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.
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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.
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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.
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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
I averaged every full decade for the last 40 years, starting with January 1970 – December 1979, through to Jan 2000 – Dec 2009, using HadCRUt yearly anomalies.
Anomalies in degrees Celsius
1970 – 1979 = -0.0772
1980 – 1989 = 0.0843
1990 – 1999 = 0.2307
2000 – 2009 = 0.4041
(I haven’t updated the figures for a few months, so there may be very minute discrepancies with the current record – of a few thousandths of a degree)
First thing you notice is that the average global temperature anomaly for 2000 – 2009 is 0.17C greater than the average for the previous decade (which included the warmest year on record). This is a layman’s way of working out 20 year trends.
Barry
I very strongly disagree!
Let us wait and see who is right.
Observation is the only final arbiter of a dispute:
After human emissions of CO2 for 60-years, there was no change in the global warming rate in the period from 1970 to 2000 compared to that in the period from 1910 to 2000. As a result, according to the data, according to the science, human emissions of CO2 has NO effect on the global warming rate.
I don’t think any such thing is proved. The relative contribution of different forcings on the climate trends is entirely absent from the argument. The untested assumption is that natural climate drivers are the same for each period. Nothing can be concluded until this is examined.
Which begs a question – what do you think is the cause(s) of overall global warming for the last 100 years?
I assume you will not be positing natural causes, as you have previously vouched that,
“I don’t believe humans are able to apportion percentages for the effects of man made and natural forces on the global mean temperature trend.”
So, I’m curious to know how you will answer.
Barry
As long as the global warming rate is less than 0.15 deg C per decade in a 30-years period, I will continue to reject man-made global warming.
The global warming rate for the the most recent 30-year period is 0.16C.
I don’t know if there’s much left for us to talk about on this topic. I have appreciated your sticking with the conversation and keeping it nice. Thank you. 🙂
Barry
Thank you to you too.
The current global warming rate AFTER THE TRURNUNG POINT of 2000 is only 0.03 deg C per decade for the CRU data.
Let us see in the next 5 to 10 years whether this global warming rate starting from 2000 decreases, stays the same or increases. If it increases to 0.15 deg C per decade the AGW camp wins. If it stays the same or decreases my side wins.
Let the observations be our judge.
Thank you and take care.
Here is what Phil Jones wrote five years:
“The scientific community would come down on me in no uncertain terms if I said the world had cooled from 1998. OK it has but it is only 7 years of data and it isn’t statistically significant.”
http://www.eastangliaemails.com/emails.php?eid=544&filename=1120593115.txt
The global warming rate since 1998 when Phil John the above statement in 2005 was 0.06 deg C per decade.
Five year later, in 2010, the global warming rate since 1998 is 0 deg C per decade as shown below:
http://www.woodfortrees.org/plot/hadcrut3vgl/from:1998/to:2005/plot/hadcrut3vgl/from:1998/to:2005/trend/plot/hadcrut3vgl/from:1998/to:2010/plot/hadcrut3vgl/from:1998/to:2010/trend
To establish conclusively that global warming has stopped requires only 5 to 10 more years. If we increase fossil fuel cost in order to reduce global warming and we find that the two are unrelated, it will be a pointless increase in cost of living without any benefit.
Excerpts from “It’s Always the End of the World as We Know It”
Apocalyptic scenarios are a diversion from real problems — poverty, terrorism, broken financial systems — needing intelligent attention. Even something as down-to-earth as the swine-flu scare has seemed at moments to be less about testing our health care system and its emergency readiness than about the fate of a diseased civilization drowning in its own fluids. We wallow in the idea that one day everything might change in, as St. Paul put it, the “twinkling of an eye” — that a calamity might prove to be the longed-for transformation. But turning practical problems into cosmic cataclysms takes us further away from actual solutions.
This applies, in my view, to the towering seas, storms, droughts and mass extinctions of popular climate catastrophism. Such entertaining visions owe less to scientific climatology than to eschatology, and that familiar sense that modernity and its wasteful comforts are bringing us closer to a biblical day of judgment. As that headline put it for Y2K, predictions of the end of the world are often intertwined with condemnations of human “folly, greed and denial.” Repent and recycle!
http://www.nytimes.com/2010/01/01/opinion/01dutton.html?pagewanted=2&_r=1
Excerpts from “The Curry Agonistes”
KK[Keith Kloor]: I question if there is really this breach of trust between the climate science community and the general public. Again, the average person is probably not paying much attention to these fractious debates between skeptics and a subset of the climate science community. I mean, every profession gets dinged by its share of controversies. The foundation for anthropogenic global warming rests on numerous solid pillars, which you agree with. So how is that a batch of intemperate emails and a decade-old scientific controversy over the hockey stick can rock this foundation, which is what you seem to be arguing?
JC [Judith Curry]: Evidence that the tide has changed include: doubt that was evidenced particularly by European policy makers at the climate negotiations at Copenhagen, defeat of a seven-year effort in the U.S. Senate to pass a climate bill centered on cap-and-trade, increasing prominence of skeptics in the news media, and the formation of an Interacademy Independent Review of the IPCC. Concerns about uncertainty and politicization in climate science are now at the forefront of national and international policy. There is an increasing backlash from scientists and engineers from other fields, who think that climate science is lacking credibility because of the politicization of the subject and the high confidence levels in the IPCC report. While these scientists and engineers are not experts in climate science, they understand the process and required rigor and the many mistakes that need to be made and false paths that get followed.
Further, they have been actively involved in managing science and scientists and in assessing scientists. They will not be convinced that a “likely” level of confidence (66-89% level of certainty) is believable for a relatively new subject, where the methods are new and contested, experts in statistics have judged the methods to be erroneous and/or inadequate, and there is substantial disagreement in the field and challenges from other scientists. The significance of the hockey stick debate is the highlighting of shoddy science and efforts to squash opposing viewpoints, something that doesn’t play well with other scientists. Energy Secretary and Nobel Laureate Steven Chu made this statement in an interview with the Financial Times:
First, the main findings of IPCC over the years, have they been seriously cast in doubt? No. I think that if one research group didn’t understand some tree ring data and they chose to admit part of that data. In all honesty they should have thrown out the whole data set.
But you don’t need to be a Nobel laureate to understand this. I have gotten many many emails from scientists and engineers from academia, government labs and the private sector. As an example, here is an excerpt from an email I received yesterday: “My skepticism regarding AGW has been rooted in the fact that, as an engineer/manager working in defense contracts [General Dynamics], I would have been fired, fined (heavily) and may have gotten jail time for employing the methodology that [named climate scientists] have used.”
http://www.collide-a-scape.com/2010/08/03/the-curry-agonistes/
Thanks Judy