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Solar activity over a number of years

14 November 2012

At http://wattsupwiththat.com/2012/11/11/solar-activity-past-present-future/ … is a post by Dr Leif Svalgaard, solar scientist and presumably an establishment figure but one that has taken part in the climate science debate over a number of years. The article is potentially important but has not been universally received with relish. A head of steam has in recent years got heavily puffed up over the possibility we are on the verge of a cooling episode – the opposite of global warming. This is due to the fact the current solar cycle has seen less sun spots than the immediately preceding cycles, the implication being that warming in the late 20th century was due to higher than normal activity on the face of the Sun. Taking this theory a step further, the accolades are suggesting the next solar cycle will have even fewer sun spots than the current one and we will drop into a Solar Minimum, pointing to the fact that the second half of the 17th century coincided with a period when sun spots dried up. This was of course a period associated with the Little Ice Age – but so was the first half of the 17th century, when sun spots appear to have been recorded. The Svalgaard article throws cold water on the idea that low sun spot activity necessarily means global cooling. He does not discount it entirely but suggests that the quality of telescopes in earlier centuries was much to be desired in comparison with the high technology of the modern world. Svalgaard is one of those people sparse of words. Where another person might spout an A4 page of verbaige he will condense it into a single sentence. In taking account of differences in recording what is a sun spot, then and now, and the technology, which still exists as an artifact, sun spots flat line. We should bear in mind that although sun spots in the present cycle are much lower than those of the 20th century global temperatures have not plunged. If lower sun spot counts are not responsible for the Little Ice Age and then something else was responsible. Clube and Napier thought dust in the upper atmosphere played a role as the orbit of the Earth passed through an area of space in which a Taurid meteor stream had dispersed at some point in the past. The residue of the dust, although dissipated from the kind of stream that may have caused more intense problems in the past, was nevertheless capable of seeding the upper atmosphere and creating an opaque atmosphere that restricted the ability of the Sun to fully heat the surface of the Earth, as it does now. More importantly, the fact the dust was dissipated over a large area of space would account for the fact that the weather was not universally cold and inhospitable throughout the period we call the Little Ice Age. If Svalgaard is correct in his analysis other ideas, such as this, might be explored. However, not everyone has received the article with goodwill – as is obvious by the post at http://tallbloke.wordpress.com/2012.11/12/leif-svalgaard-solar-terrestri… … but we might bear in mind that Tall Bloke is taken by the idea of planetary influences on the Sun.

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