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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“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.
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.”
So what you’re saying is: We have two periods with about the same length and about the same temperature increase, but it is well possible that the first warming interval has been caused by natural causes, while the second warming interval was caused by CO2 emissions.
As the first warming is not understood – only that it is due to natural causes, and we keep saying that it’s just caused by coming out of the LIA – we cannot rule out the possibility that the second warming has the exact same cause. As long as we cannot rule out this possibility, it makes little sense to concentrate our efforts on reducing CO2 emissions. Because if the recent warming has not been caused by CO2 increases, these efforts would be futile.
So, Girma Orssengo’s argument undermines the 90% certainty of the IPCC rather well, i would say. More research is needed. And it better be research without a predetermined result this time.
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
Mike says:
August 1, 2010 at 6:20 pm
“My guess is this post was not peer reviewed.”
It is being reviewed right now. We thank you for your feedback. I wouldn’t put much stock in the GISS’ reported trends. As was discussed here, http://wattsupwiththat.com/2010/07/31/graphing-lesson-part-2-crest-to-crest/#more-22799 they seem out of step with reality. As far as RC goes as a source, when they start allowing dissenting views, as we are observing here, then I’d put more validity in their assertions. If you’re speaking the truth, one doesn’t have to run from dissent as they do at RC.
Your point about an naturally occurring oscillating event to refute the assertion the temps are an naturally occurring oscillating event is interesting. I believe the AMO and the PDO are an integral part of our climate, specifically relating to the GMTA. Again, I , as least, thank you for your input. It can’t help but increase our knowledge about the mysterious climate of our world and hone our abilities to refute the doomsayers!
That being said, Mike, check your sources. While I don’t really know about sulfur emissions causing cooling or not, arguing sulfur emissions caused a played a major role in an observed global cycle seems a bit off to me. It seems to imply that without the sulfur we wouldn’t have had a cooling, but rather a lengthened warming cycle. And given the rate of increase during the warming cycles, this seems to imply we saved the earth by sulfur emissions because it would simply be way too hot right now without the cooling “oscillations”. I’m just not sure about that bit of logic. Perhaps you can go into more detail about it later.
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?
Dr. Orssengo,
Bravo, futile, but bravo anyway. What will save us will be the sheer weight of articles like this.
“Not peer reviewed”? What the H— are these comments if not a peer review? Oh, of course, we are not THOSE peers. But, the best peer review will be the next 10 years.
Gary,
“Without supporting evidence, a valid claim cannot be made that the same climate forcing were operating identically in both periods.”
Are you saying that the forcing factors can change over time? If that is true, then no climate model will EVER be able to predict anything!
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!!!!
Amino Acids in Meteorites says:
August 1, 2010 at 7:07 pm
==============================================
Mike says:
August 1, 2010 at 6:20 pm
recent one (1999-2008) equal to 0.19 ºC per decade
===================================================
AAM said:
Are you taking in to account UHI and land use?
====================================================
AAM remember that post that Anthony made a while back, the study from Calif that was about painting roofs, sidewalks, and streets white?
If you crunch their numbers on how much UHI heat is produced in just those three things, you can account for all of global warming. Crunching their own numbers showed that all of the recorded temperature rise was from UHI.
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.
It is a shame that science can be manipulated to fit an agenda. Example, you can collect temperature data of many city’s that show warming over the last 70 years, but small towns near show cooling. A much worse case.
Check this out: http://www.wolframalpha.com
Type in search box: Average Temp Marion Ohio
click current week and click all. A chart from 1940 to 2010 shows a falling temp of -0.03 deg. F per year. The same is true for Kenton and Lima and a lot of other towns that did not put there thermometer on the cement in a parking lot, like Columbus.(I guess that makes it man made.)
If we were in global warming all temperatures would be going up. This sample is every where.
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. You have to ne more specific with quantitative causes and effects, not merely with the appearance of graphs. (So, BTW, do others).
Argument 2. as put is little more than divining the waters and suffers from the impossibility of predicting future climate. The IPCC went close to astrology type standards when making its projections and its reputation duly suffered. Best to leave it at that, don’t you think?
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.”
By that same logic, a valid claim cannot be made that different climate forcings were operating identically in both periods.
All that can usefully be said is that the rate of warming was the same. Since the IPCC claim is that human activity has caused most of the warming since the middle of the 20th century, and the rates are the same, and we can’t say whether or not the same or different climate forcings were at work — then at most all that can be said is that the IPCC hypothesis still has no evidence in its favor.
Which is a long way from the science being settled.
“Further hint: solar forcing increased in the early 20th century.”
The new evolving Greenhouse hypothesis?
This is a pretty good example of why I say that the next ten years will tell the story –one way or the other.
latitude
&
Dennis R. Cooper
There’s the anomaly trick. Pay no attention to the temperatures behind the curtain. 😉
Part 1, 9:33 video
Anomaly trick
Part 2, 7:45 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.
===========
Thanks for your great analysis. The problem, however, is not facts. It is politics. AGW is a wonderful excuse for bigger government and higher taxes. Governments are loathe to let go of such a “great problem” to face. How do we change their minds?
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.
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.”
I don’t think the author was trying to prove causation. I think the point is that the trends are similar and,”to the same natural effects we must, so far as possible, assign the same causes.” (Isaac Newton) In other words, the simple answer to the observed warming is that it is a continuation of the natural warming that was already on going.
dT
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.
“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. You have to be more specific with quantitative causes and effects, not merely with the appearance of graphs. (So, BTW, do others).”
Geoff,
While i see what you’re saying, it is an argument based on nothing. Looking at the cycles of the Earth’s temps you can see that it warmed 1910-1940, cooled 1940-1970, and then warmed 1970-2000, yet you are arguing that we could be in a natural cyclic decline now? So if we were in a cyclic decline while the Earth’s temperature was increasing, how do you explain the cooling that occured in between the 2 warming periods? Or do you realize that we were in a natural cycle of warming from 1910-1940 and from 1970-2000, and we have started switiching into a natural cylce of Decline since 2000, similiar to that of 1940-1970?
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.
evanmjones says:
August 1, 2010 at 5:28 pm
Is this actually raw data?
The following are examples of CRU raw data:
http://www.robertb.darkhorizons.org/TempGr/SacCRU.GIF
http://www.robertb.darkhorizons.org/TempGr/RedBluffAveCRU.GIF
http://www.robertb.darkhorizons.org/TempGr/ReddingCRU99.GIF
http://www.robertb.darkhorizons.org/TempGr/LiverMCRU99.GIF
http://www.robertb.darkhorizons.org/TempGr/SantaCruzCRU.GIF
http://www.robertb.darkhorizons.org/TempGr/SantaCruzCRU.GIF
Conclusion: After the West was Won, it stopped warming.
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