trends would be high. Since NCDC has recently released the new USHCN2 data set for surface temperatures, which promises improved detection and removal of false trends introduced by change points in the data, such as station moves, it seemed like an opportune time to test the correlation.
At the same time, R2 correlation tests were run on other possible drivers of climate; Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO), and Total Solar Irradiance (TSI).
First lets look at the surface temperature record. Here we see the familiar plot of temperature over the last century as it has been plotted by NASA GISS:
The temperature trend is unmistakeably upwards, and the change over the last century is about +0.8°C.
Now lets look at the familiar carbon dioxide graph, known as the Keeling Curve, which plots atmospheric CO2 concentration measure at the Mauna Loa Observatory:
A comparison of the 11year running mean of the USHCN version 2 annual mean temperatures with the running mean of CO2 from CDIAC. An r-squared of 0.44 was found.
The results were striking to say the least. An R2 correlation of only 0.44 was determined, placing it between fair and poor in the fit between the two data sets.
Now lets look at other potential drivers of climate, TSI and PDO.
Scafetta and West (2007) have suggested that the total solar irradiance (TSI) is a good proxy for the total solar effect which may be responsible for at least 50% of the warming since 1900. To test it, again the same R2 correlation was run on the two data sets.
In this case, the correlation of TSI to the surface temperature record is better than with CO2, producing an R2 correlation of 0.57 which is between fair and good.
Finally. Joe ran the R2 correlation test on PDO, the Pacfic Decadal Oscillation. He writes:
We know both the Pacific and Atlantic undergo multidecadal cycles the order of 50 to 70 years. In the Pacific this cycle is called the Pacific Decadal Oscillation. A warm Pacific (positive PDO Index) as we found from 1922 to 1947 and again 1977 to 1997 has been found to be accompanied by more El Ninos, while a cool Pacific more La Ninas (in both cases a frequency difference of close to a factor of 2). Since El Ninos have been shown to lead to global warming and La Ninas global cooling, this should have an affect on annual mean temperature trends in North America.
This PDO and TSI to surface temperature connection has also been pointed out in previous post I made here, for former California State Climatologist, Jim Goodridge. PDO affects the USA more than the Atlantic cycle (AMO) because we have prevailing westerly wind flow.
Here is how Joe did the data correlation:
Since the warm modes of the PDO and AMO both favor warming and their cold modes cooling, I though the sum of the two may provide a useful index of ocean induced warming for the hemisphere (and US). I standardized the two data bases and summed them and correlated with the USHCN data, again using a 11 point smoothing as with the CO2 and TSI.
This was the jackpot correlation with the highest value of r-squared (0.83!!!).
An R2 correlation of 0.83 would be considered “good”. This indicates that PDO and our surface temperature is more closely tied together than Co2 to surface temperature by almost a factor of 2.
But he didn’t stop there. He also looked at the last decade where it has been commonly opined that the Top 11 Warmest Years On Record Have All Been In Last 13 Years to see how well the correlation was in the last decade:
Since temperatures have stabilized in the last decade, we looked at the correlation of the CO2 with HCSN data. Greenhouse theory and models predict an accelerated warming with the increasing carbon dioxide.
Instead, a negative correlation between USHCN and CO2 was found in the last decade with an R or Pearson Coefficient of -0.14, yielding an r-squared of 0.02.
According to CO2 theory, we should see long term rise of mean temperatures, and while there may be yearly patterns of weather that diminish the effect of the short term, one would expect to see some sort of correlation over a decade. But it appears that with an R2 correlation of only 0.02, there isn’t any match over the past ten years.
As another test, this analysis was also done on Britain’s Hadley Climate Research Unit (CRU) data and MSU’s (John Christy) satellite temperature data:
To ensure that was not just an artifact of the United States data, we did a similar correlation of the CO2 with the CRU global and MSU lower tropospheric monthlies over the same period. We found a similar non existent correlation of just 0.02 for CRU and 0.01 for the MSU over troposphere.
So with R2 correlations of .01 and .02 what this shows is that the rising CO2 trend does not match the satellite data either.
Here are the different test correlations in a summary table:
And his conclusion:
Clearly the US annual temperatures over the last century have correlated far better with cycles in the sun and oceans than carbon dioxide. The correlation with carbon dioxide seems to have vanished or even reversed in the last decade.
Given the recent cooling of the Pacific and Atlantic and rapid decline in solar activity, we might anticipate given these correlations, temperatures to accelerate downwards shortly.
While this isn’t a “smoking gun” it is as close as anything I’ve seen. Time will give us the qualified answer as we have expectations of a lower Solar Cycle 24 and changes in the Pacific now happening.
References:
US Temperatures and Climate Factors since 1895 , Joeseph D’Aleo, 2008
Persistence in California Weather Patterns, Jim Goodridge, 2007
Phenomenological reconstructions of the solar signature in the Northern Hemisphere surface temperature records since 1600 Scafetta and West, 2007
The USHCN Version 2 Serial Monthly Dataset, National Climatic Data Center, 2007
Gary,
some of these may be helpful
http://www.amazon.com/Global-Warming-Understanding-David-Archer/dp/1405140399
I would suggest a book on atmospheric thermodynamics such as
http://www.amazon.com/Atmospheric-Thermodynamics-Craig-F-Bohren/dp/0195099044
and a book on physical climatology, such as
http://www.amazon.com/Global-Physical-Climatology-International-Geophysics/dp/0123285305
Best bet, for quick and handy tools, is a students guide to global warming
http://www.ace.mmu.ac.uk/Resources/gcc/contents.html
the NAS and IPCC reports are always there.
So the R^2 you produced aren’t the correct values so what meaning do they have? If someone else doesn’t do it right it does it justify your error? No emotional reaction at all, why not do it properly?
Also to make any sense at all you should correlate with ln(CO2)
REPLY: You might want to read the post a little closer before making strong claims. I didn’t produce the plots or corrwlations, I just wrote blog commentary to help others understand it. Joe D’Aleo of ICECAP did the plots and the paper. An update is forthcoming from him with a CO2 correlation as you and others have suggested. You can see the paper here
http://personals.galaxyinternet.net/tunga/SolarInfluence.pdf Here is a new paper on galactic cosmic rays and cloud cover. So I think running the R^2 on the cloud cover versus USHCN2, GAT and PDO+AMO is a worth while endeavor.
Note following Mr. D’Aleo’s update to the paper. Your work is some of the most cogent and accessible on the web.
I’m just thinking that in the comparison of PDO/AMO + CO2 +TSI, TSI doesn’t really belong; there’s a time lag and implicit dependence between it and the others . What about earth albedo, or geomagnetic field strength? What do those polynomials look like. When you have time, naturally.
“This would be a perfect test case for removal of questionable sites from the data set too.”
Yes. I completely agree.
Interesting analysis here: http://*tamino.wordpress.com/2008/02/03/exclamation-points*/
More of a hatchet job.
BINGO! Anthony, I believe we have our match. Check out this paper and pay particular attention to the last few pages! http://www.scostep.ucar.edu/archives/scostep11_lectures/Pap.pdf
TSI leads the F10.7 magnetic Flux, if you will remember another recent discovery of energy transfer via magnetic knots in the sun’s magnetic lines. Run the R^2 against the F10.7 flux, I believe you will get your .90+ value with the expected phase relationship you’re looking for against the PDO+AMO.
check out comment #262 at climate audit http://www.climateaudit.org/?p=2679 Cosmic ray vs El Nino index
[…] all show sharp drops in the last year. We are in an extended solar minimum, we have a shift in the Pacific Decadal Oscillation to a cold state, and we are seeing arctic ice extents setting new records and rebounding from the summer […]
Just wondering if the correlation coefficient for PDO&TSI goes up or down if you also include CO2?
The hypothesis that the correlation between earth temperature and solar irradiance is far better than the correlation to between temperature and CO2 could very well be the case, but doesn’t mean we’re off the hook with respect to CO2. Solar irradiance is the main driver of climate and does have a more immediate effect. Long term subtle influences, however, are still possible.
As an analogy consider an airplane on a certain compass course. The fluctations in its course correlate very closely to the pilot’s actions on the stick. More subtle and less detectable, though, there’s a gentle but persistent South Westerly breeze. The correlation between course and this breeze don’t correlate nearly as well as do the pilot’s actions and course. Nonetheless, you ignore that breeze, you could end up miles and miles off course from where you thought you’d be.
That human activity could affect climate is an extraordinary claim that requires extraordinary validation. At the same time, however, the claim that huamns can dump 22 billion tons of carbon into the atmosphere every year and this has no effect is even more extraordinary a claim.
Hi Charles,
You say: “That human activity could affect climate is an extraordinary claim that requires extraordinary validation”
I think it’s plausible in terms of human perception. There is an interesting post about that in Donner’s Maribo, about the earth as man’s domain vs the sky as god’s domain:
simondonner.blogspot.com/2008/02/tom-delay-and-believing-in-climate.html
OTOH science cares only about measurable inputs: GHG emissions from fossil fuels (btw there is an erratum in your figure, the 22 billions tonnes are CO2 and correspond to 6 GT of carbon), land use change, livestock,…, and that makes the claim less extraordinary, but only in science and, if the “extraordinary claim” feeling is pervasive, that can lead to some cognitive dissonance even among scientists and other “educated” people.
Best
Yves
This is a fascinating site and the information is amazing. I have a great interest in the GW argument and GCC in general. I am not a scientist but have a good grasp of the theories. If someone could take the time, I would be interested in the following. If man has such an impact on climate at this point in history, what was the factor that caused the earth to be warmer from 300 to 800 AD than it is today? The evidence for this is partly supported by excavations in greenland showing an agricultural exhistance during that period prior to a cooling phase which drove the inhabitants out. Also the types of crops including Grapes that were able to be cultivated in northern europe and england.
I have to mention I play poker with a former governor who was touting the Carbon exchange as the greatest economic institution we will found. This scared the hell out of me and makes me ask who benefits. Who collects the juice? His claim is a ten degree increase in global temps and flooding displacing 10m people. Again, how much have the worlds oceans receded since the 3rd century. Obviously by his logic there should have been substantially more landmass.
Again not a scientist, just curious about the debate.
Michael, there is very shaky evidence for anytime warmer than the late 20th century at any point during the Holocene (globally, a lot of the evidence you cite is regional, and Europe was certainy comparable to today at least in medieval times), though the uncertanties in paleoclimate reconstructions are large enough that it could be possible– though you’d be comparing the peak of one warm period to the start of another.
Not to knock the site I am posting on and that you enjoy reading, but I strongly encourage you to read more academic sources on the subject (reports from IPCC, NAS are good and introductory textbooks, perhaps from David Archer, or if you have a solid calculus/physics background, Ray Pierrehumberts), because there are a lot of mistakes in the analysis done here.
I believe I now have the answer on the PDO + AMO leading TSI. http://www.lavoisier.com.au/papers/articles/IanwilsonForum2008.pdf
What this guy is saying is essentially that LOD leads PDO by about 5 years and that TSI and LOD are driven by the same causes but neither TSI or LOD are interacting. Think of it as a bat hitting two balls at the same time, the balls correlate as in timing of movement but neither affects the other, they just have the same bat as the cause of the movement. Interesting hypothesis. What his claim is that LOD, i.e. the rotation speed of the earth is what influences the PDO via ocean currents if I understand it correctly. The site doesn’t directly say coriolis effect, however I believe that ocean currents are driven not only by winds and salinity but also by earth’s rotation like the wind patterns. http://abyss.uoregon.edu/~js/glossary/coriolis_effect.html
Now taking this LOD and comparing to your graphs above you may get the high R^2 value you are looking to highly correlate. LOD in milliseconds certaintly doesn’t have enough cummulative effect as far as the amount of energy from daylight but it might have enough as far as ocean and air currents are concerned. Can you establish what the LOD has been since 2000?
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Is there a theory supporting the idea that PDO+AMO is driving the climate, and not that climate is driving these oscillations?
[…] the scientific consensus on global warming might be, the fact is that no positive correlation exists between increasing levels of atmospheric CO2 and temperature. People like Al Gore make the […]
Kipp Alpert:I see the game is to make the sun twice as hot as it is, to justify the warming that has increased. I have never seen so much junk science in my life.
Don’t forget to bash Dr. Hansen and Al Gore.We need scapegoats. If you base your whole sceince on invalid assumptions, then it might look true. Someone said that the PDO leads ENSO? When you measure CO2 and Solar irradiance, you have it backwards.Or don’t you accept satellite data either. How do you know so much about the PDO, and it’s timeline, when no one really knows. They think it may be cold, or hot, due to deep ocean currents, Enso, and the warm pool. That is just to start the argument. Your charts look like a pre-school coloring book.
Perhaps this posting might have made some sense if a global temperature chart was used instead of the US temperature chart. Typical of the shoddy and innacurate posts of late…has WUWT lost its Mojo?
[…] Warming Trend: PDO And Solar Correlate Better Than CO2 […]