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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You have haven’t corrected anything. I made 2 key statements, i.e.
The CET 1700-1900 trend is -0.05 degrees per century
The CET 1900-2102 trend is 0.81 degrees per century.
If you think either of those statements is wrong or “demonstrably untrue” then please show me where I’ve gone wrong. It’s time to put up or shut up, Richard.
John Finn:
At November 1, 2013 at 3:51 am you again demonstrate your lack of ability to read.
You say to me
I did “show {you} where {you’ve} gone wrong” with my post at October 31, 2013 at 5:33 pm. This link jumps to it
http://wattsupwiththat.com/2013/10/30/how-long-before-we-reach-the-catastrophic-2c-warming/#comment-1462862
It’s time for you to shut up, John. And an apology for disrupting the thread with your nonsense would be good.
Richard
The CET data is unreliable before about 1700 – and is perhaps not too clever before 1780 but after that it provides a reasonable record of Central England temperatures. It is consistent with other European long term records, e.g. Armagh.
Tell me, do you agree that there was an LIA period between the 15th-19th centuries when temperatures (global or otherwise) were 1 to 2 degrees below to-days. If so, on what do you base this conclusion?
Ok perhaps I need to make it easier for you Richard.
I made this statement
The CET 1700-1900 trend is -0.05 degrees per century
Q1 Do you disagree with this statement and if so – why?
I also made this statement
The CET 1900-2102 trend is 0.81 degrees per century.
Q2 Again do you disagree with this statement and if so – why?
No need for any arm waving – just respond to the questions.
John Finn obviously believes, like Michael Mann, that the climate never changed prior to the industrial revolution. No MWP, no LIA, just a flat, unchanging hockey stick shaft.
In reality it is scientific skeptics who know that the climate always changes. Finn is a True Believer who is desperately looking for proof that human activity is causing climate change.
But it is just natural variability. The Null Hypothesis has never been falsified. And CO2 makes no measurable difference to global temperature.
John Finn:
I am replying to your post at November 1, 2013 at 4:12 am.
I am NOT John Finn so I do not “arm wave”.
Your two questions can be answered “yes” but both of them are MEANINGLESS.
You have demonstrated that you are incapable of understanding why they are meaningless, but I will try to explain it in case there are any onlookers with average intelligence who want to know. This will help them when confronted with similar twaddle to yours from other warmunists.
Firstly, as I said, you are comparing different lengths of time. Your two periods are samples of the data from the complete CET data set. The samples are of different amounts of the data so they are not similar samples. Hence, you are comparing ‘chalk and cheese’.
Secondly, choosing samples which fit what you want to say is a form of cheating called ‘cherry picking’: it provides misleading results. And, as I and others have told you, it is what you have done.
Indeed your cherry picking is extreme. Why did you not compare ‘1900 to present’ with ‘1690 to 1803’? Could it be that such comparison would show the opposite of what you are claiming?
Thirdly, assuming your model of linear trends is correct (it is not, but I am ignoring that) each of the two numbers you provide is incomplete. At issue is whether either or both of them differ from the long-term trend and, if so, with what confidence that difference is expressed. ‘Climate science’ expresses confidence to 95%. Thus, the statement
has no meaning because its confidence is not defined.
Or, to be pedantic, the statement has an infinite number of possible meanings.
e.g. it could mean -0.05 ± 0.001 degrees per century at 95% confidence
or
e.g. it could mean -0.05 ± 100.00 degrees per century at 95% confidence
because it only says
-0.05 ± X degrees per century at 95% confidence and X is unstated.
So, the data you present cannot be known to be different from one another because their confidence limits are not stated: they are meaningless numbers obtained from cherry picked samples.
Richard
Can you point to anything I’ve written which shows that I even suggest that climate is unchanging. Even the early CET record shows fluctuations – but these are cyclical and the net effect is a ZERO trend.
However, that aside, you again misrepresent my initial points. The author of the above article made a specific claim, based on the 353 year CET trend, that it would be 800 years before the 2 degree threshold would be breached. I say this is nonsense and I’ve given my reasons, i.e. the trend between 1700 and 1900 is broadly flat while the trend since 1900 is around 0.8 degrees per century. Thus far, no-one has managed to show that my figures are wrong.
Let me be clear what I’m actually saying so there is no confusion:
Nick Catto has made a claim which is invalid basing it as he did on the 353 year CET trend.
John Finn says:
“I cannot see how I can possibly be accused of cherry picking. The author of the article cites a trend extending back to 1659. I have split the last 300 years into one period of 201 years (1700-1900) and another period of 113 years.”
Well if you had started from 1659 like the Author, then you would see the trend, but hey, if CET went back a further 9yrs then the trend would be less as it would include the hot years of 1651-54:
http://booty.org.uk/booty.weather/climate/1650_1699.htm
I do agree though that there is no long term recovery from the “LIA” through CET as such, the recovery from Maunder is the steepest rise on the series, but after that, as you say there are at least two centuries where it is largely flat. Here’s my cherry pick, 1730-1930:
http://snag.gy/2q2kT.jpg
The whole notion of a gradual recovery from LIA through CET would have to imply an influence of sea surface temperatures on CET, is that a reality, or is CET dominated by the NAO irrespective of local SST’s? I would suspect the latter.
It is natural that the 20th century should be warmer, while on average two or three solar cycles are weaker every ten cycles, the intervals wander, the last downturn ended in the first few years of the 1900’s, and the next weak cycle is this one, so the 1900’s missed out on such a period.
Warming on CET from 1906-1986 has hardly been dramatic: http://snag.gy/B2rkz.jpg
The curious bit is from 1989: http://snag.gy/fMryT.jpg (CET 1659-2012)
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.timeseries.gif
The solar wind was unusually strong around the maxima of solar cycles 22&23:
http://snag.gy/nf9SK.jpg
John Finn:
In your post at November 1, 2013 at 5:57 am you say
and
OK. So which are you claiming
“the net effect is a ZERO trend” in the early record (which is untrue, see the above graph)
OR
there is a “353 year CET trend”?
Or are you demonstrating Orwellian doublethink?
Richard
I asked you if you disagreed with the figures and you replied “Yes” but you haven’t shown what is wrong with the figures. We can assume, therefore, that the trends have been calculated correctly.
OK – let’s use time periods of equal length.
1700-1800 -0.25 degrees per century
1800-1900 0.03 degrees per century
1900-2000 0.65 degrees per century
And just for good measure
1912-2012 0.83 degrees per century
Now then, Richard, I challenge you or anyone else to find any pre-1900 100 year trend which is even half the 1900-2000 or 1912-2012 trends.
I think we’ve now addressed these concerns above.
I am slightly reluctant to use pre-1700 CET data, but if you insist we can compare 1690 -1803 to 1900-2012 as you suggest.
1690-1803 -0.3 degrees per century
1900-2012 0.81 degrees per century
Clearly, Richard, the comparison doesn’t show the opposite of what I was claiming.
Again I invite anyone to check my calculations.
Richard
It’s becoming increasingly apparent that you lack a basic grasp of Statistics. My 2 statement s are not mutually exclusive.
For the first 250 years or so, the CET record has a trend which is close to ZERO.
For the whole of the 353 years the CET record exhibits a positive trend which is due almost entirely to the warming over the past 50 years.
The graph is deliberately misleading. I’ve already explained this. See this graph of exactly the same data.
http://www.metoffice.gov.uk/hadobs/hadcet/
Can I just point out;
a). I explained this record is recognised as the longest instrumental record in the world
b). We have no other instrumental data going that far back in time – it the best we have
c). Yes there are problems with early age thermometer accuracy – the UKMO adjust for this
d). Yes there are problems with swapping site locations during the record – the UKMO ajdust for this too (I disagree they should have changed reporting site)
e). Yes there are problems with increased UHI since the industrial revolution – the UKMO adjust for this too (IMO far too small an adjustment)
f). Cherry picking is when you pick particular start/end dates or particular periods within a record
I did not cherry pick, the data I used was the start date of the record to the end of the last full year (end date) of the record. I made no attempt to size the graph, just a simple xls linear graph.
Lastly, my claim was and still is, based on the trend of this whole record 1659-2012 it would take 800 years to get to the 2 Deg C point, that some say is catastrophically dangerous.
If you want to cherry pick data: the last 20 year (1993-2012) the trend has been downward. Yes that’s right the UK has been COOLING for 20 YEARS, on that trend it is impossible to reach 2 Deg C. But we won’t cherry pick will we?
Neil
You simply cannot justify this claim. I’m going to play Devil’s advocate here. Let’s suppose I propose that increased atmospheric CO2 due to fossil fuel burning is responsible for global warming.
Clearly the warming effect is going to be most apparent in the mid to late 20th century. (CO2 forcing is currently about 3 times what it was in 1958).
To test my hypothesis/theory/belief I would like to know how much warming/cooling occurred up to about 1950 and compare that with the warming after 1950.
The CET record actually supports me.
The CET trend is essentially flat for the first 250 years of the record (even if we include the rather unreliable 1600s). It is only in the 20th century that a sustained positive trend is evident.
In fact, the strongest signal occurs in the late 20th century – exactly is it should if my hypothesis is correct. We have seen an increase of over 0.8 deg since 1950. AND if my hypothesis is corrrect then we should see a similar increase over the coming 50 years.
Whatever – if you have a flat period for 200 years followed by steady warming for 100 years you cannot assume that the 300 year trend is applicable for future warming.
I’m not accusing you of cherry picking the data. However, I do believe your graph is misleading.
John Finn:
In your post at November 1, 2013 at 6:51 am you say
Now that’s funny. It’s really, really funny!
I am accused of lacking “a basic grasp of Statistics” by an ignorant twit with reading comprehension difficulties who does not understand dissimilar samples are not comparable, does not know what cherry picking is, and does not know why a statistical datum has no meaning unless its error estimate is stated!
Funny? One could not make this stuff up.
John Finn, your error is stated by NeilC who says at November 1, 2013 at 7:44 am
But I suspect you are such a mentally deficient dolt that you will fail to understand that, too.
Richard
Crikey!
You’re clearly having trouble with this. We’ve seen lots and lots of fluctuations in the CET record – many of which have lasted 20 years and more. We know this. It’s apparent in the Hadley graph. However these fluctuations tend to be cyclical. and over time have very little influence over the long term trend.
There is a lot of difference between a 20 year trend and 100 or 200 year trend.
In any case, I’m not arguing one way or the other. Even though the data supports CO2 warming I’m not going to draw any conclusions about the temperature increase over the next 50, 100, … or 800 years.
It’s you who is making a claim which simply doesn’t stack up . 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.
Friends:
Sorry, “Crikey!” went while I was typing.
I had written that I suspected John Finn is “such a mentally deficient dolt that” he would fail to understand the post from NeilC, and he proved my suspicion was right while I was typing it!
Hence, the “Crikey!”
Richard
Richard
I’ve given you trends for equal time periods. I’ve even used 1690-1803 a period selected by yourself. None of the trends support your argument. In fact increasing it’s apparent that the CET record apart from cyclical fluctuations has been, by and large, invariant between the late 1600s and 1950.
Now run along , Richard, and learn how to perform Least Squares linear regression then you might be able to offer some to this discussion.
Incidentally you could ask NeilC if he disagrees with my calculations. The best he can come up with is that we’ve has a -0.02 degrees per decade cooling since 1993 – consistent with .many imilar fluctuations in the past. This further highlights the fact that I’m not cheery picking since the end point of my period is in a ‘trough’.
John Finn:
I will try to make this easy for you because you are clearly way, way out of your depth here.
At November 1, 2013 at 8:12 am you say
No, YOU HAVE NOT.
YOU HAVE NOT GIVEN ME ANY TRENDS; none, zilch, nada.
You have given me meaningless numbers.
The numbers would be valid trends if they had their attached confidence limits, but they don’t. Without those confidence limits it cannot be known if they differ from each other. I explained this for you in my above post at November 1, 2013 at 5:43 am.
John, I will say this two more times because iteration may get get it through your thick skull.
YOU HAVE NOT GIVEN ME ANY TRENDS; none, zilch, nada.
You have given me meaningless numbers.
YOU HAVE NOT GIVEN ME ANY TRENDS; none, zilch, nada.
You have given me meaningless numbers.
Have you got that now?
If so, then provide the confidence limits so you will then have provided some trends.
After that we can discuss what – if anything – those trends suggest.
Richard
@richardscourtney
Richard, please, chill a bit.
I’m afraid that you tend to come over as an arrogant overbearing bully whenever you come across a post (or poster) with which you happen to disagree. I, like many others I suspect, come here to learn things. I’m sure I could learn things from you but, frankly, your attitude makes that difficult as I am increasingly finding myself thinking “Oh dear, Richard’s gone off on another hectoring rant, quick, scroll down”.
There is no excuse for describing another poster as a “a mentally deficient dolt”, however vehemently you may disagree with him (or indeed, however incorrect he may be) so please stop it. You are doing youself a disservice with your attitude.
Mr Green Genes:
When a person spouts ignorant twaddle then ignores what I politely take the trouble to reply to him and writes saying to me
and
and
etc.
then you expect me to reply with respect?
No chance.
Richard
@ur momisugly John Finn,
So the temperature change from 7.2 C in about 1700 to 10.2C in about 1740 (3 degrees C in 40 years, or 0.75C per decade, wasn’t actually any warming???
In fact, we currently appear to be at about 10.8C on that same CET record, so the warming from 1740 to 2010 is 10.2C to 10.8 C for a total of 0.6C.
0.6C/27 decades = 0.0222 degrees C/decade since 1740, so I don’t think we have much to worry about.
John Finn says:
“Can you point to anything I’ve written which shows that I even suggest that climate is unchanging.”
Yes, of course I can. You were questioning any temp change as the planet emerged from the LIA. Then you go into Hockey Stick mode: T shot up recently.
If I am misunderstanding you, then just answer this: in your opinion, was there a LIA in which global T declined by ≈1º – 2ºC?
“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.”
Ummm, no, I just demonstrated that for the 40-year period of 1700 to 1740, there were 3 degrees of warming, while you could only demonstrate that from 1950-2010 there were 1.7 degrees of warming PER CENTURY, or only about 1 degree of ACTUAL WARMING during that 60 year period of 1950-2010.
It seems to me that 3 degrees of warming in 40 years (1700-1740) is FAR MORE SIGNIFICANT than 1 degree of warming in 60 years (1950-2010), so just how, pray tell, was CO2 so significant from 1700 to 1740???? I thought it was level at about 250ppm back then, no????