Story submitted by Cornelis de Jager
(past president ICSU;past pres. COSPAR)
In a recent publication entitled Terrestrial ground temperature variation in relation to solar magnetic variability, including the present Schwabe cycle, Cornelis (Kees) de Jager and Hans Nieuwenhuijzen, from the Space Research Organisation of the Netherlands have analysed the dependence of the global earth temperature on the polar as well as the equatorial magnetic fields. The new aspect in this research is that all earlier investigations in this field only sought for the dependence of the terrestrial ground temperature on the number of sunspots, which is a “proxy” for the equatorial magnetic fields of the sun. But the sun has two big magnetic areas, the equatorial and the polar one. In this research both are included.
In their analysis the Utrecht scientists restricted to the relatively long-term variation of both fields as well as the temperature, such in order to exclude short-term phenomena such as temperature variations due to volcanoes or processes like El-Nino.
By including the two magnetic field areas in their analysis it could be shown that during the major part of the four centuries investigated, i.e. the period 1610 till around 1900 – 1950 , the average terrestrial ground temperatures depend solely on solar magnetic field variations. After 1900 there is an increasing excess in the temperature which is ascribed to anthropogenic activity. After the impressive Grand Maximum of the 20thb century the sun went through an exceptional, not before observed phase transition that lasted relatively long, i.e. from about 2005 till 2010.
Usually, the transitions between solar variability phases takes no more than one to two years. During that transition period and after that, solar activity was exceptionally low. The consequent small contribution to the terrestrial temperatures is the cause for the standstill in the rise of temperature observed since the middle of the 20th century.
The above can be illustrated in figure 1, the diagram shows three curves. The middle one is the average terrestrial ground temperature (dots) through which a smoothed average curve is drawn .(The LOWESS technique is used for smoothing). The upper line shows the solar contribution and the bottom curve is the difference between the two. It shows a nearly flat variation which demonstrates that the long-term component of terrestrial temperatures is solely due to the variation of the sun’s magnetic fields. The average “zero-line” show a very slow , yet unexplained, increase over the centuries.
The paper is published in Natural Science vol. 5, pp. 1112- 1120, 2013 (open access). It can also be consulted at http://www.cdejager.com/wp-content/uploads/2013/10/2013-CdeJ-HN-Sun-climate-NS-5-1112.pdf