The Arctic screamed since winter 1918/19, warming the
Northern Hemisphere for two Decades
The shown figures indicate clearly that it started in the Europe-Arctic section!
Posting January 27, 2019, by Arnd Bernaerts
One cannot support enough any attempt for a better understanding of the Early Twentieth Century Warming (ETCW), the most pronounced warming in the historical global climate record prior to the recent warming. At beginning of World War Second 
(WWII), the Northern Hemisphere was very warm, particularly to regional anomalies like the Arctic warming in the 1920s and 1930s. Until now the attention to these two decades has been remote in the general discussion on anthropogenic global warming (AGW). Even less was the attention to the book: The Artic Heats Up, published one decade ago, which discuss its close link to the Great War (1914-1918) This war gave the decisive push to ETCW in winter 1918/19.
The attention to the ETCW needs to grow, and hopefully a small step has been done recently. In a posting Professor Judith Curry observed: A careful look at the early 20th century global warming, which is almost as large as the warming since 1950. Until we can explain the early 20th century warming, I have little confidence IPCC and NCA4 attribution statements regarding the cause of the recent warming. At Climate Etc., (Jan23, 2019). This statement was caused by a paper of Gabriele C. Hegerl et al (2018): The early 20th century warming: Anomalies, causes and consequences.
The C. Hegerl’s paper illustrates exemplarily that climate sciences is paying too little attention to the oceans. To understand ETCW particularly to the North Atlantic – Arctic Ocean sector needs attention, when from the mid-1910s until the end of the decade, the air temperatures in the regions of Svalbard suddenly ‘exploded’. From there on the temperature increased across the entire Northern Hemisphere, in North America until about 1934, in Europe until the end of 1939. Here is an extract from the paper (Summary):
Attribution studies estimate that about a half (40–54%;p> .8) of the global warming from 1901 to 1950 was forced by a combination of increasing greenhouse gases and natural forcing, offset to some extent by aerosols. Natural variability also made a large contribution, particularly to regional anomalies like the Arctic warming in the 1920s and 1930s. The ETCW period also encompassed exceptional events … (cont).
NOTE: According the papers Introduction:
“the warming accelerated) from the 1890s to the 1940s.”
Even this short text is superficial in many ways. They investigate an Arctic event (ETCW), but base their consideration on 
mean-global temperatures (page 3). They miss completely the fact, that the rise did not started in 
the 1880s, nor 1901, but in winter 1918/19. Although the Figure 1 (and others) indicate that since the mid-1910s, the temperature dropped sharply, culminating about 1917. The authors seem to know nothing about it, or ignore it. Instead of distinguish between summer and winter season [during which influence of the sun is strongly reduced] they chatter about a combination of increasing greenhouse gases and natural forcing.
The reference to greenhouse gases is for two reasons nonsense. On one hand industrialization was still low. On the other hand assuming a trapping of heat in the Arctic atmosphere (greenhouse effect) during the winter season is a joke. There was no warmer region elsewhere, from where an ETCW could have sustained. Even more frightening is to rely on natural forcing. The weather system is based on physical forcing, from heat and water. They make no try to explain what that means and how it has made the Arctic warmer. It follows an excerpt from sec.3 (p.5): “CAUSES AND MECHANISMS OF THE EARLY 20TH CENTURY WARMING”
What caused the long-term warming from 1900 to 1950? The global temperature rise during the ETCW implies a change in the energy budget of the Earth’s atmosphere, which in turn suggests either an external forcing (volcanic, solar, greenhouse gases, tropospheric aerosols), changes in clouds, or ocean heat release (Brönnimann, 2015b)..……..
The magnitude and pattern of the response to an increase in solar forcing is highly uncertain (Gray et al., 2010). A detection and attribution analysis of temperature reconstructions of the past centuries suggests a rather small influence of solar variability on hemispheric scales (Schurer, Tett, & Hegerl, 2014), which, however, does not preclude regional and seasonal effects such as an influence on circulation contributing to cold European winters (Lockwood, Harrison, Woollings, &Solanki, 2010)……
An explanation why ETAW had to come as it came is not recognizable. This is due to the lack of willingness to consider the most important question, which source was available to generate the sudden warming:
p.8: Several questions arise: to what extent was the Atlantic Ocean driving an anomalous
atmospheric circulation contributing to Arctic warming, and to what extent was the atmosphere driving the ocean. …..that the SST anomalies in the Atlantic Ocean during the ETCW were largely driven by anomalous atmospheric circulation (Wood & Overland, 2010), consistent with the idea that atmospheric variability drives decadal ocean-related variability (Hasselmann, 1976).
p.11; After 1918 a pronounced warming started in the northern North Atlantic region (e.g., Yamanouchi, 2011). In Spitsbergen, the average temperature of the years 1919–1924 was 3°C higher than in the years 1913–1918 (Grant et al., 
2009). The step like temperature increase was noted by contemporary scientists, but no obvious change could be found in the instrumentation or station surroundings, and the change concurred with a decrease of sea ice.
Although the authors mention important parameters, they avoid checking these fact for why? Each of the shown Figures indicate clearly that it is a too limited exercise to approach the ETCW issue by global temperature average as the authors did. The scientific focus is on the atmosphere and remotely on the oceans, if at all. Although several distinctive feature should have jumped in the eyes; like the fact that “the years 1919–1924 was 3°C higher than in the years 1913–1918, it does not occur to them, whether the 1st World War of 1914-1918 contributed to the climatic change. It did. There was clearly a strong human component involved in the game. but climate science still only chatter, about the ETCW, which started around 1919, back 100 years ago.
For a full picture on ETCW see online:
The Book “Arctic Heats Up”,
2009, pages 105
