Watts Up With That (WUWT) has a new post, from the Hockey Schtick, called remarkable correlation of Arctic sea ice to Solar cycle length. The post reports on a paper published by the Danish Meteorological Institute (DMI) which discusses a link between Arctic sea ice and Solar cycle. As far as I can tell, this is a scientific report to the DMI and not a peer-reviewed article. The WUWT posts reports that
The paper adds to several others demonstrating that Arctic sea ice extent and climate is controlled by natural variations in solar activity, ocean & atmospheric oscillations, winds & storm activity, not man-made CO2.
Really? If you want to read the paper, a PDF copy can be downloaded here. Maybe the crucial part of the paper is the first few lines of the abstract (which the WUWT post includes but doesn’t highlight). They are
The extent of ice in the North Atlantic varies in time with time scales stretching to centennial, and the cause of these variations is discussed. We consider the Koch ice index which describes the amount of ice sighted from Iceland, in the period 1150 to 1983 AD.
So, this paper is only discussing sea ice variations in the North Atlantic and these variations are determined using sightings taken from Iceland. This paper is not, in any way, discussing the full Arctic sea ice extent.
The paper does go on to say
In view of the large significance observed we suggest that the correlation of 0.67, between multi-decadal modes in the Koch ice index and the solar cycle length, is indicative of a relationship not due to chance.
I’m not a fan of simply using a strong correlation to imply some relationship without necessarily trying to understand the underlying physical processes involved. However, it may well be that the extent of sea ice observable from Iceland does depend on Solar cycle. The Sun clearly plays a dominant role in defining our climate. The paper concludes by saying
The considerations of the impact of natural sources of variability on arctic ice extent are of relevance for concerns that the current withdrawal of ice may entirely be due to human activity. Apparently, a considerable fraction of the current withdrawal could be a natural occurrence
So, the report does actually try to link their results with the currently observed drop in Arctic sea-ice extent (and volume/mass). Given that their paper is based on sightings taken from one point in the North Atlantic (Iceland), I would suggest that this is a rather large extrapolation.