Bishop Hill Leake on the temperature plateau
Feb 5, 2012 Climate: Surface Jonathan Leake has an excellent summary of the recent argy-bargy over the flatlining of global temperatures.
What were the rest of us meant to make of this? Some scientists appear to be warning we will fry, while other sources fear we will freeze. For the public the outcome is, increasingly, confusion. Where might the truth lie?
Perhaps the simplest first step is to put aside the arguments and get back to the data. Is it really true that global temperatures have not risen since 1997?
The simple answer is: they have risen, but not by very much. “Our records for the past 15 years suggest the world has warmed by about 0.051C over that period,” said the Met Office. In layman’s terms that is 51 thousandths of a degree.
It's paywalled, of course, but reproduced here.
Reader Comments (82)
Dr Norman Page
That was a landmark post. I am bookmarking it to my archive file.
Theo Goodwin;
“Please do not respond with hunches.”
It is not a hunch that the spectra for solar illumination and outgoing IR overlap. Nor is it one that the spectral intensity at the CO2 absorption bands within them, corrected for hemisphere/sphere area difference, appear to be roughly equal per m^2.
It would be good to find actual values for both however: I have tried and failed. If the numbers match the hypothesis, than we have nothing more than two band-pass filters at 4250 and 15000 nm. Should be easy to check if the relevant measurements exist. If they don't, then to do so is far beyond my personal ability.
Dr Page:
"In reality they are no more than expensive drafting tools to produce power point slides to illustrate the ideas and prejudices of their creators."
Exactly.
Yes!
The Met Office has said that they use essentially the same model for weather forecasting as they do for predicting climate change. The Met Office is committed to predicting catastrophic climate change.
It is hard to imagine that choosing fiddle factors for a model that failed to do this would enhance a Met Office programmer's career. No doubt this explains the Met Office's track record of predicting barbecue summers and mild winters.
Feb 5, 2012 at 8:30 PM | simpleseekeraftertruth
I did not intend to address your claims and am unclear how I did. I can say that Arrhenius' hypotheses are simply assumed to be true of Earth's atmosphere though they have never been rigorously formulated and tested in Earth's atmosphere. I have no argument with the physics of CO2. I do have an argument with climate scientists who fail to create rigorously formulated hypotheses and test them.
simpleseekeraftertruth (Feb 5, 2012 at 8:30 PM) -
Taking the solar spectrum as the ideal black-body curve at 6000 K, I compute that about 1% of incoming solar radiation lies within the
absorption bands of CO2.
By contrast, taking the terrestrial thermal radiation as the ideal black-body curve at 290 K, the CO2 absorption band between 13-17 um (source) includes about 20% of the power of that spectrum.
Dr Norman Page
I concur with Pharos, that your's was indeed a landmark post. I too am bookmarking it to my archive file.
I eagerly await a response from Richard Betts (and Tamsin Edwards).
Feb 5, 2012 at 6:06 PM | steveta_uk
His example is not helpful but his major point is not mistaken. People who are willing to take temperatures from proxies and compare them with thermometer temperatures have overlooked all the empirical science that must be done to ensure that the temperatures are actually comparable. The general point is that to compare temperature readings you have to do some empirical physics to determine that the disparate physical conditions where the temperatures are taken do not render your comparison one of apples and oranges.
HaroldW at 8:58 PM |
Hmmm, 20:1 v 2:1. I don't question your calculations but will have to think harder on the red-shift. Thank you for your consideration and the links.
It would also be interesting to hear BBD's rebuttal of Dr Page's statements.
Theo Goodwin at 8:56,
My apologies, I was overly attracted by your remark:)
HaroldW, are you sure?
http://eesc.columbia.edu/courses/ees/slides/climate/absorption.gif
“Our records for the past 15 years suggest the world has warmed by about 0.051C over that period,” said the Met Office.
Does the Met Office really say that with a straight face, the global temp rise over 15 years can be stated with an accuracy to one thousandth of a degree?
Dr Norman Page
I guess I have to agree that it is "best", but I will argue that it is totally inadequate. It is not dealing with the gradients of temperatures in the oceans, and for that reason can be and probably is misleading.
Both El Niño and La Niña are oceanographic current events, and far more complex than being driven by surface temperatures. I doubt if we will ever understand our weather patterns until we adequately understand those two phenomena as well as several others.
climatebeagle wrote:
"“Our records for the past 15 years suggest the world has warmed by about 0.051C over that period,” said the Met Office.
Does the Met Office really say that with a straight face, the global temp rise over 15 years can be stated with an accuracy to one thousandth of a degree?"
No, no. Their "records" merely "suggest" that. Wouldn't want to confuse the public with any veneer of faux certainty or anything.
My record of their recent operations suggest that we need not take their suggestions too seriously.
Feb 5, 2012 at 8:01 PM | Dr Norman Page
"Since 2003 CO2 has risen further and yet the global temperature trend since then is negative. This is obviously a short term on which to base predictions but all statistical analyses of particular time series must be interpreted in conjunction with other ongoing events and in the context of declining solar magnetic field strength and activity – to the extent of a possible Dalton or Maunder minimum and the negative phase of the Pacific Decadal a global 20 – 30 year cooling spell is more likely than a warming trend."
No, it should not be interpreted at all. It is not statistically significant. That means that it could very well have occurred by chance.
Bruce -
Actually, I wasn't sure...I had computed this a couple of weeks ago, and posted. I couldn't find the spreadsheet I used -- must not have saved it -- but I cribbed the figures from the old post.
Just now, I've regenerated the figures. Here's my method:
[Apologies in advance for formulas which are poorly represented in text form. I hope you can follow; but you can find the formulas with Google.]
I started with Planck's law, in which the amount of radiation between wavelengths lambda and lambda+dlambda is given by
2 * h * c^2 / lambda^5 / (e^(h*c/(lambda*k*T))-1) * dlambda
where h=Planck's constant, k=Boltzmann's constant, c=speed of light, T=temperature
The integral of this distribution over all lambda is given by the Stefan-Boltzmann equation, namely
sigma * T^4
where sigma is the Stefan-Boltzmann constant.
Dividing the energy distribution by (sigma * T^4) gives a normalised distribution, which sums to 1. This is helpful for defining the relative amount of each spectrum in a given wavelength region.
Now the truly accurate way to figure this is to use something like Modtran, but for rough purposes, I took the following wavelength regions as the CO2 absorption domain:
2.5 - 2.8 um
4.2 - 4.5 um
13 - 17 um
Using a solar spectrum at 5778 K [Wiki's value], and terrestrial spectrum at 290 K, I get the following for the relative amounts of each spectrum, to four places [note that it's nowhere near that accurate!]:
__________Sun_____Earth
2.5-2.8____0.0090__<0.0001
4.2-4.5____0.0015___0.0021
13-17_____0.0002___0.1876
sum______0.0107___0.1897
[I got these using a spreadsheet, evaluating the power spectrum at 10-nm increments...given the extreme crudeness of the wavelength regions, I didn't think a more precise method was required.]
While about half of the solar radiation is in the infrared region (defined as >0.7 um), relatively little of it overlaps the CO2 band, as the solar spectrum falls off quite rapidly at increasing wavelengths.
By the way, I came across this depiction of the spectra and absorption bands, which suggests that I should have also included a region at around 1.9-2 um. This would increase the solar amount somewhat from the figures above; there'd be no change to the terrestrial value.
Why the obsession with straight lines? Surely a curve would fit the data much better...
Mark Cooper, yes, climate scientists seem to have adopted the habit of insisting on drawing a straight line through irregular oscillatory data, as if this means something. Statistician Matt Briggs has recently done a good series of posts on this. Many of the sceptics make the same mistake of course.
And sorry to repeat Norman and Martin's point, but it can't be repeated often enough. The results of the climate models merely reflect the opinions, assumptions and prejudices of the people who wrote the models. I call this 'circular modelling', and it comes up quite often, not just in climate science but in all areas where modelling is used. Usually the people doing it are blissfully unaware.
Two issues that the article missed questioning. Firstly, the IPCC central claim from AR4 is that CO2 is "driving" temperature. NOT that CO2 is 'effecting' temperature. If natural variability is swamping the CO2 signal over long stretches of time than it cannot by definition be in the driving seat. Not in the shorter term of multiple decades, anyway.
The other point is that climate scientists expected to see what they had already observed from 1970-2000. Which was a basically steady rise in temperature, with pauses averaging 5-10 years. And they also expected to see an accelerating trend as CO2 rose. Observe the fairly steady incremental rise over a 30 year period from 1970-2000:
http://woodfortrees.org/plot/hadcrut3vgl/from:1970/to:2000
15 years of no temperature rise was not expected. That alone does not 'prove' them right or wrong as more data is most likely needed. However, it is incorrect to argue that the 15 year period of no warming was something that the community was going to view as 'normal'.
Now we have 10 years of rising CO2 and 10 years of flat temps and you want to shift the goalposts.
I agree with you that 10 years is not per se convincing and that the next five might be different which is why I insist on saying only that global warming has "stalled" but all the warmist propaganda has been that if CO2 rises than the thermometer will keep it company every step of the way.
It ain't happening at the moment and that is what makes it significant.
(The fact that this stall comes just at the point in the warm/cool cycle that you would expect if 1970-2000 were natural only makes the warmist argument more threadbare.)
simpleseekeraftertruth Feb 5, 2012 at 5:31 PM
Gosh, that's really interesting. A genuine refutation, if the figures work out and there is no overlooked gotcha. I'm coping with frozen pipes and a loft full of snow at the moment but as soon as I can, I'll try to work it through.
My understanding is that, for incoming, it's the area of the disk that's relevant, for outgoing, the sphere.
"Does anyone have the actual figures for spectral intensity solar/Earth at 4250 & 1500 nm?"
Would a request to the Met Office produce any response, do you think?
Feb 6, 2012 at 11:27 AM | Mike Jackson
"We have spent the last 20 years being told that CO2 and temperature march in lock-step (even though there was observational evidence that they don't)."
I don't believe any reputable source said that, ever.
Nick
There are plenty of graphs out there.
Are you suggesting that their creators were disreputable? I couldn't possibly comment.
Martin A
"but as soon as I can, I'll try to work it through"
It is measured data that is needed, both directions above top of atmosphere so is likely reside with NASA or similar. Computing black body curves does not lead to understanding the dips at absorption frequencies. The numbers that computed this might be helpful (if numbers were used). The solar spectrum does extend into the far IR, but I suspect you know that.
Illumination by sunlight should be taken as a disc for planet surface - but for a hemisphere of gas I am unsure. For outgoing it is a sphere but probably with different gradients night/day (any outgoing figure is probably an average). However, ball park figures would do for a start. My eyeballing of graphs gives 2:1, blackbody as provided by HaroldW above gives 20:1. Anything around 4:1 would be very interesting!
Martin A
Link
"The other point is that climate scientists expected to see what they had already observed from 1970-2000."
No. 1970 was still the ice age scare.
“Fifteen years is just too short a period over which to measure climate change,” said Peter Stott
Except thats what they claimed well before it had been warming for 15 years.
1943/45 was the equivalent of the 1998 peak. 43/45 were not surpassed for 40 years.
Consider that in 1943/1945 the HADCRUT temperature anomaly rose above .2 3 times in 1.5 years.
1944 0.245
1944.67 0.216
1945.58 0.306
In the last 3 years the anomaly dropped BELOW those 3 peaks 3 times.
2008 0.074
2008.08 0.198
2011 0.204
Within the margin of error, it is barely warmer than 1943/45.
http://www.woodfortrees.org/plot/hadcrut3vgl/from:1943/plot/hadcrut3vgl/from:1977/to:1998/trend/plot/hadcrut3vgl/from:1998/trend/plot/hadcrut3vgl/from:1943/to:1977/trend
Feb 6, 2012 at 7:54 PM | Mike Jackson
"We have spent the last 20 years being told that CO2 and temperature march in lock-step (even though there was observational evidence that they don't)."
It's your statement. I presume you are referring to reputable sources. I'm just asking you to produce it. Just one would be a start.
The significance of this article is that, until now, Jonathan Leake has been firmly in the 'Here's some more warmist/alarmist information to report, which makes all the carbon reduction efforts worthwhile' camp.
To write such a 'balanced' feature (I'm giving the benefit of the doubt here) is a major departure for him.
There is a shift in media reporting; its imperceptible, but it is there...
Here Nick.
All scnarios show a lock step increase in temperature as CO2 rises.
5 seconds googling.
I doubt IPCC is a reputable source for most readers here though.
Nick, the companion graph from the IPCC report.
@ 'ZedsDeadBed' Feb 5, 2012 at 3:51 PM
""No. Weather has. Not climate. It's a difference most children understand, but seems far beyond your abilities of comprehension."
are you thick or just insensitive, most people affected by cold/hot don't give at damn about global temps, only local temps, that's what will kill them & you, forget this mystical global average temp, it's meaningless to most people trying to survive (it's an abstract concept useful to an agenda but useless in the real world).