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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And here I thought Phil Jones testified today’s warming wasn’t abnormal nor particularly greater, based on the last 4 warm cycles, since the little ice age. The Medieval Warm Period was warmer than today. In fact earth is simply warming after the little ice age.
I have two additional points:
1. No one seems to be able to find where they put Al Gore’s warm CO2 blanket.
2. No one seems to be able to find where the supposed excess heat is stored.
In a sane world that would be the end of the argument.
I believe that the saying “Hoist by their own petard” is relevant here. The debate is now over, but not with the outcome that the AGW crowd wanted.
Keep up the good work.
People who don’t like themselves will find rationalizations to take the blame for almost everything.
The temperature rises for ~30 years, then plateaus, then rises, then plateaus. But the overall rate has not changed! And we’re still not confident that the temperatures published are real or “homogenised”. Interesting post.
Ken
[2] Global Mean Temperature Anomaly from Climate Research Unit of the University of East Anglia (RAW DATA)
IMPORTANT. Is this actually raw data? It does not look like raw data at all. It looks exactly like HadCRU fully adjusted data.
Do you mean data, genuinely raw and unadjusted (no FILNET, SHAP, TOBS, Homogenization, etc.) or do you mean “numbers as opposed to a graph”?
Is it gridded or just an average of all stations? Have outliers been removed?
WHAT DO YOU MEAN BY “RAW”? PLEASE EXPLAIN!
If this pattern that was valid for 120 years is assumed to be valid for the next 20 years, it is reasonable to predict:
1. 30-years of global cooling from 2000 to 2030
Don Easterbrook has also forecast ~20 more years of cooling.
3:18 video
Sub-prime primer. :o)
———-
Q: “Do you agree that according to the global temperature record used by the IPCC, the rates of global warming from 1860-1880, 1910-1940 and 1975-1998 were identical?”
A: “the warming rates for all 4 periods are similar and not statistically significantly different from each other. ”
Q: “Do you agree that from 1995 to the present there has been no statistically-significant global warming”
A: “Yes”
Q: “Do you agree that from January 2002 to the present there has been statistically significant global cooling?”
A: “No. This period is even shorter than 1995-2009. The trend this time is negative (-0.12C per decade), but this trend is not statistically significant. ”
BBC interview with Professor Phil Jones of CRU – 13 February 2010
And finally he said in answer to the Medieval Warm Period:
“Of course, if the MWP was shown to be global in extent and as warm or warmer than today (based on an equivalent coverage over the NH and SH) then obviously the late-20th century warmth would not be unprecedented.”
http://www.co2science.org/data/mwp/mwpp.php
http://pages.science-skeptical.de/MWP/MedievalWarmPeriod.html
http://www.sciencemag.org/cgi/content/short/291/5508/1497
http://uanews.org/node/30720
http://www.john-daly.com/hockey/hockey.htm
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?
Three more graphs to put the Earth’s natural warming and cooling cycles into perspective:
click1 [this is a Phil Jones chart]
click2 [this is a chart of the U.S.]
click3
Note in chart #3 what CO2 has done during the same time. The coincidental rise in CO2 at the same time the planet was naturally warming appears to be a spurious correlation with temperature.
Bravo. Can I just add a link to a posting and some maps in here that support exactly what you are saying about the parallel between the warming 1910-1940 and 1977-
http://diggingintheclay.wordpress.com/2010/01/18/mapping-global-warming/
I know many readers will have seen this before but it is very persuasive.
“Most of the observed increase in global average temperatures since the mid-20th century is very likely” man made
It’s ‘manmade’ global warming……but the men are in East Anglia, Asheville, and New York City.
Joseph D’Aleo, 7:37 video
stevengoddard says:
August 1, 2010 at 5:20 pm
People who don’t like themselves will find rationalizations to take the blame for almost everything.
I wish they’d keep it to themselves.
“Dear citizens of the world, where is the catastrophic man made global warming they are scaring us with?”
It will be “robustly” found in smaller and smaller areas of the globe where there are fewer and fewer thermometers and too few people to expose the “unprecedented” lies. It will be a travesty.
Truth Seeker says: “I believe that the saying ‘Hoist by their own petard’ is relevant here”
Sounds painful.
Smokey @ur momisugly 5:46
Yep, the grandest ‘Post Hoc, Ergo Propter Hoc’ logical fallacy of all time.
So far.
====
“If this pattern that was valid for 120 years is assumed to be valid for the next 20 years…”
This statement is not valid for a system that is at least partially stochastic. The lack of warming in the 60’s and 70’s was most likely caused by sulfur emissions. “The plateau in warming from the 1940s to 1960s can be attributed largely to sulphate aerosol cooling.”
[From Wikepedia based on IPCC 3: http://en.wikipedia.org/wiki/Attribution_of_recent_climate_change%5D
Readers may also want to review the Atlantic Multi-decadal Oscillation: http://www.aoml.noaa.gov/phod/amo_faq.php
As for the “warming pause” of the last few years, see the discussion here:
http://www.realclimate.org/index.php/archives/2009/10/a-warming-pause/
One point made there is this: “It is highly questionable whether this “pause” is even real. It does show up to some extent (no cooling, but reduced 10-year warming trend) in the Hadley Center data, but it does not show in the GISS data, see Figure 1. There, the past ten 10-year trends (i.e. 1990-1999, 1991-2000 and so on) have all been between 0.17 and 0.34 ºC per decade, close to or above the expected anthropogenic trend, with the most recent one (1999-2008) equal to 0.19 ºC per decade – just as predicted by IPCC as response to anthropogenic forcing.”
My guess is this post was not peer reviewed.
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.
So looking at the numbers that were calculated for warming from 1910-1940 and from 1970-2000, they were 0.45 and 0.48 respectively. Assuming that the rate of warming should stay the exact same, then that means there is 0.03 deg C that could be attributed to mankind after 60 years of CO2 increase. And nothing says that this 0.03 deg C is entirely from CO2, if any of it is. The world has been constantly industrializing and building more infrastructure that absorbs more heat. So for all we know, CO2 could actually have no impact, and the “man-made” impact is us building infrastructure
I suspect the general consensus in the public is that temperature is relatively easy to measure. Actually it is not. As the esteemed Mr. Watts has abundantly demonstrated, there are a myriad of factors that can confound efforts to obtain an accurate temperature reading. The instrument itself is problematic. Mercury thermometers were the gold standard for a long time, but mercury is a poor choice in cold climates (it freezes solid at temps below -38F). Alcohol thermometers work better with cold temperature but not as well at higher temperatures. Thermo-electric devices are better but their response curves are not linear or even smoothly curvilinear beyond a certain temperature range. Where I live the outdoor ambient air temperature can vary from a low of -26 degrees C in the winter to a high of over 38 degrees C in the summer. Very few instruments can accurately measure temperature to +/- 1/10 of a degree across this range.
Now, consider the development of technology. Do we use the same techniques to measure temperature today as we did 100+ years ago? This is but one reason I believe our surface temperature records are worth less than a bucket of warm spit. I’m reasonably certain that the Earth has warmed since the end of the LIA but I’m not convinced we have an accurate measure of how much we have warmed in the last century…certainly not to within 0.1 degree C.
My basic argument with the IPCC is that we have no idea what “natural” variation is. They attribute all observed increases since about 1940 to anthropogenic cause. Where is the proof?
Mike says:
August 1, 2010 at 6:20 pm
One point made there is this: “It is highly questionable whether this “pause” is even real. It does show up to some extent (no cooling, but reduced 10-year warming trend) in the Hadley Center data, but it does not show in the GISS data, see Figure 1. There, the past ten 10-year trends (i.e. 1990-1999, 1991-2000 and so on) have all been between 0.17 and 0.34 ºC per decade, close to or above the expected anthropogenic trend, with the most recent one (1999-2008) equal to 0.19 ºC per decade – just as predicted by IPCC as response to anthropogenic forcing.”
Mike,
looking at some artic ice date from the DMI and from GISS, there is a huge discrepancy. GISS is extrapolating their data and saying that the whole artic is well ABOVE normal, while the DMI has the artic being nearly 2 degress BELOW normal,
Here is a graph showing artic sea ice melt this year compared to previous years. http://climateinsiders.files.wordpress.com/2010/08/jaxa_july_ice_melt.png
based on this graph, (which is in the previous post on this site) which seems more accurate. The DMI seems more accurate, and GISS seems wrong. So i find it hard to trust the GISS data, when it is pretty clear that they are making up false data and claiming something is warm when it isn’t. IF they don’t include the made up data, those trends that you spoke of would be very different
“Most of the observed increase in global average temperatures since the mid-20th century is very likely” man made
Part 1, 8:34 video
Roy Spencer
Part 2, 8:52 video
“The correlation of the two upward trends in the 1910-1940 and 1970-2000 periods in no way proves causation.”
It is not necessary to prove causation in order to invalidate the hypothesis.
Obama is still president and Lisa Jackson still heads the EPA. Meanwhile Hansen is still employed by NASA at GISS. Any questions? (We could go beyond this circle but it is good enough to make the point).
Gary says:
August 1, 2010 at 6:22 pm “……. however, this essay fails to make the case.”
No Gary. The hypothesis of AGW fails to make the case.