The Arctic sea ice cover was the lowest in recent decades for six weeks during May and June 2010. Since it recovered above the level of the last three years. (see Fig. right from 22Aug.2010). The decline in 2007 received considerable attention, e.g. by the NYT on 2nd October, 2007: “Scientists are also unnerved by the summer’s implications for the future, and their ability to predict it”. They should blame themselves.
There had been a Artic warming period for two decades in the first half of the last Century. Start and end of the warming was already recognised by H. W. Ahlmann in 1946, a minor warming “increased rapidly during the last decades [1918-1940]” . Although science has had ample of time to understand this extraordinary period thoroughly, the results are still poor. Also their predecessors during the pre and post WWII years failed to recognise the most northern sea areas of the Atlantic, respectively the West Spitsbergen Current as the primary source (see the references on this site). Why shall be discussed along a paper from the late 1940s, I was reminded while visiting the very informative “climate4you.com” today, which had caught my interest due to its very comprehensive list of references (about 400) some years ago: “Recent climatic fluctuations” by Leo Lysgaard .
Lysgaard recognises, like Ahlmann, that the winter warming in the Arctic had been more pronounced that during the summer season, but is much more unspecific (1949: Recent climatic fluctuations by Leo Lysgaard ). Thereon he discusses in Section 5 the “Cause and Effect of the Climate Variation”, and three possible ways of explaining the observed warming of the atmosphere:
- It can, inter alia, have received more heat from the interior of the Earth.
- It can have radiated less heat into space as a result of a change of the contents of carbon-dioxide, aqueous vapour, volcanic and electrical particles of the atmosphere.
- It can have received more heat from the sun in consequence of a variation in solar radiation or the contents of volcanic and electric particles.
“climate4you” selected the following Lysgaard explanation:
____”As regards Point 1, the quantity of heat which the atmosphere receives from the interior of the earth is extremely insignificant and as far as is known, no measurements exists indicating that the rise in temperature and the increased atmospheric circulation of recent years should be due to the heat of the earth.”
____”As to the other points, no measurements exist either which indicate that the carbon-dioxide contents have so increased that they have importance for the hot-house effect of the atmosphere. The course of the curves seems also to show that the carbon-dioxide cannot have caused the climatic variation.”
____”We will, however, keep to the causes of the present climatic fluctuations and to indications that the cause is to be found in an increase of solar radiation. One must prognosticate here that an increase of solar activity does not necessarily cause a rise in temperature over the whole earth, in any case not immediately. It is so that a variation in one weather element will inevitably cause variations in all other elements, a state of affairs which makes the whole problem so intricate and beyond computation. A temporary fluctuation of the solar radiation can thus very well produce a climatic fluctuation of considerably longer duration on the earth.”
No wonder that he contributed little to the understanding of the Arctic warming many decades ago. Like many of his colleagues at that time the oceans did not exist. The important aspects that the temperatures in high latitude regions during the winter season depend heavily on heat supply from the sea, and that any fluctuation of solar radiation have a minimal, if any, effect during the polar nights, is completely ignored. That he denies a detectable impact of carbon-dioxide on the climate variation should be of interest to those who make such claims today.
Left Fig: Annual Air Temperature 2009 vs mean 1998-2006 (see Reference)
Although Lysgaard’s considerations would presumably receive little support nowadays, modern Arctic science has hardly achieved more in understanding the reasons that lead to the Arctic Warming since winter 1919. That is even more surprising when it is meanwhile called : “as one of the most spectacular climate events of the twentieth century” (Lennart Bengtsson et al , 2004), due to: “temperature increase in the Arctic was related to enhanced wind-driven oceanic inflow into the Barents Sea with an associated sea ice retreat.” That is progress, but to little. On one hand the influence of the West Spitsbergen Current has not been investigated, on the other hand the significant difference between summer and winter temperature is to little addressed. But more importantly nothing has been said on what has caused the “enhanced wind”. The matter is about an enhance winter warming over two decades, which needs a increased and permanent heat supply from the sea, which in this case from the West Spitsbergen Current.
By Arnd-Bernaerts/23 August 2010
__Ice cover 22. August 2010: Danish Meteorological Institute Arctic Sea Ice Extent
__Decadal Arctic temperature data source: NASA Goddard Institute for Space Studies(GISS), as at: climate4you.com (Arctic precipitation and temperature change during the 20th century ).
__Annual temperature in 2009 vs average 1998-2006; source: NASA Goddard Institute for Space Studies(GISS), as at: climate4you.com. (Section: Arctic temperature change )