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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Andew says: August 1, 2010 at 8:56 pm
“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.”
Or put another way…
“And the fact that there has been little warming in the last 10 years also does not prove the possibility of an underlying trend of .2C/decade.”
The burden of proof is on the theory.
So prove 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!
I wonder how many people take a quick look at figure 1 and, without thinking, automatically assume the scale runs from -8.6 to 8.6 degrees because there would be no point in making a fuss about a 130-year global warming effect that can be plotted on a -0.6 to 0.6 degree scale?
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.
Andew @ur momisugly August 1, 2010 at 8:56 pm said:
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.
The fact that the 1910-1940 warming has the same rate as the 1970-2000 warming proves or disproves nothing. It does give us an interesting problem to think over. What caused warming at that rate? See: http://www.ipcc.ch/graphics/syr/fig2-4.jpg
Remember, you will have to stay within the confines of accepted science here, so I’ve provided the link that, according to poster ‘Icarus’ explains that the current natural forcing is about 0.
Of course, to be helpful, I have also of the only natural forcing in the IPCC graph I was handed as evidence that current natural forcing is 0.
This is an interesting problem for climate scientists, I would say.
I hope I got that html right, or that post is going to be a mess!
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
Spector says:
August 1, 2010 at 9:22 pm
I wonder how many people take a quick look at figure 1 and, without thinking, automatically assume the scale runs from -8.6 to 8.6 degrees because there would be no point in making a fuss about a 130-year global warming effect that can be plotted on a -0.6 to 0.6 degree scale?
========================
But then “0” on the graph will be “8” 😉
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
Thank you Girma for another well thought out analysis of the claims of the IPCC and alarmist AGH hypothesis. You’ve succeeded again to prove their alarmist claims to be “exaggerated” (to be polite). The IPCC et. al. really are tilting at windmills and soothsaying doomsday without a leg to stand on as the DATA shows and your analysis clearly demonstrates with concise precision slicing those legs out from under their alarmist claims. Ouch that has gotta hurt the IPCC et. al. that the planet stopped warming as they, ahem, predicted.
Again, thank you.
@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.
Oops… [:)]
Ouch that has gotta hurt the IPCC et. al. that the planet stopped warming, ahem, counter to what they predicted.
That’s better.
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.
Girma
Thanks. Had to make sure!
Dave Springer August 1, 2010 at 10:41 pm:
But, then, where’s the positive feedback? That’s supposed to almost triple the raw forcing. And if any of the warming at all is non-anthropogenic, then what of the forcing equation?
It does not seem to add up, to me.
And you are assuming that the continually adjusted is correct. that’s a pretty big assumption, seeing as how CRU won’t share data and methods.
@evanjones
re; where’s the positive feedback?
Indeed. It seems reasonable to presume that any positive feedback in next century was operative in the past century so, if it exists, it’s already reflected in the past century trend. That’s why I said it had absolutely no observational data to support its existence.
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.
@evanjones
One must also keep in mind that correlation is not causation. CO2 rise correlates with 0.5C/century temp rise. It is not proven to be the cause. It may be a partial cause or not the cause at all.
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 S: I attributed a quote to you that you were merely quoting. Sorry about that!
To continue banging on the feedbacks-of-the-past drum I have been banging on lately:
If temperatures had been dead steady for hundreds of years, and warming only started in 1900, one might (possibly) expect the feedback to occur in future.
But the surface of the planet has been warming since around 1650. Surely any positive feedback would have been operating since at least the 19th century?
So it does not seem to add up. Either there is negative feedback or else the CO2 forcing equation is overblown.
And this is even assuming HadCRUt3 or whatever they are up to these days has it right, which is something I do not currently concede. Pre-satellite warming is more likely to be half of what HadCRUt or NASA says it is
Where’s the Beef?
P.S., Dr. Christy and Dr. Spencer give us absolute assurance they do not take the surface record into any account whatever when they make their conversions. I trust them. But I bet Hansen and Jones keep a fearful eye on UAH! I’d bet a third of the farm that UAH keeps ’em (kinda-sorta) honest since 1979. Well, more honest than they’d otherwise be.
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.
Reply @ur momisugly evanmjones:
But, then, where’s the positive feedback? That’s supposed to almost triple the raw forcing.
I wonder about that myself. I also wonder how much of the added water vapor in the atmosphere may have come from irrigation. If we think about the amount of water it takes to grow the food needed to feed 6 billion people, I think we have taken quite a bit of that water out of the ground and put it into circulation in the atmosphere. Hard to say what the effect would be though, unless the amount of water were quantified and given a forcing value. Of course, this may be picking nits and all, but if we are gonna dump tons of cash into studying climate, shouldn’t we at least study NATURE first instead of building fancy computer models? Understand, then model.
And if any of the warming at all is non-anthropogenic, then what of the forcing equation?
See: http://www.noaanews.noaa.gov/stories2009/20091204_cooling.html
Last winter, NOAA released a study saying that the recent cooling was all because of natural causes. Unfortunately, these natural causes are not defined in this story. This was covered on WUWT also. I can’t find the story on WUWT, which has a link to the actual paper and NOAA doesn’t provide it for some reason. All of that aside, I have been told by our warmist friends that the net natural contribution to climate is about 0. Yet, I am also told that cool spells are to be expected because of nature. It all leads to these questions:
How much of the recent warming is from natural trends?
Which natural trends?
Why aren’t those natural trends included in the 0.6C of claimed warming from 1880?
0.6C of warming over 120 years of massive technological advances could be caused by nothing more than more accurate (or just more) observations. Why is this not true?
And, a new one, why is the rate of warming from 1910-1940 from natural causes and the 1970-2000 warming from manmade sources?
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.
“People who don’t like themselves will find rationalizations to take the blame for almost everything” and people who don’t like humanity will do the same for us all.
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.
I can see the point made that the continual increase in global temperature predicted by the IPCC is not shown in the actual data, thus disproving the eventual outcomes of the theory.
It would be interesting to compare the cooling periods in the thirty year cycle as the past ten years have been to all extent more of a levelling period. Are we going to see a sharp drop off or will the next thirty year warming period start from a higher point?
If we do see a sharp drop off then the rate of change could have a far more severe impact than the actual change and this is what the IPCC should be advising about if they were doing their job correctly.