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Monday, November 30, 2009

Peter Laut, J. Atmos. Solar-Terr. Phys., 2003, Solar activity and terrestrial climate: An analysis of some purported correlations

Journal of Atmospheric and Solar-Terrestrial Physics (Status of 28. February 2003: In press)

Solar activity and terrestrial climate: An analysis of some purported correlations

Peter Laut (Technical University of Denmark, Department of Physics, DK-2800 Lyngby, Denmark. e-mail:

Received 14 February 2002; received in revised form 22. January 2003; accepted 4 February 2003.


The last decade has seen a revival of various hypotheses claiming a strong correlation between solar activity and a number of terrestrial climate parameters: Links between cosmic rays and cloud cover, first total cloud cover and then only low clouds, and between solar cycle lengths and Northern Hemisphere land temperatures. These hypotheses play an important role in the scientific as well as in the public debate about the possibility or reality of a man-made global climate change. I have analyzed a number of published graphs which have played a major role in these debates and which have been claimed to support solar hypotheses. My analyses show that the apparent strong correlations displayed on these graphs have been obtained by an incorrect handling of the physical data. Since the graphs are still widely referred to in the literature and their misleading character has not yet been generally recognized, I have found it appropriate to deliver the present overview. Especially, I want to caution against drawing any conclusions based upon these graphs concerning the possible wisdom or futility of reducing the emissions of man-made greenhouse gases.

My findings do not by any means rule out the existence of important links between sol ar activity and terrestrial climate. Such links have over the years been demonstrated by many authors. The sole objective of the present analysis is to draw attention to the fact that some of the widely publicized, apparent correlations do not properly reflect the underlying physical data.

Key words: Solar activity, solar cycle lengths, cloud cover, galactic cosmic rays, global warming

Link to complete paper in pdf file format at the website of Dr. Stephen H. Schneider of Stanford University:

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