Excerpt from Bishop Hill (plus a cartoon from Josh) showing that the claim of a statistically significant temperature rise can’t be supported, and the Met office is ducking parliamentary questions: (h/t Randy Hughes)
Met Office admits claims of significant temperature rise untenable
This is a guest post by Doug Keenan.
It has been widely claimed that the increase in global temperatures since the late 1800s is too large to be reasonably attributed to natural random variation. Moreover, that claim is arguably the biggest reason for concern about global warming. The basis for the claim has recently been discussed in the UK Parliament. It turns out that the claim has no basis, and scientists at the Met Office have been trying to cover that up.
The Parliamentary Question that started this was put by Lord Donoughue on 8 November 2012. The Question is as follows.
To ask Her Majesty’s Government … whether they consider a rise in global temperature of 0.8 degrees Celsius since 1880 to be significant. [HL3050]
The Answer claimed that “the temperature rise since about 1880 is statistically significant”. This means that the temperature rise could not be reasonably attributed to natural random variation — i.e. global warming is real.
…
The issue here is the claim that “the temperature rise since about 1880 is statistically significant”, which was made by the Met Office in response to the original Question (HL3050). The basis for that claim has now been effectively acknowledged to be untenable. Possibly there is some other basis for the claim, but that seems extremely implausible: the claim does not seem to have any valid basis.
Go read the entire essay here: http://www.bishop-hill.net/blog/2013/5/27/met-office-admits-claims-of-significant-temperature-rise-unt.html
Josh has a go at them:
Stephen Wilde says:
May 27, 2013 at 9:27 am
Rather than simply being changes in thunderstorm activity in the tropics as suggested by Willis it is a bodily latitudinal shift of the entire atmospheric circulation in response to any forcing element other than atmospheric mass, the strength of the gravitational field or ToA insolation.
What you suggest reminds me of a thought that was generated by reading how the Magnetic North had been found to be moving in the early 1900s and over the last several decades that movement has accelerated. That led me to wonder if the shifting magnetic streams could potentially pull/shift the weather systems, and effect regional changes in weather patterns? I made a comment/question regarding that idea several years ago, elsewhere. The responses were negative to the thought, but since then I have read bits and pieces from other articles that suggested correlated with the idea of magnetic streams having a tie-in with weather. Bits and pieces such as your comment.
Nick Stokes says:
May 27, 2013 at 2:02 pm
“So now it comes down to, well, maybe Keenan has a better trendless model. But no, the comparison cited is between a first order autoregressive model with trend, and a third order (“driftless”) model. That’s no fair comparison – the third order model has more parameters to play with. And as Lucia said, no-one expects that linear rise since 1850 is the expected result of AGW.”
Usermanual of model MAGICC…
http://www.cgd.ucar.edu/cas/wigley/magicc/UserMan5.3.v2.pdf
…I count 20+ parameters…
…so … what’s fair for the IPCC should be fair for skeptics, don’t you think so.
lsvalgaard says:
“So, you admit that cloud cover was low during the MM.”
For Norway as the jet stream was often more southerly yes, globally no. More cloud low clouds there in winter will raise the average temp’ more than less clouds in summer will.
Ulric Lyons says:
May 27, 2013 at 3:01 pm
For Norway as the jet stream was often more southerly yes, globally no.
Why globally no?
The UK Met Office recently mentioned the effect of the PDO and AMO on global temperature in context with their much reduced global temperature prediction out to 2017. This is encouraging since it suggests they are somewhat willing to consider the actual data.
The trouble for them is that an objective examination of this combined long phase ocean cycle is it is responsible for nearly half the temperature ‘rise’ last century, due to the cycle being at bottom in 1906 and at peak in 2005, which coincidentally are the endpoints of the IPCC’s preferred period. Immediately when you backcast a GCM to the temperature record with the cycles included (presumably implemented through more accurate thermohaline cycle modelling) then derived climate sensitivity drops by that much, ie nearly half.
Alone this is probably enough to falsify the CAGW hypothesis. Add the apparent effects of the Sun through the solar dynamo and you come down to a long term net equilibrium climate sensitivity similar to the short term response measured by Ray Spencer and Dick Lindzen, or about 0.7 C/doubling of pCO2, ie. harmless.
NASA GSFC has acknowledged the likely effect of the solar dynamo. The UK Met Office appears not to have. If, or when, they do they will have themselves a much more accurate (and precise) climate model. But I do not think they, as CAGW supporters, will like what it will say.
NAO doc
http://www.windows2universe.org/earth/climate/images/nao_lg_gif_image.html
vukcevic says:
May 27, 2013 at 3:22 pm
NAO doc
As its name implies is not global.
Reminds me of the discussion on Long-Term Persistence (LTP) at climate dialogue:
http://www.climatedialogue.org/long-term-persistence-and-trend-significance/
If one looks at variation in the surface temperature without considering known physical processes on this temperature, the LTP may be a better null hypothesis than AR1. Koutsoyiannis appears to use LTP this way and finds no significant trend. Bunde uses LTP as well but seems to control for known physical forcings and argues there is a statistical significant trend (not surprisingly smaller than using AR1). Benestad seems to argue from the global climate modeling perspective and appears to argue that a lot of the LTP is the result of known forcings, and that the models cannot explain the trend without the rise of CO2.
(Sorry for the many “seems” and “appears” above. The opening pieces of each of the authors seem ok as such, but the discussion afterwards is IMO very muddled somehow.)
Regarding Keenan’s piece, an argumentation is missing why the ARIMA(3,1,0) would be a valid assumption for the climate system against which the trend is tested. As others already remarked, it has more parameters than the AR1 (I think about everybody thinks AR1 is an oversimplification) and therefore likely to fit the data better, but also that the 1 in 3,1,0 actually signifies smth like a trend in itself. The point being that it should always be possible to find some manner of modelling interdependencies in time-series data such that there is no significant trend left on top of the data structure assumptions. The question is therefore which assumptions about the data is plausible, not which gives the most or least significant trend.
Note the MET office referring to global climate models which are made to simulate known forcings. They say that when known forcings are accounted for that the trend is clear and significant.
(And again, using AR1 to calculate significance of the trend against surface temperatures (without accounting for known forcings) is an oversimplification and significance of the trend is reached too easily.)
@Louis
This might sound Alice in Wonderland but significant has a technical definition in this context which does not mean what it does to the man in the street. Part of the problem that scientists need to overcome is in ensuring the public understand what they are saying since it is all too easy to cherry pick quotes to get one scientist agreeing that black is white, white is black and getting run over on the next zebra crossing.
Furthermore, amongst the many formulations of Occam’s Razor, I think the most accepted is the one that says we accept the explanation with the fewest and simplest assumptions. This is one of the reasons why I agree with the AGW hypothesis and not those that stack untenable assumptions upon untenable assumptions. There are sometimes good reasons to choose a more complicated explanation for a phenomenon but there must always be a physical reason for accepting it. One cannot, for instance, suggest that the oceans store heat in an El Niño event when such an event is giving energy up.
Hope this clears up any misconceptions you might have.
“…amongst the many formulations of Occam’s Razor, I think the most accepted is the one that says we accept the explanation with the fewest and simplest assumptions. This is one of the reasons why I agree with the AGW hypothesis…”
That is just false. The explanation “with fewest and simplest assumption” is that any change is natural variation.
We can’t even measure temperature reliably and you jump already to “explanations”.
In reply to:
lsvalgaard says:
May 27, 2013 at 12:28 pm
William Astley says:
May 27, 2013 at 12:20 pm
What is the point of showing a graph of GCR Vs Low level cloud for a period in which the solar magnetic cycle is inhibiting that mechanism? The inhibiting mechanism is connected with the linear reduction in the magnetic field strength of newly formed sunspots.
So, during the Maunder Minimum you would not expect GCRs to form Low Level Clouds and produce cooling, right?
The inhibiting mechanism is transient. When the inhibiting mechanism ceases the planet will cool relatively quickly.
The inhibiting mechanism causes there to be an increase in high level clouds which offsets the increase in low level clouds.
As I said the high Northern regions are now starting to cool. (Do your remember the paper that notes there is a 10 to 12 year delay in cooling when there is a change in the solar cycle length?)
The Arctic sea ice will recover. There will be a drop in temperature on the Greenland Ice sheet.
What we are observing has happened before.
@AlexS
“natural variation” isn’t even wrong! 😀
William Astley says:
May 27, 2013 at 3:51 pm
“So, during the Maunder Minimum you would not expect GCRs to form Low Level Clouds and produce cooling, right?”
The inhibiting mechanism is transient. When the inhibiting mechanism ceases the planet will cool relatively quickly.
So, how long does the transient mechanism last? [in particular during the Maunder Minimum] Presumably when it stops sunspots rapidly form again, right?
The post prompted me to look at HadCET
http://www.metoffice.gov.uk/hadobs/hadcet/
I note the chart is plotted based on “ the 1961-1990 average” and the red line (10-year running mean” is less than 0.5 at its right-side end; meaning it would be lower if the base used the 1981-2010 period. The page seems not to mention the green line of the far right-side. That’s the line that sinks to -1.0, a negative anomaly. Those with challenged vision may want to use the magnifier to view this green line.
Margaret Hardman says:
May 27, 2013 at 3:33 pm
This is one of the reasons why I agree with the AGW hypothesis
——————————————————————–
Doesn’t pass the smell test Margaret, sorry. Like the good little warmist you are, you have your conclusion in place first, and then seek to redefine Occam’s razor with an incorrect assumption count, bolstered by a strawman.
FAIL
Are you Kevin Trenberth’s Mom ??
Louis says: May 27, 2013 at 2:43 pm
“So to any honest person, this is an indirect admission from the Met Office…”
The headline said nothing about an indirect admission. It said, in bold,
“Met Office admits claims of significant temperature rise untenable”
And to any honest person, that just isn’t true.
But beyond that, what are the alleged claims? No-one claims that temperatures have been rising linearly since 1850, and this is in no way a claim of AGW. But that is what this test tests. And it is meaningless, because it pits a third order AR driftless against a first order with trend. All that says is that you can get more improvement with a higher order analysis of the noise than trying to fit a line. Since no-one expected a line to fit well, no surprise there.
The test in that answer does not mean that “The driftless model says that the .8 C of warming since 1850 is well within what could be expected from natural variations in temperature, thus it is not significant.” It is a comparison test, saying only that third order driftless does better than first order with trend. It does not say what you claim.
Gold minor said
“What a tremendous store of information it holds within its records. I thought it interesting that the very beginning of your reconstruction, at 1538, shows a tailing off from a warm period with a strong warming. That made me wonder what the previous years looked like, although I suspect that the warm trend would go back to early 1500s, perhaps to 1510. ”
Thanks for your kind comments. Ironically I use the Met Office library and archives in my research.
I am currently back to 1500 and yes it is around as warm as today during the period from then to 1538
I am currently seeking the transition decades between MWP and LIA as that will fill in the gap between around 1300 to the current start date of my reconstruction in 1538. It takes about a year to research all the material I need then months to put it all together, so hopefully look out for part 2 of ‘The long slow thaw’ in early winter.
tonyb
Margaret Hardman says:
May 27, 2013 at 3:33 pm
quote/ Furthermore, amongst the many formulations of Occam’s Razor, I think the most accepted is the one that says we accept the explanation with the fewest and simplest assumptions. This is one of the reasons why I agree with the AGW hypothesis and not those that stack untenable assumptions upon untenable assumptions. There are sometimes good reasons to choose a more complicated explanation for a phenomenon but there must always be a physical reason for accepting it. One cannot, for instance, suggest that the oceans store heat in an El Niño event when such an event is giving energy up. /quote
”..and not those that stack untenable assumptions upon untenable assumptions”.??? As far as I can tell the AGW hypothesis relies entirely upon these stacked untenable assumptions of which you speak! Things like, the sun has no real effect, feedbacks are mostly positive, the data we have collected is ‘correct’ (no UHI, or it’s been ‘taken care’ of! LOL), palaeo proxy data is ‘correct’ (Yamal anybody?), etc, etc – and of course the absolute corker – that 100 years or so of crappy (so really good, homogenised and gridded data from inumerous different stations and thermometers, etc) data can accurately reflect and predict the changes in a climate that has been going up and down like a brides nightie for the last 4.6 billion years!
As others have noted, the basic hypothesis that increased CO2 can cause warming is indeed relatively ‘valid’ – but the AGW hypothesis that the ‘alleged’ observed warming is mostly anthropogenic is based on many many assumptions (mostly that ‘other’ things are not affecting temperature!) and based on inumerable assumptions/estimations/etc in order to derive the supposed sensitivity to CO2 doubling which is the crux of the AGW hypothesis.
In short, I think you just shot your own beliefs down in one paragraph – if you care to think about it?
Wet Office at It again,Slingo should read Slygo.
D.I. says:
May 27, 2013 at 4:28 pm
I don’t care if she goes on the sly or with a frickin’ fanfare – I just wish she would go! and preferably for someone with some scientific integrity to take her place!
Reblogged this on Public Secrets and commented:
Well, well, well. Follow the link from WUWT back to Bishop Hill; it seems the Met Office, the UK’s official weather and climate forecaster and a temple in the cult of global warming, has just admitted that its claim of statistically significant temperature increase (i.e., that which can only be explained by anthropogenic causes) cannot be supported. That’s like knocking the foundation stone out from under the entire edifice.
Using 0.8c is still cherry picking since the data began, the recent temperatures really are only about 0.4c – 0.5c warmer than the 1880’s.
http://www.woodfortrees.org/plot/hadcrut3gl
That temperature range is nothing in the scale of natural variance.
lsvalgaard says:
May 27, 2013 at 2:48 pm
“So, you admit that cloud cover was low during the MM.”
================
Come on Leif, you can tell us !!
What was the cloud cover ?
The truth will never leave this blog 🙂
Stephen Wilde – I think the time has come for you to submit your theory as a post to WUWT. It seems to me to make sense, and in particular it allows the global temperature (as measured) to change without any external forcing. But I would like to see it put in a single comprehensive post.
u.k.(us) says:
May 27, 2013 at 4:53 pm
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I’m entered in the senior division of the Y1.7K running of the annual Dover Strait Cross-Channel Ice-Skating Marathon & will let you know about MM cloudiness when I get back from the Little Ice Age.
Unfortunately my green time machine is solar-powered, so a little wonky at the moment.