Did the previous Arctic warming start in 1910 or in 1919?

Guest Post By Arnd Bernaerts


Figure 1.

The posting “Mapping global warming” (Jan. 18, 2010 by “KevinUK”) demonstrated convincingly that “much of the claimed global warming is hardly global at all. In fact it looks to be more accurately Northern Hemisphere warming, and for that matter primarily Northern Hemisphere WINTER warming!”. With interesting access to data and maps it is an enjoyable read, confirming that since 1880 there had been four distinct warming/cooling time periods i.e. from 1880 to 1909 (cold), 1910 to 1939 (warm)[1], 1940 to 1969 (cold) and 1970 to 2010 (warm).  From the dates given, I would like to object the date 1909/10, which should not be considered as the change from a cold to a warm period, as this happened some years later towards the end of the decade beginning in 1910, between 1916 to 1920, presumably in winter 1918/19.  Figure 1 reflects the situation from 1921 to 1930 (Details in the figures in the annex).  Does it matter if we are precise in this respect? The answer is clearly yes.  The more precisely a shift from a warm to cold period, and the region where it occurred is identified, the more it might be possible to identify the cause.  For this reason the following discussion is about the start of the first pronounced warming period after the end of the Little Ice Age, which actually commenced as an Arctic warming, primarily close to the Fram Strait region.


Figure 2.

A substantial point observed by ‘KevinUK’, as already mentioned, is the more pronounced warming of the Northern Hemisphere and primarily during the winter season. That is exactly  what the warming period in the early 20th Century is primarily about. While the summer temperatures increased only modestly, the winters generated the steep warming as observed at Spitsbergen (Fig.2), which is also well reflected in the annual data set for north of latitude 70°N (Fig. 3 & 4). The decade from 1921 to 1930 showed a remarkable winter warming (Fig. 5 & 6), which lasted until 1940 (Fig. 3 & 4). This fact is a paramount aspect to identify the reason for this significant shift during the winter period the influence of the sun is remote north of 50°N (i.e. London, Vancouver), but any warming must have been coming from somewhere.

Figure 3.

Figure 4.

Time and Region

Figure 5

Figure 6

Figures 1, 5 & 6, give a clear indication that the previous warming period in the 1920s and 1930s was primarily located in the North Atlantic section of the Arctic Ocean.  Figure 2, 3 & 4 demonstrate equally that the temperature rise commenced before 1920 (Fig. 5 & 6), probably in 1918 (Fig. 2).  This date (1918) should be regarded as the time the Arctic suddenly moved into a strong warming period.  Actually, the warming started in the Spitsbergen region in winter 1918/19 (Fig 7, Spitsbergen D/J/F), and was only subsequently observed beyond this station. Under these circumstances it seems difficult to regard the year 1910 as starting point. With some generalisation there had been a modest temperature increase before 1910 (Fig. 4), with a significant decrease from 1910 to 1917. At Spitsbergen the shift between DJF-1912/18 and DJF-1919/23 is about 8°C, for the whole Arctic region the increase between the decades before and after 1919 (Fig.3 & 4) is about 2°C.

Causation I: West Spitsbergen Current

Figure 7.

Having established the time and region of the sudden temperature shift close to Spitsbergen and narrowed it to the winter of 1918/19, it is time to ask, what caused and sustained the warming for two decades. For example ‘KevinUK’ states in the analysis of his Figure 8 that:  “This is demonstrates clear and significant natural climatic variability during this time period in different parts of the world”, and is reasoning in one comment that: “I’ve personally far happy to convinced that these observable difference in differential warming/cooling trend could be caused by differences in water vapour concentration/relative cloud cover, particularly late evening/night-time cloud cover.” The cause is presumably another one.

Figure 8.

The Arctic Ocean winter weather is dominated by a sunless period over more than 6 months, full sea ice cover, extreme cold, low humidity, low cloudiness, and anticyclones. Neither sun spots, nor carbon dioxide, nor water vapor can be considered as a significant direct contributor to generate a sudden remarkable shift and keep it sustained over two decades.  As there is no indication that this warming was generated elsewhere, and subsequently moved to the polar region (Fig. 1, 5 & 6), it must have been a local source, namely warm high saline Atlantic water carried by the West Spitsbergen Current to the Arctic Ocean.  Whether this change was due to an increase of the water masses, or due to a change in the structure of the various sea levels over a considerable depth around the gate to the Arctic Ocean, the Fram Strait, is not known. It seems that the latter is the more likely reason. (More details in Book-Chapter 7)

Figure 9 (left) to 12 (right)

Causation II: Shift of sea level structure.

Little is known about an extraordinary North Atlantic sea ice season in 1917. To my knowledge, such a long and extensive sea ice cover occurred only once throughout the 20th Century. Usually there remains a sea ice-free tongue off the shore of Spitsbergen (Fig. 9). Against all rules, the tongue disappeared in April 1917, the sea ice extended far to the South (Fig.10), remained very high throughout June (Fig.11), and only retreated in July 1917 (Fig. 12). About the consequences one can only speculate, but it was certainly not without any.

Throughout the long freezing process the ice-covered sea surface level must release salt, which makes the sea water heavy, and thus increases the vertical water exchange with deeper levels. During the subsequent melting process through July 1917 the sea surface  would have received a huge amount of fresh water; this stays at the surface level, until the salinity and/or water temperature is back to the normal.  This highly unusual event in the Northern North Atlantic from April to July 1917 could well have contributed to a shift in the ocean structure between Spitsbergen and the Fram Strait, which subsequently caused the warming of the Northern Hemisphere from winter 1918/19 to 1940.

Causation III: The change in the northern NA ocean structure.

This is worth further discussion at another time – for now only I will make this  comment. As there was nothing in “the air” (for example a volcanic eruption, a major earthquake, a tsunami, a meteorite plunging on land or into the sea), perhaps we should recall what happened in Europe from 1914 to November 1918. Over four years a devastating battle on land, in the air and at sea took place. Huge naval forces battled in the waters in the east and west of Great Britain, it is my view that this may have  changed the sea structure with respect to heat and salinity over many meters depth. All this water moved north with the Norwegian Current, and the West Spitsbergen Current, to enter the Arctic Ocean after a time period of several weeks or months (Fig. 8). This could have influenced the exceptional sea ice conditions during summer 1917, or even may have contributed alone, via a change in the ocean structure between Spitsbergen and Greenland, the climatic shift in the high north in winter 1918/19.  (More details in Book-Chapter 8 )

Further Reading:

WebBook (2009) “Arctic Heats Up. Spitsbergen 1919 to 1939”; http://www.arctic-heats-up.com

Paper (2010) “Indian Drought and North Atlantic 1917 & 1918” (PDF, 1MB)

Paper (2009)“The Circumstances of the Arctic Warming in the early 20th Century” (PDF, 0,9MB)

Home Page http://www.arctic-warming.com/


Fig. 1; based on material by: R. Scherhag, (1936), “Die Zunahme der atmosphärischen Zirkulation in den letzten 25 Jahren.”, Annalen der Hydrographischen Meteorologie, Vol. 64, p. 397ff, Tafel 62, Figure 10.

Fig. 2; based on material by: Hesselberg, Th.,  Johannessen, T. Werner; (1958); in: R.C. Sutcliffe, ed.; ‘Polar Atmosphere Symposium – Part I, Meteorology Section; Symposium at Oslo 2-8 July 1956, London, pp. 18ff; Figure 2.

Fig. 3; download from:  http://www.climate4you.com/index.htm >>“Temperature in Polar regions: Arctic and Antarctic”, >> Arctic temperature change, showing the mean annual surface air temperature (MAAT) anomaly 70-90oN compared to the WMO normal period 1961-1990, as estimated by Hadley CRUT. HadCRUT3 temperature data from the Climatic Research Unit (CRU) has been used to prepare the diagram.

Fig.4; Download from http://www.pi-news.net/wp/uploads/2008/10/arktis3.jpg

Fig. 5; based on material by: R. Scherhag, (1936), see Fig. 1; Tafel 58, Fig. 2 (Temperature deviation from November to March 1921-1930 versus long term mean.

Fig. 6; based on material by: Ola M. Johannessen, Lennart Bengtsson, Martin W. Miles, Svetlana I. Kuzmina, Vladimir A. Semenov, Genrikh V. Alekseev, Andrei P. Nagurnyi, Victor F. Zakharov, Leonid Bobylev, Lasse H. Pettersson, Klaus Hasselmann and Howard P. Cattle;  “Arctic climate change – Observed and modeled temperature and sea ice variability”;  Nansen Environmental and Remote Sensing Center, Report No. 218, Bergen 2002; Tellus 56A, (2004), p. 328 –341, Figure 2 (SAT trends north of 30°N in the winter period from  November to April, 1920-1939)

Fig. 7; based on Giss data: Source: Paper (2010)__“Indian Drought and North Atlantic 1917 & 1918”

Fig. 8; Source: http://www.arctic-warming.com/the-warming-event-in-detail.php (here: amended)

Fig. 9 – 12: based on data from: http://polar.ncep.noaa.gov/seaice/climatology/months.shtml; Source: Paper (2010)__“Indian Drought and North Atlantic 1917 & 1918”

[1] This time period is not generally acknowledged, as many authors identify as period the 1920s and 1930s (i.e. Drinkwater, 2006; Bengtsson, 2004, Johannessen, 2004), and the IPCC Report 2007 mention the time from 1925 to 1945; details at “Arctic Heats Up”, Chapter 2, p. 16f (see Further Reading).

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6 Responses to Did the previous Arctic warming start in 1910 or in 1919?

  1. tonyb says:

    Arnd Bernaerts

    Another very nice post. I’d agree with you about the start date of the previous warming being 1918/19. By 1922 it had become so noticeable that even the MSM were commenting on it by way of newspapers and Pathe News reel film.

    Look forward to your discussion of Causation III. They were also burning an awful lot of oil, not just for transport or manufacturing, but directly into the air in order to move fog away from airfields (with which GS Callendar no less was involved) That must have released an awful lot of Co2 but where it went and what it did I don’t know.


  2. tonyb says:


    In my post above the burning of oil was of course a reference to the second world war practices (which must have had an effect on climate then) but was just meant as an indicator that it was being used for all sorts of uses in vast quantities.

    During both wars oil was commonly poured by the Navy onto the seas around the coasts in order to smooth the wqaves for military exercises and often set fire to as a practice for possible offensive or defensive use.

    So much oil and coal being expended in both wars must have had some effect somewhere!


  3. ArndB says:

    Many thanks for your interest, and that you can agree with the timing 1918/19. Why is the research of leading Arctic scientists so unspecific in this respect, as i.e. Drinkwater, 2006; Bengtsson, 2004, Johannessen, 2004) name the “1920s and 1930s”, and the IPCC Report 2007 mention the time from 1925 to 1945, usually claiming that the warming was due to “natural variability”.

    Discussing the “Causation III” is on offer and possible at any time in a not to distant future. But please be not to surprised if I would abstain in discussing the impact of marine pollution, as I try to restrict my fact presentation and consideration on winter season at higher latitude, and the impact that naval war may have on the sea water temperature and salinity structure over a considerable depth. If that is reflected in, for example, short or longer lasting air temperatures changes, then human activities contributed. This can, I am convinced, be proven with regard to the three European war winters 1939 –1942, but the WWI period has also a lot of interesting aspects.

  4. tonyb says:


    I don’t know why they get the timing wrong as its well documented that by 1922 it had been happening for some years.



    “The Arctic ocean is warming up, icebergs are growing scarcer and in some places the seals are finding the water too hot, according to a report to the Commerce Department yesterday from Consul Ifft, at Bergen, Norway.

    Reports from fishermen, seal hunters and explorers, he declared, all point to a radical change in climate conditions and hitherto unheard-of temperatures in the Arctic zone. Exploration expeditions report that scarcely any ice has been met with as far north as 81 degrees 29 minutes. Soundings to a depth of 3,100 meters showed the gulf stream still very warm.

    Great masses of ice have been replaced by moraines of earth and stones, the report continued, while at many points well known glaciers have entirely disappeared. Very few seals and no white fish are found in the eastern Arctic, while vast shoals of herring and smelts, which have never before ventured so far north, are being encountered in the old seal fishing grounds.”

    The source report of the Washington Post article on changes in the arctic has been found in the Monthly Weather Review for November 1922.
    That article also lists a number of other warming episodes.

    Look forward to Causation III


  5. ArndB says:

    The report by George N. Ifft, seems to have first appeared in the Monthly Weather Review, Nov 1922, titled: „The Changing Arctic”. However it took another 8 years that the matter got into science. At http://www.climate4you.com/index.htm is the following text:
    ____1930: Birkeland draws attention to Arctic warming One of the first scientists to publish in a scientific journal considerations on the ongoing warming in the Arctic around Svalbard was the Norwegian scientist Birkeland (1930). Apparently he was surprised to see the considerable temperature increase 1917-1923, and stated in his paper that “I would like to stress that the mean deviation results in very high figures, probably the greatest yet known on Earth”.
    The source is: Birkeland, B.J.; ‘Temperaturvariationen auf Spitzbergen’, Meteorologische Zeitschrift, Juni 1930, p. 234-236.

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