Little Ice Age thermometers – History and Reliability
Guest post by TonyB
How reliable are The Little Ice Age thermometers ?
The Little Ice age thermometers project is an attempt to compile instrumental readings from 1660 that predate the era of modern ‘global temperatures’ as recorded by Hadley (1850) and Giss (1880). These datasets are accessed from a graphic through this link;
The project will examine the reliability of these historic datasets as a means for climate researchers to gaze into our past to see if there are any lessons for the present. In this respect many of those individual stations found to date will have been included in the Cru datasets that are not readily accessible to those outside selected members of the scientific community. In order to examine these records and place them into context with Hadley/Cru and Giss, the author has produced three separate but interlinked articles as follows;
*This first one deals with activities centred around 1850/1880 a period which has had an important bearing on our current understanding of global temperatures.
*Article two will examine the development of the thermometer and our understanding of climate prior to the 1850/1880 records. In doing so we will pay particular attention to the quality/reliability of the readings used in the project, examine those who carried out the observations, and look at the circumstances under which they were collected. This should answer the question-are the readings a reliable record of the time?
* The third article examines the methods of compiling ‘modern’ records from 1850/1880-to today. In examining whether the historic temperature readings can be viewed as a useful tool for modern climate researchers, we also consider if the modern records are as reliable as they are portrayed.
In order to obtain some context of the period leading up to 1850/1880 some key historic points are outlined here to demonstrate that knowledge of weather, climate and temperatures, is not purely confined to the modern era.
An understanding of the importance of temperatures -and the climate they were a product of- goes back to the ancient Greeks who recognised the expansion of air by heat over two thousand years ago. The earliest writings concerning those phenomena were from the works of Philo of Byzantium (2nd Century B.C.) and Heron of Alexandria, each of whom constructed a crude ‘thermo scope.’
Aristotle subsequently postulated his four qualities, the hot, the cold, the moist, and the dry, and his ideas were adopted by Galen (A.D. 130-200), who was the first man to describe the heat and cold by a number about fifteen hundred years ago.
The rise of Rome coincided with the warm Roman optimum. We are fortunate that we have available the climate references from not only the Western Roman empire, but those of the Byzantine empire (the Eastern Roman empire after the collapse of Rome) approx 380-1453 AD. Collectively, the Egyptian, Roman and Byzantine empires can provide records of some 4000 years of climate change. Geographically this covers a large part of Europe, the Middle East and North Africa. Knowledge of the Vikings enables us to extend that geographic range far to the North. Studies from elsewhere in the world-including the Southern Hemisphere-provide tantalising glimpses of climate change elsewhere.
Some of the Roman climate references are fascinating. This observation from a series of cold winters -after many warm ones- around the 8th century in Byzantium (centred around Modern day Turkey)
“Theophanes’ account recalls how, as a child, the author (or his source’s author) went out on the ice with thirty other children and played on it and that some of his pets and other animals died. It was possible to walk all over the Bosporus around Constantinople and even cross to Asia on the ice. One huge iceberg crushed the wharf at the Acropolis, close to the tip of Constantinople’s peninsula, and another extremely large one hit the city wall, shaking it and the houses on the other side, before breaking into three large pieces; it was higher than the city walls. The terrified Constantinopolitans wondered what it could possibly portend.”
It would be remiss not to connect the Roman warm optimum and the series of savage winters recorded above that afflicted Constantinople, with the great medieval warming of Greenland and the age of the Vikings several hundred years later. This enables us to contemplate the astonishing notion of Romans and Vikings from respective warm periods co-existing in the same era, as Vikings guarded the capital of the Eastern Roman empire.
Constantinople was guarded by an elite mercenary squad of Russianized Vikings (who apparently were fond of the Mediterranean climate) named the Varangian Guard. According to a wonderful entry in this History of Warfare blog, (and we pick this story up in medias res)
In early 989 AD a Viking fleet arrived with the promised 6000 Norseman. A few weeks later they crossed the straits of the Golden Horn under the cover of darkness and took up positions a few hundred yards from the rebel camp. At first light they attacked, while a squadron of imperial flame-throwers sprayed the shore with Greek fire. Phocas’s men awoke to the terrifying sight of the Varangians swinging their swords and battleaxes. The result was a massacre. Basil with the aid of the Varangians soon crushed the rebellion entirely.
Figure 1: The Viking Varangian guard
After the rebellion, the Varangians were immediately established as the emperor’s personal bodyguards. Anna Komnena writing in ‘the Alexiad’ claimed that the Guard were far more reliable and trustworthy as bodyguards than native Byzantine troops.”
The Little ice age.
In due course we shall examine the Hadley/Giss data sets from 1850/80 which overlap with the final burst of the LIA. This period commenced around 1350 and is a much misrepresented era;
IPCC FAQ 6.2 Page114 of TAR4.
‘All published reconstructions find that temperatures were warm during medieval times, cooled to low values in the 16th 17th 18th 19th centuries, then warmed rapidly after that.’
Of course there were periods of bitter cold as this traditional view demonstrates
Figure 2 Hunters in the snow-by Flemish painter Pieter Bruegel the elder 1525-1569. Completed in 1565 and said to depict the first of the bitter winters of the Little Ice Age. This helps colour our view that this period was unremittingly cold-a mistake that even the IPCC make.
But these were interspersed with much warmer periods, illustrating that even through this anomalous period the summits and valleys that typify climate patterns through the ages still operated, as observed from the Roman optimum and Medieval warm period to the Modern warm period.
Figure 3 –Little Ice age and warm periods
Some of these temperature summits will be explored through the medium of the LIA thermometers projects in Article two and are even more startling than they appear in this graphic, demonstrating the periods of warmth during the LIA were not that much different to today.
It enables us to refute the comments of the IPCC by paraphrasing Michael Mann and assert that ‘the LIA is an outdated concept’.
Early temperature devices
Although there are many claims as to who built the first thermo scope (a thermo scope does not have a scale, a thermometer does) most authorities attribute its invention to the Italian scientist Galileo (1564–1642), probably in 1592. There are independent reports of air thermo scopes invented by Galileo’s medical disciple, Sanctorius (1561–1636). It appears likely that these were directly derived from Arabic translations of Philo and Heron’s work -compiled in Greek- from millennia before, referenced earlier.
Figure 4. Thermometers (1–5) and a hygrometer (6) of the Accademia del Cimento. (From Middleton ).physician and mystical philosopher, Robert Fudd (1574–1651); the clock maker, Cornelius Drebbel (1572–1633); and the engineer, Salomon de Caus . The first thermometers had the common property of being a tube of different construction opened to the atmosphere. They either did not have a scale, or they were crudely graduated with notches. They were usually intended for medical or meteorological purposes. The thermometers built by Evangelista Torricelli (1608–1647) had blown glass bubbles of different weight; the ball that floated determined the particular level of temperature. None of the scales were comparable with other instruments or accurate from one day to the other because of changing barometric conditions. The earliest air thermometer that corrected for air pressure seems to be the one described by Guillaume Amontons (1663–1705) to the Académie des Sciences in 1702 .
In January 1660/61-the year the Royal Society was established- English diarist Pepys observed; “It is strange what weather we have had all this winter; no cold at all; but the ways are dusty, and the flyes fly up and down, and the rose-bushes are full of leaves, such a time of the year as was never known in this world before here.”
One of the earliest attempts at calibration and standardisation between thermometers was made in October 1663 in London. The members of the Royal Society of London agreed to use one of several thermometers made by Robert Hooke as the standard, so that the reading of others could be adjusted to it. Thus the reading in one laboratory could compare a temperature to reading in another laboratory through the standard correction.
The Danish astronomer Rømer (1644–1710), discoverer of the finite speed of light, is assumed to be the first to build reproducible thermometers. In 1702 he proposed using two fixed points.
The development of stable Fahrenheit thermometers was a watershed point in the development of thermometry. The methods of making scale were in confusion at that time, because the craftsman in different countries used different calibration points (there were 18 scales up to 1841 and around 40 at the start of the 18th century).
Thermometers from their earliest days were precision instruments made with great care and at great cost. Some of the early manufacturers included Dolland and Newman, Adams and GB Fahrenheit. They were used as serious scientific instruments to observe, measure and record, but as ever the rich and powerful adopted the new technology and thermometers became fashionable
Frederik became King of Prussia in 1701 and immediately set up a measuring station that became Berlin Tempelhof, one of our oldest records (and mentioned in LIA thermometers) and this started a rash of similar stations that caused Samuel Horsley to comment in 1774:
‘The practice of keeping meteorological journals is of late years becoming very general’. The weather was seen to be important for our well-being. ‘We shall always search for ways to make observations more exact, both for the sake of agriculture and our health’, said Johann Hemmer in 1780. Records were kept for years in the hope of seeing patterns emerge which could have future use. As the LIA thermometers project illustrates, that is exactly what has happened as we are able to view climatic cycles through the centuries, somewhat disproving the Met Offices observations of limited climatic variability in the past. . http://www.metoffice.gov.uk/climatechange/policymakers/policy/slowdown.html
Extract “Before the twentieth century, when man-made greenhouse gas emissions really took off, there was an underlying stability to global climate. The temperature varied from year to year, or decade to decade, but stayed within a certain range and averaged out to an approximately steady level.”
The 1850/1880 dividing line which this article has taken as its focal point is a useful one, as 1850 is the date from which Phil Jones based his Hadley Cru set.
Figure 5-Global average land temperature from 1850-Crutem3 from Hadley/Cru
1880 is the date from which James Hansen chose to start his global records from.
Figure 6-Global average land temperatures from 1850-Giss
The link below is Hansen’s original 1987 paper where he identified the stations that he felt could be used in his own dataset. Figure 2 sums the numbers up.
GS Callendar -who in 1938 published his theory of man made warming caused by Co2- was a respected amateur meteorologist and believed the number of reliable temperature datasets (as opposed to available temperature datsets) numbered only a couple of hundred when he was making his study. Numbers tailed off dramatically as he regressed through each decade, with extremely poor coverage in the Southern Hemisphere throughout the study. It was for the resons of spatial numbers- not measurement quality- that Hansen decided that 1850 was not a practical start date and chose a later one which had slightly better spatial numbers. Even then there were very few thermometers giving consistent readings for anything other than the Northern Hemisphere and those mostly in Europe/North America.
This from Chiefio http://chiefio.wordpress.com/ illustrates the surprisingly small number of thermometers used in the GISS database (from the 1879 decade). (Article three draws much more from the remarkable work of E M Smith.)
The March of the Thermometers
Year, and 20 degree latitude bands, south to north. Thermometer years.
SP – South Pole SC – Southern Cold ST – Southern Temperate
SW – Southern Warm EQ – Equator NW – Northern Warm NT – Northern Temperate NC – Northern Cold NP – North Pole.
(So everything to the left of the EQ column is SH everything to the right of EQ is NH)
SP SC ST SW EQ NW NT NC NP
DecadeLat: 1709 0 0 0 0 0 0 0 1 0
DecadeLat: 1719 0 0 0 0 0 0 0 1 0
DecadeLat: 1729 0 0 0 0 0 0 0 1 0
DecadeLat: 1739 0 0 0 0 0 0 0 2 0
DecadeLat: 1749 0 0 0 0 0 0 1 3 0
DecadeLat: 1759 0 0 0 0 0 0 3 6 0
DecadeLat: 1769 0 0 0 0 0 0 6 10 0
DecadeLat: 1779 0 0 0 0 0 0 9 14 0
DecadeLat: 1789 0 0 0 0 0 0 16 16 0
DecadeLat: 1799 0 0 0 0 0 0 19 16 0
DecadeLat: 1809 0 0 0 0 0 1 24 20 0
DecadeLat: 1819 0 0 0 0 0 1 32 28 0
DecadeLat: 1829 0 0 0 0 0 2 54 48 0
DecadeLat: 1839 0 0 0 0 0 4 74 72 0
DecadeLat: 1849 0 0 1 0 2 6 93 82 1
DecadeLat: 1859 0 0 3 0 2 11 137 92 2
DecadeLat: 1869 0 0 15 0 3 7 173 103 1
DecadeLat: 1879 0 0 27 2 15 20 336 110 2
DecadeLat: 1889 0 0 44 10 18 48 624 184 3
DecadeLat: 1899 0 2 57 26 31 87 1175 309 3
DecadeLat: 1909 0 9 111 61 44 133 1510 382 5
DecadeLat: 1919 0 11 174 124 57 160 1789 479 8
DecadeLat: 1929 0 11 187 145 66 212 1961 545 16
DecadeLat: 1939 0 13 220 180 91 304 2156 713 26
DecadeLat: 1949 0 20 261 259 116 407 2412 887 37
DecadeLat: 1959 9 43 347 453 421 1010 3417 1249 80
DecadeLat: 1969 32 68 466 650 729 1310 4121 1511 105
DecadeLat: 1979 34 85 580 747 661 1269 4204 1511 103
DecadeLat: 1989 25 68 495 605 452 916 3805 1307 82
DecadeLat: 1999 9 32 212 250 224 429 2128 314 27
DecadeLat: 2009 7 20 102 132 159 316 1339 241 17
Figure 7-Thermometers by decade
More specifically in 1880 Africa had 14 thermometers; Asia 26, North America 233, Australia 30 and Europe 118.
There was a big upsurge in stations in N America from around this time and numbers rose to 1446 in 1914. Around 1880 there were a number of US weather related developments.
*General Hazen became the chief officer for the Signal Service (1880), but he was later discredited for allegedly embezzling $237,000 dollars. During his administration, other strife existed as the Army became increasingly unhappy that the enlisted men in the Signal Corps could not be pulled away from their duties and the weather.
*After General Hazen’s death in 1887, General Greely and President Benjamin Harrison were able to quiet some of the unrest and pushed to have the Signal Corps transferred to the Department of Agriculture on October 1, 1870. On July 1, 1891, all weather instrumentation and staff were transferred from the Signal Corps’ to the Department of Agriculture’s new civilian Weather Bureau.
*State Weather Services were organized starting in 1883 by Lieutenant. H. H. C. Dunwoody. In October 1895 control of the State Weather Services passed to the larger United States Weather Bureau formed in 1891.
Whilst there was a lot happening in the States, they were by no means the prime weather service in the world-the British, Dutch, or Swedes would claim that honour. . There was an upsurge in the numbers of stations precipitated by the demands of the embryonic weather services in various countries, military requirements, and partly because this was the age of mass production and thermometers became cheaper and more readily available. It thus made a final progression from a scientific instrument in the hands of well trained recorders to a more workaday tool, with all that meant in terms of the quality of observations made at the ever expanding station network.
There were other driving forces in the weather world at this time, and the most important of these was the invention of the Stevenson screen by British civil engineer Thomas Stevenson- father of author Robert Louis Stevenson- in 1864
It is this device that tends to be the great dividing line between historic and modern era -in as much instrumental reliability is considered better after its creation than before. This impression is somewhat mistaken as shall be illustrated in article two, as it assumes trained observers- whose life work was often recording weather and temperatures- did not understand how to observe temperatures accurately before the advent of the Stevenson screen. Any potential shortfalls there may have been in the accuracy of the historic records have been corrected by later generations of dedicated researchers. One of the most famous of these is G Manley who spent a lifetime researching British temperature records and published his findings in an article dated 1974. The UK has the longest instrumental records of anywhere in the world, allowing recent climate changes to be judged in the context of the last 250-350 years. The Central England temperature (CET) series starts in 1659 and was enhanced by Parker et al. (1992) who added the daily series back to 1772, it is routinely updated and the monthly data can be found online.
The Stevenson screen
The Stevenson Screen or thermometer screen is a standard shelter (from rain, snow and high winds, but also leaves and animals) for meteorological instruments, particularly wet and dry bulb thermometers used to record humidity and air temperature.
It is kept 1.25m/4.1ft (UK standard) above the ground by legs to avoid strong temperature gradients at ground level, has louvred sides to encourage the free passage of air, and is painted white to reflect heat radiation, since what is measured is the temperature of the air in the shade, not of the sunshine.
Proper siting and construction are vital if an accurate reading is to be obtained and the early practice of constructing screens of asbestos board, size variations, siting confusion, internal coatings of paint, all had accuracy impacts, many of which persist to this day
and this; http://www.surfacestations.org/
It took some decades before the Stevenson screen became universal. This paper calls on the work of Parker and others in examining the effects of the Stevenson screen and earlier shelters on instrumental readings.
“Many early thermometer-stands were open to poleward, allowing reflected solar radiation to affect the thermometers by day, and permitting radiative heat-loss at night. As a result, recorded diurnal ranges were enhanced relative to what would have been measured in Stevenson screens (Figs. 2 and 3). The effect was greatest in summer. There were differences between types of thermometer-stand: for example, the night-time cooling evident in the Glaisher stand (Fig. 2; Margary, 1924) was not found in the French stand (Dettwiller, 1978). Also Young (1920) only found generally small biases in the USA’s fruit-region shelter. His sample, however, was small.
Wild’s apparatus, common in Russia and eastern and central Europe in the late nineteenth century was more complex, consisting of a cylindrical shield inside a
louvred screen. Parker (1994) provides illustrations. However, its biases also enhanced the recorded diurnal ranges (Fig. 4), though with less of an annual cycle than for the open stands. In the tropics, thatched or felted sheds were common until the 1920’s, the thermometers being suspended from the eaves in a cage, or fixed to a trellis in the shed. Receipt of reflected solar and emitted longwave radiation from the ground outside the shed made maxima too high relative to a Stevenson screen, and minima were also too high owing to retention of heat by the roofing material. According to the results of Field (1920) (Fig. 5a) diurnal ranges were slightly reduced on an annual average, but with some seasonal variation; Bamford (1928), however, obtained an enhanced diurnal range throughout the year (Fig 5b). The biases will have been affected by the material used in the shed, by the reflection and emission properties of the ground outside it, and by the radiation and advection (wind)
climate of the site. The results of all instrumental comparisons must be to some extent site-specific.
North-wall screened exposures yield reduced diurnal ranges (Fig. 6; Marriott, 1879). These exposures were common in much of central, northern and eastern Europe in the late nineteenth and early twentieth century, Russia before the 1870’s, USA until 1890, Canada in the late nineteenth century (Parker, 1994).
Hazen (1885) examined unscreened north-wall exposures, which were common in the USA and Prussia until the early 1890’s. His results were for fixed hours (as opposed to maxima and minima) and suggest a slight enhancement of the diurnal range. However, the results will have been dependent on the particular sites used, and generalizations must be made with caution. Some old exposures have never been compared with Stevenson screens. A particular example is the Canadian screen and shed described by Kingston (1878) and illustrated by Parker (1994). Reconstruction of the apparatus, and a series of comparative measurements have been recommended (Parker, 1994).
The above results show that in most, but not all, cases, apparent diurnal ranges were reduced by the introduction of new instrumentation.”
The slow spread of the screen can be seen in this article about the Australian experience;
“There is ample contemporary evidence that most meteorological thermometers in Australia were not exposed in Stevenson screens until very late in the nineteenth century, and in many places not until well into the twentieth century. There is also evidence, from a long-running comparison at Adelaide, that mean temperatures in a Stevenson screen are lower than in an open stand in Australian conditions. Thus, there are strong grounds for expecting that nineteenth century, and some early twentieth century, Australian temperatures are biased warm, relative to modern exposures.”
So if objections are made to the accuracy of pre Stevenson screen temperatures- and bearing in mind the effective date of almost universal introduction is around 1920- then logically some 70 years of Hadley and 40 years of Giss must be discounted.
At this stage three things must be considered -firstly that mercury or alcohol thermometers can not be used to compute fractional temperature differences. At best they may be accurate to 0.5 to 1 degrees in well trained professional hands.
Secondly, in these days of ‘global’ temperatures it is easy to forget that a thermometer was designed to merely record the microclimate immediately around the device, and thirdly that using such devices to record an accurate global temperature takes an extraordinary leap of faith that sufficient numbers of properly sited, consistently monitored and accurate thermometers are used, and that these stations were never moved, deleted or had all sorts of debatable corrections made to them. That the end result can only be approximate is evident –to believe we know global temperatures have risen by a figure as precise as say 0.7c since 1880 is rather fanciful.
The LIA thermometers project makes no claim beyond the recording of the micro climate around the instrument. The global temperatures go much further in gluing together numerous micro climates which often bear little relationship to the original reading as they have been adjusted so comprehensively.
This observation is fundamental to understanding the relative merits and accuracy of the individual LIA thermometers and the global datasets from Hadley and Giss. What a micro climate is, how they are affected by a variety of factors, and what lessons they can teach us in examining the viability of historic or modern records is explained by the following series of article-this first explains the general principles;.
This next link is a good document of a practical study of micro climates (Teignmouth on the South coast of England, and Princetown on the uplands of Dartmoor a few miles away ) This also has very good study of London weather stations, amply illustrating micro climates and the impact of UHI (which will figure prominently in article three).
This about world climate zones;
The considerable impacts of land use on local/regional temperatures are discussed here;
As can be seen microclimates are influenced by many factors, prevailing winds-which can change, the warmth of the sea, humidity, forestation/ground use, relative sunshine, developments, prevailing weather systems etc. These can all alter microclimates characteristics over time so that it becomes warmer, cooler, wetter or dryer relative to another microclimate in which the characteristics –such as a change in the prevailing wind direction-come into play in a different manner.
The emphasis on global temperatures obscures the data the micro climates are providing. One of these is that there are dozens perhaps hundreds of locations from around the world that have been cooling for at least thirty years, some from the 1930’s and even earlier, in contradiction to the IPCC who assert;
“Over 1901 to 2000 as a whole, noting the strong consistency across the land-ocean boundary, most warming is observed over mid- and high latitude Asia and parts of western Canada. The only large areas of observed cooling are just south and east of Greenland and in a few scattered continental regions in the tropics and sub-tropics.”
Global data also obscures the fundamental impact of UHI on many individual locations, and also that some modern micro climate data no longer actually comes from the micro climate it originally began recording. Add to this data that has been adjusted to such a degree that any rational comparison becomes difficult, and the complexity of unravelling what is really happening becomes evident.
1850/1880 marks a watershed in the transition of the recording of micro climates to that of it being used to measure global temperatures. It also marks a fundamental clash in interpretation of history in as much Dr Hansen’s 1987 paper appears to make no acknowledgement that what was being recorded from 1880 was an upswing in temperatures from the lowest point of the climate cycle that heralded the final epoch of the little ice age. Indeed Dr Hansen says that he could find no sign of a cold period around 1880.
Clearly this interpretation is of fundamntal importance as there also appears to be no mention that taking readings from the top of the previous warm cycle would have caused entirely diferent conclusions to be reached than have been, namely that todays temperatures were nothing out of the ordinary when seen in context against the pre 1880 datasets when coupled with contemporary acounts of the times reaching back through the LIA to the MWP and Roman optimum.
These are themes that will be taken up in the next articles.
Acknowledgements and references not carried in the body of the article
(About Greek thermoscopes)
Figure 3-. Origin unknown.