Physicist Luboš Motl of The Reference Frame demonstrates how easy it is to show that there is: No statistically significant warming since 1995
First, since it wasn’t in his original post, here is the UAH data plotted:
By: Luboš Motl
Because there has been some confusion – and maybe deliberate confusion – among some (alarmist) commenters about the non-existence of a statistically significant warming trend since 1995, i.e. in the last fifteen years, let me dedicate a full article to this issue.
I will use the UAH temperatures whose final 2009 figures are de facto known by now (with a sufficient accuracy) because UAH publishes the daily temperatures, too:
Mathematica can calculate the confidence intervals for the slope (warming trend) by concise commands. But I will calculate the standard error of the slope manually.
x = Table[i, {i, 1995, 2009}]
y = {0.11, 0.02, 0.05, 0.51, 0.04, 0.04, 0.2, 0.31, 0.28, 0.19, 0.34, 0.26, 0.28, 0.05, 0.26};
data = Transpose[{x, y}]
(* *)
n = 15
xAV = Total[x]/n
yAV = Total[y]/n
xmav = x - xAV;
ymav = y - yAV;
lmf = LinearModelFit[data, xvar, xvar];
Normal[lmf]
(* *)
(* http://stattrek.com/AP-Statistics-4/Estimate-Slope.aspx?Tutorial=AP *)
;slopeError = Sqrt[Total[ymav^2]/(n - 2)]/Sqrt[Total[xmav^2]]
The UAH 1995-2009 slope was calculated to be 0.95 °C per century. And the standard deviation of this figure, calculated via the standard formula on this page, is 0.88 °C/century. So this suggests that the positivity of the slope is just a 1-sigma result – a noise. Can we be more rigorous about it? You bet.
Mathematica actually has compact functions that can tell you the confidence intervals for the slope:
lmf = LinearModelFit[data, xvar, xvar, ConfidenceLevel -> .95]; lmf["ParameterConfidenceIntervals"]
The 99% confidence interval is (-1.59, +3.49) in °C/century. Similarly, the 95% confidence interval for the slope is (-0.87, 2.8) in °C/century. On the other hand, the 90% confidence interval is (-0.54, 2.44) in °C/century. All these intervals contain both negative and positive numbers. No conclusion about the slope can be made on either 99%, 95%, and not even 90% confidence level.
Only the 72% confidence interval for the slope touches zero. It means that the probability that the underlying slope is negative equals 1/2 of the rest, i.e. a substantial 14%.
We can only say that it is “somewhat more likely than not” that the underlying trend in 1995-2009 was a warming trend rather than a cooling trend. Saying that the warming since 1995 was “very likely” is already way too ambitious a goal that the data don’t support.
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P Wilson (18:42:04) :
“… its safe to assume that if there is no significant increase in the airborne fraction then anthropogenic c02 doesn’t accumulate whilst natural c02 does.”
I think you’ve lost everyone now. How does a CO2 molecule know whether it’s anthropogenic or natural? Do they come with little labels?
Tom P (19:09:55)
According to present propaganda they certainly do come with labels. the 97% natural co2 is quite benign, whilst the 3% Anthropgenic has all the force of doom that makes the vast difference between cataclysm and perfection, such is its potency.
I don’t agree that my statement was nonsense. I did agree that it was inelegantly worded and over-simplified. But… Fair enough.
The falseness of your analogy is this simple:
The delta-CO2 still lags behind the delta-T.
The source of ignition always precedes the fire.
It is impossible for “B” to cause “A” if “A” always occurs first.
The only “smoothly increasing” CO2 curve is in the instrumental record (eg. Mauna Loa Observatory); which only dates back to 1960. It’s quite possible, maybe even probable that a significant part of the increase in the MLO data is anthropogenic. Mankind’s CO2 emissions
The ice core CO2 data represent a moving average of CO2 with a century-scale period. So… At decadal scales, the curve should be very smooth.
The CO2 concentrations derived from plant SI data (eg. Jay Bath) have an almost annual resolution back almost 2,000 years. These curves are anything but smooth (as one would expect in a stochastic system). And there is a very consistent pattern of the temperature peaks and troughs preceding the CO2 peaks and troughs by anywhere from 100 to 400 years. Now this doesn’t prove that temperature changes have been driving CO2 changes… But the correlation certainly forms the basis of a hypothesis worthy of investigation. The CO2 rise since the mid-1800’s could largely be the result of oceanic warming that began at the nadir of the Little Ice Age in the 1600’s.
The lack of a correlation between CO2 and temperature that would indicate enhanced greenhouse warming at the Phanerozoic scale and the presence of a correlation that supports temperature-driven changes in atmospheric CO2 at the glacial-interglacial and Dansgaard-Oeshger/Heinrich/Bond cycle (~1,470-yr) scales ought to be a clue that temperature changes have far more impact on atmospheric CO2 than relatively minor changes in CO2 have on temperature.
Correction to: David Middleton (07:03:24)
I forgot to finish a sentence…
Mankind’s CO2 emissions accelerated after 1950, a few years before Keeling started recording CO2 levels at MLO; so the secular trend in the MLO curve probably does carry an anthropogenic signal.
David Middleton (07:03:24) :
“It is impossible for “B” to cause “A” if “A” always occurs first.”
Not true – a bachelor party always precedes the marriage, but it is the marriage which is the cause of the party, not the other way round.
Anyway, this is not the relevant statement. What we actually have is:
“It is impossible for “B” to cause “A” if “A” has up to now always occurred first.”
which is a failure of inductive reasoning and logically false.
Happy New Year/Decade!
“Not true – a bachelor party always precedes the marriage, but it is the marriage which is the cause of the party, not the other way round.”
I know this is how you guys think. But the fact is that a bachelor party is a celebration of the end of bachelorhood, not a celebration of marriage.
.
“Marriage isn’t a word, it’s a sentence.”
~K. Vidor
…as I sometimes tell Mrs. Smokey when I’m out of range.
Happy New Year folks! And may AGW suffer the same ignominious fate as Y2K, Alar, and killer bees.
Correlating social convention to the laws of physical causality might be entertaining, tho David Hume wrote a treatise on this very subject on the pitfalls of inductive reasoning during the 18th century, due to the fact that we cannot trace a contiguity between a cause and an effect, or their respective origins. Its even online fortunately for us.
http://www.class.uidaho.edu/mickelsen/ToC/hume%20treatise%20ToC.htm
The debates he threw are still used to day in the latest scientific discoveries.
However, here’s a test of such a relation: Miss Jones is single and teaches mathematics. Mrs Smith is married and teaches mathematics in the same school and a different class, to the same proficiency as Mrs Smith. Miss Jones’s pupils achieved better results than Mrs Smiths’, therefore all mathematics teachers who are single will achieve better results than those who are married, since marital status seems to be the only discernable causal affinity.
Oh – forgot – if a bachelor’s party precedes the cause, then the cause was still in advance of the effect, since the marriage arrangements came prior. But to use the former logic, we’d say that eggs cause water to boil in the pan, since the requirement was that cooked eggs were the greater necessity than boiling water, and must therefore have been the cause.
Climate science is indeed similarly metaphysical.
Happy 2010
Icarus (13:33:14) :
“The long-term warming trend is around 0.13C per decade according to the entire UAH record. What you should be calculating is whether there is any statistically significant deviation from that warming trend – otherwise you’re just grasping at straws.”
Is that figure before adjustments a la Darwin airport, Australia?
http://blogs.telegraph.co.uk/news/jamesdelingpole/100019301/climategate-another-smoking-gun/
investigation courtesy of Willis Eschenbach
and
http://www.surfacestations.org/
scroll down to the title: “Here is a well maintained and well sited USHCN station”
and imagine that a lot of world weather stations give anomalous readings due to their maintenance.
I’m curious as to why less attention is brought to Essenbach and Anthony Watts when they seems more meticulous that NASA or CRU!
Incidentally (Icarus) the satellite data was adjusted in various ways when it was found to deviate from weather station temperatures, since it showed no warming. One of the chief reasons was orbital drifting. The logic of satellites is that if they lose velocity and drift they lost altitude, and so it would be appropriate to adjust temperatures inferred from satellites downwards, since they’re recording more than they should for the original altiude. What diid they do? They did the opposite and adjusted them upwards, which defies all logic. They adjusted them upwards to obtain the 0.6C that they were looking for – that is, adjustment in line with *adjusted* surface temperatures.
@ur momisugly P Wilson:
“Mrs Smith is married and teaches mathematics in the same school and a different class, to the same proficiency as
Mrs SmithMiss Jones.”“therefore all mathematics teachers who are single will achieve better results than those who are married, since marital status seems to be the only discernible causal affinity.”
This is formalized as the “common factor fallacy” or the “whiskey-and-soda fallacy.” Here’s one version of it that I just picked up by googling:
“This logic reminds me of one of Husserl’s favourite anecdotes: There is this man who drinks whisky and soda and it makes him sick, then he takes gin and soda and he gets sick; then he takes vodka and soda and he is sick, and he concludes that soda makes him sick.”
Other versions have it that the drinks make him drunk, not sick.
P Wilson:
So, you are suggesting that Roy Spencer and John Christy have purposely or accidently adjusted the satellite data the wrong way despite the fact that both of them clearly have their allegiance on the side of believing that man-made global warming is no big deal? What a novel idea!
REPLY: yes, I’ll have to agree with Joel, this is a pretty screwy idea. – Anthony
P Wilson:
Oh, and by the way, the effect of the satellite decay is not obvious as Christy and Spencer difference two different measurements and “the presence of a spurious cooling trend introduced into the MSU2LT data by neglect of the differential effects of satellite orbit decay on the near-limb and near-nadir observations” (quoting from http://www.ssmi.com/papers/msu/A_Reanalysis_of_the_MSU_Channel_2_Tropospheric_Temperature_Record.pdf )
David Middleton says:
However, if by “A” you mean a temperature change, then it does not always occur first. It may tend to start first…but much of the temperature change occurs after the CO2 levels have already been changing.
You might also want to think about chickens and eggs. Certainly, we have never seen a (chicken) egg that hasn’t first been laid by a chicken. And, it turns out to be correct to conclude that chickens “cause” chicken eggs. However, far from being logically impossible that chicken eggs “cause” chickens, it in fact turns out also to be the case.
No…It is not. For one thing, the rises in CO2 and the associated temperature rises seen in the ice core record are not compatible with this large a change in CO2 from the global temperature change. For a second thing, evidence shows that the oceans are actually absorbing CO2, not emitting it. It also begs the question of where the CO2 that we know we are producing by burning fossil fuels is going.
Smokey (12:22:36) :
Of course the engagement is the original cause of both the party and wedding just as the Milankovitch cycle was the original cause of the past excursions in temperature and CO2. These cycles produced an increase in the input of energy into the global climate.
But this time Milankovich forcing is not driving the change – we’re at the peak of an interglacial cycle. Hence we need to look for a different underlying cause than has been seen in the climate record to date.
Joel Shore (18:12:19)
If satellites lose velocity and altitude their readings should surely be adjusted downwards, whouldn’y you agree?
Joel Shore (18:12:19)
If satellites lose velocity and altitude their readings should surely be adjusted downwards, wouldn’t you agree?
Joel Shore (18:12:19
Fair enough: GISS/Schmidt were the arbiters of this temperature correction of satellite data.
Roger Knights (16:17:36)
Thanks for the correction!
Joel Shore (18:47:50)
The salient characteristic that traps heat is air pressure than c02 or water vapour concentrations, and air pressure changes constantly – so do temperatures. Over a longer term its ocean heat content. However, the problem for whether oceans are net emitters or net absorbers of c02 is that no-one is measuring it and such exchanges, since its well nigh impossible to. I’d suggest that given SST’s over the course from the 20thC-21’st, that oceans have been net emitters of c02, particularly since the late 1970’s
P Wilson: I have explained to you both why it is ludicrous on the face of it to make the claim that Christy and Spencer are adjusting the satellites in the wrong way for this effect (and even Anthony agrees with me on this) and also given you an explanation of why it is more complicated than you envision. I think there is really nothing more that need be said.
It was Wentz, et al who proposed that an artificial cooling trend occurs when satellites lose their orbit and fall closer to the earth’s surface, and i’m not sure that Strong and Christy agree with his theory.
http://spacescience.spaceref.com/newhome/headlines/notebook/essd13aug98_1.htm
the idea that the atmosphere cools as you get closer to the surface of the earth and lose altitude is certainly a novelty to me. I can see the case for adjusting diurnal adjustments that show an artificial warming or cooling trend.
ok i can’t make it much clearer.. Is something in orbit slows down and moves closer to the earth, its going to give a higher reading, is it not?
On the issue of residence times, I was just re-reading the relevant section of “Global Warming: The Hard Science” by L.D. Danny Harvey ( http://books.google.com/books?id=8zBRAAAAMAAJ ). He calculates a residence time on the order of 5-6 years for the atmospheric reservoir. Here is what he then has to say (pp. 20-21):
test
Interetsing. You calculate a warming trend of 0.95 deg C/century based on the raw UAH data. And then you set about some rather Jonesian “tricks” and –voila!–the trend goes away.