Paper finds Arctic climate & sea ice extent related to solar activity

A paper published by the Danish Meteorological Institute finds a remarkable correlation of Arctic sea ice observations over the past 500 years to "the solar cycle length, which is a measure of solar activity. A close correlation (R=0.67) of high significance (0.5 % probability of a chance occurrence) is found between the two patterns, suggesting a link from solar activity to the Arctic Ocean climate." 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.

Solar Cycle Length [SCL] shown by dotted line, Koch sea ice extent index from observations in the Greenland Sea shown by solid line.

Multi-decadal variation of the East Greenland Sea-Ice Extent: AD 1500-2000



Knud Lassen and Peter Thejll



Abstract: 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. This measure of ice extent is a non-linear and curtailed measure of the amount of ice in the Greenland Sea, but gives an overall view of the amounts of ice there through more than 800 years. The length of the series allows insight into the natural variability of ice extent and this understanding can be used to evaluate modern-day variations. Thus we find that the recently reported retreat of the ice in the Greenland Sea  may be related to the termination of the so-called Little Ice Age in the early twentieth century. We also look at the approximately 80 year variability of the Koch [sea ice] index and compare it to the similar periodicity found in the solar cycle length, which is a measure of solar activity. A close correlation (R=0.67) of high significance (0.5 % probability of a chance occurrence) is found between the two patterns, suggesting a link from solar activity to the Arctic Ocean climate.