This is a reply and extension to Pat Frank’s “Earth Abides” post (sorry, couldn’t resist) which appeared here recently. The post features an intriguing interpretation of the temperature record to deduce climate sensitivity to CO2. I thought I would try to recreate it and see where it took me. First I got the HadSST records from http://www.cru.uea.ac.uk/cru/data/temperature/.
I generally prefer to use sea-surface temperatures when looking at global trends for several reasons:
- they have a lower variance, indicating a better stability to short-term perturbations
- the surface water temperature is measured directly, eliminating some of the definitional issues of surface air temperature
- SST’s are free of siting issues, UHI, land use, and other local human climate effects
- The seas are 70% of Earth’s surface and its major heat reservoir. Temperatures can go up and down on land like a wagging tail, but the oceans are the dog.
So let’s take the SST record and fit a sinusoid to it. However, a linear fit to the secular rise simply can’t be right. It would retrodict an ice age right at the peak of the Roman Empire. Since things in nature are much more often cyclical, I tried fitting another sinusoid to the secular rise, using all the HadSST data back to 1850:
Here we have the data as dots, decadal smoothing in blue, and the fitted sum of cosines in red. (Decadal smoothing means that I convolved the data with a Gaussian with a 5-year standard deviation.) The red curve is simply the sum of two cosines, one of period 62.7 years, the other 259.9. Just how good a match is it for the data? Ignoring intra-decadal variability (weather, not climate!), let’s plot the decadally-smoothed residual:
Something very unusual happened around 1950 — that’s nearly an 8-sigma excursion. And I haven’t the slightest clue what it was. (There was a major mode shift in the PDO about that time; it was also the era of atmospheric nuclear weapon testing … and there was probably a drop in the number of pirates.) If you look at the actual data you’ll see that 1945 marks the only really drastic discontinuity in the entire record — so I feel reasonably comfortable saying that something unusual happened then. Given that the fit was so good outside the “1950 notch”, I did the fit treating the notch as an outlier (yellow line) for an even better fit (especially to recent temperatures). (That means, of course, that the model isn’t just the fit but the fit with an exception for the notch.) The red lines are one standard deviation, the magenta two. But outside of the notch, this model — a tiny one, 6 parameters — fits the decadal average SST to within 0.05 degrees for 160 years.
Here are the variances, again with the notch taken out (We take the notch out because it makes all the series correlated, so the variances wouldn’t sum. Since we explicitly say the model can’t explain the notch, we’ll concentrate on where it does match the data.):
| Raw SST data | 0.0687 |
| Model fit curves | 0.0534 |
| Residual to fit | 0.0153 |
| Data – smoothed (decadal variability) | 0.0145 |
| Smoothed – fit (model error) | 0.000513 |
In other words, decadal variability (weather!) accounts for 21% of the variance of the raw temperature series, the model accounts for 78%, leaving about 1% unaccounted for. (There’s still a tiny amount of correlation.)
But this kind of messes up the notion that there was a V-shaped piecewise linear structure to the residual across the twentieth century: the data much more clearly show a straight line with a dip than falling and rising linear trends. Yet Frank’s graph looked a lot more like the trends — what happened?
The key to the puzzle is that his data were (or included?) land temperatures, the CRUtemp data. Let’s plot that too, also as a residual to our fit curve:
Lo and behold, there really is a linear rise above the sinusoid in the land data — which isn’t there in the SST data. In other words, the divergence since 1950 is more a land-water difference than a CO2-no CO2 one. Sorry to rain on the parade, but I can’t really buy the climate sensitivity deduction. As mentioned, there are several possible explanations for the difference. We can add another one, even assuming the land temperature measurements are perfectly accurate: cloud feedbacks may operate differently over land and ocean.
I think you have the 2nd and 3rd graphs switched.
REPLY: Edit error in loading graphs – fixed and thanks for pointing it out – Anthony
There was non-stop war with all requisite air and surface bombardments from 1939 to the early 1950’s followed by the atmospheric “nukular” testing. Is what you are seeing perhaps the lagged effect of the non-stop conflagration?
The only way I can make sense out of this is to assume that the last two graphs were transposed.
REPLY: Edit error in loading graphs – fixed and thanks for pointing it out – Anthony
On the 1945 discontinuity:
http://climateaudit.org/2007/03/18/the-team-and-pearl-harbor/
http://www.realclimate.org/index.php/archives/2008/06/of-buckets-and-blogs/
If you run the 5 year gaussian smoother by itself without the applying the model first, it will absorb both the 259.9y and 62.7y low frequency signals represented by the model, and you’ll probably get the rsultant smoother to explain 78+21=99% of the variability.
Further, if you intend on using the model to apply beyond the range of the data, you’d need something more to justify extrapolating from the 160y data range of the to the rest of the 259.9y period of half of your model.
Discrete Cosine Transformation is a great data compression technique, but I’m not sure much inference about causality can built from the first few wavelets or their residuals.
I am a bit puzzled about your last graph. I am assuming it is temperature anomaly on the x. Is that Fahrenheit or Celsius? Would help if you could include dimensions/ If it is Celsius, it does not make sense to my own measurements of 0.018 degrees C warming per annum since 1974 / measured by linear regression, see
http://www.letterdash.com/HenryP/henrys-pool-table-on-global-warming
Something very unusual happened around 1950 — that’s nearly an 8-sigma excursion. And I haven’t the slightest clue what it was. (There was a major mode shift in the PDO about that time; it was also the era of atmospheric nuclear weapon testing … and there was probably a drop in the number of pirates.) If you look at the actual data you’ll see that 1945 marks the only really drastic discontinuity in the entire record — so I feel reasonably comfortable saying that something unusual happened then.
J Storrs Hall
Nothing unusual happened arround 1950, if you look at proper data records for real temperatures, rather than the dubious (& irrational) global SST.
If there was anything unusual in the 20th century is the winter warming 1900-1930, while other seasons are left lagging behind , while the other seasons are left lagging behind, then the sudden drop 1930 – late1940 while the rest continued on the upward slope.
Sorry forgot the link to the graph
http://www.vukcevic.talktalk.net/CET-NAP.htm
I believe we have a big problem with understanding the mechanisms of temperature rises and falls on Earth because we take too large a time-frame and location view. For example, if you look to find the big temp rises that lead to Hansen’s fears, you have to look outside the contiguous US, as the temps haven’t risen since 1996. The same is elsewhere – sometimes the area is cooler now than before. To cut to the chase, for the global temperature rise of concern, you have to include the Arctic. The Arctic is the only place with large numbers.
I looked at the SST on a longitude basis and a year-to-year basis. If you line the records up you get a y-axis of location and an x-axis of time. The variations in the record are temperature. In geology and geophysics we do this, though the y-axis is depth and the x-axis is location. The variations are lithology or fluid content changes. What you get geologically is how formations rise, fall and change over a depositional area. What you get with the same display style for the SST is how heat moves through the system along longitude through time.
The analysis is not easy, no more easy than it is for a geologist or geophysicist to interpret the changes in his “graphs” (we call them cross-sections or seimsic lines). But gross changes are visible to anyone who doesn’t need a white cane.
You could do the same with latitude changes vs time, obviously. The work would come down to finding which area shows the greatest concordance, determining the pattern and then fitting in the noisier or more complicated areas. Clearly heat travels from the equator up through the Arctic (and Southern) Ocean; how and when that heat moves determines very significant changes we see.
There is so much to see now that all this data is available. It is overwhelming. A person needs to be paid to do it or, like the gentlemen-scientists of the 19th, to be self-sufficient on their estates AND lack TV and video game distractions. (A family looked after by nannies and servants helped them, too.)
Dave X: Yep. I would expect to see the 60-year mode outside the data range; the 260 one, not so much.
HenryP: all x-axes are date, all y-axes are delta temperature in celsius
Zeke: note there is a matching dip in land temps, meaning it was probably physical and not (entirely) measurement problems
I enjoyed your article very much. I especially liked one statement which proves beyond the shadow of a doubt that you have the instincts of a scientist. It is: “We can add another one, even assuming the land temperature measurements are perfectly accurate: cloud feedbacks may operate differently over land and ocean.” I say “fie” on anyone who says Earth has an albedo. There are many varied albedos with many different effects. Unfortunately, climate science has not yet shown itself capable of undertaking studies of them.
It is interesting, and the post that preceeded this too. Hard to explain the divergence though with anything but wild speculation, arguments could be made for and against greenhouse as the culprit. The close sychronicity of previous years would seem to rule out a delay. Also greenhouse warming isn’t new, it’s just said to be enhanced and is present in those previous years. I take it a sea temperature does mean the sea i.e. the water, though a surface temperature is really air temperature at the surface, perhaps the two aren’t linearly connected for a changing greenhouse forcing? Wild speculation….
“First I got the HadSST records from http://www.cru.uea.ac.uk/cru/data/temperature/.”
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Weren’t the records from 1945 into the early 70s mal-adjusted due to the “bucket” issue?
http://climateaudit.org/2008/06/01/did-canada-switch-from-engine-inlets-in-1926-back-to-buckets/
Also, somewhere I seem to recall Mr. McIntyre posting an off-hand comment that by a simplistic back-of-the-envelope type undoing of the bucket adjustment, the correlation with Solar improved to approx 80%.
In that second link above, there’s also a nice graph from Thompson et al 2008 comparing SST measurements to proportional UK and US shipping registry, and how the SST correlates to which nation ships were flagged under.
Something very unusual happened around 1950 — that’s nearly an 8-sigma excursion. And I haven’t the slightest clue what it was.
That’s when I came to America.
Does this “model” have any predictive skill whatsoever?
I think not at all.
Correlation does not equal causation.
Oh and why don’t you use the term “convolved Gaussian kernel” as that sounds so techy?
When all that techy term really means is a moving average using a bell curve.
With only half a bell curve populating the start/end of the smoothed time series.
So all smothing functions have end effects, if the low pass filter is carried out to the actual ends of the higher frequency time series, as you have done, no getting around that one, as we have no idea of what the unknown past/future time series was or will be.
Do love that presistence of the ~60 year cycle though, kind of like claiming that Earth’s climate runs in clockwork like fashion, sort of like placing the Earth at the center of the universe and what all.
Your treatment is more akin to astrology than it is to the scientific method.
Nuff said.
If the ≈40% rise in CO2 had a measurable effect on temperature, then current temperatures would be accelerating above trend, no? But they are not. The planet is still warming on the same trend line from the LIA. Anomalies occur, but they always revert to the mean.
Further, the current very mild warming cycle [0.7° – 0.8°C over the past century and a half] is indistinguishable from numerous similar [and often greater and more rapid] warming spikes throughout the Holocene, when CO2 remained low.
Certainly if CO2 caused any more than minuscule warming, temperatures would be rising geometrically above trend. But they are not. Observed temperature rises are fully explained by natural variability, and facts such as the failure of accelerating thermal expansion of the oceans, and numerous other failed predictions by the climate alarmist camp, should make every reasonable scientist question the basic AGW hypothesis – which still remains an evidence-free assumption.
In theory the nuclear testing could have temporarily warmed the stratosphere to push the jets equatorward or make them wave about more meridionally for increased global cloudiness and albedo with reduced solar input to the oceans.
I’ve no idea whether the data supports that though.
Found it….
I expect that he’s done followup since then…so this may well not reflect his current conclusions.
If the last graph is Celsius
there must be a mistake somewhere
Most people (including Anthony Watts) have reported a value of 0.015 degrees C/ annum warming for the last 4 decades
I reported 0.018
http://www.letterdash.com/HenryP/henrys-pool-table-on-global-warming
This includes more stations than currently shown there in the file…
There is no UHIE at sea.
gdn: A high sensitivity to solar is required because all they examine is the TSI directly.
No assesment is made of the Svensmark affect.
No assesment is made of the fact that not all wavelengths change equally during the solar cycle.
Basically, they are looking for an excuse to dismiss anything that isn’t spelled “CO2” as a factor in climate change.
http://wattsupwiththat.com/2011/06/06/earth-fire-air-and-water/#comment-674784
Three great cherry picks.
The first shows several long term time series of temperatures with NO discernible ~60 cycle whatsoever. Go figure.
The second shows a single location, at the top of the Greenland ice sheet, like at 10,000 ft above sea level, as if this were some kind of a true representation of the global temperature time series over the Holocene. And a proxy time series no less, I thought you people abhored paleo reconstructions. Go figure.
The third proports to show the aforementioned ~60 cycle + linear trend, I wonder what the R^2 is on that particular one, surely not even the 0.78 claimed at here. Smooth any time series enough and you’ll get any R^2 you desire, doesn’t make it real or suggest any predictive skill whatsoever. A Clockwork Orange. Go figure.
gdn says:
June 6, 2011 at 9:03 am
“First I got the HadSST records from http://www.cru.uea.ac.uk/cru/data/temperature/.”
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Weren’t the records from 1945 into the early 70s mal-adjusted due to the “bucket” issue?
http://climateaudit.org/2008/06/01/did-canada-switch-from-engine-inlets-in-1926-back-to-buckets/
http://climateaudit.org/2008/05/31/lost-at-sea-the-search-party/
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Interesting post. As far as I know, shortly after the introduction of the diesel engine, data entered into the ship’s logs is taken from the engine inlet manifold. Likewise when a ship reports to weather routing agencies (such as Oceanroutes and the like), the data the ship provides to these agencies is that extracted from the ship’s logs, ie., engine inlet manifold temperature.
The depth at which the cooling water is extracted depends on the size, design and configuration of the vessel and in this I include whether the vessel is fully laden or only partially laden or sailing in ballast. That said on deep water crossings, most ships are operated fully laden (for obvious profit reasons), and one nay therefore consider that the inlet manifold temperature is that drawn from about 7 to 13 metres below the surface.
I have pointed out on several occassions that ship’s logs (and hence the data they provide to weather routing agencies) represents typically water temperature drawn at about 10 m below sea level and thus ships are if anything underrecording sea surface temperature and one needs to adjust their temperatures upwards not downwards.
Additionally, whilst I am not saying that this is a wide spread practice, some ships may be deliberately under recording sea temperatures. A number of products carried (Veg Oils, some chemicals) need to be heated during the voyage and the shipowner in effect gets paid for this service. It may therefore be in the interest of the shipowner to say that the sea temperature was so low that heat was required when in practice no heat may have been required or applied because ambient sea temperature was sufficient to keep the cargo warm withiut using bunker fuel for heating purposes (eg in the Indian Ocean, the Gulf, some parts of the Pacific etc). Thus once again, the ship’s logs may be recording a lower sea temperature than the true and proper sea surface temperature.
It therefore appears that the proposed adjustments by the ‘Team’ is the wrong way around. I do not know whether this is out of ignorance not knowing how ship’s record their data, or whether it is a deliberate attempt to ‘cool’ down the oceans post 1940s so that the ‘Team’ can argue that there has been more warming between the 1940s and the introducrion of ARGO.