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Some comments on "The Manic Sun"

Recently a book by Nigel Calder with this title was published. This book partly deals with the work of the Danish meteorologists Lassen, Svensmark and Friis-Christensen.

The Danish researchers found a rather striking correlation between the length of the solar spot cycle and the temperature on the Northern Hemisphere (The Southern hemisphere was not considered.). Initially no (proposed) hypothesis to explain this could be given. (In 1990)
Later on they presented the hypothesis that the level of cosmic radiation had an influence on cloud formation in the atmosphere. When the Sun is active the level of cosmic radiation is lower (the solar wind, and its accompanying magnetic field, hinders high energy particles to reach the inner solar system).
A lower level of cosmic radiation leads to less cloud formation. So, the claim is: An active sun leads to less clouds and a higher temperature. Secondly it is stated that a shorter solar spot cycle coincides with a more active sun. This correlation is illustrated with impressive graphs with almost perfect fits.

In the news papers it was said that "the greenhouse theory does not exist", apart from the minds of "the greenhouse lobby".

My view:

First of all, in general, I thoroughly dislike conspiracy theories. The meteo scientists who participated in the IPCC were no "Greenpeace like catastrophists" but critical scientists with high standards with respect to integrity. Just consider the way how the final text of the 1995 IPCC report was agreed upon: Representatives from Kuwait and Saudi Arabia did NOT participate in the work to word the text of the report. In the final plenary editing meeting, however, they did their utmost to reach a "zero result" (no conclusions). If there is a bias in the 1995 IPCC report it might be over-cautious.

So let us stick to the facts. The Danes have generated some extremely interesting results, which certainly deserve a closer look.

But first of all there is the question: In what way is cloud formation stimulated by cosmic rays, and to what extent?
Secondly the influence of clouds on the temperature is rather ambiguous; Low clouds cool, high clouds warm; Clouds above oceans are different than over continents (over continents their droplet size is smaller due to a larger amount of condensation nuclei). Also the terrain above which they form (high or low albedo) is of importance when one considers their warming or cooling effect.
So saying "More clouds = cooler Earth" is, in my opinion, somewhat jumping to conclusions.
Thirdly the recent observations from satellites show an increase in cloud cover together with a weaker cosmic radiation level.

To conclude:
It way well be that the findings of Lassen, Svensmark and Friis Christensen are a valuable addition to the description of the atmosphere. However, the statement "the greenhouse theory has been refuted" is premature.

Later on some studies were made by meteo scientists of the KNMI (The Netherlands). They found the following:

  • The statistic correlation, found by Friis Christensen, Svensmark and Lassen, being an 80 year cycle in the Solar spot cycle is significant. It co-incides with the temperature rise on Earth in the 40-ties of this century, the cooling in the 60-ties and 70-ties, and the recent warming.
  • It is unknown where this 80 year period originates from. Nobody knows. Up to now it is nothing more than a statistic observation.
  • The variations of the Sun are not completely explaining the temperature variations in the 20th century on Earth.
  • The temperature variations on Earth can be explained much better than before using the refinement by Friis Christensen, Svensmark and Lassen combined with "the greenhouse signal".

So it seems a controverse similar to the C-T catastrophe. Asteroid or Volcanoes? May well have been both. Global warming: The Sun or greenhouse gases? Probably both!

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Below some extra graphs are shown on the subject solar spots and temperatures.
The following data were used (obtained from the KNMI internet site):

And finally: An example of rubbish on solar spots ...