Guest post by Tony Brown
This short paper is a preliminary examination of BEST data to 1753, as compared to the Central England Temperature Record (CET) to 1660 (instrumental record) and 1538 (Extended by Tony Brown using thousands of contemporary observations)
This extension to 1538 was a central part of my article ‘The Long Slow Thaw,’ which also examined historic temperature reconstructions by Dr Michael Mann and Hubert Lamb
http://judithcurry.com/2011/12/01/the-long-slow-thaw/
In the article, warming from the start of the CET instrumental record in 1660 to the present day was noted, albeit with numerous advances and reverses.
The extended CET record coincides well with a 2000 year reconstruction by Craig Loehle here;
http://www.econ.ohio-state.edu/jhm/AGW/Loehle/
And one by M. V. SHABALOVA and A. F. V. VAN ENGELEN : Evaluation of a reconstruction of winter and summer temperatures in the Low Countries, ad 764–1998
http://www.springerlink.com/content/gu62270140g7r854/
According to studies made by a number of climate scientists, CET is a reasonable proxy for Northern Hemisphere -and to some extent global temperatures- as documented in ‘The Long Slow Thaw’. However, as Hubert Lamb observed, it can ‘show us the tendency but not the precision’. In that light there are a number of comments that can be made about the Combined CET/BEST graph which are shown above in two versions that, viewed together, provide the opportunity to follow the ups and down of the ever changing climate over the 350 years of instrumental records.
(Note; The BEST extension to 1538 and the extension to both trend lines after 2012 in the first graphic are merely a graphing feature.)
There are a complex set of important UHI corrections applied to CET and described by the Met office as follows.
“The urbanisation corrections to the CET series have been applied since 1974. Initially they were just 0.1 degree C, in certain months, then gradually for more months of the year; from about 1995 onwards some of the corrections increased to 0.2 deg C, and by about 2002 all the corrections were 0.2 deg C.
The above applies to Mean CET. The urban heat island effect is much more noticeable for minimum temperatures than for maximum, so for the Minimum CET series the corrections are double those for Mean Temperature, whereas for Maximum Temperature it was deemed in fact that no correction was required.”
That the Met Office correct for urbanisation is interesting in itself, whether it is sufficient is also a matter of debate, but is outside the current scope of the current paper. BEST do not correct for UHI, in fact they make some mention of it having a cooling effect.
The crossover point of BEST and CET around 1976 –when BEST starts to rise steeply- may or may not therefore reflect that one record allows something for uhi whilst the other doesn’t.
CET has been in steep decline since around 2000.
http://www.metoffice.gov.uk/hadobs/hadcet/
BEST has been broadly level in recent years, which does not reflect the reasonable historic correlation between the ‘tendency’ of the two graphs as can be seen by following the trend lines since the start dates, albeit those of BEST seem at times to be exaggerated, perhaps reflecting Britain’s temperate climate.
The cold BEST period around 1750-1760 possibly reflects the very small number of stations used in their reconstruction-all in the Northern Hemisphere-which are not necessarily as representative of the global climate as CET has been found to be. Also, most of them were part of the Mannheim Palatine-a network of stations that predated GISS by 200 years. Each of these older stations have been very thoroughly scrutinised and their temperature record often adjusted downwards under the EU funded ‘Improve’ programme, as it was generally felt there was a warm bias.
The BEST trend line from 1753 to the present day is somewhat exaggerated through not being able to reflect the very warm period centred round 1730 which would provide a better balance than starting the record in a trough. The CET warming period from 1690 to 1730 (un-paralleled even in the modern record ) is well documented by such as Hubert Lamb and was noted here in the 2000 book ‘History and climate-memories of the future?’ This chapter from Phil Jones-page 61;
‘All five series show long term warming from either the late 18th or early 19th centuries. Recent years are only marginally the warmest of the entire series because of the warmth of the 1730′s (particularly in Western Europe) and the 1820′s (Northern Europe) The five series are CET, De Bilt, Berlin, Uppsala, Stockholm.’
That the start of the temperature rise noted in ‘The Long Slow Thaw’ precedes the start date of GISS and Hadley by many centuries is illustrated by Tony Brown (CET extended), Craig Loehle (revised reconstruction) M. V. SHABALOVA and A. F. V. VAN ENGELEN, and BEST. In this context such records as Hadley, GISS, and even BEST itself, can be seen as merely plugging into the long established warming trend at various points along the way, and do not mark the start of it. There is no sign in observational records, or in many well regarded scientific reconstructions, of the 900 year long sequence of gently falling temperatures as noted by Michael Mann in the ‘hockey stick’ handle, nor an ‘uptick that is any more notable than many periods in the past.
That there was a gradual warming of winter temperatures-the severity of which had substantially reduced the overall mean annual temperature during much of the earlier historic record- was noted by Reginald Jeffery in his book ‘Was it Wet or was it fine,’ written in 1898.
“By 1708 the middle aged would say where are our old winters?”
“Mais où sont les neiges d’antan?” (François Villon, circa 1530)
Mervyn says:
August 14, 2012 at 8:10 pm
This gradual warming also sits well with solar/galactic cosmic ray activity.
NASA estimate that since the 1970s the solar output has been increasing by 0.05% per decade.
http://www.nasa.gov/centers/goddard/news/topstory/2003/0313irradiance.html
My own calculations suggest that this accounts for 17% of the warming since tthen,some 0.02C/decade. If the trend in solar output has been ongoing since the 1700s and the end of the LIA, it would fit the BEST data quite well.
John Marshall
I covered your question about the suitability of CET in my article ‘The Long slow thaw’ referenced above.
Yes, CET is very suitable as it is the most scrutined data set of its type in te world. As always I would add Lambs caveat that it shows the tendancy and not the precision. \it closely follows the ups and downs of BEST both of which appear to demonstrate a warming cycle much longer than from G|iss or \hadley.
tonyb
The CET temperature data is indeed interesting. Superimposed on the general thawing out from the Little Ice Age are temperature ups and downs that appear to have some sort of decadal cyclicity. Just for fun, I plotted the 1500 to 1950 delta 18O values measured by Stuiver and Grootes (1997) from the GISP2 Greenland ice core and dropped it onto the CET graph. The result is intriguing—the better-known climatic episodes (Maunder, Dalton, 1880-1915 cooling, etc) coincide quite nicely, as do many of the other warming and cooling periods. Not perfect, but a better correlation than I expected. The GISP2 oxygen isotope curve fluctuates through a range of 2 per mil with good definition and corresponds very well with known temperature fluctuations from 1500 to 1950. About 40 warm and cool periods show up with an average duration of 27 years, remarkably similar to the Pacific Decadal Oscillation (PDO). We don’t have good PDO records that far back in time, so can’t make positive correlations, but the cyclicity is suggestive.
Another other tantalizing aspect of the CET curve is good correlation with the glacial record of advances and retreats. Alpine glaciers reached their Holocene maximum extents during the Little Ice Age (LIA) around 1550-1700, then fluctuated back and forth to the present. The latest advance around 1880-1915 was not far from the Little Ice Age (LIA) maximum. Glaciers retreated during the 1915-1945 warm period, advanced again during the 1945-1977 cool period, and retreated again during the post-1978 warm period. The present termini of most glaciers are well upvalley from their LIA maximums, attesting to the general thawing out since then.
There are also some suggestive correlations of the CET temperatures with solar variations—both sun spot numbers and total solar insolation (TSI). TSI variations aren’t large enough in themselves to be causing the temperature fluctuations, but may be indicative of changes in the sun’s magnetic field and its effect on incoming terrestrial radiation and cloud generation (a la Svensmark). Peaks and valleys in the TSI curve correspond pretty well with temperature variations in the CET curve.
What does all this mean? The data suggest some very interesting possibilities, although, as an old-time geologist once noted, “if you look hard enough, you can find a pattern in a keg of nails.”
tonyb says: August 15, 2012 at 12:33 am
I will be expanding on this work-in particular I want to examine the period around 1730 which seems little different to today.
Hi Tony
I will look very much forward to that. As you may know I have looked at ‘alternative data’ from which this graph is constructed.
I would not be surprised that the CET data for that period are on conservative (low) side and surprisingly they do follow the same pattern as the current rise. Since data were assembled before the latest CET warm spell starting in 1990, I would assume that compilers had an eye on 1740 to 1950 period and made certain that the peak of 10.5C was not exceeded.
What a shock for the ‘hockey stick and CO2 puffing club’ that would be if indeed the 1730’s were warmer than the 2000s.
Sharp drop in 1740 I suspect was due to eruption of Shikotsu (V5 explosive with 4 cubic Km of tephra).
Wish you calm seas.
Vuk
I used to work in London and every year in November starlings used to congregate in the squares before flying off to warmer places for the winter. Today starlings were congregating in our little Central England village looking like they were getting ready to migrate and it’s only August!
Kelvin Vaughan says:
August 15, 2012 at 7:31 am
I used to work in London and every year in November starlings used to congregate in the squares before flying off to warmer places for the winter. Today starlings were congregating in our little Central England village looking like they were getting ready to migrate and it’s only August!
I know the feeling! I was just in Frankfurt for a few days and the contrast with recent British Summer weather was astounding. While we,ve had endless rain, they have hot dry conditions and the trees are shedding leaves early under water stress.
CET shows that we have had several years of bad Summers. If we accept recent speculation that the reducing temperature gradient across the Polar Front is reducing the strength of the jetstream and making its path more meandering, climate change may deliver more variable weather to the UK, even hotter and drier when the jetstream runs North, even colder and wetter when it runs South.
Why does that sound familiar? Ah, yes. Hansen(2012).
Is Hansen 2012 the same paper where he leaves out the southern hemisphere and cherry picks his start and end dates to prove his point?
Some of us older starlings migrated years ago and didn’t bother going back. Winter in Prague is cold & icy but the czechs cope easily with the weather. Summer has been here since early May 27-32C and sunny most days 🙂
Entropic man says:
August 15, 2012 at 8:05 am
and the UAH Lower Atmosphere Temperature Anomalies – 1979 to Present is swinging back and forth by about 0.5C since 2011..
Tony Brown, thank you for the impressive charts. The CET line shows an increase of 3C in the 40 years from 1695 to 1735. Naturally this is a very localized record but it does make NASA-GISS’s favorite adjective, “unprecedented,” look somewhat misleading.
MangoChutney says:
August 15, 2012 at 9:10 am
Is Hansen 2012 the same paper where he leaves out the southern hemisphere and cherry picks his start and end dates to prove his point?
No, its the paper where he uses only Northern Hemisphere data because
a)it is more extensive.
b) because it avoids the added complexity of separating out the effect of differing land/ocean ratios in the two hemispheres.
c) because it avoids the added complexity of filtering out the differences due to the reversed seasons in the two hemispheres.
Regarding start and end dates, I have no idea why he chose them. The way to demonstrate cherrypicking would be to rerun his calculations using different dates and see if they come out different. For his main point that frequency plots of temperature are showing an outward drift of the upper boundary with time, I doubt that different dates would make much difference.
Kelvin Vaughan says:
August 15, 2012 at 9:21 am
Entropic man says:
August 15, 2012 at 8:05 am
and the UAH Lower Atmosphere Temperature Anomalies – 1979 to Present is swinging back and forth by about 0.5C since 2011..
Sorry, you’ll need to unpack this point somewhat . As it stands, its too cryptic for me.
George E. Smith; says:
August 14, 2012 at 10:36 pm
“What IS WRONG is believing that it is valid to use that Temperature to represent the Temperature of other places up to 1200 Km away from the UHI thermometer.
Also UHI s radiate faster and at shorter wavelengths that are less susceptible to CO2 interception. So I would expect UHI s like the tropical deserts to be good for cooling the earth. The polar regions certainly don’t do anything useful to cool the planet.”
I live next to a small national park, between two good sized cities, and have thermometers on both the east and west side of the house, you can see solar heating differences between them, as well as the local (35miles) airport which runs much hotter. If they can’t find UHI, they can’t be looking very hard. All you really need to do is go for a motorcycle ride from the city to the country and back.
I also think melting polar ice could act as a thermostat, exposing additional (relatively) warm waters to arctic temps and skies, especially during arctic winters.
Any-one Interested in old weather may find these links usefull,
http://booty.org.uk/booty.weather/climate/histclimat.htm (mainly U.K.+ some Europe).
http://www.breadandbutterscience.com/Weather.pdf (Broader reports+some early American)
climatereason says:
August 15, 2012 at 12:44 am
…..All our attention is focused on warming, I think we need to have a plan ‘b’ for cooling
tonyb
_______________________________
On that I certainly agree.
A couple of degrees warmer might be uncomfortable but no real biggy. A couple of degrees cooler has a major impact on what plants will grow where. A major freeze in places like Mexico, Florida and California such as happened a few years ago can not only wipe out the years crop, but in the case of fruit trees can damage or even wipe out an orchard. 02/04/2011: Freezing temperatures across a wide swath of Mexico the night of Feb. 3-4 could have a huge effect on supplies of tomatoes, peppers and other winter vegetables. A major freeze in the spring further north can wipe out the apple, cherry, peach, pear… crops April 2 2012: … I used to think that as long as my tree had finished blooming before a major frost like this hit, it was okay and [I was] going to have fruit. Last year proved me wrong. And this year, my tree is just starting its bloom with this frost coming…
As E.M. Smith so rightly pointed out in his article on Bond events, Of Time and Temperatures, it is cold weather that destroys civilizations not hot.
Tony,
It would intersting to look at apples and apples.
BEST for england
http://berkeleyearth.lbl.gov/regions/united-kingdom
As I pointed out in a WUWT comment at the time, their UHI-detection methodology was seriously flawed. What they did was to use MODIS satellite data to identify the bright spots caused by quite large cities, and treated stations outside those spots as rural.
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No, the product used was MODIS “urban”. It has nothing to do with nightlights.
Stations were defined as very rural if MODIS showed NO built pixels within 10km of the station location.
Stations were divided into two classes: very rural ( no built pixels with 10 km) and OTHER.
By comparison WATTS 2012 used categorization provided by UHSCN. That categorization is based on nightlights, specifically a nightlights product which the principle investigator has said is unsuitable for analysis.
Looking at the very rural stations of BEST you can determine that the average population is less than 10 people per sq km. This population figure is LESS THAN the 14 people per sq km
implied by the nightlights criteria. For comparison if you look at the CRN stations, the gold standard in the US, you will find that a number of them would not qualify as very rural by the modis classification but they do classify as rural by USHCN standard.
In addition to the Classification used in the paper, we did sensitivity tests on the classification itself. Here are the things we tried.
1. we lengthened the “radius” we look at. we classifed very rural as sites with no built
pixels out to 25 km. No difference.
2. We took out all rural airports. a rural airport will have no built pixels because the runways
are more narrow than the pixel! also rural airports have 0 population. So we did a run
with no aiports whatsoever in the very rural catagory. No difference.
3. I built a super restrictive filter based on the work that Zeke and I did when we found
a small ( .04C per decade ) UHI bias. That filter consisted of
A) no airports
B) no built pixels within 11 km
C) Zero nightlights ( more restrictive than WATTS 2012 urban/rural)
D) zero population.
E) no impervious surfaces as measured by a different sensor than MODIS.
this is important because the MODIS dataset can show snow in northern
latitudes and snow comes up as “unbuilt” so I cross check using a different
Sensor which doesnt have this potential problem.
Still no effect.
That said, work on the problem continues with 30 meter data instead of 500 meter data.
and some work on land use and land use changes.
Mosh
Thanks for the BEST graph you posted-it seems to be a composite of the UK rather than a direct equivalent to CET?.
England is said to be the same size as New York State, so with 60 million people (in the UK) plus a lot of development (especially close to the triangulation of sites they use for CET) it would be interesting to try to work out if the Met office allowance for Uhi was correct and if the principle ought to be carried over to other station records.
Now we are roughly back to the 1730’s temperature in England I want to try and see if the crops/observations from today are the same as during that time, which may help to indicate the accuracy of the instrumental record then and now.
I will send you the Mannheim stuff I promised but have been preoccupied as we kept winning Olympic medals!
tonyb..
Entropic man said
“CET shows that we have had several years of bad Summers. If we accept recent speculation that the reducing temperature gradient across the Polar Front is reducing the strength of the jetstream and making its path more meandering, climate change may deliver more variable weather to the UK, even hotter and drier when the jetstream runs North, even colder and wetter when it runs South. Why does that sound familiar? Ah, yes. Hansen(2012).”
I made exactly the same point after looking at contemporary observations back to 1538. I mentioned this in ‘The Long Slow Thaw’ because the periodic effect of the jet stream meandering was very noticeable.
tonyb
Paul Martin
Your quote is fascinating
“Mais où sont les neiges d’antan?” (François Villon, circa 1530) (Where are the snows of yesteryear?)
and exactly correlates to my comment in another article I wrote;
“Our modern bouts of amnesia regarding previous climatic conditions can be seen to be nothing new by reading the comments from the annals of Dumfermline Scotland from 1733/4, when it recorded that wheat was first grown in the district in 1733. Lamb wryly observes that was not correct, as enough wheat had been grown further north in the early 1500′s to sustain an export trade (before the 1560’s downturn).”
There are enough pieces of the ‘anecdotal’ climate record to put forward a compelling story when combined with scientific research, but it is extremely time consuming.
tonyb
Gail Combs ; ‘A couple of degrees cooler has a major impact on what plants will grow where’.
– It doesn’t even need to be a couple of degrees cooler to impact on crops like wheat.
Here, in the UK, the June CET was only -0.82 centigrade below its monthly average (KNMI) yet the wheat crop appears to be completley stuffed; more a matter of rain/drizzle and a lack of susnhine hours rather than temperature on its own (though all these factors tend to be linked in summer).
Interestingly, It will only need this June CET anomaly to carry through to September for the trend from 2000 to be significant at the 5% signifcance level.(at -0.58 C/decade) .
BEST chart, before and after “adjustments”.
More crap over crap data.
Kelvin Vaughan says:
August 15, 2012 at 7:31 am
I used to work in London and every year in November starlings used to congregate in the squares before flying off to warmer places for the winter. Today starlings were congregating in our little Central England village looking like they were getting ready to migrate and it’s only August!
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Interesting. Here are a few studies on bird migration:
Now all someone has to do is look at those Bird Migration cards and correlate with information about the sun/cosmic rays/magnetic field to see if the birds are sensitive to the earth’s magnetic field the 11 yr solar cycle or other solar cycles.
Gail Combs says:
August 15, 2012 at 4:39 pm
Now all someone has to do is look at those Bird Migration cards and correlate with information about the sun/cosmic rays/magnetic field to see if the birds are sensitive to the earth’s magnetic field the 11 yr solar cycle or other solar cycles.
Nature could be a conglomerate of haphazard coincidences, or may be result of a more harmonious evolution. It would be indeed strange world of the haphazard coincidences if the sun, earth’s deep interior, land and oceans have all conspired to have almost identical oscillating period just under 22 years, unless there is some fundamental underlying reason.
http://www.vukcevic.talktalk.net/GSOa.htm