Little Ice Age Thermometers- Historic variations in temperatures Part 3 -BEST confirms extended period of warming.

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)

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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.

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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?”

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68 thoughts on “Little Ice Age Thermometers- Historic variations in temperatures Part 3 -BEST confirms extended period of warming.

  1. BEST do not correct for UHI, in fact they make some mention of it having a cooling effect“.

    BEST do indeed not correct for UHI. Muller, Curry et al published results of a study they did to try to detect UHI, and they did indeed say that they detected a possible cooling effect but thought it very unlikely and ignored it.

    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. The problem is that UHI is not exclusively related to city size, and development in even small urban areas can affect temperature trends. I did a very quick check of the list of stations that BEST supplied to me on request. I concentrated on Australia, and found that of the 800 or so stations listed as rural, over 100 were at airports and over 100 were at post offices. The idea that these stations were truly rural is laughable, especially in light of the more recent Watts 2012 study of station siting.

  2. Perhaps it would be use to draw a distinction between general urban heat islands. And the (possibly equivalent) microclimate consequences of station siting. BEST may not have had the methodology to discern the latter; MODIS stands for moderate resolution.

  3. Good points Mike. And if we think back to yesterday’s post, I imagine that the Lake Tahoe station is rural but could be impacted by having a trash burning bin adjacent to the station. I wonder if this blog was the only site to cover that.

  4. Hi Tony
    Informative as usual. Your pre-1660 reconstruction should be taken note of; current temperatures are nothing exceptional, only fraction higher (about 1/4 degree C, well within margin of error) then 400 years ago.

  5. Brilliant work Tony! And a lot of it too, to compress into a short vignette. Hopefully you can provide follow-on articles along the lines of ‘The Long Cold Thaw’. It seems quite obvious that many climate scientists have their heads stuck up computer models or dodgy treemometers. A trip to the real historical record would do them good. Also, it would be fascinating…

  6. I would like to see some indication of the significance values applied to these slopes. The CET data is noisy enough for a 0.0013 slope to be possibly spurious.
    The BEST data may be more significant, but since it starts at a low point in the CET, an increase in temperature over its period of record may be an artefact of its starting point, rather than a significant trend.

  7. Thanks TonyB. I’ve also noticed this. Berkeley Earth has a 48% higher trend for the United Kingdom than the official HadCentralEnglandTemperatures going back to the start of Berkeley in 1743.

    The only explanation is that their record-splitting by identified breakpoints algorithm is faulty.

    Berkeley is also 28.3% higher for the US (lower 48) than the NCDC back to 1895 which we know has already adjusted the trend up by some 0.5C to 0.84C already. Berkeley was supposed to be using raw data. Not homogenized and TOBs-adjusted and a 28.3% adjustment increase added on top.

    Sunshinehours has been documenting the same issue with individual states.

    http://sunshinehours.wordpress.com/

    This is not an insignificant problem that must be addressed. Until it is, we have to assume the Berkeley Earth temperature series is faulty by significant margins.

  8. “CET has been in steep decline since around 2000.”

    No, not really. 2010 was a cool year, but otherwise the temperature have been holding pretty steady.

    To be more precise, here is the results for a linear regression fit to the Annual CET data for 2000-2011.

    The regression equation is
    T(2000-2011) = 89.2 - 0.0393 YEAR

    Predictor Coef SE Coef T P
    Constant 89.15 89.63 0.99 0.343
    YEAR -0.03934 0.04469 -0.88 0.399

    S = 0.534431 R-Sq = 7.2% R-Sq(adj) = 0.0%

    So the linear fit explains basically 0% of the variation, and the trend (which admittedly is downward at -0.4K/decade) is not statistically significant (p-value = 0.4 >> 0.05). This is a far cry from a “steep decline”, although it is also a far cry from warming. I few more cool years might make the drop significant. A few more years of warming could erase the downward trend.

  9. The 1991 paper below documents how the CET was constructed.

    It contains monthly trends and these show that all the warming is in the winter months (October to March). Were UHI due to retention of solar heating thru low albedo surfaces, the Urban Canyon Effect or other mechanism, this should occur primarily in the summer. The winter warming trend (as well as increasing minimum temperatures) is consistent with my argument that the post 1950s warming is due to reduced urban aerosols, which in the UK would have been primarily from the domestic burning of coal in the winter months.

    There is also a winter warming trend starting from the late 19th century. This might be related to the replacement of gas lighting – notorious for soot and sulphate emissions- by electric lighting, which started in the 1890s and was largely complete by 1930.

    http://www.metoffice.gov.uk/hadobs/hadcet/Parker_etalIJOC1992_dailyCET.pdf

  10. Tonyb,
    Great work as always. One thing I would like to see people do when presenting temperature series like this is to put it in proper perspective. Anomalies exaggerate the fluctuations. Itz like looking at an ant with a magnifying glass. Oooooh, sssssccccaarrryyy… but take the magnifying glass away and it is just an ant. Plot that graph using the baseline temp on a scale relevant to the human experience, like -40 to +40 and suddenly all those “huge” fluctuations, past and present, stand out for what they really are. Pretty much flat.

  11. A station in NE Oregon was in the local paper this year due to an award given to a person connected with it. The picture shows tree limbs hanging over and down the side of the Stevensen screen. Unfortunately, the volunteers that spent their days recording data without fail, were clearly not provided with the guidance needed to keep these sensors artifact free. This rural sensor is a prime example of why city lights are no measure of UHI affects. It sits in a county entirely devoid of stop lights.

  12. The extreme conditions of that winter had a big impact on world history, to include weakening Charles XII’s Swedish army in the Ukraine…
    =================
    I think I can spot the defeat of Napoleon’s Grande Armée (1812) in there also.
    I used to think I was so lucky to have enjoyed a few childhood years in the 40s when the planet was at the optimum temperature (before Man began to cause dangerous climate change™); then Muller came along and declared “…I concluded that global warming was real and that the prior estimates of the rate of warming were correct. I’m now going a step further: Humans are almost entirely the cause…”.
    According to Muller the global land temperatures have increased 1.5 C since c. 1750.
    A temperature rise of that magnitude must have caused considerable climate disruption, species extinctions, not to mention earthquakes etc. ( http://www.numberwatch.co.uk/warmlist.htm ).
    Or did the human-caused warming 1750 – 1980 (1990 or 2000?) merely restore global temperatures to an optimum level, only further rises being perilous?

  13. “The Little Ice Age” by Brian Fagan is an excellent exposition of why warm is good and cold is bad. For those in Northern Europe, it was a truly horrible time. What a shame Mann, Hansen and co. could not experience it, or they might change their incessant keening about recent temperatures.

  14. “””””…..Mike Jonas says:

    August 14, 2012 at 2:26 pm

    “BEST do not correct for UHI, in fact they make some mention of it having a cooling effect“.

    BEST do indeed not correct for UHI. Muller, Curry et al published results of a study they did to try to detect UHI, and they did indeed say that they detected a possible cooling effect but thought it very unlikely and ignored it……”””””

    There is absolutely nothing wrong with UHIs, or their being included in Weather station Temperature records. They are actual physical places that have a real measurable Temperatures.

    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.

  15. Mike Jonas says: August 14, 2012 at 2:26 pm
    “BEST do not correct for UHI, in fact they make some mention of it having a cooling effect“.
    BEST do indeed not correct for UHI. Muller, Curry et al published results of a study they did to try to detect UHI, and they did indeed say that they detected a possible cooling effect but thought it very unlikely and ignored it.

    Gill et al 2007 did a study showing greening roofs in Manchester (England) reduced the local temperature by 4C (I haven’t read the full paper) and I recall reading up to 10C could be achieved in Rio de Janeiro
    .
    Seems to me, if greening roofs in Manchester can reduce the local temperature by 4C, then concreting over chunks of land can raise the temperature locally be 4C.

  16. cui bono

    Thanks. I will be expanding on this work-in particular I want to examine the period around 1730 which seems little different to today. It takes me about six months to research material for a major article such as ‘The Long Slow Thaw’ but a few snippes-such as this one-tend to naturally fall out of the wider research.
    tonyb

  17. tjfolkerts.

    The ‘steep’ declne is shown in the graph from the Met office (|back to the levels of the 1730’s) Also anecdoally the gardening weathe has changed. It has become more diffcult to grow outdoor tomatoes, cucumbers and runner beans for example, whilst many of the succuents we have taken for granted can be grown outside have suffered very badly even in my garden in the mild South West of England.

    All our attention is focused on warming, I think we need to have a plan ‘b’ for cooling
    tonyb

  18. Seems to me, if greening roofs in Manchester can reduce the local temperature by 4C, then concreting over chunks of land can raise the temperature locally be 4C.

    Concrete has a high albedo (fresh concrete around 0.55) and is therefore a cool surface relative to most surfaces. In fact there is much discussion in urban planning circles about using high albedo concrete to reduce UHI.

    Urban centres tend to have relatively high levels of concrete surfaces (as well as high albedo reflective glass) compared to suburban areas and this could have been the reason BEST found urban cooling.

  19. Can we keep away from graphs with red/green in them? 30% of males are like me, unable to follow graphs like these. Can we have some dots and dashes to assist?

  20. Much has been claimed for the Central England Temperature Record but is it that reliable?
    I would not have thought so. Thermometers were not very good back then as no standard had been established or accurate method of calibration. OK so we have two points, melting point and boiling point of pure water but these depend on atmospheric pressure which complicates the calibration, at least to the accuracies required. There were no stations back then where thermometers could be sited to a standard only rich landowners who had time on their hands and the money to buy a thermometer. (Remember back then Newton paid £3 for a quartz prism to do sunlight spectra experiments which was several month’s salary then). Readings were taken at odd times by some with no training so data sets would have been limited to say the least.
    So is the CET a good basis to use for current discussion about past climates?
    I do not think so.

  21. Tony:

    Thankyou for this article. As always, you provide ‘good stuff’. And it gives me great pleasure that at last – and after all my pleading – you have started to present your work on WUWT.

    My reason for writing now is that I notice you have had some interaction with tjfolkerts in this thread, and I suggest that direct communication and interaction between the two of you would be beneficial.

    I said to him on another thread

    I think it would be valuable if you and Tonyb could make contact. The two of you are near opposite ends of the ‘AGW-debate’, you share an interest in the same data, and neither of you addresses the subject in an adversarial or bigoted way.

    Richard

  22. 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.

  23. 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

  24. 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.”

  25. 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

  26. 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!

  27. 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).

  28. 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 :)

  29. 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..

  30. 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.

  31. 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.

  32. 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.

  33. 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.

  34. 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.

  35. 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.

    ############################

    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.

  36. 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..

  37. 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

  38. 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

  39. 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) .

  40. 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!
    ====================================
    Interesting. Here are a few studies on bird migration:

    Sunlight is key for bird migration

    Biologists have known for decades that migrating birds use celestial cues and the earth’s magnetic field to find their way across continents and oceans… researchers from Virginia Tech in Blacksburg and Lund University in Sweden say experiments with savannah sparrows in Alaska show the birds take readings of polarized sunlight at sunrise and sunset and use them to periodically recalibrate their magnetic compasses….
    …Muheim caught 50 savannah sparrows in the Yukon Delta National Wildlife Refuge and threw off their celestial compasses by placing polarized light filters over their cages for an hour at either sunrise or sunset.

    The filters allowed the birds to see some sunlight and sky, but it shifted the alignment of the polarized light from the sun, making it seem as though the light came from a different direction.

    The researchers found that shifting the light made the birds alter or recalibrate their magnetic compasses, so that when the birds were returned to observational funnels, they tried to fly off in the direction indicated by the filtered polarized light….

    The Effect of Elevation on Bird Migration [College Internship Project - nice to see a decent one]

    Birds migrate as a result of internal and environmental cues instructing them when to begin travel. Bird Migration cards from 1760-1880s are available at the Bird Phenology Program (BPP), and provide information on bird arrival date, and location amongst other information. But over time bird arrival dates have become increasingly later due to some unknown factor and through this research, elevation patterns and how they have affected bird arrival dates were studied….

    The variables tested played a role but not as large of a role as hypothesized. This sheds light that the earth and climactic factors may also play a larger role than previously assumed.

    CIRCADIAN AND CIRCANNUAL PROGRAMMES IN AVIAN MIGRATION
    The only environmental factor known to be capable of changing the time course of the programme is photoperiod. Photoperiod synchronizes the circannual rhythms and, by doing so, it also affects the programmes that depend upon the basic clockwork. The circannual mechanism frequently responds to photoperiod in a functionally adaptive way. Two major effects have been described for the long-distance migrating garden warbler (reviewed in Gwinner, 1989a, 1996; Fig. 5). (1) The onset and the end of the post-juvenile moult and the onset of autumn migratory restlessness are advanced by short photoperiods. This accelerating effect of short photoperiods in summer is important for young birds that have hatched from late clutches and, hence, grow up under shorter photoperiods than young hatched from earlier clutches. To be able to leave the breeding grounds in time, the birds from late clutches must start migration and complete the preceding processes of development at an earlier age.

    The end of autumn migratory restlessness, the onset and end of the winter moult and the onset of spring migratory restlessness are advanced by long photoperiods. This accelerating effect of long photoperiods in winter is of high adaptive value because it truncates autumn migration in individuals that happen to have been carried too far into the southern hemisphere by their endogenous time programme. At the same time, it enables these birds to initiate spring migration earlier. This is probably necessary for them to reach their breeding grounds in time, i.e. not later than conspecifics that have spent the winter further north…..

    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.

  41. 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

  42. Steven Mosher – For their UHI study, BEST used “the MODIS 500m Global Urban Extent classification map (MOD500)“, and yes, I described it incorrectly. However, the main point remains, namely that it is useless for identifying the impact of development.

    Even examining the satellite data down to a single pixel, as you have been trying to do, doesn’t solve the problem. A MOD500 pixel (as per the BEST paper berkeleyearth.org/pdf/berkeley-earth-uhi.pdf) is 15 arc-seconds, ie. nearly 100m. As Watts2012 showed, what matters most is what is going on a lot nearer than 100m to the station. It seems the only real solution is to examine each individual station properly, ‘on the ground’, which is where surfacestations.org started.

    In reality, it’s altogether too much work, so I suspect that the solution will be to find a relatively small number of well-distributed long-life well-sited stations, and to use just those.

  43. The extended CET record coincides well with a 2000 year reconstruction by Craig Loehle

    Not to my eyeball. In Loehle’s graph, the 1920s/30s (Loehle corrected only goes to 1935) are nearly half a degree C warmer than the 1540s/5os, and nearly 1C warmer than the early 1600s. In your CET extended, all these periods appear to be about the same temperature. There is a clearly and sharply rising trend in Loehle’s reconstruction from the 1540s, but there is a much shallower trend in yours. While there is some similarity in ‘tendency’, there are some very strong dissimilarities, too, From 1700 to 1800 in Loehle’s, there is a very sharp increase. This is not apparent in your CET graph. From 1600 to about 1675 there is a definitie downward trend in your CET chart. In Loehle’s, the trend is clearly upward.

    I was curious to see how you corroborated the notion that CET are a sound proxy for NH temperatures. After reading Long Slow Thaw, I’m impressed by the detail, but not with the conclusion on that as given above (“CET is a reasonable proxy for Northern Hemisphere”) as applied to assess the validity or otherwise of millennial reconstructions.

    I agree that MBH99 did not display the variability inherent in its own data, and emphasised in later studies, including by Mann. But I think a simpler argument may be made just be showing more up-to-date reconstructions from the literature, including those by Mann, which show this well enough. I understand that the ‘hockey stick’ is so iconic for some (in a political sense) that it is still being mulled over more than a decade after its publication and despite a slew of superior work on offer that verify its basic conclusions, if not the implied long, slow decline of temperatures since 1000, but OTOH, can we stop beating the moribund nag yet?

  44. says: August 16, 2012 at 1:47 am
    If all the rythms coincided it would be enough to make you believe in gaia.

    Belief is an individual’s choice, I am not really into ‘gaia theory’, apparently it was surpassed before I got to hear about it .
    If there are number of oscillating systems loosely connected, then after period of time the dominant one (in this case sun) would eventually pull the less stable ones into a common frequency.
    Nature abhors coincidence, it is ruled by laws of cause and consequence.

  45. Anthony, this has probably been mentioned before, but hopefully Josh can run a cartoon of Hansen and Gore caught painting thermometer boxes black.. and the cop says: “YOU again!” whilst arresting Hansen..

  46. barry

    I stress that CET shows the ‘tendancy but not the precision’ and this can be seen in the BEST global graphs where there are some clear correlations, albeit that CET is generally more moderate.

    I think precision is impossible in any proxy type graph, especially the further back in time one tries to stretch, which brings into play some dubious proxies (tree rings as accurate proxies? Sorry, no).

    In this respect. I comment specifcally on the very earliest part of my reconstruction, that the 1540’s/50’s need closer examination as it appears to be a significant period. (i was interested in the French quotation in the comments and that Lamb saw this as a warm period.)

    I had expected the early 1600’s to be as cold as the latter part of that century but it would appear that it wasn’t.

    As for Dr Mann, the hockey stick is still, to this day, an icon, and all other reconstructions are measured against it. I do show plenty of ‘spaghetti’ alternatives, but ultimately it is the slight downwards trend from 1000AD with very little variability until its dramatic uptick that remains the take home message for the publc, politicians and activists, and one that our own Met office adhere to in their belief of the lack of variability.

    I am acquiring numerous pieces of documenttry records from a variety of sources to reconstruct further back firstly to 1200, and in the process try to identify if there is clear evidence of a change from MWP to LIA.

    Do I think that CET is a better proxy than the hockey stick? Yes I do, albeit that global temperatures is perhaps a pointless measurement and any proxy isnt going to shpw the temperature shape fpr the entire globe.
    tonyb

  47. Tony, your CET temperature records and pre CET proxy records, backed up by extensive historical records, would seem to give a truer record of temperature trends than BEST.with its low temperature starting point, omission of the well documented MWP and apparently no 20th century adjustments for UHI . Your exhaustive, (possibly exhausting as well :-)) examination of historic records provides a valuable cross referencing of the science, what Winston Churchill referred to in military map making, as taking a cross bearing. And no tweaking of models or suspect tree ring studies involved.

  48. Tonyb,

    the current information from the Met Office on past temperatures is as follows;

    4. Has climate changed in the past?

    There is little doubt, from the evidence so far, that there have been enormous changes in climate in the past. These ranged from a complete absence of ice over the Poles to ice sheets extending across much of Europe, Asia and North America. The last major extension of polar ice retreated only 10,000 years ago.

    5. Has the climate changed recently?

    Global average temperature 1850-2009, 2000s are warmest decade so far : This link opens in a new window Global average temperature 1850-2009, 2000s are warmest decade so far Enlarge image Enlarge Earth is warming. Over the last 100 years Earth has warmed by about 0.75 °C.

    Natural sources, such as tree rings and glaciers, as well as human records, show that climate has changed significantly over the past few hundred years. There was a relatively warm period in Europe during the 14th century, followed by a quite sudden change to cooler conditions in the 15th century. This extended into the Little Ice Age of the 17th and 18th centuries, followed by a warming trend that has recently accelerated. The evidence for this recent warming comes largely from direct measurements of temperature. In the more temperate northern latitudes, winters are less severe than 30 years ago, with cold snaps generally being short-lived.

    http://www.metoffice.gov.uk/climate-change/guide/faq

    This is based on updated millenial reconstructions.

    The Met Office page you link to in order to support your contention that the Met Office defers to MBH99, is an archived page, not current. Here again, you are beating a dead horse.

    You say:

    “As for Dr Mann, the hockey stick is still, to this day, an icon, and all other reconstructions are measured against it.”

    “As for Dr Mann…”? Why bring personality into a comment about an iconic graph? What about Dr Mann is so important that you include him in this sentence? You do not finish your opening here – “As for Dr Mann…” what? I detect a personality based argument that you don’t quite go for.

    In any case, where in the world is the hocket stick the measure of all other reconstructions? I mean, apart from skeptic blogs and other critics of it, who in the mainstream is holding MBH99 as some kind of standard for other reconstructions? The only reason MBH99 is a current issue is because of skeptics criticising it, not because of anyone else.

    Please corroborate your assertion here (minus the personalities, please).

    I applaud your seeking to extend the temperature record, but wonder if you are relying too heavily on anecdotal evidence. And I think it is unwise to consider Lamb’s 1965 graph, with little information supporting it, no Y-axis figures, and data only to the mid-20th century, as a reliable representation of past – and certainly recent – temperatures. Science has moved on. so should we.

  49. Re yr comments on CET 1540 – 2012 and Loehle 1540 – 2000, Barry, my eye-balling sees correspondence. On Michael Mann, hmm, disregarding his many public diatribes in defence of his HS, it was analysed in depth and found wanting, both on data selection and statistical method, and follow up Hockey Sticks have fared no better, including Gergis et al, which has now been withrawn from publication.

  50. Barry

    As Beth says Dr Mann is still an important figure and the hockey stick still much referenced. Science moves on but leaves consequences in its wake. The Met office for many years has maintained that there was little variability as did the IPCC. Dr Mann was perhaps their role model or merely a standard bearer of a view that had become fashionable.

    What we are left with is a generation that believes that variability was very limited until Man caused a sudden uptick through increased co2 concentration.. That generation includes politicians who are, as a consequence of the past viewpoints and science, now making far reaching decisions that affect us all.

    I’m not a politician and think the debate has become much too politicised and too acrimonious but if we were able to rewind to 1998 and start from the basis that the evidence still suggested a gently rising trend for hundreds of years with some notable upticks and downturns and not a gently decling trend for a thousand years with one recent dramatic uptick, I suspect the political decisions would have been different. We also might have been able to examine the reasons for the trend (and the one that seemed to have occurred from around 850 to 1250 or so) and not fixate on just co2. My concerns are that IF the climate should turn down again we have no ‘plan B’ to cater for it as we are so convinced that the Plan A to cope with a warmer world is all we need.

    Lambs graph and the hockey stick were an interesting and useful general representation but we know a lot more now and can finesse their work and adjust it to suit what we have learnt. The trouble is that the latter still has considerable resonance and it contnues to cloud the debate.
    Tonyb

  51. Continuing ter ‘cloud the debate,’ yes Tony, the models sure have trouble with them pesky clouds. To quote from a denizen at Judith Curry:

    ‘I think I’ve never heard so loud
    The quiet message in a cloud.’

    H/t Kim.

  52. Lambs graph and the hockey stick were an interesting and useful general representation but we know a lot more now and can finesse their work and adjust it to suit what we have learnt. The trouble is that the latter still has considerable resonance and it contnues to cloud the debate.
    Tonyb

    Agreed. The hockey stick is over ten years old now and a lot of extra data has come in since then.

    Look at Figure 1 here.

    http://www.worldclimatereport.com/index.php/2005/03/03/hockey-stick-1998-2005-rip/

    The error bars after 1600 are fairly small. Before 1600 they are much larger, and could encompass a significant warming or cooling trend.
    Part of the problem now is that it has become contentious. The sceptics attack it and, almost by reflex, the consensus defends it.Both inflate its relative importance once you move beyond the last 130 years.
    It has assumed an excessive importance as an icon, rather than an analysis.

  53. entropic man

    Yes, almost by conditioned reflex people attack or defend the stick, but its continuing importance remains as a symbol of what Mann is supposed to have done and it is difficult to move on and find out the truth behind it
    tonyb.

  54. Tony, thanks for your historical perspective. In the Sept/Oct issue of Archaeology Magazine, in an article on the LIA in Iceland, Mann is quoted as saying a volcano near the equator erupted in 1258, sending the temperature down 2-2.5°C (3-4.6°F). If one inserts this information into the the HS, it rather disrupts the fantasy of a stable past, and makes the current warming, well rather small, since we have had to recover those two degrees already, prior to the current warm period. http://i48.tinypic.com/2qlxtkz.jpg

  55. Steve

    Thanks for that. That is the exact period I am currently studying in order to extend CET further although the error bands will become much wider. I have looked at original scrolls from the 12/13/14th century and the various translations. These few snippets from such places as the library of Medieval Exeter Cathedral might be of interest
    ——– —–
    1228-30 it ‘rained non stop’

    Ad1230 the harvests having failed for two successive years, owing to continual rain which caused great overflowing of the river there was so great a scarcity of provisions that the people were obliged to eat horse flesh and to substitute bark of trees for bread

    AD 1286 the summer proved very wet which caused great inundation-

    ‘The winter period was defined as the beginning of November to the end of the 11th or 12th weeks of the Christmas term-so winter lasted up to 20 weeks (note subsequent change of calendar) During this period (1279 to 1353) ‘the work force was much reduced in number on account of the weather, (in the winter) though work does not seem to have ever altogether ceased on this account.’

    —- —-
    To date I haven’t found any observational evidence of the 1258 volcano although there is a great deal of talk about its effects.

    tonyb

  56. Tony, here is a bit more information, as A.M. makes no footnote reference for what they are quoting from. This was proposed as the paper the reference came from:
    Mann, M. E., M. A. Cane, S. E. Zebiak, and A. Clement (2005), Volcanic and solar forcing of the tropical Pacific over the past 1000 years, J. Clim., 18(3), 447–456

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