Guest post By Girma Orssengo, MASc, PhD
Comparison of the claims by the Intergovernmental Panel on Climate Change (IPCC) of 1) “Most of the observed increase in global average temperatures since the mid-20th century is very likely” man made, and 2) “For the next two decades a warming rate of 0.2 deg C per decade is projected” are shown in this article not to be supported by the observed data, thus disproving IPCC’s theory of man made global warming.
FIRST IPCC CLAIM
In its Fourth Assessment Report of 2007, IPCC’s claim regarding global warming was the following [1]:
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.
Let us verify this claim using the observed data from the Climate Research Unit (CRU) of the University of East Anglia [2]. In this claim, “mid-20th century” means year 1950. As a result, according to the IPCC, global warming since 1950 is mostly man made.
To verify the claim that global warming since 1950 is mostly man made, we may compare the global warming rate in degree centigrade (deg C) per decade in one period before 1950 to that of a second period after 1950 to determine the effect of the increased human emission of CO2. To be able to do this, we need to identify these two periods, which may be established from the Global Mean Temperature Anomaly (GMTA) data of the CRU shown in Figure 1.
In Figure 1, the GMTA could be visualized as the sum of a Linear GMTA that has an overall warming rate of 0.6 deg C per century and an Oscillating GMTA that oscillates relative to this overall linear warming trend line. This Oscillating GMTA indicates the relative warming and cooling phases of the globe.
As our objective is to verify the claim that global warming since 1950 is man made, we need to identify two global warming phases before and after 1950. To clearly see the global warming and cooling phases, we plot just the Oscillating GMTA, which is the GMTA relative to the overall linear warming trend line shown in Figure 1. This can be done by using an online software at www.woodfortrees.org by rotating the overall linear warming trend line to become horizontal by using a detrend value of 0.775 so that the Oscillating GMTA has neither overall warming nor cooling trend. The noise from the Oscillating GMTA is then removed by taking five-years averages (compress = 60 months) of the GMTA. The result thus obtained is shown in Figure 2.
”]
Figure 2 shows the following periods for relative global cooling and warming phases:
- 30-years of global cooling from 1880 to 1910
- 30-years of global warming from 1910 to 1940
- 30-years of global cooling from 1940 to 1970
- 30-years of global warming from 1970 to 2000
If this pattern that was valid for 120 years is assumed to be valid for the next 20 years, it is reasonable to predict:
- 30-years of global cooling from 2000 to 2030
Figure 2 provides the two global warming phases before and after 1950 that we seek to compare. The period before 1950 is the 30-years global warming period from 1910 to 1940, and the period after 1950 is the 30-years global warming period from 1970 to 2000.
Figure 2 also provides the important result that the years 1880, 1910, 1940, 1970, 2000, 2030 etc are GMTA trend turning points, so meaningful GMTA trends can be calculated only between these successive GMTA turning point years, which justifies the calculation of a GMTA trend starting from year 2000 provided latter in this article.
Once the two global warming periods before and after mid-20th century are identified, their rate of global warming can be determined from the GMTA trends for the two periods shown in Figure 3.
”]
According to the data of the CRU shown in Figure 3, for the 30-years period from 1910 to 1940, the GMTA increased by an average of 0.45 deg C (3 decade x 0.15 deg C per decade). After 60 years of human emission of CO2, for the same 30-years period, from 1970 to 2000, the GMTA increased by an average of nearly the same 0.48 deg C (3 decade x 0.16 deg C per decade). 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.
SECOND IPCC CLAIM
In its Fourth Assessment Report of 2007, IPCC’s projection of global warming was the following [5]:
For the next two decades, a warming of about 0.2 deg C per decade is projected for a range of SRES emission scenarios. Even if the concentrations of all greenhouse gases and aerosols had been kept constant at year 2000 levels, a further warming of about 0.1 deg C per decade would be expected.
Let us verify this projection using the observed data from the CRU [2]. This may be done by comparing the global warming rate between the last two decades as shown in Figure 4. In this figure, the global warming rate decelerated from 0.25 deg C per decade for the period from 1990 to 2000 to only 0.03 deg C per decade for the period since 2000, which is a reduction by a factor of 8.3, which further disproves IPCC’s theory of man made global warming. If the current global warming trend continues, the GMTA will increase by 0.27 deg C (0.03 x 9) by 2100, not the scary 2.4 to 6.4 deg C of the IPCC.
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.
”]
SUMMARY
As shown in Figures 3 and 4, claims by the IPCC of 1) “Most of the observed increase in global average temperatures since the mid-20th century is very likely” man made, and 2) “For the next two decades a warming rate of 0.2 deg C per decade is projected” are not supported by the observed data, thus disproving IPCC’s theory of man made global warming.
According to the CRU data shown in Figure 3, the 30-years global warming from 1970 to 2000, after human emission of CO2 for 60 years, was nearly identical to the 30-years global warming from 1910 to 1940. In the intervening 30-years, there was a slight global cooling from 1940 to 1970. Furthermore, since year 2000, as shown in Figure 4, the global warming rate decelerated by a factor of 8.3 compared to the decade before. This is the story of global mean temperature trends for the last 100 years!
Does not the observed data in Figures 1 and 2 show a cyclic global mean temperature pattern with an overall linear warming rate of 0.6 deg C per century?
Dear citizens of the world, where is the catastrophic man made global warming they are scaring us with?
Or is the scare a humongous version of the “Piltdown man”?
REFERENCES
[1] IPCC: “Most of the observed increase in global average temperatures since the mid-20th century is very likely” man made
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/spmsspm-understanding-and.html
[2] Global Mean Temperature Anomaly from Climate Research Unit of the University of East Anglia (GRAPH)
[2] Global Mean Temperature Anomaly from Climate Research Unit of the University of East Anglia (RAW DATA)
[3] Oscillating Global Mean Temperature Anomaly
[4] Comparison of global warming rates before and after mid-20th century (GRAPH)
[4] Comparison of global warming rates before and after mid-20th century (RAW DATA)
[5] IPCC: “For the next two decades, a warming of about 0.2 deg C per decade is projected”
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/spmsspm-projections-of.html
[6] Deceleration of global warming rate in the last two decades
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Those who make the assertion must be able to back it up better than just saying that they can’t think of another explanation.
Yeah. That logic works fine for Sherlock Holmes. Thing is, you gotta be Sherlock Holmes for that to work. And as for these dudes, well, Sherlock Holmes they ain’t!
Stating that the trend “could be” linear plus oscillating does not make it so.
The AGW theory is that other influences come into play – a linear trend is most certainly *not* expected. So the Argument is using a mis-statement of the theory to disprove the theory. You can do that with any theory you like.
A quote from Orssengo’s latest paper on brain mechanics should indicate that the author ought to realise that linear models are not always appropriate: “Numerical studies showed also that the linear, viscoelastic model of brain tissue is not appropriate for the modelling brain tissue deformation even for moderate strains.”
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.
having discovered a comparison of annual CO2 sources entering the atmosphere I learned that sources other than manmade ones outweigh them by a factor of about 30:1! See blog above. Mike, CleanEnergyPundit
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!
Mike says:
August 1, 2010 at 6:20 pm
My guess is this post was not peer reviewed.
It’s being peer reviewed right here right now. My guess is that you are one of the less competent reviewers.
Thanks for pointing out the AMO in your post though. How much of the 1970-2000 warming did the IPCC attribute to its positive phase?
From your link to the NOAA:
“Is the AMO a natural phenomenon, or is it related to global warming?
Instruments have observed AMO cycles only for the last 150 years, not long enough to conclusively answer this question. However, studies of paleoclimate proxies, such as tree rings and ice cores, have shown that oscillations similar to those observed instrumentally have been occurring for at least the last millennium. This is clearly longer than modern man has been affecting climate, so the AMO is probably a natural climate oscillation. In the 20th century, the climate swings of the AMO have alternately camouflaged and exaggerated the effects of global warming, and made attribution of global warming more difficult to ascertain. “
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.
It maybe a silly question but i’m a novice at this, but i’ve seen stated that CO2 follow’s temp, now i understand that we are pumping CO2 into the air but should the CO2 levels then drop over the next 20 years as the temp drops? which we all know around here it will following natural cycles.
“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).
Boris says:
August 1, 2010 at 7:01 pm (Edit)
“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.
Solar forcing increased from low to medium 1900-1930
It decreased from Very high to high 1960-1990
Remembering the decade lag between solar activity and global temperature response noted by the Norwegian study on David Archibalds thread here recently, the solar answer still looks like the right one to me.
It has been shown many times that increases in co2 over and above 200ppm or so have negligible effect:
http://tallbloke.wordpress.com/2010/07/29/john-eggart-laymans-guide-to-the-greenhouse-effect/
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. 😉
Jim hogg
Please tell me honestly what you see from the data shown in Figure 2?
Does not it show global warming is cyclic? Disregarding the obfuscations of the AGW camp.
Girma says:
August 2, 2010 at 2:23 am (Edit)
Please tell me honestly what you see from the data shown in Figure 2?
Does not it show global warming is cyclic? Disregarding the obfuscations of the AGW camp.
For a look at other phenomena which correlate with detrended temperature better than co2 does, have a look at this:
http://tallbloke.wordpress.com/2009/11/29/planetary-solar-climate-connection-found/
“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.”
The point of the original post is to point out the weakness of the IPCC theory of CO2 induced global warming, not to offer an alternate theory. That would be the job of GISS or CRU or NASA or the EPA or …..no wait……………..
Boris says (7:01 pm):
“…This is really, really bad logic.: Hint Co2 contributed to early 20th century warming…”
CO2 from human fossil fuel use could not possibly be a major factor in the c.1910 – c.1940 warming:
http://photos.mongabay.com/09/0323co2emissions_global.jpg
James Sexton says: August 1, 2010 at 8:32 pm
Geoff Sherrington says:
August 1, 2010 at 7:45 pm
Actually James you might be onto something here – possibly we are at the beginning of an upward “trend” (love that word).”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!!!” Perhaps we are moving forward on the Kardashev scale – Type I — a civilization that is able to harness all of the power available on a single planet. Type II — a civilization that is able to harness all of the power available from a single star. Type III — a civilization that is able to harness all of the power available from a single galaxy. It has been calculated that we are at 0.72 on the scale at present, so with our abilities to alter the climate at will, in 30 years or so we will be at 0.73. Maybe the alarmists should relax a little; this is just a small step in man’s evolution to ultimately controlling the universe.
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”)
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.
Girma says:
August 2, 2010 at 2:23 am “Does not it show global warming is cyclic? Disregarding the obfuscations of the AGW camp.”
Girma, I’m not picking on you. I’m merely using your expresion as similar to many others, so I can make a counterpoint.
Yes, it is possible to use statistical deconvolution to tease out cycles of various periods in the data of the past. There is however, not always certainty that a given cyclicity will continue into the future. Simply because we have a rise from 1910-1940 and another that loks a bit similar from 1970-2000 (author’s graph 3), there is no guarantee at all that the future will give us a more or less similar rise from 2030-2060, thus completing a graphical pattern. It might happen, it might not. The fact that we cannot predict that it will, is a travesty.
I carry no torch for CO2 warming of the range of IPCC values – don’t get me wrong there. I simply used CO2 in my example above, as one of several mechanisms that plausibly can produce some warming. I used it because mechanisms are needed, not merely graphical repetitions. Climate science continues to lack a quantitative explanation of the warming that CO2 change produces.
I hope that this clarifies the objections I raised on August 1, 2010 at 7:45 pm .
Finally, people who adopt a temperature/time series for analysis have to use extreme care in their choice of data. I simply do not have faith in hadcrut3. I’ve examined some of its parts in detail.
Tenuc says:
August 1, 2010 at 11:49 pm
I’ve come to the conclusion the governments have enticed and prodded some scientists into building the AGW model, not the other way around. After all, the UN asked the scientists asked the scientists to find evidence of AGW. The first question should have been “Do natural variations account for AGW”?
Governments have no problem making decisions resulting in the deaths of million. Ponder the behavior of governments during WWI and WWII if you don’t believe this. Or consider the decisions made by governments after WWII regarding the potential use of nuclear weapons.
The death of millions?
I used to think the quote of breaking eggs to make omelets was an original with Stalin, it is actually much older and used by other ruthless politicians. See http://lawsoflife.co.uk/stalins-law/.
The other thing governments have no trouble with is raising taxes, which is the whole point to AGW.
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.
Mike Haseler says:
August 2, 2010 at 1:24 am
Global warming graphs are like those butterfly ink blots which tell you more about the psychology of the observer than about the ink blot.
It’s called Rorschach inkblot test . And I agree. What people say about global warming reveals more about them than about the ‘science’ of global warming.
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.
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.
We need to be able to describe what is driving these cycles.
– Without a cause, we would have to say the climate can have some random up and down cycles that can add up to a few tenths of degree. Not impossible but it would be random. Maybe we will now enter a random up cycle.
– The Sun could have 60 year up and down cycles. There are clearly 11-year cycles but they don’t change enough to cause much temperature change at the surface. There was clearly a Maunder Minimum which reduced temperatures somewhat but in the last 170 years, there has just been a small uptick in solar output causing about a 0.05C increase in temperatures. Generally, we are still arguing about whether there is longer cycles in the Sun.
– Snow and Ice on the planet can vary and through reflecting sunlight, the Albedo can change the temperature on the planet. Sea Ice in the Arctic has clearly gone up and down but the data is uncertain. My calculations of potential Albedo impacts from these potential cycles shows that it would be very, very small – less than 0.1C.
– Clouds also affect Albedo. More than half of the 30% reflected sunlight comes from clouds. We have certainly seen changes in cloud levels in the last 30 years (not looked at enough in my opinion because these changes are relatively large). Maybe there are longer cycles but we have no data to base that on.
– The Climate Models incorporate a large upswing in sulfur Aerosols starting in 1948 and peaking out at about 1990. The Aerosols guesstimates used in the models actually off-set ALL OF THE WARMING until 1970. In fact, between 1880 and 1970, Aerosols have more negative impact on temperatures than GHGs has a positive impact on temperatures. The Climate Models address these 60 year cycles by varying the impact of the assumed Aerosols impact (you just need an acceleration starting in 1948 versus building in a cycle). The math doesn’t actually work and I’m not certain whether the modellers know they did this.
– The Ocean surface certainly has cycles. We have the ENSO with a +/-0.2C direct and very clear impact on temperatures. No one doubts this. A particularly long period of El Ninos leading up to 1944 may have had a longer-term impact, A cycle up and then a cycle down – The AMO and the PDO also have 60 year cycles which matches the up and down cycles very closely. So, we now have a solid explanation for these cycles. The surface and deep ocean exchange energy which has matched the 60 year cycles seen since 1850. There is no reason to assume it will continue like this because there is some evidence the cycles can vary. The climate scientists are careful to exclude these impacts in their back-cast reconstructions. They don’t appear to be big enough to explain all of the 0.7C warming-to-date, however, so there is still a warming left-over probably caused by GHGs.
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.