by J Storrs Hall
In my previous post, I argued that sea-surface temperatures hadn’t shown an inflection in the mid-twentieth century, and that the post-50’s rise was essently a land-based phenomenon. To take the analysis further, I thought I could try to find just what the climate signal from CO2 was. The method is to find a fit to the temperature record that included the CO2 forcing signature as a component, and see how big its contribution was compared to the other components of the fit.
First, the CO2. To get a curve since 1850, I got the estimated emissions from here, integrated for accumulation, scaled by matching to the Mauna Loa measured CO2 (red), and took the log for forcing. (No arguments, please; this is the bog-standard story. Let’s assume it’s true for the sake of argument.)
There’s clearly a knee in the curve ca. 1960. Also note that it’s been essentially straight since the 70’s — it’s the log of an exponential.
For components of the fit function, I used a cosine to capture the cyclicity we already know is in the record, a quadratic, and the forcing curve. I had used a second cosine before, and we know it produced two inflections in the result. The quadratic can only produce one, so the forcing curve has a better chance of matching the other one.
The idea is to find the overall best match and then look at the components to see how big the signal from the forcing is in comparison with the other components, which we will assume represent natural variability. We’ll plot each curve with the amplitude the optimizer gives it. Here’s what we get:
The blue line is the overall fit. Cyan is the 61-year oscillation, as before. No surprises here. Magenta is the quadratic, looking a lot like the sinusoid of the previous fit. Red is the CO2 forcing.
The CO2 forcing is upside down.
I gave the optimizer an initial guess for the forcing coefficient of 1; it came back with -1.67. This was, frankly, unexpected. I had seriously thought I would find some warming contribution from the forcing component.
So what on earth is going on? Here’s what we get if we add just the quadratic and the forcing curve:
For comparison, I’ve also plotted the second sinusoid from last time (green). It seems that the secular trend that the optimizer really, really wants is the shape of a Nike swoosh. If given only a quadratic to work with, it has to subtract the forcing curve to straighten out the twentieth-century rise. And it really, really wants the knee of the curve to be in 1890.
Does this mean that CO2 is actually producing a cooling effect? Absolutely not. It simply means that the secular rise in the twentieth century was a straight line, and the fit would do whatever it took to produce that shape. (This is why Pat Frank’s linear fit worked so well. As he noted, the linearity of sea-level rise would tend to confirm this.) What it does mean, though, is that there is no discernable CO2 warming signal in the HadSST temperature record. The (very real) twentieth century warming trend appears to have started about the time Sherlock Holmes was investigating the Red-Headed League.
A must read
http://climateguy.blogspot.com/
just look at the exchanges with RC people. Opinion on this paper would be welcomed is it valid?
I am willing to accept the CO2 values as correct.
I think Fred Haynie may have a point.
It appears to me that so far nobody has ever brought any convincing scientific evidence that the net effect of more CO2 is warming rather than cooling.
I mean: did you ever see a forest grow where it is very cold?
By taking part in the life cycle, CO2 must cause cooling because plants and trees need warmth (and CO2) to grow.
But nobody can tell me EXACTLY how much cooling and how much warming it causes.
I am guessing the net effect is zero or something close to that…..
http://www.letterdash.com/HenryP/more-carbon-dioxide-is-ok-ok
1. Any chance of a commentary on this that I could use to explain to my non-mathemtaical, but intelligent g/f? Or even a UK governement minister?
What did you do, why did you do it, and what did it show…but leaving out (or explaining) the acronyms and the deeper maths? More about the general idea of the method, rather than just the details themselves?
2. Any thoughts on the obvious question ‘if it’s this easy, why haven;t zillions of others found these result also?’
And the intolerance of the Australian MSM doesn’t help either.
http://www.smh.com.au/opinion/society-and-culture/you-are-just-plain-wrong-about-climate-change-mr-jones-20110601-1ffhd.html
The comments give real insight into the success of official left/liberal propaganda.
“there is no discernable CO2 warming signal in the HadSST ”
Yeah, well, that would be because back radiation doesn’t heat the bulk of the ocean, as Stephen Wilde and I have been saying for a long time. Much to Willis’ annoyance. 🙂
http://tallbloke.wordpress.com/2011/03/03/tallbloke-back-radiation-oceans-and-energy-exchange/
Please check the definition of inflection point.
Speaking of unique properties of water another of those is that the solid phase is less dense than the liquid phase. In pure water the density begins to rise at about 3C IIRC correctly. However seawater is a different animal. The salt content lowers the freezing point from 0C and -2C and, very unlike pure water, the density of seawater keeps rising all the way up to its freezing point.
This raises the question of why the average temperature of the global ocean is about 4C and that nearly everywhere below 400 meters in depth the temperature is a constant 3C. This constant temperature deep water comprises 90% of global ocean volume.
The reason the average temperature of the ocean is so far below the average temperature of the air at the surface right now is because 4C is the average ocean surface temperature taken over the entire range of a glacial/interglacial cycle. A glacial/interglacial cycle these days is approximately 100,000 years. Although the mix rate between the upper ocean and lower ocean is slow it isn’t non-existant. Conduction and convection over the course of 100,000 years is sufficient time for the deep ocean to equalize with the average temperature of the surface layer.
What we should REALLY be worried about is that huge bucket of nearly freezing cold water called “the global ocean”. We live and breathe in a temporarily warmer interglacial surface environment. There’s a huge mass of frigid water with over 1000 times the heat capacity of the atmosphere above it and 10 times the mass of the warmer ocean surface layer just waiting for the right conditions to mix into the surface water and once the ocean surface layer cools it quickly takes the puny atmospheric mass above it down in temperature too.
Dave Springer says:
June 8, 2011 at 7:25 am (Edit) . . . . .
. . . “Land surfaces can absorb downwelling CO2 and the net effect is that the rate of emission from surface to space is decreased i.e. the ground doesn’t cool down as fast.” . . .
Do you really mean this or is it shorthand?
“Ric Locke says:
June 8, 2011 at 6:03 am”
Made my jiggly bits jiggle. Yeah, the garbage truck IS in the room…yet, like the Elephant, no-one sees it!
Correction to my last. Pure water begins to fall in density at 3C not rise – I was thinking volume and wrote density. Seawater keeps rising in density (or falling in volume) all the way to its freezing point where it then behaves like pure water and expands (lowered density) when it becomes a solid.
Dave Springer says:
You need to adjust your curve labeled “CO2 Forcing” to reflect the fact that the IR absorption characteristics of CO2 is not linear across the range of atmospheric concentrations in the graph
Dave, I am sure we can all agree that CO2 has absorption in the 14-15 um causing some warming. (24 hours per day, earthshine)
The question is: how much cooling does it cause because of quite a few absoptions in the 0-5 um range, including newly found UV absorptions (12 hours per day, sunshine)
In addition we have the cooling caused by CO2 by taking part in the life cycle. How much is that?
http://wattsupwiththat.com/2011/06/08/the-climate-swoosh/#comment-676008
Keith Battye says:
June 8, 2011 at 8:04 am
Dave Springer says:
June 8, 2011 at 7:25 am (Edit) . . . . .
. . . “Land surfaces can absorb downwelling CO2 and the net effect is that the rate of emission from surface to space is decreased i.e. the ground doesn’t cool down as fast.” . . .
Do you really mean this or is it shorthand?
—————————————————————————-
I really mean that. It’s been an experimentally demonstrated fact for over 150 years and the basis of how electronic CO2 sensors have worked since their invention. Basically the sensors work by shining 15um LWIR through two samples of atmosphere. One sample is calibrated to a known known CO2 concentration and hermitically sealed while the other sample is ambient air. A matched pair of phototransisters measures the LWIR energy emerging from each sample and the difference in LWIR energy can then be converted by formula to difference in CO2 concentration.
Basically a modern electronic CO2 sensor is John Tyndall’s 1850’s experimental setup reduced from a space the size of a gymnasium to that of a thimbal, and far more sensitive than Tyndall’s setup too. But the principles behind Tyndall’s experimental work with LWIR absorptive gases is exactly as the principle behind a modern electronic CO2 sensor. If CO2 did not absorb LWIR coming in one direction and re-emit it equally in all directions then modern electronic CO2 sensors would not work correctly. But in fact there are millions of these instruments that work as perfectly in practice as theory predicts they should. Anyone who argues the point about the mechanism of greenhouse gases work is simply and demonstrably wrong – proven wrong millions of times every moment of every day by millions of electronic CO2 sensors working according to the gas physics being argued against.
Sorry, I get the instrumentation issue and why it is accepted but you talk of “downwelling CO2” but I have the sensation you wish to talk of downwelling CO2 LWIR.
I am probably being rather thick.
Warm Regards
I’m a tiny bit confused.
The rise in CO2 concentrations is almost linear, and slightly declining, shouldn’t the forcing be increasingly declining?
tallbloke says:
June 8, 2011 at 7:55 am
Exactly. In several peer-reviewed publications of ocean mixed layer energy budget it was found that less than 20% of heat loss in the lower latitudes takes place through radiative emission. Less than 10% leaves through conduction. The lion’s share of over 70% leaves as latent heat of vaporization. In fact it was found that a large fraction of summer heating of the mixed layer by shortwave radiation to a depth of 100+ meters was stored by the mixed layer until winter when the air is dryer and evaporation rate increases.
The greenhouse effect is dominated by the liquid water in the global ocean. Sunlight warms it radiatively to a depth of about 100 meters but for that heat to escape radiatively the warmed water must rise to within a few micrometers of the surface. Winds, waves, convection, and conducution are the only mechanisms which can bring the warmed back to the surface. The mixed layer of the global ocean works like greenhouse gases on steroids. It has the same properties, transparency to sunlight and opacity to long wave infrared, as greenhouse gases. Both liquid water and water vapor are fluids. It would be far more apt to say the earth is warmed by GHF (greenhouse fluid) effect than to say GHG (greenhouse gas) effect because so long as the surface remains largely covered by a liquid ocean it is liquid water that does most of the greenhouse warming. Land surfaces warmed by greenhouse gases is a significant factor but not a dominant one. As we both agree there is no significant greenhouse gas effect over the ocean but, and I’m not sure we agree on this, there is a large greenhouse effect from liquid water.
Dave Springer says:
June 8, 2011 at 7:25 am
“. . . it has no greenhouse effect over the ocean.”
I have always preferred the term “atmospheric effect” rather than GH but the phrase above in your text destroys my interpretation. If instead of “over the ocean” you were to write ‘with the surface of the ocean” then it makes sense to me. The shape of the gas molecules (linear for nitrogen and oxygen; non-linear for the absorbing ones: water vapor, carbon dioxide, etc.) control the absorption and emitting of energy and the atmosphere is thought to delay [trap; produce the blanket effect (?)] the return of this energy out of the earth-system – thereby elevating the temperature. (Common reported temperatures are air, not surface measurements.) Land surfaces become involved in the process because of their varying absorption characteristics. This should not disqualify the non-linear gasses of the atmosphere above the oceans from the physical (physics) processes. Or are you really saying that what is going on in the atmosphere is of no concern?
Just curious
what does J. stand for
in J.Storrs Hall
@tallbloke
Woud you agree that if anthropogenic activity did something to change the average turbidity (or rather the lack of turbidity) of the mixed ocean layer this would then alter the mixed layer energy budget? It seems like greater turbidity would cause sunlight to be absorbed in a shallower layer and then if conduction, convection, wind and wave mixing remained equal those mechanisms would be more effective in bringing the warmed water to the surface where it can cool.
By the way google “continentality” which is a phenomenon first noted and so named hundreds of years ago. It refers to the fact that the difference in ocean temperature between summer and winter is far less than the difference in interior contenental regions. This is observational proof of what was more recently and more precisely meausured in mixed layer heat budgets studies to which I referred. The ocean stores summer heat and releases it in the winter greatly moderating the temperature differential. This is only made possible by the fact that water is a greenhouse fluid able to be radiatevly heated by sunlight to significant depth and impaired in its ability to release that energy radiatively due to its opacity to long wave infrared.
Why sure, the CO2 forcing could be negative. One reason is that CO2 is taken up by plants, especially trees, and considerable data exists that vegetated areas are cooler, especially forests
And warmer is better. We are more comfortable in tropical climes than arctic ones. Crops grow best in the summer, the death rate is highest in winter, not summer.
The atmosphere on Mars is 95% CO2 and the average temp is -100F
Really? No one is going to question the validity or explain why there is a quadratic term included in the fitting procedure?
Dave Springer: Look again — I’m using the log of the concentration for the forcing, not the concentration itself. I did somewhat confusingly plot the log of the Mauna Loa measurements to show the match, and didn’t mention that was a log too. Sorry for any confusion.
Duncan & David Ozenne: A quadratic represents the response of a system under a constant acceleration — cf the trajectory of a thrown ball. They are found fairly often in the traces of dynamical systems when one force dominates.
That said, it is rarely valid to extrapolate from one since forces change — as they clearly did in this case.
I actually tried the analysis with everything from a linear to a quartic. For everything quadratic and up — any form capable of modelling the 1890 knee — i got the same results. For linear you get a positive simply to fit the fact that the curve overall is concave upwards — but it’s still matching to the 1890 knee. Fit a linear+forcing to the century centered on the knee in the forcing curve, 1960, and it goes negative again.
The bottom line that the SST curve doesn’t show any signal of the forcing, either way. Nothing else should be read into it.
Ric Locke: You’re absolutely right, especially if you’re thinking of extrapolation instead of factor analysis. If you’re extrapolating, go for the PDEs (actually, ODEs should work fine here) or a new technique, symbolic regression. Google Eureqa. Maybe when I have a free week to play around 🙂
ZT: Haha! You are right — well, almost right. I didn’t say inflection point. Colloquially, “inflection” is commonly used to mean simply a bend, even though we mathematical sticklers know that “inflection point” refers to the boundary between opposite concavities. Happy Heteroskedasticity to you!
@J Storrs Hall says:
June 8, 2011 at 9:46 am
What is the cause of the quadratic term?
I don’t know but I’m able to paste. Maybe it’s because I’m logged out of my WordPress account.
As a note, since WordPress updated their “Leave A Reply” input form, my 3rd party cookie alert is now showing that WordPress is tracking your usage.
OK S.
There isn’t enough CO2 in the atmosphere to get beyond insignificant forcing.
There is 3 to 30 times the RH (H2O vapor) in the atmosphere, and thats where the focus should be.
Why is so much time wasted with a puny 395 ppm trace gas?
RBateman said: “There isn’t enough CO2 in the atmosphere to get beyond insignificant forcing.
There is 3 to 30 times the RH (H2O vapor) in the atmosphere, and thats where the focus should be.
Why is so much time wasted with a puny 395 ppm trace gas?”
The answer is that while most of the GHE comes from water vapour, the extra bit from human emitted CO2 can still be significant. The usual analogy is that the atmosphere is like a bathtub that is being filled and emptied at the same rate, so remains at a given level (over the timescales we are talking about). The added effect of CO2 emissions is like adding a tiny but persistent extra inflow to the bathtub – it may be tiny, but it can still be significant, the bathtub will get fuller.
Yes, that is only an analogy. if you want more information, google “greenhouse effect”. There is a lot of science supporting CO2 as a significant greenhouse gas.
Hope that helps.
John