7 January 2023

Arctic sea ice contradicts with the climatic model predictions, but is that changing now?

One of the items I am deeply interested is the development of the climatic change in the Arctic area. For that purpose, I have made statistical analyses on the dependence between the atmospheric carbon dioxide concentration and the area of the arctic sea ice.

I published today my most recent analysis in Finnish, and decided also to write a short summary of that in English. I have also previously written a post on this topic into this blog, and recommend reading it in case you - my highly valued reader - are interested in details of this analysis. 

The idea of the analysis is simple: I am using September data (i.e. annual minimum) for arctic sea ice area of the National Snow & Ice Data Center (NSIDC) and carbon dioxide concentration measurements conducted in Mauna Loa. The latter ones are not available for year 2022 due to the eruption of the volcano, and therefore I had to use an estimate based on two previous measurements. The development of the concentration is given in the figure below, where the measured concentrations and estimated value are marked with blue and red color, respectively.



In the next figure I have marked the number of years after which a connection between the carbon dioxide concentration in the atmosphere and the area of the Arctic ice sheet is statistically significant in two consecutive years. In X-axis I marked the year from which each analysis series started.


The left side of the figure (yeasts 1979-2001) is according to the hypothesis, and the blue columns - i.e. number of years needed for statistical significance - are shortening from left to the right as predicted by the climatic models. However, starting from 2002 there are no consecutive two years with statistical significance, and therefore these columns are marked with red color. And their height is simply the number of data years used for each analysis. 

Thus, my analysis suggests that the prediction based on climatic models are supported by data from 1979 to 2001, but thereafter there is a strict contradiction between the models and observations. Normally such a discordance between observations and theory is used to falsify scientific hypotheses. I have, however, not seen that the such a decision would have been made or even discussed among the community of climatic researchers.

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Before ending this blogpost, I would like to point out that the most recent daily measurements of the Arctic sea ice extent have shown an extremely interesting change, where the relative extent of the ice has decreased compared to previous years. As a result, right now (January 5th) the size of the Arctic sea ice is the second smallest ever measured (for the fifth day of each year) despite the fact that e.g. in 5th November it was only at 11th position. 

Therefore it will be extremely interesting to follow how the Arctic sea ice develops in this year. Will its development return back to the development predicted by the climatic change, or will the last weeks´ phenomenon turn out to be only a temporary exception caused by e.g. exceptional weather conditions in the Arctic region. 

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