The value of very long instrumental data series

by Alan Longhurst

Because the climate change science community habitually concentrates attention on surface data from a very short recent period – nominally a little more than 100 years – it would be very interesting to know how the pattern habitually derived from these data compares with longer data archives that have been processed independently by the observing nations.

In just a few parts of the world there exist meteorological agencies of high competence that have inherited the observations of their predecessors, processed them in acordance with modern requirements, and made them available to the community through the GHCN system operated by NOAA.

So a small investigation was made of the reliability of some early instrumental data by comparing GHCN2 data for three central European cities at which air temperature measurement extends back over a 225-year period: the observations were made and processed by different national agencies: Czech, Slovak and Austrian.   They exhibit a uniform pattern of temperature change over a large part of central Europe that which gives confidence in the precision of the measurements themselves and, by inference, in similar data from other reliable national meteorological agencies.

slide01

Throughout this long period, each station responded similarly to major changes in rates of warming or cooling although, as might be expected from their geographical position, temperature changes at Prague and Vienna were closer to each other than either was to Budapest, farther to the east on the Hungarian plain. This result suggested that it would be useful to assemble a larger file of major European cities from the GHCN2 archives, so 21 such were selected (together with the Central England data, actually centered on Oxford) being grouped for use into four regions: Western, Scandinavian, Central and Eastern. Useful data are sustained back to 1700, and demonstrate the evolution of SAT in the region from Lisbon to St. Petersburg and from Trondheim to Milan over this long period; this is similar to – but more detailed than – the pattern of the 731 GHCN stations that represent the European region.

slide02

The data also conform to (and confirm) the trend of air temperature for this region that is indicated by proxy data, and many of the features in this record had impacts on human affairs that were described in historical records. Some of these were associated with a recurrent cooling and incursion of arctic air that is a characteristic feature of the European climate that may be sustained over several years: at least eight such incursions are recorded in these data.

slide03

Some of the worst European famines have been associated with these cold events, of which at least one, that of 1816 “the year without a summer”, has been historically associated with a major volcanic dust veil from the explosion the previous year of the magma chamber of Mt. Tamboura in Indonesia.

slide04

But the instrumental data show that 1816 was no colder in Europe than the previous several years and that it was the final year (see the above plot) of an incursion of cold air over Europe (indicated as #4 in the previous plot).   So, although a sulphurous dust veil undoubtedly occurred, especially over North America, the cold European summer of 1816 was probably not the consequence of Tamboura, but of the state of the atmospheric circulation over northern Europe. So it is plausible that the series of the eight cold incursions that have marked European climate during recent centuries were all similarly forced, and have little or nothing to do with the more popular suggestion that at least some were the consequence of a volcanic dust-veil, but may be associated rather with trade wind failure over the Pacific Ocean.

The very similar cold incursion of 1940-43 has been analysed in detail, and no volcanic influence is required for its explanation; this event attracted special attention because of its influence on recent European history. The planners of the German invasion of Russia in 1941 were apparently not advised by their meteorologists that eastern Europe was then in the third year of an incursion of Arctic air, and the consequent problems faced by the German army in northern Russia that winter were perhaps the first steps towards their eventual defeat.

slide05

The bitter cold in eastern Europe was caused by a persistent 24-month global climate anomaly that was coincident with the strong and prolonged Niño episode of 1939-1942; this was an intense example of a now well-understood phenomenon that links atmospheric processes over the two northern oceans through changes in the Hadley circulation and in Rossby wave generation.

In 1942 an intensified Aleutian low induced warm anomalies over Alaska, while a pattern of weak Icelandic low and strong Scandinavian high led to an unusually persistent flow of cold arctic air over eastern Scandinavia.[1] The local mechanism was apparently typical: a high pressure ridge over the eastern Atlantic and a trough over western Russia were present throughout the winter 1941-42 and steered the migratory cyclones approaching Europe to the north of Scandinavia or into the Mediterranean. Such conditions, even temporary, are well known to bring frigid arctic air down across eastern Scandinavia and over western Russia and are associated with the strength of vorticity in the mid-latitude jet stream (see below).

To what extent we may assume that each of the cold incursions noted above in the historical European temperature records were similar in origin is not clear from the historical occurrence of Nino-type events which suggests a greater frequency than the 8 cold incursions suggested from the figure on p. NN.   But when Napoleon faced Moscow in 1812, he did so in the first year of another European cold wave, while the 1789 revolution was at least partially the consequence of crop failures in France during the 1780s cold spell that led to unrest in the countryside and hunger in the towns.

These events have been associated with agricultural crises, famines, civil disturbance and migrations: the great Irish potato famine (when a third of the population starved because the tubers froze in storage) occurred during the 1740s cold incursion.

slide06

Much of European history has been marked by the effects of such irruptions of arctic air into a region that is habitually under the influence of warm Atlantic air – to which, consequently, European agriculture and economy has been adapted. But at the end of the 20th century, an anomalous and very rapid warm shift in surface temperatures occurred that has been described as a “jump” in the temperature record. Over just a 3-year period from 1987-1990, SAT anomalies inceased rapidly over about a full degree.[2]

slide07

Regional SAT was maintained through to the end of the record in 2014 at a higher mean temperature than had been recorded during the previous century. One may choose to ignore it and simply draw a trend line from 1890 to 2015 – or one may choose to interpret the record differently, as here: both positions are valid and in the present state of climate science your choice will largely depend on your confidence in the reliability of simulation modelling of complex Earth systems.

The flowering dates of plant communities in Britan, analysed for their response to long-term change in the Central England surface air temperature record, responded closely to this regime shift. [3] The fit between ambient temperature and flowering dates (both at community level and for individual species) is excellent over each 25-year segment of the entire record back to the 1750s. The series terminates in a very clear 15-day advance in the dates of community flowering after 1985 that was maintained to the end of the record in 2008.

Such a rapid change in surface air temperature over this large region is compatible neither with anthropogenic nor with volcanic forcing, but is consistent with the expected result of an equally major and rapid change in the distribution of atmospheric pressure over the entire North Atlantic-Arctic region.

slide08

This is indicated by change in the values of both the wintertime NAO and the Arctic Oscillation (northern annular mode of Hurrell) which together describe the state of the polar vortex north of the mid-latitude jet stream; when polar surface pressure is low (positive AO index) this flows strongly and consistently, with relatively weak meanders, so that cold polar air tends not to intrude down into mid-latitude Europe. But when polar surface pressure is high (negative AO index) the jet stream weakens and meanders more strongly, so that cold polar air is routinely carried down into mid-latitudes. Because of the existence of the western mountain ranges in North America that perturb its flow, the jet stream has a preferred number and location of southerly waves appropriate to each state of the AO. Periods of strongly negative AO are, in western Europe, associated with irruptions of cold polar air, as occurred rather commonly in the period 1935-45, discussed above.

Major warm excursions in surface air temperatures on the Japanese islands have already been noted for these same years (see plots for two rural stations on p. NN) and although these excursions were brief and cooling set in after only a single peak warm year, they were peraps related to the same rapid change in the value of the Arctic Oscillation after 1985. Changes in the AO has consequences for the strength of the winter westerlies that bring cold air from central Asia down across the Japanese islands, affecting winter temperatures generally in East Asia; this effect is modified by the strength of western Pacific cyclonic activity, and the 1985-1990 warm event over Japan (see p. NN) appears to have been the result of complex interaction between these two processes.[4]

[1] Papineau, J.M. (2001) J. Climatology 21, 1577-1592

[2]Le Mouel, J-L et al. (2008) C.R. Geoscience doi.10.1016/j.crte.2008.06.001 and see also “Nouveau voyage au centre de la terre” (Odile Jacob, 2009),

[3] Amano, T. et al. (2010) Proc. Roy. Soc. B, 277, 2451-2457

[4] Park, H.-J. and J.-B. Ahn (2016) Clim. Dyn. 46, 3205-3221.

Moderation note:  As with all guest posts, please keep your comments civil and relevant.

133 responses to “The value of very long instrumental data series

    • The main message from this is: Cold Bad – Warm Good

      • Good for tax hikes!

      • I believe the main message is that there may be other processes at work affecting SAT

      • It doesn’t matter what other explanations there are for climate changes. If warming is not a threat – or if GHG emissions will do more good than harm – then the whole debate and investment in the “Climate Industry” is a massive waste of resources. There is no rational justification for the enormous funding and the enormous ideological and political focus on CAGW. Importantly, the post shows that cold was bad, warm was good. Very important.

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  2. Throughout this long period, each station responded similarly to major changes in rates of warming or cooling although, as might be expected from their geographical position, temperature changes at Prague and Vienna were closer to each other than either was to Budapest, farther to the east on the Hungarian plain.
    Just a small point. Vienna and Budapest are closer together than either are to Prague. Vienna and Budapest being along the Danube valley and Prague further to the north on the Czech plain.
    Not that it changes anything, just like to get things in the right order :)

  3. Pavel Belolipetsky

    Alan, thank you for drawing attention to shift in surface temperatures. The majority of climate scientists, climate modellers, policy makers and the public consider that climate, over decades to centuries, is changing gradually and can be represented by a trend. Against this view research by at least three independent teams working in Russia, Australia and UK (international), shows that temperature and other Earth system variables may exhibit sudden changes (shifts) with stability or a trend between (Belolipetsky et al., 2015, Jones & Ricketts, 2016, Reid et al., 2016).

    1. Belolipetsky et al. 2015. Hidden staircase signal in recent climate dynamic. Asia-Pacific Journal of Atmospheric Sciences, 51, 323-330.
    https://www.researchgate.net/profile/Pavel_Belolipetsky/publication/284879739_Hidden_staircase_signal_in_recent_climate_dynamic/links/565bc41208ae1ef92980fba7.pdf

    2. Jones and Ricketts 2016. Reconciling the signal and noise of atmospheric warming on decadal timescales. Earth Syst. Dynam. Discuss., 2016, 1-52.
    https://www.researchgate.net/profile/Roger_Jones6/publication/305989759_Reconciling_the_signal_and_noise_of_atmospheric_warming_on_decadal_timescales/links/57a91bf908aed1b226244e87.pdf

    3. Reid et al. 2016. Global impacts of the 1980s regime shift. Global Change Biology, 22, 682-703.
    https://www.researchgate.net/publication/284484997_Global_impacts_of_the_1980s_regime_shift

  4. Because the climate change science community habitually concentrates attention on surface data from a very short recent period – nominally a little more than 100 years – it would be very interesting to know how the pattern habitually derived from these data compares with longer data archives that have been processed independently by the observing nations.

    Geologists learn early in their career to start with the largest possible view. We used to call it “the view from space” (although conceptual in those days). Then we come down to the regional maps and high level air photograph view. Then the helicopter view. Then we progress down to the area we need to study. Eventually to the microscope view and chemical analyses of the rocks. Similar approach applies to time scales. Using this approach, I suggest your study should begin with context from very long time scales to get the big picture and to understand the limits of temperature changes, impacts and how life has thrived in the past.

    Therefore, I suggest you should begin with the time that multi-cell life has existed and thrived on Earth – roughly the past 600,000 years:

    Notice from this chart, Earth is currently in a very cold period. Only the second time the planet has been this cold during the past half billion years!.

    Also notice that even 3C warming would not raise the GMST to even the midpoint of the normal temperature range over this period.

    From IPCC AR4 WG1 Chapter 6 Figure 6.1 notice that is it rare for Earth to have ice at the poles. In fact, for about 75% of the past half billion years there been no ice at the poles.

    Life thrived when the planet was warmer and struggled when colder.

    I do not see persuasive evidence that warming is dangerous.

    Furthermore, I doubt that warming 3C is likely until the tectonic plates realign so the planet can get out of the current ice age.

  5. “GHCN2 ” is deprecated.

    • Curious George

      Criticizing Alan is not science. CORRECTING him is science.

      • “Criticizing Alan is not science. CORRECTING him is science.”
        What a great line CG.
        I saw it somewhere else I recall.
        What ever made you use it just now?
        Only joking.

      • Simple. He is using the incorrect data.
        Correct ing him is easy.

        Use the right data dummy.

      • So now you add an insult but still are not able to provide a correction.

        A correction would read like : “GHCN2 ” is deprecated, I suggest you use XXXX because ….

        Once a smart-ass always a smart-ass I guess.

      • Curious George

        A correction is what Steven declares a to be a correction. When Curious George finds an incorrect physics in a model and proposes a correct one, that’s not science.
        https://judithcurry.com/2013/06/28/open-thread-weekend-23/

    • Alan Longhurst

      Steve
      If you had read the piece, you would have seen that I chose a very selected set of GHCN data that originated in met services at least as competent as CRU and Goddard in ensuring the data were sound and not contaminated by station moves and so on. For this text I wanted data that had not been homogenised with surrounding, perhaps less complete, stations or regions. I believe the resultant plots give a secure series of point temperature data from which some limited conclusions may be drawn. I’m sorry you dont agree, but there it is. I think its a perfectly respectable approach to a difficult problem.

      Alan

      • “Steve
        If you had read the piece, you would have seen that I chose a very selected set of GHCN data that originated in met services at least as competent as CRU and Goddard in ensuring the data were sound and not contaminated by station moves and so on.”
        1. you used the wrong data.
        2. the NWS have updated data since GHCN2
        3. A competant analyst would not use data that has been deprecated
        BY THE VERY PEOPLE YOU SITE AS COMPETANT

        ” For this text I wanted data that had not been homogenised with surrounding, perhaps less complete, stations or regions. I believe the resultant plots give a secure series of point temperature data from which some limited conclusions may be drawn.”
        1. GHCH V3 has raw data, if you knew anything you would have checked. You didnt
        2. It is a tested and scientifically “proven” fact that failure to correct
        for changes in observation practices, will give you corrupt
        data. The raw data is corrupt .
        3. your beliefs about what is secure are not science.

        “I’m sorry you dont agree, but there it is. I think its a perfectly respectable approach to a difficult problem.”

        1. Using the wrong data ? FAIL
        2. Using the wrong data for a bogus reason ( its NOT the only source
        of raw data. FAIL
        3. failure to provide a copy of the data as used. FAIL
        4. failure to supply code documenting what you did. FAIL
        5. failure to rgorously justify the use of corrupt raw data. FAIL

        Zero repsect

      • Alan, Mosher only believes people should use data that he has Mannipulated with his AlGoreithims to support his quasi-religious views on climate change.

        And he HATES anyone contradicting them.

      • Catweazle666

        And [Mosher] HATES anyone contradicting them.

        Your dead right on that. He flies into a rage when he is shown up as not knowing what he is talking about. He hates being questioned when he has made a dumb statement and is corrected or asked to explain his statement. He has often told me I have no right to ask questions.

      • Alan,

        Special accommodations will be accorded those who changed data to fit models: https://jonrappoport.wordpress.com/2016/10/12/goodbye-to-the-matrix-2/#comment-185236

    • Yeah yeah, your data, after its manipulation, is correct, How do you know? You can only know it is correct by comparing it with data you know to be absolutely correct.

      So where exactly is the absolutely correct data you are using?

      Oh look, it doesn’t exist.

      So your claims are simply meaningless. You have done something, and it may or may not be right. Yet for some reason you think that makes you not only omnipotent but more virtuous than everybody else. Some might say you have a bit of problem.

  6. “a larger file of major European cities from the GHCN2 archives, so 21 such were selected being grouped for use into four regions: Western, Scandinavian, Central and Eastern. Useful data are sustained back to 1700”
    My limited understanding is that the GHCN records are only used from 1860 on. is this correct?
    It is nice to know that earlier records are archived and available but should not GCHN be putting out these records as well?
    One problem might be that the records [print] are resistant to lowering of past records as USHCN and presumably GCHN do from the current data [computer] back the last 100 or so years by their adjustments.
    Presumably they have a cut off point of active data which must be interesting to compare to the unadjusted data.
    The 1700’s would have been quite warm in comparison to 1900, by George, whoops meant by Steven.
    In fact quite a fall which needs homogenizing away.
    Strange that these records, Alan, show no such expected shift.
    What is wrong with them?

    • You are wrong about the data.
      Give up.

    • You are wrong about the data.
      Give up.

    • Alan Longhurst

      On the KNMI site, you may select ‘monthly temperatur data’, then a data base, then a region, then a minimal period of data and get down lists and data of stations – many with several hundred years of data originating in long established national services whose observing practice may presumably be trusted – as suggested by my first figure.

  7. the “jump” in the lat 1980s over Europe we documented here:

    A Late 20th Century European Climate Shift: Fingerprint of Regional Brightening? A. T. J. de Laat, M. Crok , Atmospheric and Climate Sciences Vol.3 No.3, Pub. Date: June 26, 2013.

    http://file.scirp.org/Html/4-4700136_33658.htm

    It does not just occur over Europe, but also over East Asia. It is persistently present in all available temperature datasets as well as OHC. We hypothesized that a possible explanation could be a combination of warming due to GHG, rapid coincident decrease in air pollution (most notably sulphur dioxide), and particular sequence of years with unusual but also changing circulation patterns.

    Recently, Kim et al. [2015; JGR] published an analysis arguing that this “abrupt jump” is most likely associated with a regime shift in Northern Hemisphere circulation patterns, causing both Europe and East Asia to be subject to more persistent southerly flow and advection of “warmer” air.

    Kim, Y.-H., M.-K. Kim, W. K. M. Lau, K.-M. Kim, and C.-H. Cho (2015), Possible mechanism of abrupt jump in winter surface air temperature in the late 1980s over the Northern Hemisphere, J. Geophys. Res. Atmos., 120, 12474–12485, doi:10.1002/2015JD023864.

    http://onlinelibrary.wiley.com/wol1/doi/10.1002/2015JD023864/abstract

    Expect more to be published in this the coming years.

    • Alan Longhurst

      The observations are not consistent with forcing by changes in forcing by GHGs, particulates and SO2, and require a regional explanation such as is emerging from various sources.
      I think Le Mouel et al (2008) CR Geoscience doi:10.1016/j.crte.2006.06.001 were about the first to point this out.

      • doi typo (2008, not 2006):

        doi.10.1016/j.crte.2008.06.001

      • Le Mouel et al. [2008] presents a statistical analysis, showing some resemblance between some temperature statistics and some solar statistics. But statistics cannot prove causality.

        Statistics may be used to decide in case of multiple explanations which explanation would be more likely – but only if for all possible explanations appropriate statistics exist.

        Beyond that, one would need a proper (physical) understanding of the mechanisms of the causal relation. I doubt that this is understood in case of solar influences, and even for radiative effects of aerosols (like brightening/dimming) this is not simple.

        That doesn’t mean that we can exclude that the “jump” and the regime shift have been caused by solar effects. But it could also have been a random fluctuation. Or that aerosols or clouds play a role. Or all at the same time, reinforcing each other. But there is no simply way to figure out which – if any – is more important.

        What we do know that there has been a shift (in a statistical sense), and that there appear to be associated changes in circulation patterns. And that these effects have a strong regional footprint: some regions are affected, others are not. We are talking here about a 1C warming, twice the global average for the same period. We also do know that air quality in Europe has improved drastically and quickly during the 1980s, and we do know that incoming solar radiation has increased in sync (either by chance of causal). The rest is supported speculation and statistics.

  8. “So it is plausible that the series of the eight cold incursions that have marked European climate during recent centuries were all similarly forced”

    Yes, and can be hindcast in monthly detail from their solar causes.

    • Alan Longhurst

      Or perhaps response of ocean tides to same changes in geometry of solar system as sunspot frequency? See series of papers authored or coauthored by CHarles Keeling of CO2 fame on the consequences of variable tidal mixing on sea surface temperature at all scales from decadal to Milankevitch. Effects of tidal mixing on SST may be a major ignored factor on global surface temperature. Look at PNAS 94, 8321-8328 or 97, 3814-3819 and also at J. Climate 15, 370379 and finally Deep-Sea Res.I 45, 1977-2010 – for starters.

      • Alan, often these events last just a month or two. The oceans are not driving them, but the changes in atmospheric circulation does effect the oceans.

    • It’s also plausible that they were unforced.

      • Alan Longhurst

        Ulric – the 8 cold incursions over Europe I’m referring to each lasted for several years and amounted to a change of climate state – see the third graph in my post. Alan

      • Alan, that is not true, 1741 wasn’t cold, 1743 was very warm, and 1784-86 was colder then it warms again from 1787. There is in fact an astronomical analogue of 1740 at 1919, and and analogue of the 1783-84 winter at 1962-63. These events happened outside of solar minima. These type of events are purely down to specific heliocentric configurations of the gas giants, and then the timing of the colder months through 1-3 years of the Jovian event is decided mostly by where Earth and Venus are in relation to them. What we are seeing with these events, just as with any short term hot event, is short term solar effects on the atmosphere. And the 179.05yr analogue for your number 6 event is just coming up, and through a solar minimum, unlike the large SC8 that it mostly occurred in.

      • Anyway the increased negative will drive the North Atlantic (AMO) warm.

      • Alan Longhurst

        Ulric – the cold incursion I refer to is #2 on my graph and does not at all confirm your 1741 “wasnt cold” – but what region & data are you referring to? I do not mean to extrapolate my conclusions beyond the region sampled by these 22 data sets.

      • sorry… increased negative NAO etc

      • CET

  9. A minor nit pick. I don’t think that there was mass migration to America from Ireland in the 1750’s. Just did not happen. Perhaps Alan is confusing the period with the 1850’s? The 1740/41 famine was real enough, however.

    Tony.

    • Alan Longhurst

      Thanks for the rectification; obviously, the 1750s big freeze of harvested potatoes stared people too quickly to lead to emigration: one wonders, too, if aid (mostly in the form of maize, apparently, shipped in by the British government) arrived rapidly enough to do any good?

      • Alan

        Nice article. Of course we have numerous long term instrumental records together with a mass of supporting literature. There is very much more lying un digitised in such places as the Met office library and archives.

        Climate is highly variable. Winds change direction. Precipitation levels rise and fall. patterns of heat and cold alter. It is difficult to see that volcanic eruptions have much global effect although they may impact locally in the short term.

        People need to get out from behind their computers and look at the mass of evidence in the archives that show that variability is the natural order of things. This can also be seen on the ground with tree lines showing changes in the altitude they can grow at and in some places such as upland dartmoor the type of crops grown can be seen to alter as the climate changes.

        Tonyb

      • The “standard” economic history texts (meaning those in use 50 years ago, in my case!) used to say that from the 1750’s on, the “new” productivity of potatoes as a crop combined with better weather permitted the peasant population of Ireland to increase steadily until the blight hit in the 1840’s. As a boy in Sligo in the late 1940’s, I recall that the 1740 great freeze was not perceived as destructive as the 1840’s despair (to the extent the first was remembered at all in folk memory), since the ready availability of “free” peat as a fuel for cutting meant that while the country areas suffered some, it was not to the same extent as the bigger centres like Dublin and Cork where cheap peat was not available.

        Tony.

  10. The population of Ireland was growing in the 1750s.

    I’d suggest that the inconvenient truths shown by this post, are why temperature records prior to the turn of the 20th century, are ignored by Climastrologists. The story is wrong for their purposes.

  11. Pretty much what I’ve been telling you all for the past 10 years.
    The sun works on the ozone creation/destruction process in the stratosphere so as to alter the gradient of tropopause height between equator and poles which affects jet stream behaviour and global cloudiness.

  12. How about using PCA on all this? Without trying to turn everything into a “proxy” for temperature or anything else. Just look for PC’s in terms of the native data?

  13. Regarding Tambora and prior cold years, there is strong evidence for a very large eruption in 1809 of unknown, but likely tropical, location. It is also true that the climatic influence of even a Tambora-level eruption is about the same size as normal subdecadal internal variability in Northern Europe so extracting a clear signal is difficult.

  14. Paulskio

    The people in 1809 weren’t stupid. If there had been such a major eruptionn in 1809 that it radically affected the climate I think they would have noticed. I note from your link that part of the evidence comes from bristle cone pines so I guess we can surmise who is at the bottom of it . similarly bristle cone pines were used as the basis for the alleged dive into the LIA after a 1256 eruption but evidence shows the cold had already commenced.

    After studying many of these cold periods I find it difficult to see they precipitated major long lasting changes in the global climate although they may have had a short term mostly localised seasonal effect.

    Tonyb

    • If there had been such a major eruptionn in 1809 that it radically affected the climate I think they would have noticed

      What would ‘noticed’ mean? The tropics are a large place and communications at the time weren’t great. As the wiki indicates there were contemporary reports which may correspond to the event, just not enough to be conclusive. The Tambora eruption was well-observed because it occurred in the middle of Indonesia. An eruption somewhere more like the Central Pacific wouldn’t have been seen, or documented, as clearly.

      Deposits found in ice cores have been the main evidence for an eruption at that time, not bristle cone pines, regardless of irrational fears about them.

    • To clarify, I meant to say that it is difficult to see that volcanoes precipitated major long lasting changes to the climate

      Tonyb

    • > I note from your link that part of the evidence comes from bristle cone pines […]

      I don’t see where, TonyB, but I did note this sentence, which seems to be tailored made for you:

      De Caldas served as Director of the Astronomical Observatory of Bogotá between 1805 and 1810 and in 1809 reported a transparent cloud that obstructs the sun’s brilliance at Bogotá.

      Was De Caldas stupid?

      • Willard

        It mentions ithem in the first paragraph of ‘ background’

        You surely make my point. If someone in bogota observed the cloud, if it had been a global event others in places around the world would also have commented on it?

        Tonyb

      • TonyB,

        Here’s what PaulS paraphrased: A study of Greenland and Antarctic ice cores in the 1990s found markers that implied that a massive volcanic eruption had occurred in early 1809.

        Here’s your “but bittlescones”: Further research and bristlecone pine tree ring data pointed to the eruption being in 1808..

        You’ve used “further research pointing it may been a bit earlier” to dodge “strong evidence for a very large eruption in 1809.”

        Bristlecones were problematic a bit later, BTW.

        ***

        > You surely make my point.

        You’re making the same points over and over again, TonyB, but they shift from one comment to the next. Notice the shift from

        If there had been such a major eruption in 1809 that it radically affected the climate I think they would have noticed

        to

        If someone in bogota observed the cloud, if it had been a global event others in places around the world would also have commented on it

        .

        Counterfactuals are at best arguments. They’re not really points.

        Incidentally, I could use the same kind of counterfactuals to raise concerns about your pet project. Who in Bogota noticed anything from your extended CET reports?

      • Willard

        I said

        ‘If there had been such a major eruption in 1809 that it radically affected the climate I think they would have noticed

        to

        If someone in Bogota observed the cloud, if it had been a global event others in places around the world would also have commented on it’

        One person in Bogota is not ‘they’ is it, let alone ‘they’ from around the world.

        Give us hard evidence that such a major eruption occurred that was so massive that it ushered in possibly a decade of (possibly) global cold temperatures (which according to other records had already commenced, at least in localised areas.)

        Tonyb

      • Tony,

        My understanding is that people at the time did not link the massive Tambora eruption to any wider scale or global effects, so it would be completely normal to not hear anything about the global ramifications of such an eruption. We had extensive reports about Tambora because of its major local effects – massive death tolls, huge ash clouds – not because people thought it was influencing global weather.

        Give us hard evidence that such a major eruption occurred that was so massive that it ushered in possibly a decade of (possibly) global cold temperatures (which according to other records had already commenced, at least in localised areas.)

        Talking about cold decades ‘commencing’ like that is just not a useful approach. You can have a few cold years due to normal internal variability then a large volcanic eruption which causes another few cold years (which might have been normal or warm otherwise) then followed by another few cold years due to a mix of internal variability and continued volcanic influence. In this scenario there were cold years preceding the eruption but you wouldn’t have had a cold decade without the eruption. You have to think in terms of probability and tendency.

      • > Give us hard evidence […]

        Ice cores are not hard enough for you, TonyB?

        Sometimes, evidence simpliciter seems enough for you, e.g.:

        similarly bristle cone pines were used as the basis for the alleged dive into the LIA after a 1256 eruption but evidence shows the cold had already commenced.

        Note, not just “part of the evidence” or “strong evidence.”

        Was that hard evidence?

    • Steven Mosher

      It’s in my grandmother’s diary. It happened.

      • Curious George

        That’s not an anecdotal evidence. It is a HARD fact.

      • The one who lived to 101 and was know as that crazy old Mosher lady?

        I agree that diary entries are not scientific evidence. However as someone with both history and science degrees, I will argue that they can’t be dismissed out of hand.

    • There are many eruption types and all produce gas even though they do not produce dust. You might research the difference between Strombolian vs. Plinian. Even better yet:

      1808/1809 mystery eruption
      A colossal volcanic eruption in the VEI6 range is believed to have taken place in late 1808 and is suspected of contributing to a period of global cooling that lasted for years.[1][2]
      wiki- 1808/1809_mystery_eruption

      • Ccsquid

        Temperatures had already begun to slide by 1809 according to various data sets including Berkeley

        They also collate eruption details with the 1809 one being rather smaller than laki or Tambora, both of which had a limited global effect for a protracted period, Tambora fitting into this period whereby temperatures had already subsided

        As I said above, I think it would be interesting to see an objective volcanic article here at CE.

        Tonyb

      • Ccsquod

        Sorry, that graphic must have remained in my iPads memory, this is what I wanted to link to

        Tonyb

      • Curious George

        This CET graph looks like a Donald Trump’s signature. A coincidence?

      • Curious George.

        It’s not CET it’s BEST.. Does best trump cet?

        Tonyb

    • > 1256 eruption but evidence shows the cold had already commenced.

      Not there:

      • Willard

        Thank you. I already have the complete Prybil data including the paper and graphic in my archives and think I referenced it here some time ago. They presented it at a conference at CRU a little while ago. Fortunately the manorial records are available prior to 1256 from a variety of different estates together with other crop records and a variety of observations. These can fill in the large gaps as they mention autumn and winter

        John Kington of CRU wrote a good book on the period. The 13 th century temperature generally was on a declining trend since around 1205 as evidenced also by le Roy ladurie and his glacier observations.

        Tonyb

      • Willard

        Didn’t mean to sound supercilious, I am always happy to see any info on English temperatures in the medieval period that you may come across.

        Manorial records are specially interesting and we translated some in latin from an estate in Hampshire in southern England just last year. Their problem, as with tree rings, is that they generally cover just the growing period.

        Fortunately some estates also cover the other seasons.

        Tonyb

      • > Didn’t mean to sound supercilious,

        I don’t mind much. It may be too late:

        I note from your link that part of the evidence comes from bristle cone pines so I guess we can surmise who is at the bottom of it

        ***

        > Fortunately the manorial records are available prior to 1256 from a variety of different estates together with other crop records and a variety of observations.

        This contrasts with what Prybil says in 2014:

      • Willard

        Fortunately there are many manorial records and new ones are being found all the time.

        For example the met office archives have a number which as uet don’t appear to be digitised. Here is the national archive

        http://discovery.nationalarchives.gov.uk/results/c?_st=mdrc&_col=500&_sf=textstman&_ocn=Berkshire&_naet=M&_p=0&Refine+dates=Refine

        I would agree with pribyls comments, other than there are a number of good records from around 1150 and they commence in a meaningful but limited way from the domesday book.

        Tonyb

      • Have you heard of tambora.org, TonyB?

      • Willard

        I contacted them about this time last year but at the time their documentation and retrieval systems were not really working well as they were a pretty new organisation

        It’s good to be reminded about them, thanks.

        Tonyb

  15. Pingback: The value of very long instrumental data series | Climate Etc. | jamesbbkk

  16. Paul

    Here is a chart I created for an earlier article. Clearly there were periods of cold weather in the Years before and after the 1809 eruption

    There is little evidence to suggest that 1809 was the cause of anything
    Longer lasting

    Tonyb

    • I’ve already said the size of normal internal variability in Northern Europe is about equal to the expected size of Tambora climate influence so it’s probably not possible to extract any definitive signal from these highly regional records. We can see that two of the coldest years in the HadCET record occur during this volcanically-active period and that the five-year running mean centered on 1814 is the coldest after 1700. We can therefore say that it’s consistent with what would be the expected under influence of 1808/09 + Tambora eruptions.

      What I was pointing out was that a general tendency for colder years prior to 1815 is expected due to this apparent earlier eruption.

      • Paulskio

        I have had this discussion many times on this blog whereby a specific volcano is cited as precipitating a global and long lasting reduction in global temperature. On closer examination, either the event is short lived or the reduction in temperature had commenced Years before the volcanic event occurred.

        Consequently my conclusion is that major eruptions, depending on their location, can have an effect ranging from global to only local, but it is inevitably short lived, perhaps a season or so.

        I do not think we have had an article about volcanoes on climate etc that objectively sets out the case so perhaps this is something Judith might feel worth sourcing?

        Tonyb

      • > On closer examination

        Of the hard evidence, no doubt.

    • Hi tonyb,
      Reading a book about Edward 1 and much of the information comes from the national archives at Kew, near London. Goes from 1240 up to the present. Just wanted to say thanks for awakening a dormant interest in early middle age history. thanks for all you have done with the CET temps over the years and historical exploration of the shadowy past.
      Scott

      • Scott

        There are some great sources of material, including Kew, the British Museum and the British Library

        Here is King Alfred’s will

        http://blogs.bl.uk/digitisedmanuscripts/2013/07/the-last-will-and-testament-of-alfred-the-great.html

        There is currently a great series on Alfred on the BBC. In earlier research I discovered that he had a meeting with a Viking trader who tried to persuade him to fund an expedition to the Arctic in order to profit from the great number of bowhead whales they had found, so guess that was around the time of the warming up of Greenland and Iceland

        There is also a fascinating letter in the British Museum from a wife whose husband was serving on Hadrian’s wall, about a birthday party she was organising which dates back to the early Roman conquest of Britain.

        Incidentally 1240 is slap bang in the middle of the century I am currently researching, which will look at the climate of the 13th century and in particular the weather around the time of the 1256 or so volcano referenced above.

        This is the account of Matthew Paris concerning the year 1240, we have lots of corroborative evidence of the conditions, from such as Manorial rolls from the great estates.

        “1240 dry Jan to March, wet from April to December but fruitful and abundant but wet and rainy autumn greatly choked the abundant crops.’

        tonyb

      • Tonyb
        They Vikings were known ideological conservatives. They were hetero-patriarchal, completely lacking in compassion for indigenous cultures, and practiced a ruthless form of hegemony.
        Their anecdotal observations were biased and should be ignored.
        Here in the US we are busy erasing our Confederate history from public view so that our children may feel comfortable.
        You guys in the UK should follow our enlightened example and bulldoze York.
        Especially if York voted Brexit.

      • Rebelronin

        I have given instructions to dismantle Stonehenge, even as we speak…

        Tonyb

      • “They Vikings were known ideological conservatives. They were hetero-patriarchal, completely lacking in compassion for indigenous cultures, and practiced a ruthless form of hegemony.”

        So Muslims are today’s Vikings?

      • Harkin,

        Islamic jihadists and Wahabists (sp?) maybe.

  17. I had not been aware that the Irish already cultivated potatoes in the 1700s. I have read somewhere that it was Joseph Banks who encouraged their cultivation in Ireland – but perhaps this was a matter of the intensiveness of their use as a means of upholding the Corn Laws.

    Off topic- I’m a huge fan, Alan, of your Mismanagement of Marine Fisheries, which has helped to guide my understanding of recent fisheries science. I am a historian of marine science and fisheries biology, and am delighted by your clear writing style and how easily you integrated historical elements into your account of the problems in the basic reasoning and science used to develop (flawed) fisheries policies. Your treatment of the political aspects of the cod crisis on the part of the government and scientists was particularly elegant. I also appreciated your hints of scepticism re climate alarmism (and your subsequent treatment of the problems in the science).

    Wish I could sign off with my name, but as a practicing academic in our current climate-totalitarian environment, whose most immediate colleagues do not share my scepticism, I cannot.

  18. Some early instrumental data from European central cities also indicate the power of urban warming to induce/facilitate changes in local vegetation. From Sukopp and Wurzel (2003), http://www.urbanhabitats.org/v01n01/climatechange_full.html:

    In big cities, the effects of global climate warming since the 1850s have been exacerbated by the heat-island effect. Berlin grew from a city of about 170,000 inhabitants in 1800 to a metropolitan area with 3.7 million inhabitants in 1910. Calculations of the increased warming effect of the urban climate are 0.2°C for 1798–1804, 0.7°C for 1831 to 1837, and 1.4°C for 1886 to 1898 (annual mean temperatures). For the period 1961 to 1980, there was a difference in the annual mean air temperature of more than 2°C between the center of Berlin and the surrounding areas. This warming correlates with a significant reduction of frost days: 102 days in the surrounding areas (Stülpnagel et al., 1990). Consequently, in Berlin, an accelerated invasion of nonnative species that tolerate higher temperatures could be expected. This hypothesis is supported by Figure 12, which shows an obvious increase in woody species that began to invade Berlin by the middle of the 19th century, coinciding with the changes in temperature: In the period 1756 to 1847, the winters were colder by -0.7°C than they were in 1848 to 1907, and before 1846, extremely cold winters were much more common.

    Similar trends have been observed for annual and perennial herbs in Berlin and for all established nonnative plant species in Germany. At first these trends were explained only by the huge increase in introductions and subsequent dispersal, promoted both by new transportation systems and the increasing commercial exchange of goods, which coincided with the diversification of habitats in the urban environment. But many of the nonnative invaders are native to warmer areas, and they are believed to benefit from a more favorable local climate, even on the small spatial scale of cities (Kowarik, 1995).

    • Its a good thing that we have about 15,000 rural stations then.

      Cluebird: every station is not berlin

      Even SO..

      The two longest records for berlin ( one in former east berlin ) both
      show NO MORE WARMING than rural stations. About 0.5C per century

    • and 1.4°C for 1886 to 1898 (annual mean temperatures).

      sounds most unlikely.

      For the period 1961 to 1980, there was a difference in the annual mean air temperature of more than 2°C between the center of Berlin and the surrounding areas.

      That is not surprising, a difference of 2 to 3 degrees C is about right for rural to urban areas.

      If I go for a night out in the nearby city in autumn or winter, I know I’m going to get a shock on the way home on the bike ( m/c ). There are some very cold spots out in the country. It’s marginally warmer as I enter the small town were I live. Just enough to provide some mild relief before I get home.

      It’s the initial growth that tends to bias records. The change from city to big city does not seem to add much more.

      • Greg

        Agreed. There is a very large difference in temperature from completely rural to substantial conurbation but once it reaches that stage I see little evidence that temperature will continue to increase, just that the warmer urban temperature will be spread over a much wider area.

        Tonyb

  19. In just a few parts of the world there exist meteorological agencies of high competence that have inherited the observations of their predecessors, processed them in acordance with modern requirements, and made them available to the community through the GHCN system operated by NOAA.

    Yes there are several long european records which are potentially very interesting. However, be aware that few of them with have escaped the attention of the homogenisation Nazis. They must be “corrected” to tell the right storey before being released.

    It’s bit like letting the police officers confer with each other about what they are going to say happened before asking them to write their statements.

    HISTALP in under the control of the Austrian meteorological service but they will not release the original untampered data. That means that no one can ever check and validate the sizable modifications they have applied.

    You can eyeball the graphs in the published papers and see two “corrections” of about 0.5 deg C each. Those are non verifiable and thus non scientific data tampering.

    The late Dr Bohm was in charge of that work and was also an attendee at european conferences on “data homogenisation” along with other star players like UEA’s Phil Jones.

    So if several data sets seem to corroborate each other do not be too surprised.

    don’t believe any data set until you ask ( and get ) the unmodified record. If you get told that the dog ate it , it got lost when we moved house or it’s not available because it is protected by intellectual property rights, or you can have it if you pay us 500 euros/dollar/pounds in order to “extact” what we already have sitting in front of us and you must sign a non-disclosure agreement …. you can be pretty sure that someone has their finger on the scales and does not want any one to check the “corrections” and “homogenisation” they have applied.

    As the old saying goes : why should I give you our data? You only want to find something wrong with it.

  20. Is this Michael Hart the author of “Hubris”?

  21. The ultimate value of very long temperature records is that, contrary to the presumptions of piecemeal index-makers, they alone contain unequivocal information about multi-decadal and centennial scale variations. They alone can show whether cross-spectral coherence at these crucial low frequencies is uniformly strong (indicating a common climatic regime) or weak (indicating site-specific variations typical of UHI and other corrupting influences in the record.)

    The notion that meaningful long-term data series can be reliably synthesized from decadal-length snippets of station data is the apotheosis of scientific ignorance, both physical and analytic. Given the characteristic imprint of siting upon temperature measurements in the face of natural variations, there simply is insufficient information available in mere snippets of data to maintain a consistent datum-level over quasi-centennial and longer intervals.

    • … and that “ultimate value” has been lost if the data have been fudged and manipulated to agree with each other or to some external expectations about long term warming trends being bigger or smaller than that shown in the raw data.

      “… they alone contain unequivocal information.. ”

      well it’s not unequivocal if it has been manipulated, that is my point. Others would argue that it’s unequivocal if it contains unchecked measurement biases.

      Nobody lives for 300 years, so I don’t see any more reason to believe that long records are necessarily any more self consistent than joining shorter records together.

      There are always equipment changes, observation method changes, personnel changes over centuries of data collection. Unequivocal, certainly not. That is why biases need to be checked and why any changes made MUST be done in the open, fully disclosed and scientifically verifiable and refutable.

      Sadly the usual opaque “corrections” are applied and raw data are carefully hidden away from view, and any attempt at validation is resisted by all means possible.

      I long ago gave up attributing any value to these long records because they have no objective value until they are open to validation.

      • Alan Longhurst

        Thats exactly why I went to the long data from European met agencies, who will have edited the data for technical issues before it was submitted to the GHCN; the same data show up in the standard archives – but after adjustment and homogenisation I dont trust, and very often also after truncation of everything prior to the 20th century.

      • Unequivocal, certainly not. That is why biases need to be checked and why any changes made MUST be done in the open, fully disclosed and scientifically verifiable and refutable.

        It should be apparent from the context, that I’m making an intrinsic analytic point about the information content of records that have been carefully vetted. as is the case here. You miss that intrinsic point entirely in writing:

        I don’t see any more reason to believe that long records are necessarily any more self consistent than joining shorter records together

        The fact that the longest period about which spectrum analysis provides any information is that of the given record length plainly escapes you.

      • Alas, WordPress ignored the blockquote designation for the first paragraph in my last comment.

  22. Eighty percent of volcanic eruptions occur under the ocean. That is four Krakatoas per century. Such events must surely affect ocean circulation which must, in turn, affect surface temperatures on land. See

    http://quadrant.org.au/opinion/doomed-planet/2014/05/ocean-vents-faulty-models/

    • John

      Around five years ago I was at a Cambridge university function and sat next to a volcanologist. She told me that they suspected there were ten thousand times more underwater volcanoes than had currently been discovered .

      I don’t know what has happened in the interim to validate or refute this comment. If true, presumably they must have a greater mpact than previously thought.

      Tonyb

      • The volcanologists would regard the impact of volcanoes on ocean circulation as a matter for oceanographers but they are not going to do it because they would regard such a study as volcanology.

  23. Temperature at great depth in the ocean is 0-2 *C. Large heat capacity but rapidly equalizes any volcanic or sea floor spreading heat input to remain largely stable at near 0*C. If one can’t measure the tempeature difference with current technology, which is as your comments before at some open forum indicated, we can’t know what the “greater impact or previously thought” impacts are. Could be a lot or might be trivial. All so uncertain.
    Scott

    • It is a question of plume dynamics. As hot water rises it is cooled by entrainment of surrounding cold water but at the same time the pressure is falling with decreasing depth. If the plume is sufficiently large it is conceivable that boiling may occur in the interior of the plume. Should this happen the buoyancy of the steam will radically alter the plume dynamics leading to faster rise times, more boiling and so on, as in a geyser. Such a boiling event could entrain a much larger amount of cold water and carry it much higher in the water column. A Krakatoa-size eruption in the right place could, perhaps, initiate basin overturning. It is about time someone modeled this.

    • Scott, that was my first thought as well. While it sounds like an interesting field of study, I can’t help but fall back on how vast the oceans are and how difficult it is to effect any significant change.

      Something all those pushing the acidification meme would do well to remember.

  24. A very long series of coin tosses will not tell you anything about the result of the next toss. Not even any chaos involved.

    If you believe that a longer chaotic record (weather parameters) will help to forecast, project, or predict the future, accurately predicting the result of the next coin toss should be a snap. Of course, only a fool would believe so. Hence the old saying that “A fool and his money are easily parted.”

    One use for a record of any length might be to assess the skill of any model you might care to design. Of course, it is much easier and cheaper to “eyeball” the data series backwards, and assume that your “average” will continue into the future.

    Oh, remember to include the proviso that you cannot be held responsible for acts of God, unforeseen circumstances, natural variations, or unknown unknowns.

    Ah, the rich tapestry of life – emerging slowly from the loom in all its chaotic complexity!

    Cheers.

  25. willard,

    I’m assuming you mean “fair” rather than calibrated, but anyway . . . Saying it “may” implies that “may not” is equally valid.

    That’s my point. Deny all you wish. The past tells you nothing about the future – probably because the future hasn’t happened yet.

    I think it was Robert Burns who said –

    “The best laid schemes o’ mice an’ men
    Gang aft a-gley.”

    But anyway. What were you disagreeing with me about? Should I have been more precise with my definition of “coin tosses”? I was trying to communicate to an audience who routinely redefine scientific terms to suit their changing purpose, and who can’t even produce a scientifically acceptable falsifiable hypothesis to support their bizarre claims that CO2 can raise the temperature of a planet by virtue of existing in the atmosphere!

    By the way, maybe you meant to write “your” (possessive) rather than “you’re” (you are), but GHE disciples are not always noted for their command of the niceties of science, let alone English. Even Steven Mosher (that scion of English grammar and punctuation), might exhort you to “Try harder”.

    Cheers.

  26. The Irish potato famine occurred in 1840s, this was when the fungus spread.

    The earlier one in 1740s was as a result of very cold and wet weather.

  27. Alan Longhurst, thank you for the essay.

  28. A great article Alan. It is very revealing that the official line does not fit the evidence available. I think that the connection to changes in NAO and AO is very opportune, although causality cannot be drawn from the coincidence, as both temperature and climatic modes could be responding to the same cause.

    I can only add, even if worth very little, that your temperature reconstruction does fit my personal experience in Central Spain. I was acutely aware of the warming that took place during the 80’s as the climate became quite different from what it was in the 70’s. As an avid skier at the time, it certainly affected the length of the skiing season in the very sensitive ski resorts of Central Spain. I have not experienced anything similar since the early 90’s, and I have looked at climatic records from Spain that clearly demonstrate that no significant change in temperatures or precipitations has taken place during the last 25 years in Spain.

    Global warming did take place, and frankly it was great except for skiing so far South. As for global warming still taking place, I would say the evidence is not very strong. The dissonance between what the data shows and what we are told is becoming too large and a lot of people are responding with skepticism, while in the 90’s almost nobody was skeptic. We had lived through it.

  29. Steven Mosher,

    I assume you are attempting to appear “sciencey”, if you will pardon my use of such a neologism. You wrote –

    “3. A competant analyst would not use data that has been deprecated
    BY THE VERY PEOPLE YOU SITE AS COMPETANT”

    It is no high recommendation to intentionally mutilate the English language in this fashion, without good reason. Have you any particular reason for expressing yourself in this fashion?

    If you really have difficulty with spelling, maybe you could look into using some sort of computer assisted spelling help. A useful computer application might also prompt you to capitalise cities such as Berlin. I apologise if you are intentionally trying to offend the citizens of other countries.

    In most cases, they will tend to excuse you on the grounds that you are an ignorant foreigner of little culture or understanding.

    There are several basic books on English, if you wish to learn how to express yourself effectively. These cover spelling, punctuation, grammar etc. Let me know if you need some help.

    Cheers.,

  30. Quote:
    “In 1942 an intensified Aleutian low induced warm anomalies over Alaska, while a pattern of weak Icelandic low and strong Scandinavian high led to an unusually persistent flow of cold arctic air over eastern Scandinavia.”

    We have had the Scandinavian high and flow of cold winds in Sweden for a week now and it seems to persist. I hope we are not facing an reiteration, because I am freezing.

    I do appreciate your texts for the facts contributed and the open minded interpretations they give raise to and I hope that Steven Mosher one day will accept that even discussions based on doubtful data is meaningful in the scientific context, just as discussions without data are in astronomy and elementary particle physics.

  31. Pingback: Weekly Climate and Energy News Roundup #245 | Watts Up With That?