Reposted from Jennifer Marohasy’s website.
THERE are four official global temperature data sets and there has been much debate and discussion as to which best represents change in global temperature.
Tom Quirk has analysed variations within and between these data sets and concludes there is 1. Substantial general agreement between the data sets, 2. Substantial short-term variation in global temperature in all data sets and 3. No data set shows a significant measurable rise in global temperature over the twelve year period since 1997.
Global Temperature Revisited
Article by Tom Quirk
One of the most vexing things about climate change is the endless debate about temperatures. Did they rise, did they fall or were they pushed? At times it seems like a Monty Python sketch of either the Dead Parrot or the 5 or 10 Minute Argument.
However it is possible to see some of the issues by looking at the four temperature series that are advanced from:
GISS – Goddard Institute for Space Studies and home of James Hansen,
Hadley Centre – British Meteorological Office research centre
UAH – The University of Alabama, Huntsville, home of Roy Spencer with his colleagues including John Christy of NASA and
RSS – Remote Sensing Systems in Santa Rosa, California, a company supported by NASA for the analysis of satellite data.
The first two groups use ground based data where possible with a degree of commonality. However since 70% of the surface of the earth is ocean and it is not monitored in a detailed manner, various procedures with possibly heroic assumptions and computer modelling, are followed to fill the ocean gap.
The last two groups use satellite data to probe the atmosphere and with the exception of the Polar Regions which are less than 10% of the globe, they get comprehensive coverage.
One question is of course are the two groups measuring the same temperature? After all the satellite looks down through the atmosphere, while the ground stations are exactly that.
There is an important distinction to be made between measuring the temperature and measuring the change in the temperature. Since the interest is in changing temperatures then what is called the global temperature anomaly is the starting point. The issue of measuring absolute temperatures should be put to one side.
Data from 1997 to 2009 was drawn from the four group websites on the 28 April 2009. When data for 1997 to early 2008 was compared to data acquired in early 2008 differences were found as shown in the first table.
This is evidence of substantial reprocessing and re-evaluation of data. This is not unusual with complicated analysis systems but there is so much interest in the results that adjustments are regarded with great suspicion. This is the fault of those publishing the temperature data as they fail to make the point that monthly and even yearly measurements are about weather and not climate.
The latest series of temperature anomalies are shown in the graph where the monthly data has been averaged into quarters. All statistical analysis that follows is on the monthly data unless stated otherwise.
From inspection, there is substantial agreement over the years 1997 to 2008. This can be statistically measured through correlations. This is a measure of how closely related the series may be. A value of 0 implies independent series while a value of 1 implies complete agreement. The correlation in turn indicates the degree of commonality in the comparison.
This is remarkable agreement given the two very different techniques used.
It is important to note that the two satellite analysis groups draw measurements from the same satellites. So the differences in temperatures are a result of analysis procedures that are not simple. In fact corrections to the data have been the subject of exchanges between the two groups.
The ground based measurements also have a common data base but it is clear and acknowledged that the two groups have different analysis procedures. While the satellite analysis procedures have converged to reduce their differences over the last thirty years, this has not been the case for the ground based procedures.
It is also clear looking at the measurements that there are substantial short-term, say less than 2 years, variations over the period 1997 to 2009. In fact, while the overall monthly variations show a scatter with standard deviation of 0.20C, the month to month variations are 0.10C. This is a measure of features that are clear in the data. The short run sequences of temperature movement are a reflection of variability in the atmosphere from events such as El Ninos (1997-98) and La Ninas.
Looking for a simple trend by fitting curves through a highly variable series is both a problem and a courageous exercise. The results on an annual rather than a monthly basis are given in the third table. The problem of dealing with real short term variations was resolved by ignoring them. 
So for twelve years there has been a rise 0.10C with a 140% error, in other words, no significant measureable temperature rise. You can play with the data. If you omit 1998 then you can double the change. But 1998 was an El Nino year followed in 1999 by a La Nina. If we omit both years then the results are unchanged.
However the lesson from this is to look at the detail.
There is so much variability within the 12 year period that seeking a trend that might raise the temperature by 20C over 100 years would not be detectable. On the other hand there are clearly fluctuations on a monthly and yearly scale that will have nothing to do with the predicted effects of anthropogenic CO2.
The twelve year temperature changes from the data of the four analysis centres reveal some possible differences. Since there is a high degree of commonality amongst the results, any differences may be systematic. Both the GISS and Hadley series show a larger temperature increase then the satellite measurements. This may be due to urban heat island effects.
Finally, if you are looking for temperature increases from CO2 in the atmosphere, then you should choose the satellite approach of measuring temperatures in the atmosphere!
Short term, less than thirty years, temperature series are not the place to seek evidence of human induced global warming.
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Tom Quirk lives in Melbourne, Australia.
To read more from Dr Quirk click here http://jennifermarohasy.com/blog/author/tom-quirk/
The photograph is from Anthony Watt’s website that details his program of photographically surveying every one of the 1221 USHCN weather stations in the USA which are used as a “high quality network” to determine near surface temperature trends in the USA, read more here http://wattsupwiththat.com/test/
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New Scientist 9 May: In an article on the Wolfram Alpha engine, it says “Wolfram’s site is aiming to be as trustworthy as gold-standard sources, such as NASA’s climate data sets” Author Jim Giles, a name to remember.
This whole thing confuses the heck out of me. I think there needs to be an international grid standard of definable points ( every 5 minutes around the globe ) that are measured upon at definable intervals ( hourly ) and in 3 dimensions and get the stinking data. The temperature at any defineable point in the grid should independently verified and then there can be no debate on the temapeature differentials between points in time.
I see GISS has managed to “massage” 1998 right down to nothing unusual. Brilliant, that… because of course in 1998 it was fire and brimstone. Now it’s just, oh, another year.
That’s a very interesting study, thanks.
So… *no* data set shows a “significant measurable rise in global temperature over the twelve year period since 1997”!
What would the warmists say?
Can anyone explain me how two datasets can have a strong cross-correlation factor (minimum 75%) on one side, and on the other side trends which are different by a factor of 10? There’s something strange there…
What would happen if you removed the ,oh ,say, 5 lowest anomalies from the series, then infilled the missing data with RegEM? Would that help prepare us for the sacrifices we all have to make?
Afraid the UK Met Office doesn’t agree! Global Warming Goes On… http://www.metoffice.gov.uk/corporate/pressoffice/2008/pr20080923c.html
“Anyone who thinks global warming has stopped has their head in the sand” http://www.metoffice.gov.uk/corporate/pressoffice/2008/warming_goes_on.pdf
Good post. At last someone who says what I’ve been saying for months. That is, while we cannot say whether global warming is continuing, we most definitely cannot say that the earth is cooling.
The agreement between the 4 data sets is also striking and, I believe, goes back before 1997. Any disagreement between UAH & RSS (and the others) originates in the pre-1992 period.
Finally whatever disagreement exist can easily be explained by some or all of the folllowing.
1. The 1998 EL Nino did not amplify GISS temperatures as much as the others.
2. GISS extrapolates over the arctic. The arctic has been particularly warm in recent years.
3. Satellite and surface appear to have a different ‘lag’ in response to ENSO events.
4. Most obvious of all. The satellites and surface thermometers are measuring quite different things.
Can we now put the ‘fraud’ and ‘corruption’ nonsense to bed.
Interesting artikle that clarifies who is who and who does what.
Can anyone tell me;
1) A 140% error was mentioned. Surely you can’t possibly begn to accept data with this degree of error. Is that figure correct or does it mean something different in this context?
2) From a ground station we presumably mean a weather station that has temperature sensor at say 3 foot above the ground level (ignoring those with UHI/A/c issues, or those stuck at 40 foot on a roof)
3) At what height is the satellite measuring temperature. 3 foot? (so being directly comparable to ground stations) 10 feet? An average of all the lower atmosphere?
Thanks for the clarification.
Tonyb
Please feel free not to accept this as it is off topic. However, I thought it is of interest in the way that a judge has said that :
[snip – yes OT I’m sorry, while there are parallels to the AGW issue, it is really not relevant here- Anthony]l
One of the major issues in detecting “climate change” (which usually really means 30 year plus weather) is that we have not got a decent global scale history of temperatures for any length of time. We have the thermometers concentrated in the USA, Europe, and Japan (to a lessor extent) and if you go back in the historical record at all, it’s even more sparse.
This is, IMHO, why folks are so desperate to “interpolate” missing data and just make stuff up (with fancy math, but still “made up”…) See:
chiefio.wordpress.com/2009/02/24/so_many_thermometers_so_little_time/
Short term, less than thirty years, temperature series are not the place to seek evidence of human induced global warming.
Damned if you do and damned if you don’t.
Would you say that his conclusion is “use the land based data for climate, i.e larger than 30 year changes?”, which is what the IPCC has done? Hmm
Should emphasize that corrections should be audited.
“since 70% of the surface of the earth is ocean and it is not monitored in a detailed manner, various procedures with possibly heroic assumptions and computer modelling, are followed to fill the ocean gap.”
Nonsense. No computer modelling or heroic assumptions are needed. GISS use satellite data for ocean temperatures. HadCRUT use the HadSST dataset which is based on direct measurement. Did you read any of the documentation?
“This is the fault of those publishing the temperature data as they fail to make the point that monthly and even yearly measurements are about weather and not climate”
Don’t be absurd. They make this point time and time and time again. If anyone chooses to ignore this point, they’ve only got themselves to blame.
“for twelve years there has been a rise 0.10C with a 140% error”
Firstly, you don’t say how you calculated the error on the trend in each individual dataset. Unless you properly modelled the autocorrelation then these figures will be wrong. Second, it appears that you simply averaged the errors you calculated to get the error you quote on the average trend. This is incorrect.
Doing the errors properly would most likely increase them. The conclusion does remain that even a decade or more of measurements is insufficient to detect climate change of ~0.2°C/decade. Remember this when you see the endless claims that ‘global warming stopped in X’! These claims are based on statistical ignorance, and you may also notice that X constantly shifts forward. X used to be 1998. 2002 is now pretty common, and I’ve recently seen 2005 put forward. All these claims are wrong.
“Finally, if you are looking for temperature increases from CO2 in the atmosphere, then you should choose the satellite approach of measuring temperatures in the atmosphere!”
This statement is completely unsupported by anything presented here.
“Short term, less than thirty years, temperature series are not the place to seek evidence of human induced global warming.”
The analysis is incomplete. It has been shown that over the last 12 years, no trend in global temperatures can be measured (though you only got the right answer by chance as your method was wrong). It has not been shown that the same is true over 30 years.
I think this is a good, rational analysis of recent temperatures.
Comparing UAH and Hadcrut3 from 1979 to 2008 I get ~0.20 to 0.25C greater warming in Hadcrut3, or ~0.07 per decade, essentially identical to the above for the most recent ~decade (0.11 – 0.04 = 0.07C). See Fig. 1 at
http://icecap.us/images/uploads/CO2vsTMacRae.pdf
I have assumed that this difference is due to UHI, etc., as per McKitrick and Michaels recent paper and Anthony et al’s excellent work on “weather stations from hell” (or less critically, “weather stations from heck” – after all, we haven’t summarized third-world weather stations yet, have we?).
What is perhaps equally interesting is that there has been no net warming since ~1940, in spite of an ~800% increase in humanmade CO2 emissions.
See the first graph at
http://www.iberica2000.org/Es/Articulo.asp?Id=3774
I find all this anxiety about humanmade global warming to be rather undignified, to say the least. It is the result of the current state of innumeracy in the general populace, and says more about the hysterical tendencies of those who advocate for CO2 reduction than it does about the science itself, which provides no evidence for their irrational fears.
Then there are those darker types who would seek to profit from these irrational fears, and have chosen to exacerbate rather than calm the disquiet of the general populace.
In summary, the current movement to curtail CO2 emissions is unsupported by science, but is strongly supported by scoundrels and imbeciles.
Regards to all, Allan :^)
Well Good science mixed with laughter might helpa few here weary of Agw idiocy..
http://speakyourmindnews.com/site/index.php?itemid=20
It will be my goal to provide such
I wonder how many people realise how much this AGW hoax is likely to cost them?
In testimony before the Senate Energy and Natural Resources Committee last year, Peter Orszag, Obama’s Director of the Office of Management and Budget, admitted that a 15 percent cut in carbon dioxide emissions would reduce American incomes. According to Orszag, the lowest quintile of households would pay an average of $680 more each year for goods and services (3.3 percent of their incomes) and the highest quintile would pay $2,180 more (1.7 percent of their incomes) than they would have in the absence of carbon rationing.
http://www.reason.com/news/show/133572.html
Many here might be interested in the excellent discussion found at http://tinyurl.com/oyrj3e.
The author takes great pains to fully document each graph and the reasoning for each presentation. As new information is provided, each of the graphs is updated and these updates are carefully documented.
With all the talk about the differences between the various temperature data sets, it is remarkable how closely they match each other and seem to say the same story.
Climate4You also avoids the charge of ‘cherry picking’ data. All the data is made available, from 1979 forward for the satellite data, 1958 for the Mauna Loa CO2 data, 1850 for the HADCRUT3 data, and so forth.
Its fairly clear CO2 is not driving temperatures for the planet. It is also clear the trends over the last ten years or so have proven to be an embarrassment for those advocating such a connection.
Climate4You is my second favorite site on climate issues, after WUWT.
Regards to all.
What happened to the fifth data set; that of NCDC/NOAA?
Steve (Paris) (03:24:09) :
Along those same lines, a good read here:
http://tinyurl.com/p5wbfx
Keith Rattie, CEO of Questar, delivered a speech to a student gathering about what was facing their generation. Many excellent points, including the fact a switch to the now abundant supply of natural gas, will result in significant reductions in this nation’s carbon footprint, without resorting to massive tax increases. By the way, this natural gas was found and is being developed in spite of the open hostility of the environmental community.
Some observations made by Keith:
And the costs?
The 140% error bar is not the problem. It only reflects the fact that the variation was very small. If the mean approaches zero of course the percent error will approach high values.
If the trend in temperature were on the order of 1 C, or higher, per decade, 10 years would be enough to detect it.
EM Smith
Dont forget there is some civilisation in the Southern Hemisphere including New Zealand, Australia, South Africa etc and that these long lost civilisations actually have some reasonably long climate records.
Allan M R MacRae (02:29:57),
Excellent post:
That says it all. Imbeciles can learn the truth; they won’t sit on a hot stove twice. Scoundrels are identified by their insistence that black is white, down is up, evil is good — and that global warming causes global cooling. They know the truth, but like all scoundrels they have ulterior motives.
The great thing about this site is that the few scoundrels posting here have apparently not converted one skeptic to their way of thinking — while at the same time, we routinely read about those who formerly bought into the belief that CO2=AGW, but who now understand that the real world evidence doesn’t support that mistaken conjecture.
With all the empirical data that has been made available over the last few years, people are beginning to grasp the fact that a change in a minor trace gas, from 4 parts in ten thousand to 5 parts in ten thousand, will not and can not cause runaway global warming. And if CO2 is benign, which it is, then there is no reason to spend one more penny on the global warming scam.
As you correctly note, the central question in the entire debate is over the [non] effect of CO2 on global temps. Without the CO2 boogeyman to scare the populace with, the entire CO2=AGW house of cards comes tumbling down.
Even as global temperatures continue their steady decline, there are still some true believers trying to convince the readership of the “Best Science” site that a *very* minor trace gas is the culprit. But the planet itself is proving them wrong.
John Finn (01:29:56) :
“we cannot say whether global warming is continuing”
So doesn’t that put the AGW community in a spot given that CO2 has continued to rise inexorably?
Why should law makers pass a bill that is going to cost Americans over $1,000 p.a. [at least] if the theory is not standing up in the real world?
John Finn (01:29:56) : “.. while we cannot say whether global warming is continuing, we most definitely cannot say that the earth is cooling.”
From atmospheric data – correct. But from ocean temperatures (body of the ocean not just the surface layer) we can tell if the Earth is warming or cooling. The Earth is warming (cooling) if the rate at which heat is leaving the planet is less (greater) than the rate at which heat is coming in [AGW is all about CO2 reducing the rate at which heat leaves the planet]. If the Earth is warming (cooling) then under the basic laws of physics the heat must exist (come from) somewhere. The only relevant heat body of sufficient size is the ocean. Hence we can tell if the Earth is warming or cooling if we can detect warming or cooling in the oceans.
The oceans are indeed cooling …
Cazenave, A., et al., Sea level budget over 2003–2008: A reevaluation from GRACE space gravimetry, satellite altimetry and Argo, Glob. Planet. Change (2008), Doi:10.1016/j.gloplacha.2008.10.004
Loehle, 2009: “Cooling of the global ocean since 2003.″ Energy & Environment, Vol. 20, No. 1&2, 101-104(4)
… or not warming …
Willis, J. K., D. P. Chambers, and R. S. Nerem (2008), Assessing the globally averaged sea level budget on seasonal to interannual timescales, J. Geophys. Res., 113, C06015, doi:10.1029/2007JC004517.
Leuliette, E. W., and L. Miller (2009), Closing the sea level rise budget with altimetry, Argo, and GRACE, Geophys. Res. Lett., 36, L04608, doi:10.1029/2008GL036010.
http://farm4.static.flickr.com/3400/3428934674_a9512a4fbe.jpg
http://climatesci.org/wp-content/uploads/dipuccio-2.jpg
There is a good analysis on Roger Pielke Sr’s website here :
http://climatesci.org/2009/05/05/have-changes-in-ocean-heat-falsified-the-global-warming-hypothesis-a-guest-weblog-by-william-dipuccio/
TonyB (01:32:21) : “A 140% error was mentioned. Surely you can’t possibly begn to accept data with this degree of error.”
It’s a high % only because it’s relative to a low figure. “0.1 +- 0.14” is IMHO a better way of expressing it. It does tell you that the actual rise is unlikely to be over 0.24 or under -0.04 – still useful information.