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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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.
As others have commented, the AGW hypothesis is not falsifiable.
Post WWII warming that allegedly can’t be attributed to identified natural factors like solar irradiance, volcanic activity etc. is assumed to be anthropogenic.
It is a rudimentary logical fallacy (argument to ignorance) — “the defendant has no alibi, therefore must have committed the crime”.
Boris:
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).
I’m pretty sure the OP used that figure to show that the IPCC was wrong even using their own data. Not many here would argue with you about the quality of the data.
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.
JohnH
Jones was worse than that. He said to Harridin that because the warming wasn’t caused by the sun nor by volcanoes (????) it must be caused by man, because he couldn’t think of any other cause..
That’s just the argumentum ad ignorantiam. It means that Jones and therefore the IPCC haven’t got a clue why the temperature could be going up or down at any given time or over any given period. That means their “predictions” are worthless.
“”” 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.
Which is why they had to adjust pre-satellite temps down, to make modern warming seem higher.
Smokey,
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.
New AGW Theory:
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.
Have others beaten me to the term “Meltdown Man”?
James Sexton: August 1, 2010 at 8:32 pm
I recall a G8 summit where the guys and gals promised not to raise the global temp by 2 degrees or such.
They can only accomplish that by sitting quietly in the corner.
It’ll reduce the Political Heat Island effect created by their blathering..
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.
Don’t you just love the way pseudo-scientists can model anything and get the result they want. The paper progresses thus:-
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.
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.
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.
The pdf report this article refers too is excellent.
I wondered if there could be any correlation between the rapid decrease in the numbers of surface stations (in colder locations, like Canada and Siberia) and the rapid warming observed in the latter 20th century.
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.
I also overlaid this with the 30 year negative and positive PDO phases and this shows that given the reduction in stations, the PDO, El nino and La Nina activity combined to create an almost entirely natural warming and cooling oscillation.
I estimate that anthropogenic forcing is very low accounting for 0.1-0.2 degrees and the removal of surface stations would balance the current temperature to be approximately 1.8 – 2.2 degrees above the zero in the GISS chart rather than the 4.2 in their chart.
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?
Ken Hall says:
August 3, 2010 at 4:44 am
I estimate that anthropogenic forcing is very low accounting for 0.1-0.2 degrees and the removal of surface stations would balance the current temperature to be approximately 1.8 – 2.2 degrees above the zero in the GISS chart rather than the 4.2 in their chart.
The premise of this paper (article) is:-
Within reasonable bounds of tolerance do we accept this to be true?
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 don’t know how you think any of this is legitimate. I don’t care about winning any argument, there is no hook, and it’s up to you whether you want to educate yourself enough to begin to have a conversation about attribution of climate change.
Many papers come to the same conclusion – natural forcing dominated the early part of the 20th century warming, and was supplemented by CO2 warming. Late 20th century warming was dominated by CO2 forcing, while natural forcing had an overall cooling effect (eg, declining solar irradiation).
Here are some specific texts.
http://www.cawcr.gov.au/bmrc/clfor/cfstaff/jma/meehl_additivity.pdf
http://www.cawcr.gov.au/bmrc/clfor/cfstaff/jma/meehl_solar.pdf
Similar conclusions in this paper (not copyable, but full version).
http://articles.adsabs.harvard.edu//full/2000ESASP.463..201T/0000206.000.html
This one concludes similarly to the others, but was not cut’n’pastable, either:
http://www.geofaculty.org:16080/figures/Rood_Climate_Change_AOSS480_Documents/Andronova_Causes_of_dT.pdf
This paper looks at the cooling/warming periods of the 20th century – again similar conclusions.
http://www.geofaculty.org:16080/figures/Rood_Climate_Change_AOSS480_Documents/Andronova_Causes_of_dT.pdf
Here is a scientific primer on detecting attribution over the 20th century:
http://www.pewclimate.org/docUploads/PewSB1-Attribution-SMALL_102606.pdf
These results are all pretty consistent. You could read the IPCC chapter and learn the same thing with less trouble – they collate the science after all.
The failure of the top post is that it neglects various forcings on the centennial climate, pitting it as a bi-polar, either/or mechanism involving only CO2.
It appears the early 20th century warming was a combination of natural effects (increased solar radiation, possibly less vulcanism) and CO2, and the late 20th century warming of similar rate is primarily CO2 forced while solar forcing had flat-lined or declined, with little vulcanism. Natural forcing dominated the warming of the early 20th century, but was supplemented by CO2 forcing (about 0.1K, 1910 to mid-1940s). CO2 dominated the late 20th century warming, with a flat or cooling contribution from natural forcings. Mid-20th century cooling is considered to be a result mainly of aerosol dimming, possibly exacerbated by decreasing solar radiation (period 1946 – 1975).
I chose to plot 1946 – 1975 for solar radiation, as this is the period commonly associated with mid-century flat or cooling (depending on data set) temps. 1944 was the warmest year in the HadCRUt record.
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)
Andrew says:
August 3, 2010 at 8:47 am
“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.“
It is very easy to explain the ‘climatically-short’ term trend since 1900 without resorting to the desperate fraud of increasing CO2. Just get yourself a good primer on deterministic chaos, paying particular attention to how driven oscillators work.
It will all start to make sense!
barry,
So because it’s convenient to your point of view, someone flipped a switch in 1950 and the previously harmless and beneficial CO2 became the evil cause of runaway global warming and climate catastrophe?
Ri-i-i-i-i-ght.
George E. Smith (#5:09 pm)
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.
Pure obfuscation!
Just imagine the near zero probability for the effects of nature and 60-years of human emission of CO2 on global mean temperature rate to be equal but opposite after exactly 60 years.
Just incredible!
Girma,
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.
I posted this video 6 months ago after our local media wetted itself again over NASA’s reporting the ‘most hellish heat in the history of the earth’ or something similar.
[youtube=http://www.youtube.com/watch?v=6QfP291qgag&hl=en_US&fs=1]
Knowing that the temperature has been more or less gradually increasing since the last ice age, I became unhappy with our local media hyping each new temperature ‘heat record!’ So I decided to consider this a bit more. This is a 2 minute summary of another way of looking at NASA GISS’s late January temperature plot and record.
I really wish they’d stop scaring our children!
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