A new paper published in Climate of the Past reconstructs temperatures over the past 1100 years from Eastern Arctic ice cores. The dating was done by Oxygen 18 isotope dating and the O18 data shows the highest Eastern Arctic temperatures of the 20th century occurred in the 1920′s-1940′s. The data shows that after that peak, there was a cooling or a warming ‘pause’ over the remainder of the 20th century.
The peak in the 1920′s likely explains this classic WUWT post showing observations from 1922:
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Great masses of ice have been replaced by moraines of earth and stones, the report continued, while at many points well known glaciers have entirely disappeared.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 Hockey Schtick writes:
Fig. 5a below shows a double peak in O18 proxy temperatures in the 1920′s and 1940′s followed by cooling to the ice age scare of the 1970′s, and temperatures in 2000 below those of the peaks in the 1920′s-1940′s. Five compilations of meteorological data of the Eastern Arctic in Fig 5b show good agreement to the proxy data.
This is the opposite pattern to what would be expected if man-made greenhouse gases were the cause, as even alarmists claim the increase in greenhouse gases has only had a significant effect since 1950. Instead, this new paper demonstrates Eastern Arctic temperatures peaked in the early 20th century, followed by a declining trend to the end of the record in 2000.
Of course, just like the surface temperature record, the long term trend is up, but clearly there is also a pause since the double peak, and that’s hard to explain in the face of a linear increase of (some claim exponential) GHG emissions.
Proxy temperature reconstruction from the paper in graph A, followed by other meteorological data and compilations of the Eastern Arctic.
Eurasian Arctic climate over the past millennium as recorded in the Akademii Nauk ice core (Severnaya Zemlya)
T. Opel, D. Fritzsche, and H. Meyer
Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Research Unit Potsdam, Telegrafenberg A43, 14473 Potsdam, Germany
Understanding recent Arctic climate change requires detailed information on past changes, in particular on a regional scale. The extension of the depth–age relation of the Akademii Nauk (AN) ice core from Severnaya Zemlya (SZ) to the last 1100 yr provides new perspectives on past climate fluctuations in the Barents and Kara seas region. Here, we present the easternmost high-resolution ice-core climate proxy records (δ18O and sodium) from the Arctic. Multi-annual AN δ18O data as near-surface air-temperature proxies reveal major temperature changes over the last millennium, including the absolute minimum around 1800 and the unprecedented warming to a double-peak maximum in the early 20th century. The long-term cooling trend in δ18O is related to a decline in summer insolation but also to the growth of the AN ice cap as indicated by decreasing sodium concentrations. Neither a pronounced Medieval Climate Anomaly nor a Little Ice Age are detectable in the AN δ18O record. In contrast, there is evidence of several abrupt warming and cooling events, such as in the 15th and 16th centuries, partly accompanied by corresponding changes in sodium concentrations. These abrupt changes are assumed to be related to sea-ice cover variability in the Barents and Kara seas region, which might be caused by shifts in atmospheric circulation patterns. Our results indicate a significant impact of internal [natural] climate variability on Arctic climate change in the last millennium.
[Note: this original post was written during my workday and making a comparison to the Cowtan and Way paper, and like sometimes happens during my day, I got interrupted, and then got off on a tangent that wasn't correct. To correct my mistake, I've republished this post sans that tangent. Later I'll get back to my original idea when I have more time. - Anthony]