Guest essay by Neil Catto
The other day I conducted a presentation using the UK CET, like I have on several occasions. Along with explaining it as the longest recognised instrumental record of historical temperature anywhere on Earth, it is the best record we have to understand long the past.
Fig 1 Central England Mean Monthly Temperatures 1659-2012
As part of this presentation I point out that the temperature from 1659 to 2012 has only increased 0.87 Deg C in 353 years, or equivalent to 0.025 Deg C/decade. Considering this is a recovery period from the Little Ice Age it is hardly surprising and just part of natural variation. At this stage I normally get a few “really?” questions.
“The UK MetOffice’s own figures”, I reply.
The other day however was a bit different, someone in the audience asked “so how long will it take to get to the dangerous 2 Degrees C?”
Pause, why hadn’t I worked that one out before? Quick calculation done, 800 years I replied.
“Say again?”
I recalculate, and say “800 years given the current trend”. Gobsmacked audience!
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No I wasn’t. I was questioning the temperature change in the CET record. I have calculated the trend between 1700 and 1900 and it is as near to zero as makes no difference. In other words there is no evidence for warming or cooling in the Central England region over that 200 year period. That’s what the data tells us. I’m sorry you if it doesn’t agree with your preconceptions.
I suppose I should thank you, Peter B, for giving us a perfect example of “cherry picking”. You have selected an individual local low reading and compared It with an individual selected high value.
Tell you what, Peter, I’ve got an even better cherry pick than that. Check this out
2006 10.62
2010 8.83
That’s a 2 degree decline in 4 years – or 50 degrees per century. That’ll make the last ice age seem like a picnic by comparison, but hang on a minute, Peter, look what happened in 2011
2011 10.7
A 1.9 degree increase in just one year. What do you think might be going on, Peter?
I take it you don’t understand the concept of Least Squares linear regression. Basically this method of calculating linear trends ensures that anomalous dips or spikes don’t unduly influence the calculated trend. You also need to gain some understanding of data ‘noise’.
John Finn says:
“1950-2012 1.7 degree per century. All the warming has taken place in the last few decades.”
1903-2012 is less than 1°C and about 75% of that was from 1988 onwards.
Mr Green Genes:
I have deliberately kept out of the discussion for a while because PeterB in Indianapolis attempted to start a polite and informative discussion with John Finn as I had, and I did not want to interrupt it.
Please read the response John Finn provided to PeterB in Indianapolis at November 1, 2013 at 10:35 am. It is similar to all the replies I obtained from John Finn. And please suggest what you think would be an appropriate response of PeterB in Indianapolis in reaction to that offensive, insulting and blustering reply which John Finn provided to cover his ignorance and stupidity.
Richard
The warmists’ position is that only the 1850 to present time period is relevant, and only from 1975 onward :”shows” signs of CO2 warming. As much as it might show that today’s trends are not much different from yesterday’s, the long term records are not pertinent to the CAGW debate. In fact, what your CET record shows is a step-function at 1983 or so. Step-functions may or may not be related to CO2 suddenly “breaking through” regional dullness.
Sorry, but argument based on historical trends/data holds no grounds with the understanding the IPCC/Al Gore has. If you want to discount the IPCC, you have to start with 1850, with a particular focus on post-1975, and really grind on the observations and the match between observations and models/predictions.
richardscourtney says:
November 1, 2013 at 9:38 am
Richard
Insofar as I failed to mention that he should also cease the name-calling and denigration of another’s point of view, you have a good point.
So, to modify my original post, EVERYONE should behave with decorum. That way, those of us who know little but hope to learn do not have either to wade through name calling etc. or to skip past any post from someone with “a history”.
That is all.
Mr Green Genes:
I read your November 1, 2013 at 3:15 pm.
I notice that you did not answer my serious request that you suggest what you think would be an appropriate response of PeterB in Indianapolis in reaction to that offensive, insulting and blustering reply which John Finn provided to cover his ignorance and stupidity.
There are two options; i.e.
(a) leave the untrue point of an aggressive blaggard stand (as PeterB seems to have chosen in this case) which encourages others to provide falsehoods in similar manner
or
(b) fight fire with fire (which – as you note – I have a history of doing) to discourage others using the same tactic.
I always treat people with the respect they accord to me. Your reframing of your point is spurious.
Richard
Personally, I completely agree with Mr Green Genes at November 1, 2013 at 3:15 pm.
And I disagree with my father’s response.
Two wrongs do not make a right.
Fighting fire with fire wins battles but scorches the Earth, a Pyrrhic Victory.
Once upon a time RichardSCourtney debated a Greenpeace spokesman called Jeremy Leggett. Leggett legged it before the public questions began – clearly a victory!
But Greenpeace have refused all further debates and Leggett does too. The War went badly for those who want debate to winnow out the truth.
In this case being too vigorous in duelling-online leads to people scrolling past the rudeness.
If you have a point then make it.
Then repeat it.
And politely repeat it.
In this precise case the point is:
Picking points in the CET and drawing straight lines between them is meaningless. The lines need error boundaries, a justification for the error boundaries and a justification for being straight.
But no-one will have.got that from the debate. It was too fierce.
Doug Proctor says:
November 1, 2013 at 11:39 am
The CACA time period remains fungible, intentionally. You can’t pin them down. Since CO2 levels allegedly started accelerating after WWII, the relevant period ought at least to start in 1945, but that doesn’t work because from about then to c. 1977 was a cooling time frame. If you go back to the end of the LIA in the mid-19th century, then they have to explain the apparent warmings comparable in amount & rate during the early 20th & late 19th centuries, without benefit of steadily increasing CO2.
Instead of confronting these problems honestly, CACA advocates simply cook the data books to lower actual surface station T readings during older decades & raise it as much as satellite observations will allow in recent decades.
This is not just post- but para-normal “science”.
John Finn says:
“In other words there is no evidence for warming or cooling in the Central England region over that 200 year period. That’s what the data tells us. I’m sorry you if it doesn’t agree with your preconceptions.”
My preconceptions?? That, coming from Mr Junior Hokey Stick!
Your preconceptions assume that there is no evidence for warming or cooling over that 200 same year period. Having your preconceptions, you ignore the fact that there is agricultural and other real world evidence that deconstructs your beliefs.
That is the problem with the alarmist crowd: they cherry-pick only the evidence that supports their alarming scare story. Scientific skeptics, OTOH, take all the evidence into consideration, not just one thermometer record — and all the evidence together deconstructs Mann’s hockey stick, which was based on one single tree, YAD061.
There was natural global warming [MWP] and global cooling [LIA] before the ramp-up in CO2. But the alarmist crowd just cannot admit to the evidence that contradicts their belief.
richardscourtney says:
November 1, 2013 at 3:34 pm
I notice that you did not answer my serious request that you suggest what you think would be an appropriate response of PeterB in Indianapolis in reaction to that offensive, insulting and blustering reply which John Finn provided to cover his ignorance and stupidity.
==============================================================
Apologies, I missed that. I have no excuse other than that I’m on holiday.
You could always ask him politely to stop it.
I try (but do not always succeed) to remember 2 small dictums (dicta???):-
1. Never wrestle with a pig – you both get dirty and the pig enjoys it.
2. Don’t argue with an idiot – (s)he will inevitably bring you down to his/her level.
Dear Mr Green
I’m sure you won’t bother going to the trouble but if you scan back through the posts you’ll find that it is Richard Courtney who began the insults – as per usual. Richard is well known for it. He has, over time, somehow managed to become accepted (by some) as an authority on the subject of climate. He is no such thing, He has no training or expertise in Maths, Physics, Chemistry or any associated discipline. That shouldn’t matter and I have no problem with Richard offering an opinion. I do, though, object to constantly being referred to as “stupid” and “thick” by someone who is nowhere near as qualified as myself (I hate saying this but it’s true).
Throughout this thread I have maintained that Neil Catto is wrong to conclude that the 2 deg threshold will be reached in 800 years based on the 353 year CET trend. I have given my reasons and provided the data to back them up. Basically there was very little net warming in the first 250 or so years of the CET record. The vast majority of the warming has occurred since 1950.
I have invited readers (including Neil himself) to check my numbers and if they are shown to be in error then I will accept that I am wrong. Thus far, no-one has managed to do this.
Mr. Courtney
Your father’s request for error boundaries came relatively late on in the discussion, His first complaint was that I was cherry picking the time periods. (i.e. a period of 200 years in a 353 year record was apparently “cherry picking”). Despite disagreeing with him on the “cherry picking” accusation I, nevertheless, calculated the trend for a 113 year period suggested by him. Have you got that.
Richard Courtney asked why I didn’t calculate the 1690-1803 trend and compare that with the recent 112 year (1900-2012) trend
So I did – and I found the following trends.
1690-1803 -0.30 degrees per century
1900-2012 +0.82 degrees per century
Now, apparently, Richard thinks the numbers are meaningless because there are no error bars. First thing to point out is that the numbers are NOT meaningless. For example, we know that the central value for the 1690-1803 trend is negative and error bars will only show one of 2 things:
(i) There is a statistically significant cooling trend between 1690 and 1803.
(ii) There is NO statistically significant trend between 1690 and 1803.
For the purposes of this discussion that would have pretty much settled the debate because it would have shown there was no warming in Richard’s preferred 113 year trend.
However, just to satisfy everyone on this issue, I will present the trends with 95% confidence Intervals.
1690-1803 -0.30 (+/- 0.4) degrees per century
1900-2012 +0.82 (+/- 0.29) degrees per century
i.e. No significant 1690-1803 trend; Significant 1900-2012 warming trend.
I do, though, find it a bit strange that your father made no such demands on the author of this article. How come he was happy to accept the 353 year trend AND the 800 year prediction based on the trend without any error boundaries being specified?
You still don’t get it. I don’t have any preconceptions. I am simply interpreting the data in a single dataset. The CET record shows NO significant trend between 1700 and 1900 (and probably longer) – but does show a significant warming trend since 1900.
That’s what I’ve found.
That’s what the data says.
That’s all I am going on … nothing else.
I am only commenting on the CET record because that is the data referenced in the above article.
Is that clear enough?
Now it is possible that I have made an error in my calculations, so I invite anyone who feels competent enough to get hold of the CET data and check my workings. If I am found to be wrong I will admit to the fact.
Finally, take a look at this Realclimate blog post from December 2004
http://www.realclimate.org/index.php/archives/2004/12/myths-vs-fact-regarding-the-hockey-stick/comment-page-1/
and take particular notice of comments 4, 5 and 6.
If you’re able to follow the argument you might notice that I picked up on the “hide the decline” trick about 5 years before Climategate. So much for me being a Hockey Stick supporter.
Go back 200 years before the MET numbers (which were starting at the Little Iceage Through) and tell me what the trend is up until today?
Negative?
Oddgeir
Question everyone should ask is
How much did our ocean’s CO2 solubility change for which temperature increase?
Very nice to learn that the 2 degree target is set as a result of reverse understanding of what does NOT constitute a problem…
How much CO2 was released from our oceans due to said 2 degrees?
Oddgeir
John Finn says:
November 1, 2013 at 8:03 am
” The warming trend since 1950 has been stronger than any other 50-odd year period, EXACTLY what we would expect if CO2 was the cause.”
Here’s 1950 to 1987: http://snag.gy/r8Usk.jpg
It all happened with a sharp step up from 1988 onwards: http://snag.gy/fMryT.jpg
Probably because there was a cooling phase of the CET cycle in the 1950-80 period. I’ve already acknowledged there are clear cycles evident in the CET record. However, the net effect of these in the past was ZERO.
But you are correct – most of the warming has occurred since 1980. Even more reason to reject the 353 year trend as a predictor of future warming. Note I wouldn’t use the post-1980 trend either – but I’m not the one making claims about 800 years to reach 2 degrees C
John Finn,
Here is a chart by your alarmist pal Phil Jones that deconstructs your contention that the warming is mostly recent.
It isn’t. The planet has been warming — naturally — since the LIA. And it has nothing to do with “carbon”.
Neil Catto
Can you do a similar estimate for HadCRUT4 and then post it?
John Finn says:
“Probably because there was a cooling phase of the CET cycle in the 1950-80 period. I’ve already acknowledged there are clear cycles evident in the CET record. However, the net effect of these in the past was ZERO. ”
I agree that from the very early 1700’s to 1950 CET is almost flat, but to argue that there was natural cooling from 1950 to 1987 that mitigated CO2 warming, one would have to acknowledge a far larger forcing value for natural variation that for CO2 to allow for the rapid step up from 1988 onwards.
“But you are correct – most of the warming has occurred since 1980.”
From 1988 onwards actually, from when the NAO went strongly positive, I already showed that 1950 to 1987 is flat.
You really do appear to have trouble understanding the issue. The ABOVE post by Neil Catto uses a 353 year trend from the CET record to predict the time taken to breach the 2 degree warming threshold.
You have posted a graph of global temperatures which extends back to 1860 – so it’s completely irrelevant to the conclusion of the author.
However, even if it were relevant, there are a number of reasons that the graph is misleading and should not be used graph.
1. As I’m sure Richard Courtney would point out – the graph shows the trends for non-equal periods of time, i.e.
1860-1880 20 years
1910-1940 30 years
1975-2009 34 years
So as RC would tell you this is “cherry picking”
2. We are well aware of cyclical nature of global temperatures (probably governed by the PDO) and this can be seen in the graph. However, cycles tend to return to have a net ZERO effect. This is seen in the first 2 cycles. Note that the 1860 trough is at roughly the same level as the 1910 trough. However the 1970s trough is not that much different to the 1910 peak.
The cycles exist but there is also an underlying warming trend which accelerated over the 20th century – probably due to an increase in Greenhouse gases.
I note you’ve still failed to respond to the Realclimate and WUWT which show that I was challenging Michael Mann about the “hide the decline” trick long before “climategate”
The WUWT link is given in the last comment of this post
http://wattsupwiththat.com/2013/10/31/blind-faith-in-climate-models/
John Finn says:
“However, cycles tend to return to have a net ZERO effect.”
So if the step up since 1988 is not CO2 forced, that would imply that have cooling ahead then.
November 4, 2013 at 7:53 am
sorry typo: that would imply that we have cooling ahead then.