A primer for disproving IPCC’s theory of man made global warming using observed temperature data

I believe that the saying “Hoist by their own petard” is relevant here. The debate is now over, but not with the outcome that the AGW crowd wanted.
Keep up the good work.

If this pattern that was valid for 120 years is assumed to be valid for the next 20 years, it is reasonable to predict:
1. 30-years of global cooling from 2000 to 2030
Don Easterbrook has also forecast ~20 more years of cooling.
3:18 video

This is a point I have made many times. The slope of the warming from 1910 to 1945 is at least as great as from 1978 to 2000. Why is one manmade and the other not?

stevengoddard says:
August 1, 2010 at 5:20 pm
People who don’t like themselves will find rationalizations to take the blame for almost everything.
I wish they’d keep it to themselves.

“If this pattern that was valid for 120 years is assumed to be valid for the next 20 years…”
This statement is not valid for a system that is at least partially stochastic. The lack of warming in the 60’s and 70’s was most likely caused by sulfur emissions. “The plateau in warming from the 1940s to 1960s can be attributed largely to sulphate aerosol cooling.”
[From Wikepedia based on IPCC 3: http://en.wikipedia.org/wiki/Attribution_of_recent_climate_change%5D
Readers may also want to review the Atlantic Multi-decadal Oscillation: http://www.aoml.noaa.gov/phod/amo_faq.php
As for the “warming pause” of the last few years, see the discussion here:
http://www.realclimate.org/index.php/archives/2009/10/a-warming-pause/
One point made there is this: “It is highly questionable whether this “pause” is even real. It does show up to some extent (no cooling, but reduced 10-year warming trend) in the Hadley Center data, but it does not show in the GISS data, see Figure 1. There, the past ten 10-year trends (i.e. 1990-1999, 1991-2000 and so on) have all been between 0.17 and 0.34 ºC per decade, close to or above the expected anthropogenic trend, with the most recent one (1999-2008) equal to 0.19 ºC per decade – just as predicted by IPCC as response to anthropogenic forcing.”
My guess is this post was not peer reviewed.

So looking at the numbers that were calculated for warming from 1910-1940 and from 1970-2000, they were 0.45 and 0.48 respectively. Assuming that the rate of warming should stay the exact same, then that means there is 0.03 deg C that could be attributed to mankind after 60 years of CO2 increase. And nothing says that this 0.03 deg C is entirely from CO2, if any of it is. The world has been constantly industrializing and building more infrastructure that absorbs more heat. So for all we know, CO2 could actually have no impact, and the “man-made” impact is us building infrastructure

Mike says:
August 1, 2010 at 6:20 pm
One point made there is this: “It is highly questionable whether this “pause” is even real. It does show up to some extent (no cooling, but reduced 10-year warming trend) in the Hadley Center data, but it does not show in the GISS data, see Figure 1. There, the past ten 10-year trends (i.e. 1990-1999, 1991-2000 and so on) have all been between 0.17 and 0.34 ºC per decade, close to or above the expected anthropogenic trend, with the most recent one (1999-2008) equal to 0.19 ºC per decade – just as predicted by IPCC as response to anthropogenic forcing.”
Mike,
looking at some artic ice date from the DMI and from GISS, there is a huge discrepancy. GISS is extrapolating their data and saying that the whole artic is well ABOVE normal, while the DMI has the artic being nearly 2 degress BELOW normal,
Here is a graph showing artic sea ice melt this year compared to previous years. http://climateinsiders.files.wordpress.com/2010/08/jaxa_july_ice_melt.png
based on this graph, (which is in the previous post on this site) which seems more accurate. The DMI seems more accurate, and GISS seems wrong. So i find it hard to trust the GISS data, when it is pretty clear that they are making up false data and claiming something is warm when it isn’t. IF they don’t include the made up data, those trends that you spoke of would be very different

Roy Spencer
Part 2, 8:52 video

Obama is still president and Lisa Jackson still heads the EPA. Meanwhile Hansen is still employed by NASA at GISS. Any questions? (We could go beyond this circle but it is good enough to make the point).

“That is, the effect of 60 years of human emission of CO2 on change in global mean temperature was nearly nil, which disproves IPCC’s theory of man made global warming.”
This is really, really bad logic.: Hint Co2 contributed to early 20th century warming. Further hint: solar forcing increased in the early 20th century.
“Note that the projection for the current global warming rate by the IPCC was 0.2 deg C per decade, while the observed value is only 0.03 deg C per decade. As a result, IPCC’s Exaggeration Factor is 6.7.”
It has been three years since the IPCC statement, not two decades. Girma Orssengo Exaggeration Factor is, ironically enough, 6.7.

Mike says:
August 1, 2010 at 6:20 pm
recent one (1999-2008) equal to 0.19 ºC per decade
Are you taking in to account UHI and land use?
0:59 video

From Mike:
“This statement is not valid for a system that is at least partially stochastic.”
And from Gary:
“The correlation of the two upward trends in the 1910-1940 and 1970-2000 periods in no way proves causation. Without supporting evidence, a valid claim cannot be made that the same climate forcing were operating identically in both periods.”
—
Could one not say the same things about tree proxy temperature reconstructions? In fact, the situation would be much worse, no?

Damn! I said, “I believe the AMO and the PDO are an integral part of our climate, specifically relating to the GMTA.”
I’M TURNING INTO ONE OF THEM!!!!! ARRGGGGHHH!!!!

Mike says:
August 1, 2010 at 6:20 pm
“My guess is this post was not peer reviewed.”
=============================================
My guess is that you think peer reviewed papers are always right.
Yes, Mike it was peer reviewed.
They pasted it in word.

“Further hint: solar forcing increased in the early 20th century.”
The new evolving Greenhouse hypothesis?

latitude
&
Dennis R. Cooper
There’s the anomaly trick. Pay no attention to the temperatures behind the curtain. 😉
Part 1, 9:33 video

Over at the Air Vent, in a fascinating discussion, Eduardo Zorita has made the point that the most recent warming episode has the spatio-temporal footprint of GHG warming. He’s discussing a paper by Christiansen et al that demonstrates that the Hockey Team’s statistics artificially decrease past variability in paleoclimatological reconstructions. He doesn’t make the point without challenge, though.
===========

Geoff Sherrington says:
August 1, 2010 at 7:45 pm
“Sorry, but I don’t buy argument 1. There could be susbstantial GHG warming in the last 20 years, offset by a natural cyclic decline so that the sum is neutral.”
Well, yes, it could be. Or maybe GHGs don’t warm us very much. The fact is, no one knows very much about our climate and the engines at work.
Remember, this was a “primer”. You raise a valid point which has been mentioned before. Of course, it is entirely unverifiable in either direction at this point in time. Given we don’t know all the factors involved in our climate, how would one prove or disprove the assertions? We should probably study it a bit more and rely on that rarely used but time tested form of critical thinking called logic. Or maybe, as was posited earlier here, we could just emit more sulfur and we could cool the earth to the point the CAGW crowd would be satisfied. Of course, then we’d run into that rotten luck and cool the earth while it was in a cooling cycle thus doubling the cooling and then we’d really be cold. Maybe we should put a little more effort in determining if warmer is indeed worse than cooler. Maybe we could used unwashed cool during cooling periods and washed cool during periods of warmth to seek an equilibrium. I don’t see why not. If man can change the climate by accident, surely we can nudge it here and there on purpose! It could be roses and sunshine forevuh!!!
With all of the grand knowledge we’ve gained about sulfurs and aerosols and CO2, if they are indeed true, then controlling our climate shouldn’t be such a big trick, but then, the assertions regarding the previously mentioned substances would have to be true. Maybe our world leaders know something we don’t. I recall a G8 summit where the guys and gals promised not to raise the global temp by 2 degrees or such.
Sorry for the sarcasm, I had a whole paragraph full of zingers, decided not to post it, deleted it, but wound back to sarcasm anyway.

The fact that the 1910-1940 warming had the same rate as the 1970-2000 warming does not disprove the conclusion that most of the warming 1950-present has been man made. This post is simply playing with numbers and trendlines and tossing around terms like ‘exaggeration factor’ to make it seem more meaningful than it actually is.
And the fact that there has been little warming in the last 10 years also does not disprove the possibility of an underlying trend of .2C/decade.

JamesS says:
August 1, 2010 at 8:02 pm
….then at most all that can be said is that the IPCC hypothesis still has no evidence in its favor.
After 22 years of focus and still no verifying evidence how about we just scrap any possibility manmade global warming could be real.

Andew says:
August 1, 2010 at 8:56 pm
The fact that the 1910-1940 warming had the same rate as the 1970-2000 warming does not disprove the conclusion that most of the warming 1950-present has been man made
Andrew,
so basically you are also associating that the warming from 1910-1940 is also mainly man-made. I disagree with this. The same natural factors that caused the warming from 1910-1940 occured from 1970-2000. However, with a big increase in CO2, one would expect that the rate from 1970-2000 would’ve been much higher, IF CO2 had an actual impact. Since they are the same, with the increase CO2, it disproves that the warming in 1970-2000 is man-made, in favor of natural cycles causing it

Ahh, but theres a flaw here….
Firstly, the sun (that is claimed to have little effect on global temperature) was responsible for the signifcant warming up to 1950, but since it has stopped causing warming (if you cherry pick your data source re: the ACRIM gap) and you of course havent accounted for the IPCC aerosol data they guestimate to enable them to force fit their models… if you had factored all of this into a an un-validated model that cant replicate PDO / ENSO etc with assumed feedbacks and parameters for various forcings… you would know that ONLY co2 can explain the warming since 1950!
You can not win against the IPCC Black Box!

Clear, concise, and devastating article.
Alas, explaining factual science to corrupt ideologues is no better than preaching morals to hardened criminals: the only things they understand and respect are money and power, and the only convincing argument for them would be a conviction at a trial.
And even then, all the way to the prison of public contempt, they will loudly protest their innocence.

Nope, looks like I missed a bracket or apostrophe. Moderator, if you would be so kind as to let me know which for future reference, I would appreciate it. 🙂
REPLY: Fixed. Just stop trying to embed links and just put the URL’s in …WP will auto link it, less hassle and work for everyone – Anthony

Evanmjones (5:28pm)
Do you mean data, genuinely raw and unadjusted (no FILNET, SHAP, TOBS, Homogenization, etc.) or do you mean “numbers as opposed to a graph”?
I mean “numbers as opposed to a graph”
Sorry about that

@girma ossengo
Sorry to rain on your parade but nothing was disproven.
CO2 level from 1880 to 1950 increased from about 285ppm to 310ppm.
CO2 level from 1950 to 2000 increased from about 310 to 360.
A 25ppm increase in the earlier record and 50ppm increase in the later.
One must keep in mind the physics here. All CO2 increases are not equal. It’s an insulator and the more you have the less effect adding more will have. It works like adding blankets to your bed. The first blanket makes a big difference. A second blanket will help but not as much as the first. A third blanket will help but not as much as the second and so forth.
Where the IPCC bungled is not attributing the warming from 1880 to 1950 to CO2 increase.
So we’re left with 0.8c of warming from 1880 to 2000 which on the face of it could very well be anthropogenic CO2 warming so we get a rate of 0.06C/decade possibly due to CO2.
Thanks largely to Anthony’s surface station project it seems safe to assume some opportunistic pencil whipping and systematic errors in the temperature record have inflated the temperature change somewhat so we’re probably looking at 0.05c/decade or 0.5C per century.
Presuming for the sake of argument that anthropogenic CO2 is responsible for the temp increase over the past century whether the trend continues, accelerates, or decelerates depends on exactly how much more CO2 gets added. If the last 75ppm increase resulted in 0.5C per century it will take 150ppm to get a 0.5C increase in the next century and to get an additional o.5C above that will require 300ppm more.
So it’s credible that a doubling of CO2 from present level will raise global avg. temperature about one degree C.
This is actually about what the IPPC predicts for CO2 alone. They get the rest of their 3-6C increase by wholesale invention of an implausible positive feedback mechanism that has absolutely no observational data that supports its existence.
So that 25ppm increase 1880 to 1950 is just about as effective as the next 50ppm increase and that will have the same effect as the next 100ppm and so forth.

Mike:
“The lack of warming in the 60′s and 70′s was most likely caused by sulfur emissions.”
Sulfur levels were close to the same level as the 1910-1940 period until the mid 70’s when they accelerated. From figure 2 above, cooling began in the 1940’s, and ended late 70’s.
Interestingly, sulfur levels have really only dropped off to near 1900’s levels just before 2000, when warming levelled off.
I’m referring to NASA’s website:
http://earthobservatory.nasa.gov/Features/GISSTemperature/giss_temperature4.php
If I were making a correlation between the two simply based on those observations and totally ignored the physics, that would tell me sulfur causes warming, not the other way around.
Hansen even says the cause has just been a “suggestion”. It seems it was a fleeting thought without even checking the actual observations. It also seems most alarmists have grabbed onto the idea because it (mistakenly) supports their propaganda.

James Sexton says
If man can change the climate by accident, surely we can nudge it here and there on purpose! It could be roses and sunshine forevuh!!!
Man can not change the climate by accident but 6 billion, going on for 7, surely could. Just as one cyanobacterium could not produce much oxygen but quadrillions certainly did.

Gary says:
August 1, 2010 at 6:22 pm
“There’s a logical fallacy in the author’s argument against IPCC claim #1. The correlation of the two upward trends in the 1910-1940 and 1970-2000 periods in no way proves causation. Without supporting evidence, a valid claim cannot be made that the same climate forcing were operating identically in both periods. The conclusion that “the effect of 60 years of human emission of CO2 on change in global mean temperature was nearly nil, which disproves IPCC’s theory of man made global warming” extrapolates way beyond the data presented here. It may very well be true that CO2 emissions have a small effect on the global average temperature; however, this essay fails to make the case.”
Sorry Garry, but you’re completely missing the points the author made. This post shows that the IPCC statements were wrong, and that CAGW conjecture has been falsified. The 1910-1940 rise was due to ‘natural causes’ however, as CO2 levels were much less than they are now, clearly the IPCC climate scientists have failed to prove the link.
History shows that climate is never stable, rather it oscillates up and down quasi-cyclically. Because the system is driven by deterministic chaos the cycles never repeat themselves identically, but broad patterns emerge like the 60y(ish) cycle shown above and the more significant 100y(ish) cycle shown below:-
1410-1500 cold – Low Solar Activity(LSA?)-(Sporer minimum)
1510-1600 warm – High Solar Activity(HSA?)
1610-1700 cold – (LSA) (Maunder minimum)
1710-1800 warm – (HSA)
1810-1900 cold – (LSA) (Dalton minimum)
1910-2000 warm – (HSA)
2010-2100 (cold???) – (LSA???)
It is a travesty that governments around the world are being badly misled by climate scientists and they and their supports will have to take responsibility for not preparing for the coming cold which could prevent the deaths of millions of people in the third world.

Dave Springer, you’re bang on the money.
If more people realised these essential properties of CO2 and that every scary news story they read about big temperature, sea level rises and disaster was wholly reliant on the entirely unproven and logically unlikely positive feedbacks, they’d stop worrying straight away.
‘Stop worrying’. The most dreaded words in the english language for alarmists.

This is a point I have made many times. The slope of the warming from 1910 to 1945 is at least as great as from 1978 to 2000. Why is one manmade and the other not?
False dichotomy. There are other processes at work. The basic flaw in the reasoning from the top post, which is perpetuated in the comments., is the implication that there is only CO2 acting on temperature at all times in the instrumental record. Thus, a portion of the earlier warming period can be attributed to industrial CO2, another portion to solar increase, waning volcanic activity and so on. The difference with the latter period is that there has been little solar influence (neutral or negative depending which data set you look at), and neutral long-term volcanic influence. One of the reasons that the post-195 period is highlighted is that the period is little influenced by other forcings – hence, the warming can be attributed more readily to human industry.
So a proper examination of human contribution to climate change would factor in the other influences on climate, rather than pitting a bi-polar argument. That this rounder treatment is entirely lacking in the top post fatally compromises its conclusions.

The fact that there are 3 different instances of Global Warming with roughly equal periods of frequency, magnitude, and length does not prove that the third instance is not caused by CO2.
It does require that those who claim that the 3rd is caused by CO2, but not the first 2, find a plausibly different reason for nearly identical phenomana.
Those who make the assertion must be able to back it up better than just saying that they can’t think of another explanation.

Here we have again a false dichotomy. ‘Caused by CO2/not caused by CO2’. Attribution has been and is discussed at great length in the scientific literature, and those suggesting that ‘they can’t think of another explanation’ are clearly completely ignorant of the subject.
At the woods for trees site, you can run trends for solar influence for the periods in question.
http://www.woodfortrees.org/plot/sidc-ssn/from:1880/to:1910/trend/plot/sidc-ssn/from:1910/to:1940/trend/plot/sidc-ssn/from:1940/to:1970/trend/plot/sidc-ssn/from:1970/to:2000/trend/plot/sidc-ssn/from:1880/to:2000
This is a very basic start to doing some research. We see that the solar trends anti-correlate for two out of the four temperature periods mentioned in the top post. For a reasonable enquirer, this would lead to more questions being asked, rather than any conclusions. What other influences are there, how strong are they etc?
If you think these questions have not been addressed, start with the IPCC, and then go to google scholar and put in some well-selected search terms. There is plenty of information out there.
I’ll provide references if anyone is interested, but I’m leery of wasting time with people who have fixed opinions and are only into jousting.

Global warming graphs are like those butterfly ink blots which tell you more about the psychology of the observer than about the ink blot. Glass half full, glass half empty, the two faces that turn out to be a vase.
If you were to look at the global warming plot and believe it to be part of a natural cycle, then you can’t imagine how anyone could be afraid of it. If however you look at it as someone unnatural and increasingly unnatural, then you project the graph to explode “climatixally” upward.
Fortunately for me I’m an electronics engineer by background and have the tools to analyse signals by mathematics and can bypass the brain’s tendency to over-interpret such graphs.
So … it’s totally consistent with 1/f type noise. This kind of signal will appear to the untrained eye as if it has patterns: short cycles, up or downward trends. These are just illusions of the mind and if there were any real signal in the last 150 I would have found it by now!

Boris on August 1, 2010 at 7:01 pm – I’m an AGW sceptic, but I have to agree with you completely. The weaknesses in this piece are elementary. It doesn’t deserve the space on this site. Intelligent warmists (yes, of course there must be some) will be licking their lips at the thought that so many “sceptics” have fallen for it’s simplistic approach. I think the believers on here need to re-read this with Boris’s 2 simple criticisms in mind, and to allow their natural scepticism at least to come to the fore. It’s school kid stuff. The idea that’s it’s of PhD calibre is farcical.

“One must also keep in mind that correlation is not causation.” – David Springer
Yes, if only the IPCC and other alarmists would keep that in mind when they are soothsaying doomsday scenarios in papers and to the media or writing their “climate projection” software and marketing the results as “valid certain futures” rather than admitting that it’s pure speculation (and usually Nostradamus has a better track record).
Correlation is not causation. Prediction without understanding the causal relationships is no better than soothsaying dead tree ring entrails. Nature’s simple systems of weather and climate produce internal randomness preventing any prediction at all. Climate is not an equation that can be solved. No model is the territory of Nature. To truly know the future of systems that generate their own internal randomness you must observe the present and let the future unfold (Stephen Wolfram). To be complete and valid all good scientific hypotheses must state how they can be falsified (Richard Feynman). It is easy to fool others when you’ve fooled yourself in science (Richard Feynman).

If you look at the Jones BBC interview, when this same info was presented to him and he was asked why this last warming period was different, his explanation was that the Climatologists could explain the earlier warming periods but not this latest one. No details were forthcoming and not likely to be either.
But foundations of sand come to mind. 😉

Re: Dave Springer, August 1, 2010 at 10:41 pm
“[..]If the last 75ppm increase resulted in 0.5C per century it will take 150ppm to get a 0.5C increase in the next century and to get an additional o.5C above that will require 300ppm more. So it’s credible that a doubling of CO2 from present level will raise global avg. temperature about one degree C. This is actually about what the IPPC predicts for CO2 alone. They get the rest of their 3-6C increase by wholesale invention of an implausible positive feedback mechanism that has absolutely no observational data that supports its existence. [..]”
Just in order to clarify, since I am not sure how much of the statement above is Dave and how much is reciting from IPCC:
There is a recent trend of about 0.5C per century in measurements, which can be attributed to CO2 and from there (at least that what I understand) you conclude, that inceasing the CO2 from now by 150ppm should have roughly the same effect.
So I just want to point out that this measurment, seems to indicate about 1C total warming since 1880 until 2100 as a maximum CO2-effect concluded from the measurements. However this already includes all feedback and contradicts the IPCC-estimate of 3C per doubling.
I asked a similar question at RC and if I understand Gavin’s answer correctly the IPCC-position depends on delayed effects (which are not found in nature AFAIK).
I think you can write the IPCC-point of view in the following relations:
280 -> 560ppm 3.7W/m^2 additional forcing (without feedback) => 3C
280 -> 380ppm +X1 1.7W/m^2 additional forcing (without feedback)+X2 => 1.4C+X3
Where the X1,2,3 are all other (natural!?) effects which happened during the increase of CO2. Gavin points out, that these estimates might have huge error bars!
(Actually I thought direct the forcing for different CO2 levels is known quite well)
In any case it seems to me, that the IPCC seems to count on almost 1C warming which is caused by the actual CO2-level but somehow delayed/hidden (the lack of evidence for that is what K. Trenberth called a “travesty”)

Girma
Yes, I agree that there is a roughly 60 year cycle (30 years up and 30 down) that can be abstracted from the total process – it’s been identified on here many times – and there is every likelihood that it will persist, but according to the temp data, the up and down steps are not self cancelling within the whole, ie their removal doesn’t leave the trend neutral – you had to level it out of the upward trend of the 20th C. to illustrate its dimensions clearly. I’m not saying of course that the upward trend is caused by the increase in atmospheric Co2, because so far as I can see there has been no entirely convincing explanation for it; it may even be the case that we don’t have the wherewithal to explain it yet, given the complexity of the beast.
Nor should we be entirely convinced that the temperature trend is upwards to the extent claimed either. The comparability of much of the data with previous data is not as strong as it should be for various environmental reasons, and so much processing has been inflicted upon it, that its value is questionable. I’m still waiting for someone to identify only those sites which have not been contaminated and which give a continuous record for 100 years plus, and to present the data (unprocessed) for consideration.
The final leg of the argument depends upon the passing of the next twenty years at least – probably 50 – before your case is made. Modelled evaluations and the collision of opinion over models may be interesting and occasionally revealing, but the only test worth quoting conclusively is the reality test. But to fully make sense of the reality test I think we need to know a little more than we do at present. The AGW group may turn out to be right – or wrong – but as much by chance as anything else . . . Toss a coin – an apparently simple act with many unknown factors at work – and there’s a fair chance you’ll guess which way up it lands . . . . It’s going to be some time yet before the climate coin lands . . . I see much groping in some serious darkness until then.

barry says:
August 2, 2010 at 1:12 am
At the woods for trees site, you can run trends for solar influence for the periods in question.
Indeed they can. If we do a little cherry picking.
http://www.woodfortrees.org/plot/sidc-ssn/from:1880/to:1910/trend/plot/sidc-ssn/from:1910/to:1940/trend/plot/sidc-ssn/from:1940/to:1970/trend/plot/sidc-ssn/from:1970/to:2002/trend/plot/sidc-ssn/from:1880/to:2009
This is a very basic start to doing some research. We see that the solar trends anti-correlate for two out of the four temperature periods mentioned in the top post.
The first person to mention solar forcing was:-
Boris says:
August 1, 2010 at 7:01 pm
This is really, really bad logic.: Hint Co2 contributed to early 20th century warming. Further hint: solar forcing increased in the early 20th century.
Up until then nobody mentioned it. So it’s a red herring he used to patch up the infallible hypothesis of AGW.
Tenuc takes the bait
August 1, 2010 at 11:49 pm
1910-2000 warm – (HSA) High Solar Activity
He didn’t attribute any solar forcing too the upstep in temps between 1970-2000, that was your invention. So is was right?
http://www.woodfortrees.org/plot/sidc-ssn/from:1910/to:2000/trend/plot/sidc-ssn/from:1880/to:2000
Indeed he was. So barry the article is not about attributing any thing too the warming since the LIA. It is just assumed to be natural. I’ll leave you to demonstrate the Marxist approach to science with a masterful example of how to construct infallible hypothesis, using your own words.

Thus, a portion of the earlier warming period can be attributed to industrial CO2, another portion to solar increase, waning volcanic activity and so on.

Throw in rice farming and get Nature or New Scientist to peer review it and you have publish work to your name. Welcome to the consensus.

By the way, Dr. Orssengo this was an outstanding article.
Very clear and understandable with compelling evidence for your assertion.
Thank you for taking the time to write this excellent article.

Oh yes. One more “thing” for the scientist that want all this regulations.
Be warned. The regulations you seek will turn around and bit you or your children or your grand kids or their grand kids. It just a matter of time.
What freedom are you NOT WILLING to give up before you make a stand?

barry: At the woods for trees site, you can run trends for solar influence for the periods in question.
Martin: Indeed they can. If we do a little cherry picking.
Why on earth are you cherry-picking? I used the same time periods as the top post did. You did not.
Up until then nobody mentioned it. So it’s a red herring he used to patch up the infallible hypothesis of AGW.
What, are you saying that nobody mentioned it upthread of Boris’s post, or that this wasn’t mentioned in the early part of the 20th century?
Well, the former is irrelevant, and the latter is irrelevant because scientists had not attempted to plot the global temperature in the early 20th century.
I can’t make sense of much of your post. I pointed out some anomalies re the advice in the top post, in order to encourage enquiry. Ignorance can be cured by curiosity. There is no cure for a lack of curiosity.
I’m still willing to link up to sources on attribution if any genuine enquiry is forwarded.

Girma says:
August 2, 2010 at 3:30 am
Is it not extremely curious for the AGW camp in effect say the global warming rates for the period from 1910 to 1940 is nearly identical to that for the period from 1970 to 2000 because nature and human emission of CO2 swapped sides to produce equal effect in opposite directions after a 60-years interval?
I wonder who organized nature and human emission of CO2 to swap sides exactly after 60 years to produce the same effect!
I am extremely curious to know.

It’s quite understandable once a person examines the year to year history of ppm CO2 concentration. 25ppm rise 1880-1950. 50ppm rise 1950-2000. Additionally one must understand how insulation works to see that it takes twice as much additional Co2 to get the same effect as the last increment.
In short, the two periods are perfectly consistent with each other and with hypothetical anthropogenic CO2 warming ocurring over the entire period at the rate of about 0.05C/decade or one half degree per century.

Excellent and clearly expressed article.
When the complex concept of Man-made global warming that can never be falsified due to the contrary qualities assigned to it by its proponents is given some consideration, suspicions arise that the UN strong-armed various governments to entice tame scientists to provide the unfalsifiable scenario to enable the UN to take over the reins (and the Revenue) of national governments around the world and redistribute that Revenue to favoured nations. I am beginning to think that many scientists are ‘willing fools’, eager to do ‘science’ for gain.
Thanks are due to WUWT for providing a sane, rational and gentlemanly forum which will allow the scientific truth to emerge.

Isn’t the accepted premise amongst the proper scientific community that heat increase pre-dates any CO2 increase by a factor of 500-800 years. If this is the case, isn’t the recent increase in CO2 therefore attributable to the MWP and not AGW? Just a thought………….

I wonder who organized nature and human emission of CO2 to swap sides exactly after 60 years to produce the same effect!
Well, only you, I think. It’s not as seen as one or the other in the literature.
Basically, solar activity increased during the early part of the instrumental record, supplementing the warming from CO2, such that the rate is similar to the morwe recent period, when the solar trend has been flat or slightly declining.
But that’s only a piece of the puzzle. There are other factors at play. Without assessing as much as possible, there isn’t enough data to draw any kind of conclusion.
Once again, it’s not an either/or situation. Solar activity, volcanic activity, industrial CO2 and aerosols and so on contribute to climate change. These effects have been teased out to the best of our ability, and should be read up on.

Isn’t the accepted premise amongst the proper scientific community that heat increase pre-dates any CO2 increase by a factor of 500-800 years. If this is the case, isn’t the recent increase in CO2 therefore attributable to the MWP and not AGW?
No.
CO2 increased by 100 ppm over 4200 years during the temperature rise out of the last ice age. We’ve had a 100 ppm increase in 150 years in the modern era.
Further, the planet warmed by 5 – 6C out of the last glaciation. Medieval warming – according to the highest figures suggested by skeptics – was barely half that.
Also, the isotopic ration of industrial CO2 is different to that naturally occurring. We can measure the anthropogenic portion of CO2 change, and we find that what we estimate from calculating how much we’ve burned, is a good match with chemical analysis.

Martin, your post is illogical, and you have misinterpreted my contribution and the thrust of the top post. I have no interest in sorting that out with you, but here are some scientific papers on attribution, most available in full text. There’s been plenty of work done on it.
http://agwobserver.wordpress.com/2010/03/25/papers-on-formal-attribution/
IPCC dedicate a whole chapter of the latest report to attribution:

“A key objective of this chapter is to understand climate changes that result from anthropogenic and natural external forcings, and how they may be distinguished from changes and variability that result from internal climate system processes.”

http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter9.pdf
If you have any curiosity in you, happy reading.

MartinGAtkins (#10:52)
Thanks a million for your excellent response to their questions.
I loved this one:
Chuck in a little bit of this, throw in a little bit of that and bingo, the train wreck that is AGW lives to fight another day.

Gary says:
August 2, 2010 at 8:15 am
“J.Hansford, DirkH, Vorlath, Ed Caryl, JamesS, DoubtingThomas, and Tenuc:
To varying degrees you miss my point which simply is that this essay assumes correlation is causation in it’s refutation of the “IPCC first claim.” Read carefully and avoid jumping to conclusions that I support the IPCC or that I think CO2 is the sole or even primary cause of warming (neither of which I do, btw). I’m only criticizing the author’s naive argument here. He needs to do better. Jumping to the defense of poor arguments and misrepresenting criticism of them does nothing to advance understanding.”
Gary, just to be clear that this is the IPCC statement you refer to.
“Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations. ”
Please explain how, given the long-term climate warming trend since the Little Ice Age, the rate of warming from the period starting 1920, is the same as the rate of warming seen since the mid-20th centuary? CO2 levels were vastly different between those two periods. This means that the extra CO2 had no statistical effect on temperature trend or the influence of CO2 was so weak in was drowned out by natural changes. In either case, the CAGW conjecture is falsified.
Dr. Girma Orssengo’s post is a brilliantly simple refutation of the IPCC’s extraordinary and risible claims. In science, the null hypothesis (in this case natural changes due to the vagaries of the deterministic chaos inherent in this complex system) remains in place, until a new conjecture makes better predictions. CAGW has failed and needs to be consigned to the waste bin.

I posted this many hours ago and it has still not appeared. I’ll give it another go.
—-
This post makes several very basic errors.
The method proposed to answer the first question is absurdly simplistic. It could only work if a) no climate-influencing variable other than CO2 concentrations were varying; b) the effect of CO2 concentrations on temperature was linear. We know, in fact, that the effect of CO2 is logarithmic, not linear, and that many other things differed between the first and second halves of the 20th century, such as solar and volcanic activity. The attempt to conclude that CO2 is not a greenhouse gas is ham-fisted in the extreme.
The attempt to disprove the second claim is yet another confusion of “weather” and “climate”. 10 year temperature trends are largely meaningless in climate terms – they are too short. I would have thought that anyone who was actually interested in the science of Earth’s climate would have learned this distinction very early on. And yet, this blog continually, and presumably deliberately, confuses the two.
On a broader point, it is strange to see the post talking about “the IPCC’s theory of man-made global warming”. There is no “theory of man-made global warming”; there is the theory of atmospheric physics, and predictions of anthropogenic global warming are a consequence of that theory. And the IPCC certainly did not invent this non-theory in the first place. I think this shows a certain ignorance of the scientific background and the nature of the IPCC.

Boris:

This is really, really bad logic.: Hint Co2 contributed to early 20th century warming. Further hint: solar forcing increased in the early 20th century.

There was a net zero contribution to warming from anthropogenic activity, anthropogenic CO2 being balanced by sulfates… and we don’t know solar forcings increased, that is an inference (it is required to explain the early 20th century warming…chicken meet egg).

If somebody had turned in a graph like that (fig 1) with that green “trend line” on it in my Physics class; they would have gotten a failing grade.
The green line clearly contains much less information than the Red line. Why not simply get rid of ALL of the information, and simply replace the graph with a single number; the simple average of all the points; or maybe the RMS average of all the points; or maybe the average of the fourth power of all the points; or maybe the RMS of the 4th power of all of the points.
Alternatively; why not just leave the information alone to tell its own story.

“”” RW says:
August 2, 2010 at 2:12 pm
I posted this many hours ago and it has still not appeared. I’ll give it another go.
—-
This post makes several very basic errors.
The method proposed to answer the first question is absurdly simplistic. It could only work if a) no climate-influencing variable other than CO2 concentrations were varying; b) the effect of CO2 concentrations on temperature was linear. We know, in fact, that the effect of CO2 is logarithmic, not linear, and that many other things differed between the first and second halves of the 20th century, such as solar and volcanic activity. The attempt to conclude that CO2 is not a greenhouse gas is ham-fisted in the extreme. “””
“”””” We know, in fact, that the effect of CO2 is logarithmic, not linear “””””
So T2 – T1 = (cs).logbase2(CO2,2/CO2,1) where the symbols are obvious to anyone with ordinary skill in the art.
So where are your FACTS that establish this; either actual observed peer reviewed measured data; or a peer reviewed Physics theory that explains why the relationship is logarithmic and not linear; or something else.
Since (cs) is uncertain to the tune of +/- 50 % giving a 3:1 range of values; and since we have less than 1/3 of one doubling of CO2 of actual measured global CO2 abundance since 1957/58 IGY, how could anyone possibly distinguish between a linea fit to that data, and a logarithmic fit; or for that matter a fit to the function:- y = exp (-1/x^2)
The decay time of a radioactive nuclide species is logarithmic with the abundance of the nuclide. The forward Voltage of a semiconductor diode is logarithmic with the forward Current.
There is no basis for claiming that the mean global surface Temperature is logarithmically related to the atmospheric CO2 abundance; they do not even always move in the same direction; and by the way; just what is the time delay between the value of the atmospheric CO2 abundance, and the mean global surface temperature that it is logarithmically related to; or does the same relationship hold for any time delay ?
Enquiring minds want to know.
By the way; the primary “FORCING” that drives the CO2 causation of mean global Temperature change is in fact the surface emittance of LWIR thermal radiation from the suface of the earth; that is where everything must start. That “forcing” is itself a function of the fourth power of the very surface Temperature it purports to cause; and from point to point on the earth that emittance varies by more than an order of magnitude; and everywhere in between at the same time; somewhere on earth.
So please straighten all that out for us; and please don’t introduce any other possible causation sources like say some effect due to other materials like water for example; which is permanently present in the earth’s atmosphere in all three phases of ordinary matter; we are only interested in the CO2-Tempertaure connection; not the entirety of known Physics and Chemistry.

Smokey,

The UN/IPCC is thoroughly corrupt.

So you say. My point was that attribution has been studied – against Martin’s notion that no work had been done on it. There is another link in my post to a list of scientific papers on the subject.

barry says:
August 2, 2010 at 10:31 pm
Martin’s notion that no work had been done on it. There is another link in my post to a list of scientific papers on the subject.
After reading through my posts I cannot find any instance of my having said that “no work had been done on it” with regard to attributing causes for past climate variations. Threads can become complex and errors can occur but please in future be more careful about attributing something to me that is not based on fact.
Thank you for the links, I will read through them at length and I’m sure you will agree that each paper in the first link would deserve detailed examination before an in depth response. We may at some later date and in an appropriate threat pickup this subject again. I will however give you a first glance response.
I have read through various chapters of the IPCCs report and I am not going to do it again. It’s you who are positing causation for past climate responses. Virtually throwing a pile of papers at me and thinking this lets you of the hook won’t work. It only shows you have no grasp of the subject and defer to a higher authority to do your talking for you. Do you think I’m going to trawl through pages of crap just to find out what you think supports your position? Here you are using the debating tactic of the organized retreat. When you can’t answer the question you hand your opponent a book and ask them to find the answer for you.
So we can chuck the IPCC pdf in the trash can unless you can cite the study and on what page you think supports whatever position you hold.
As for the link to:-
http://agwobserver.wordpress.com/2010/03/25/papers-on-formal-attribution/
These papers would take detailed study but let’s have a few brief snippets of the quality we can expect from them.

Anthropogenic forcing dominates sea level rise since 1850 – Jevrejeva et al. (2009) “
“Here we use a delayed response statistical model to attribute the past 1000 years

Don’t you just love the way pseudo-scientists can model anything and get the result they want. The paper progresses thus:-

We show that until 1800 the main drivers of sea level change are volcanic and solar radiative forcings. For the past 200 years sea level rise is mostly associated with anthropogenic factors.

Brilliant! With a little data input here and a radiative forcing there we can run our model for a few cycles and show that evil humanoids have been buggering up the climate for two hundred years. Gosh darn, if we run the model some more we can eliminate the Chicxulub impact from killing the dinosaurs and blame it on the carbon dioxide that mankind was going to produce some time in the future, just like we can get those wicked wealth producing nations to compensate under developed nations for the all the climate catastrophes that occur now and in the future. Is there anything Marxist science cannot prove if it is so wishes?
The next paper is another toy town study.

A Multimodel Update on the Detection and Attribution of Global Surface Warming – Stone et al. (2007)
“This paper presents an update on the detection and attribution of global annual mean surface air temperature changes, using recently developed climate models”.

This next paper can apparently model anything with or without the required parameters. It’s hard to tell because the link to the full text doesn’t work.

The Detection and Attribution of Climate Change Using an Ensemble of Opportunity – Stone et al. (2007) “This paper presents an extension to the fingerprinting technique that permits the inclusion of GCMs in the multisignal analysis of surface temperature even when the required families of ensembles have not been generated.

And so on. I’m getting tired now, so I’m going to model My self some sleep after I’ve drunk my modeled cup of tea.

Does the argument hold if you go back into the 19th century also: think it’s Grand Slam in the 7th Game of the World Series if it does?

Andew says:
August 1, 2010 at 8:56 pm
The fact that the 1910-1940 warming had the same rate as the 1970-2000 warming does not disprove the conclusion that most of the warming 1950-present has been man made
Andrew,
so basically you are also associating that the warming from 1910-1940 is also mainly man-made. I disagree with this. The same natural factors that caused the warming from 1910-1940 occured from 1970-2000. However, with a big increase in CO2, one would expect that the rate from 1970-2000 would’ve been much higher, IF CO2 had an actual impact. Since they are the same, with the increase CO2, it disproves that the warming in 1970-2000 is man-made, in favor of natural cycles causing it

No, I am saying some of the warming 1910-1940 was probably man made, man-made warming moderated the cooling 1940-1970, and intensified the warming 1970-2000. Thus the long term trend is upwards, and man-made warming is contributing an increasingly large % to the rate of temperature change. Perhaps the natural factors for warmign 1970-2000 were not quite as strong as those 1910-1940, or the starting point in 1910 was just much lower. But man-made warming is perfectly consistent with a long-term trend with two periods of equal rapid warming. In fact, it is the only way to fully explain the long-term trend since 1900.

I overlaid the number of stations graph over the GISS temperature anomaly graph and lo and behold there is a sharp climb in temperatures when the stations were being reduced.

Analysis of the temperature record including the dropped stations have shown that they make the later temperatures warmer, not cooler.
http://clearclimatecode.org/the-1990s-station-dropout-does-not-have-a-warming-effect/
http://rankexploits.com/musings/2010/a-simple-model-for-spatially-weighted-temp-analysis/
(The second link is from a well-known skeptical blogsite)

Girma,

Barry (#10:06)
This is what you are saying in effect:
For the period from 1970 to 2000, after human emission of CO2 for 60 years, the effects of nature and human emissions of CO2 swapped places to produce the same global warming rate as for the period from 1910 to 1940.

No, that’s what you are saying. I said something different, and I said it three times in the last post. I also backed it up with corroborating papers – as requested. Try reading them. Until someone can properly iterate and respond to what was actually said, then there’s no point continuing. I’ll check in over the next couple of days to see if anyone has something informed and substantive to say. If you’ve read up on the subject, please share your insights. Some reference material would be great, too.

Interesting. My calculations were off by 5 years as compared to yours. My mid-points were 1930 and 1990 for the warming periods. I used mid-points for the reasons discussed in the recent WUWT posting about peak to peak. — John M Reynolds

A better way to get the underlying trend (and smoothing the supposed cycle instead of emphasisng it), is to run a series of trends with a fixed start point, to see how the trend behaves over longer data periods.
Linear regression runs:
1850 – 1910
1850 – 1940
1850 – 1970
1850 – 2000
1850 – 2010.5
The trend lines get progressively steeper in the positive.
That was done using as much data possible. The same result is achieved using 1880 as a start point, and running trends to each of the nominated phase transition points.
Apart from the statistical benefit of increasing significance with the longer trends, we better map the progress of the underlying centennial trend instead of subjecting the data to a questionable cyclicity.
Girma, the linear trend for the time period in the top post (1880 – 2010) is 0.6. After compression, the detrend value selected is 0.775. Does this ring any alarm bells?
I’ve replicated Orsengo’s graph at woods for trees.

This is also shown in the top post. Missing from the argument is analysis of the contribution of various forcings for those time periods – the study is known as ‘attribution’. I have posted numerous scientific references that DO examine attribution, and the findings are as follows.
Increasing CO2 forces temperature upwards over the century.
For the time period 1910 – 1940, natural forcings provide a positive contribution to the temperature trend. So does CO2. Natural and anthropogenic forcing combine to increase temperatures.
For the time period 1970 – 2000, natural forcings provide a negative contribution to the temperature trend. CO2 provides a positive contribution. The trend is similar to the previous period, but the contribution of natural forcings is negative.
Subtracting the natural forcing from each trend, we find that the forcing from CO2 has increased.
Please refer to my post upthread for references.
The flaw in the your argument is the assumption that natural processes contribute equally to the trends.

Barry
The global warming rate of about 0.15 deg C for a 30-year period recorded 100 years ago for the period 1910 to 1040 has not been exceeded.
The current global warming rate is only 0.03 deg C per decade.
No alarm.
No catastrophe.
Start to worry if, in the future, the global warming rate in any 30-year period exceeds 0.15 deg C.
STOP SCARING THE WORLD AND BRAIN WASHING KIDS!

At this stage, I don’t believe humans are able to apportion percentages for the effects of man made and natural forces on the global mean temperature trend.
Barry, we are at 0.03 deg C per decade. Why worry?
Thanks by the way, unlike others in your camp, you play the ball, not the man.

Disprove the AGW myth? For me the easiest consideration is at http://cleanenergypundit.blogspot.com

I see a lot of assertions but no references. Is there anything to back up these opinions?
For instance:

At this stage, I don’t believe humans are able to apportion percentages for the effects of man made and natural forces on the global mean temperature trend.

Ok, can you point me in the direction of the material you’ve read that helped you establish this position?
There is, of course, uncertainty, particularly in the early part of the record. But the same goes for temperatures. The error bars on early temps are wider than recent temps. Do you think this qualification should appear in the top post, and modify the quite absolute conclusions? I do.
And;

Considering this 1970 – 2000 period you claim that doesn’t make any sense at all. Natural ocean cycles and albedo have clearly contributed towards the period.

In what way? What caused ocean and albedo changes? Where are the scientific references that helped you form your opinion on the 1970 – 2000 period?
It’s far too early to discern the climate trend from 2000. We’ll be able to say something meaningful (statistically significant) about climate from 2000 in 10 years. Weather influences dominate any trend from then at this time.
Just for fun, though, seeing as we’re playing with short time periods, the global temperature trend since 2008 is 1.1C/decade. Global warming has returned with a vengeance! 😉

Why worry?

I have no emotional attachment to the issue of global warming. I am fascinated by science, how people interpret it, and how people think, particularly amongst the skeptical milieu. I’ve learned that as a general rule, scientists qualify their conclusions (read just about any scientific paper): blog-based skepticism usually expresses itself in absolute terms (like news headlines – on either side). There’s plenty to keep me interested here, and enough convivial conversation to engage. I return the compliments on keeping to the subject, Girma. 🙂

Where does the IPCC posit that it wants to increase fossil fuel prices? I haven’t seen that in the report. My inclination is to reject this assertion outright, but I’ll wait to see if you can provide a reference from the body of the report. A page number would be good so I can check the context.
IPCC posited a 0.2C rise per decade over the following two decades (from 2007, when the report was published). It is premature to judge three years out, and ten-year cool/flat trends are observed in the centennial trend, which is warming overall. Mid-range model projections ensembles also have runs with decadal flat or cooling trends, that wind up hot over the long-term.
I don’t know how many times it takes to point out that a ten or twelve year trend is not statistically significant with respect to climate, before it sinks in. We will likely get neutral or cool trends for a decade into the future, even if the centennial trend winds up matching projections.

destroy the world economy and cause immense pain

Economic forecasts of mitigation costs put the figures around 1 – 2% of GDP. Forgive me, but I see your comment as the skeptics brand of alarmism.
Personally, I doubt governments, particularly democracies, will do much for the foreseeable future. They are systemically unequipped to deal with long-term issues. Why worry?

Girma, you realize that your reply to my query on your sources for attribution – has nothing to do with attribution?

Yes, Girma. I agree that’s what the graph shows.

Barry
Girma, you realize that your reply to my query on your sources for attribution – has nothing to do with attribution?
As IPCC’s projections as shown in the above link are wrong, its attribution cannot be right.

Barry
Because someone is wrong about X, they must also be wrong about Y
No. It is actually Because someone is wrong about X, they must also be wrong about X; where X is determination of global warming rates.
Don’t you think it is more meaningful to look at a decadal global warming trend as indicator of global warming than talking about the “maximum annual temperature since record began”? (Look at Figure 4)
Since global warming rate is positive and was 0.15 deg C per decade 100 years ago, does not this mean that the temperature in a given decade is in general greater than the decade before? Why is this used as scaring tactic by environmentalists?

Wow. Barry suggests that the natural contribution is negative or neutral for the 1970 – 2000 period. That was when the warming rate was around 0.06 deg C per decade. We are now at 0.03 deg C per decade. Since CO2 levels are still rising, the natural forcing must be much more negative now in Barry’s eyes to cancel out the CO2 forcing.
Either we are in the middle of a large cooling period that is being counteracted by our emissions, or Barry is wrong. Just in case he is not wrong, we should continue our emissions to keep us from freezing!
John M Reynolds

Mike Hohmann
August 6, 2010 at 1:55 am
It would be excellent if we could provide links for your list of CO2 proportions from various sources.

Mike Hohmann
Thank you for providing the link.

Barry
I agree with your previous post.
How about if we compare the global warming rate since 2000 with all the other 10-years global warming rates for the two warming periods of 1910-1940 and 1970-2000 as shown in the following graph:
http://www.woodfortrees.org/plot/hadcrut3vgl/from:1910/to:1940/compress:12/plot/hadcrut3vgl/from:1910/to:1920/trend/plot/hadcrut3vgl/from:1920/to:1930/trend/plot/hadcrut3vgl/from:1930/to:1940/trend/plot/hadcrut3vgl/from:1970/to:2000/compress:12/plot/hadcrut3vgl/from:1970/to:1980/trend/plot/hadcrut3vgl/from:1980/to:1990/trend/plot/hadcrut3vgl/from:1990/to:2000/trend
Here are the periods and their corresponding global warming rate in deg C per decade.
For the first 30-years warming period of 1910-1940
1910-1920=>0.21
1920-1930=>0.07
1930-1940=>0.22
For the second 30-years warming period of 1970-2000
1970-1980=>0.09
1980-1990=>0.07
1990-2000=>0.25
When you compare the global warming rate since 2000 of 0.03 deg C per decade with the above results, we see the current warming rate is about half of the minimum rate of 0.07 deg C per decade above, showing that the current global warming rate has decelerated.
Don’t you agree?

Global Warming Rates Per Decade

Anthony
The instruction given at the bottom of the comment does not work.

This one works
“title”

When you compare the global warming rate since 2000 of 0.03 deg C per decade with the above results, we see the current warming rate is about half of the minimum rate of 0.07 deg C per decade above, showing that the current global warming rate has decelerated.
Don’t you agree?

If you are talking about weather trends, yes. If you are talking about climate trends, no.
We’re agreed that 10-year trends are too short to reflect climate trends. This is seen with the data you have provided on decadal trends and the climate periods nominated in the original post. (30 years is a statistically valid length of time to measure climate)
Now, if ten-year trends are too short to reflect climate, let’s use time periods that are long enough. 20 years is a valid minimum period.
I will plot the temperature from 1980 – 2000. This is a 20 year period, the minimum we can safely use.
Then I will plot the period 1980 – 2010 to compare.
If global warming has ‘decelerated’ in the last 10 years, we would expect to see the second trend line at a lower rate than the first, right?
Here is the result.
Let’s try the same thing with the period 1970 – 2000, and then add ten more years up to 2010 and compare the trends.
Here is the result.
The logic of doing it this way is as follows.
1) We are using time periods that are statistically significant with respect to climate
2) Both trend analyses use the same data, and the second adds the last ten years (we’re comparing apples to apples)
Let’s use the most up to date data in 20 year blocks. I will plot the trend lines 1970 – 1990, and 1990 – 2010 to compare.
Here is the result.
Global warming, with respect to climate, has not decelerated in any of these analyses. In each case, it has accelerated slightly.

Barry
You wrote:

In the top post, the 0.03C/dec temperature trend is calculated for the period January 2000 to December 2009 inclusive. However, we have data up to June 2010. What happens if we include that in the analysis?

I disagree.
As the day time temperature cannot tell you the average for the 24 hours, half years GMTA averages cannot tell you the average for the whole year. As a result, you must include the average for the whole your in your calculation of trends. We have to wait until December to calculate the new value for the warming trend since 2000.
You wrote:

If we run the trends for 20 years on each data set, one thing we notice immediately is that there is much less divergence between them.

I disagree.
As shown in Figure 2, there is a GMTA turning point at year 2000. As a result, it is not meaningful to calculate trends for the last 20 years, which includes the GMTA turning point. You need to start your calculation for current trends from year 2000.
You wrote:

The top post looks at only one data set – HADCrut.

Barry, we only have two long range datasets: gistemp & hadcrut3vgl
Unfortunately, gistemp manipulates its data as shown here:
http://jonova.s3.amazonaws.com/graphs/giss/hansen-giss-1940-1980.gif
As a result, the gistemp data is not cyclic and there is no GMTA turning points for 2000 or for any year since then as shown below:
http://www.woodfortrees.org/plot/gistemp/from:1880/to:2010/compress:60/detrend:0.746/offset:0.394/plot/gistemp/from:1880/to:2010/trend/detrend:0.746/offset:0.394
As a result, unfortunately, the deceleration of GMTA & Cyclic GMTA does not apply for the gistemp data. I wish I could get the untempered gistemp data.
For the CRU data, GMTA has decelerated as CLEARLY shown in Figure 4 of my article.

Deceleration of global warming rate for all dataset in the last 20 years can be clearly seen in the following graph:
http://www.woodfortrees.org/plot/uah/from:2000/to:2010/plot/rss/from:2000/to:2010/plot/gistemp/from:2000/to:2010/plot/hadcrut3vgl/from:2000/to:2010/plot/uah/from:2000/to:2010/trend/plot/rss/from:2000/to:2010/trend/plot/gistemp/from:2000/to:2010/trend/plot/hadcrut3vgl/from:2000/to:2010/trend/plot/uah/from:1990/to:2000/plot/rss/from:1990/to:2000/plot/gistemp/from:1990/to:2000/plot/hadcrut3vgl/from:1990/to:2000/plot/uah/from:1990/to:2000/trend/plot/rss/from:1990/to:2000/trend/plot/gistemp/from:1990/to:2000/trend/plot/hadcrut3vgl/from:1990/to:2000/trend
For UAH, from 0.26 to 0.07 deg C per decade
For RSS, from 0.32 to 0.02 deg C per decade
For GIS, from 0.17 to 0.01 deg C per decade
For HADCRU, from 0.25 to 0.03 deg C per decade

Gah. Please mods delete the last post. I’ve fixed the formatting in this one (I hope).

As the day time temperature cannot tell you the average for the 24 hours, half years GMTA averages cannot tell you the average for the whole year. As a result, you must include the average for the whole your in your calculation of trends. We have to wait until December to calculate the new value for the warming trend since 2000.

You miss the point. I was showing that a mere six months additional can alter a ten year trend by a significant amount. I’m not trying to figure out the new trend, just to show how much it deviates if you use time periods that are too short.
But, to satisfy you, I will demonstrate by adding one whole year, and I will use a time period within the period 1970 – 2000.
I’ve plotted 1988 – 1998, and 1988, – 1999 here.
The first trend is 0.1C/dec
The second trend is 0.23C/dec
The deviation is greater than 100%
The point is, these analyses are not of any climate trend, but instead reflect the variability in the data. I chose this series because 1998 was an extraordinarily hot year.
Now let’s see what happens if I use a 20 year period that ends with the anomalously high 1998.
Plot
As expected, there is a noticeable deviation because the end of the series includes an extreme anomaly, but the deviation is reduced to 30%. If we add more data, say by starting from 1970, we get a more robust result.
By the way, there is no reason to restrict my analyses to within the nominated 30-year periods. The point of running a long term trend through the last GMTA is to explore whether the decade 2000 – 2010 has introduced a cooling to the global climate. It hasn’t. Even though the period itself is one of little warming. If we’re talking about interannual variability, then the last decade has slowed from the previous. but this, as we agree, is not telling us anything about climate. 10 years of data tells us more about the variability than the trend.

“Do you agree that from 1995 to the present there has been no statistically-significant global warming?”
“Yes, but only just “

I’m not sure what point you are attempting to make here, but Jones is saying what I am, except he is referring to a 15-year period. 1995 – 2010 is not statistically significant with respect to climate. I bolded the key part of the question that many people seem to misunderstand.

Barry, we only have two long range datasets: gistemp & hadcru

Actually, we have 5, but only two are used at woodfortrees. We also have two satellite temperature records available at that site. All of these have data for the last decade, and they all show a higher trend than HadCRUt, which should be at least mentioned in any analysis.
It should also have been mentioned the analysis of the top post that 10 years of data is not meaningful with respect to climate. Instead, 10 the ten year trend is pitched as a climate indicator. We don’t have nearly enough data to work out what the climate trend is for the current GMTA.

As a result, unfortunately, cyclic GMTA does not apply for the gistemp data. I wish I could get the untempered gistemp data.

All global temperature records are adjusted, including HadCRUt, to account for inhomogeneities in the data sets and to try and balance the weighting of locations around the world. For the periods 1900 – 2009, 1960 – 2009, and 1978 – 2009, GISTEMP has the lowest trends against HadCRUt and analyses done by skeptics using raw data. (The link is to a skeptical site)
The satellite records, of course, have no urban heat bias to influence them, the measuring devices are not located near any city.

Deceleration of global warming rate for all dataset in the last 20 years can be clearly seen in the following graph

True, but as these are in 10-year blocks, we’re not assessing climatic trends. We’re looking at trends that are heavily influenced by the year-to-year variability, as you agreed in a previous post.
As you’ve agreed that ten year trends do not reflect climate trends, we should let go of the idea that the last 10 years is telling us anything about the supposed GMTA period (2000 – 2040), right?

Phil Jones (5-Jul-2005), (Five years ago!)

The scientific community would come down on me in no uncertain terms if I said the world had cooled from 1998. OK it has but it is only 7 years of data and it isn’t statistically significant.

http://www.eastangliaemails.com/emails.php?eid=544&filename=1120593115.txt
The global warming rate from 1998 to 2005 was 0.06 deg C per decade
The global warming rate from 1998 to 2010 is 0.00 deg C per decade
http://www.woodfortrees.org/plot/hadcrut3vgl/from:1998/to:2005/plot/hadcrut3vgl/from:1998/to:2005/trend/plot/hadcrut3vgl/from:1998/to:2010/plot/hadcrut3vgl/from:1998/to:2010/trend
After 5 more years of Phil’s statement above, the global mean temperature trend still does not show any global warming. How many more years do you require to declare the global warming rate is flat?

How many more years do you require to declare the global warming rate is flat?

If we abide by the 20-year benchmark, we have to wait another 7.5 years if we start the trend analysis in 1998. But we must be cautious here.
When starting or ending a series with an extreme anomaly (1998 was the hottest year so far), that variation will have a bigger impact on the trend than if it appeared in the middle. As I demonstrated above, there is a 30% deviance in a 20-year trend with 1998 and then 1999 as the end year. While 20 years is sufficient, a longer time period will give us a clearer trend.
You see a lot more variation in 20-year trends in the satellite records (el Nino years are hotter, and la Nina years cooler in the satellite records compared to the surface records). Consequently, they need longer time periods to achieve statistical significance. Sea ice trends, on the other hand, show less variance, and don’t need as long periods of data for deriving statistically significant trends.

Hi everyone,
please help me, because I think this discussion is missing to recognise ‘the wood’ by only looking at the ‘trees’ (of temperature trends alone). Are the following figures anywhere near correct (if not, who knows of any more authorative ones):
<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>
Or, please, tell me where I am wrong in crediting the above figures (haven’t found any better ones) or in arriving at the musings about what constitutes the real problem facing ‘my grandchildrens’ grandchildren’. Yes, the research about what influences climate needs to go on by those equipped to deal with that (I definitely am not one of those, but I can read and count to 200+ and muster the 3 Rs and a bit more), but not at the expense of just exposing the IPCC Lysenkoism and thereby missing what the problem is (starting with my Clean Energy Primer, perhaps).

So you agree that the science of man made global warming is not settled yet?

I think, like all climate scientists, skeptical and otherwise, that if CO2 accumulates in the Earth’s atmosphere, the planet will warm. I think this is ‘settled’ science. How much the planet will warm is less certain.

But don’t you agree that it is more in favor of the no “man-made global warming” camp than the AGW camp? (as our position of no global warming was true for the last 12.5 {20 minus your 7.5} years)

No – I think the planet is still warming. Picking a 12.5-year trend starting from an extreme anomaly is completely and utterly statistically invalid. When one uses time periods that are statistically valid (long enough), there has been no deceleration of global warming with respect to climate.
As an exercise, try averaging every five years from the present back in time. I think you’ll find that every five year average is warmer than the last for the last 40 years. Each decade has been warmer than the last for the last 40 years.

Barry
I very strongly disagree!
Let us wait and see who is right.
Observation is the only final arbiter of a dispute:
After human emissions of CO2 for 60-years, there was no change in the global warming rate in the period from 1970 to 2000 compared to that in the period from 1910 to 2000. As a result, according to the data, according to the science, human emissions of CO2 has NO effect on the global warming rate.

Barry
As long as the global warming rate is less than 0.15 deg C per decade in a 30-years period, I will continue to reject man-made global warming.