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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@Steve Oregon,
Your post has got me thinking. Is Global Warming/Climate Change really just an artefact of all of this high and low resolution monitoring of literally everything, and NOT knowing what it means? For example, there is some discussion that there has been an increase in tornadoes in The US. Is this because there is a legitimate increase, or because of better monitoring, we see all of them? Are we being “hypochondriacs” because we fuss over every little change?
For more on the CET and Met office projections, read this:
“Global Warming – The Social Construction Of A Quasi-Reality”
http://scienceandpublicpolicy.org/reprint/social_construction.html
Original Paper at http://multi-science.metapress.com/content/v84152h64m5r36t5/
GLOBAL WARMING: THE SOCIAL CONSTRUCTION OF A QUASI-REALITY?
Journal Energy & Environment
H.R. says:
October 31, 2013 at 3:14 am
Global temperature, she goes up. Global temperature, she goes down. Up, down. Up, down.
DUH!
Homer Simpson
John Whitman and Marcos
The following link gives the “history” of the 2 degree C figure. As Marcos says it was invented by the Germans and like alot of these issues had a large dose of politics in it.
http://www.spiegel.de/international/world/climate-catastrophe-a-superstorm-for-global-warming-research-a-686697-8.html
– – – – – – –
RossP & Marcos,
Hey, thanks for the linked reference and the idea of where to look for source of the claim of a 2 degree C danger threshold / limit. I am very very skeptical of such a claim.
I owe you two a brew or two. Are you ever in Northern California or the Adirondack Mtns in New York State or in Taipei Taiwan? I spend pretty much all my time among those three locations. : )
John
Look at the red line.
1. There is no CET data which extends back to 1538.
2. The small scale of the y axis has been chosen deliberately so as to obscure the detail in the fluctuations.
3. Whether or not there has been a recovery from the LIA, it is not obvious in the CET record.
The trend between 1700 and 1900 is flat (-0.05 degrees per century)
The trend since 1900 is 0.81 degrees per decade.
If you disagree with these figures then please tell us why.
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. The trend for the first period (1700-1900) is essentially flat at -0.05 degrees per century . The trend for the second period is 0.81 degrees per century .
If you disagree with these figures then please show me where I have gone wrong. That goes to anyone out there who thinks I may have made an error. Let’s do the science the way it should be done. If Bob Tisdale or anyone else who is competent at calculating statistical trends would care to check my numbers – I’d be grateful.
Re the graph: The author has used an old trick of using large y axis increments and compressing the axis to mislead the reader. The CET temperature data as displayed on the Hadley web-site gives a clearer indication of the different period trends.
http://www.metoffice.gov.uk/hadobs/hadcet/
“This is a ridiculous conclusion. As far as AGW is concerned the first 300 years of the record are largely irrelevant.
…
1700-1900 -0.05. degrees per century
That’s about as flat as you can get. Now what about the trend since 1900 ”
If choose to draw the line from 1679 to 1700, you get very steep increase.
You drawing line from peaks in temperatures to valleys in temperature and
deluding yourself. You are cherry picking [perhaps in your mind, fairly].
“1900-2012 0.81 degree per century
So virtually ALL the warming in the CET record is in the last 100 years or so – but even that trend is dwarfed by the last 50-60 years. ”
Though glacier have been retreating since 1850. And as we know it takes prior warming to cause
glacier retreating.
Or the present warming will take time to cause glacier to melt.
And the temperature record given, indicates such prior warming.
Also what takes time to warm is the ocean which again have rising for more than last 100 years.
“The Little Ice Age was a period from about 1550 to 1850 when the world experienced relatively cool temperatures compared to the present. Subsequently, until about 1940 glaciers around the world retreated as the climate warmed. Glacial retreat slowed and even reversed, in many cases, between 1950 and 1980 as a slight global cooling occurred.”
http://water.wikia.com/wiki/Retreat_of_glaciers_since_1850
” 1950-2012 1.7 degree per century
or warming of about 0.85 degrees per 50 years. There was essentially NO warming trend for at least 250 years . All the warming has taken place in the last few decades. The CET record doesn’t provide much support for either natural variability or LIA recovery.”
It shows that during the LIA there were cycles of warming in which the natural variability in temperature peaked at warmer temperatures and dipped to lower temperature which appear to be greater than we seen in last century.
The coolest of dips in temperature has not come close to being matched in the last 100 years, but steepest warming may have been greater though not reaching as warm as in last century.
It add to the period after 1900 the warming of 0.025 Deg C/decade for 2 centuries: .5 C, then
warming peaks in temperature for the last 100 years is not significantly warmer as compared to past warmer periods during LIA. Though if add ,5 C to LIA dips in temperature, these declines in temperatures are still more severe than any we seen in last 100 year.
So in terms yearly changes in global climatic temperature, they were more severe during the LIA with most significant feature being the extent in which one got many periods with years having cooler average temperature.
This is in agreement with historical records indicating more severe weather during the period prior to 1900.
John Finn:
I refuse to believe you can be as stupid as you pretend in your reply to me at October 31, 2013 at 4:04 pm.
Your reply says to me
I explained that in my post you claim to be answering. It is at October 31, 2013 at 1:15 pm. To save you needing to find it I copy it to here.
I do not know how to put that more simply. If – as you claim – it really is beyond your reading comprehension skills, then I suggest that you ask a typical 11-year-old school child to read it for you and explain it to you.
Richard
John Finn says:
“The trend for the first period (1700-1900) is essentially flat at -0.05 degrees per century…”
You presume to know the trend, and give a specific degree/century rise?
So therefore, you can specify a number — but others cannot, because you say there is no record??
Take an aspirin and lie down before you hurt yourself.
“The CET temperature data as displayed on the Hadley web-site gives a clearer indication of the different period trends.
http://www.metoffice.gov.uk/hadobs/hadcet/ ”
It seems Met graph indicates we going to freeze to death.
Whereas Bob Tisdale’s graph shows we actual still in a warming period and a continuation of the pause in temperature, no need of alarm. Or it would need a much longer or steeper decline in temperature before we begin to approach the climatic conditions of LIA.
Oh dear, Courtney’s losing the argument so he resorts to name calling. This is totally unacceptable and I’m surprised the moderators have allowed your comment.
I have no problem with people disagreeing with me. In fact I’ve invited anyone whose competent enough to check my figures. I can only assume you have no competence or knowledge of statistical analysis else you would have made some attempt to counter my original argument.
I’ll repeat the points again……
1. There is effectively no trend between 1700 and 1900 in the CET record.
2. There is a trend of 0.81 degrees per decade since 1900.
Get the data and calculate the trends – or get someone to do it for you if you’re not capable.
I’ve explained to you why the graph is misleading. I’ve also – more than once – explained that most of the warming (in fact ALL of the warming) in the CET record has happened since 1900 – and more likely since 1950. Check out the Hadley graph which provides a better perspective.
http://www.metoffice.gov.uk/hadobs/hadcet/
I didn’t say there was no record. I said there was no data which extends back as far as 1538 – as shown in on of your links.
I am very familiar with the CET record. I live in the region covered by the record and have had a special interest in it for some time.
John Finn says:
“I said there was no data which extends back as far as 1538…”
John, apparently you did not read the comments regarding real world data such as glaciers, olive trees, and other evidence showing that the MWP was warmer than the current global climate.
The alarmist crowd has contorted themselves int pretzels trying to erase the MWP. They have been unsuccessful. But supposing they found convincing evidence. Then they would just be facing the fact that the MWP and the current global temperature is cooler than the various other warming episodes during the Holocene.
You are fighting a losing battle trying to convince people that we face runaway global warming and climate catastrophe — when the much more likely threat is global cooling.
The planet has been much warmer, and much cooler in the past. CO2 had nothing to do with it.
You’ve made some attempt to counter my main points but to be honest your argument is muddles.
This is a silly argument. I’ve used a period of 200 years, for crying out loud. The odd peak or trough is going to make a great deal of difference over that length of time. But, ok – I’ll play the game. You choose the period. We need one which starts in the 17th or early 18th century and finishes some time in the late 19th or early 20th century.
Incidentally, are you aware that the early pre-1700 CET record only records mean temperatures to the nearest degree and later to the nearest half degree so there has to be some doubt about the reliability of 17th century measurements.
John Finn,
You stated that there was no data which extends back as far as 1538, but your argument depends upon such data. You don’t see a problem with that?
In fact, there is ample data that extends much further back in time, as you can see here. Notice that natural variability encompasses extremes of both warming and cooling.
Our current climate is not unusual or unprecedented. In fact, the planet is on the cool side of the Holocene. And again, CO2 has no corellation with temperature.
That being the case, how can you justify the widespread demonization of “carbon”? Because without that unfounded belief, the whole AGW scare collapses.
John Finn:
gbaikie had said to you
In your reply to that at October 31, 2013 at 5:15 pm you say
No! The silliness is yours.
In your post at October 31, 2013 at 12:57 pm you actually said
So, you compared a period of 200 years to a period of 113 years. That is cherry picking.
And your use of different units is not good practice. You should have reported your cherry picked periods as follows:
The trend between 1700 and 1900 is flat (-0.05 degrees per century)
The trend since 1900 is similarly flat (+0.081 degrees per century).
And if you wanted to assert that they are not similarly flat then you should have provided confidence limits on the stated linear trends.
Richard
“Incidentally, are you aware that the early pre-1700 CET record only records mean temperatures to the nearest degree and later to the nearest half degree so there has to be some doubt about the reliability of 17th century measurements.”
One could same argument about the vast majority temperature reading prior digital age, which is not to say CET had improved their measurement accuracy prior to digital age, but rather most temperature reading as rule even at present [post digital] is inaccurate.
And at CET we didn’t same or worse problem with global siting which can have error 1 to 5 C or worst.
So only problem in terms of accuracy with CET in it’s limited regional location. And compared to using trees as thermometers, we assume with much more confidence that a 17th measurement is the more accurate.
“But, ok – I’ll play the game. You choose the period. ”
My choice is much longer period. Unless you are interested in natural short period [less than century] variability. This way you focus on global climate rather weather or global weather.
But you concerned about last 50 years. Therefore the only way to address your concern is understanding short term variability. And this is not understood at this point in time.
But if you understand global climate, you would have to know that we are in Ice Age which started around 50 million year ago. This is called Ice Box climate.
And you would also know that there is no danger from CO2 having a significant impact upon this Ice Box climate.
In terms short term variability, in my opinion, Stadium Waves, might be useful:
http://judithcurry.com/2013/10/10/the-stadium-wave/
So could be useful approach in understand short term variability. Which not to say I think it’s the answer or that we now understand short term variability- but seems like it could be the right direction.
But everyone admits there is no system to accurately predict short term variability- meaning a proven and dependable way to predict it. Of course predict volcanic eruptions may not be available until we get much understanding about Earth’s dynamics, but perhaps if we exclude volcanic eruption [anything more than 10 Km cubic km of ejecta- would only be somewhat significant] then we might get to this point within say 10 years.
@dennisambler says:
October 31, 2013 at 2:38 pm
Re: “DUH”
Some people think global temperature, she go only up. To those people, up and down is a revelation.
So few seem to get the point(s).
1. Warming has been mild to moderate, on average.
2. Extrapolations are generally wrong.
3. Any assumption we can’t adapt to 2K in 800 yrs., or much less, is laughable.
4. Alarmists have been prevaricating through their incisors.
800 years! We’re doomed. Eventually.
I have to laugh at heated posts from John Finn, richardscourtney, and others arguing about how many angels dance on the head of a pin !!
You are all silly. The CET data is ALL sh*t, likely not accurate to plus/minus 2 to 5 degrees Celsius over long periods. You got that ?
We have, in CET, reconstructed temperatures, temps taken inside buildings, temperatures essentially taken with a wet finger, bogus adjustments, calculations of means based on observation sets with different internal time periods. We have instrument error, observational error, adjustment error, statistical error, yada yada, yada. There are no replicates at ANY POINT IN TIME, no random samples, no observational consistency. The data is just SH*T.
ANY data with ONE observation has a standard-error of infinity !! Do the math – typical northern hemisphere daily data needs 20-40 observations per data point to yield a reliable single datum point with a decent standard error of the mean. SHEESH – this is not rocket science !!! Look up how to do field sampling and how to calculate a statistically reliable mean.
BioBob:
re your post at November 1, 2013 at 12:01 am.
We are discussing the CET data and what it is claimed to indicate. John Finn made some demonstrably untrue statements. You seem to be saying that untrue statements should not be corrected: I do not agree.
And I have been fully aware of the nature of climate temperature compilations for a long time. Clearly, you have not read this, especially its Appendix B.
http://www.publications.parliament.uk/pa/cm200910/cmselect/cmsctech/memo/climatedata/uc0102.htm
Richard
What are you on about? I was commenting on THIS thread about the way the CET record was being used. Why would I bring up evidence (or otherwise) about the MWP. The MWP is irrelevant as far as the CET record is concerned.