More evidence that cloud cover – and not carbon dioxide – dominates climate

The Hockey Shtick reports on a recent paper by Aldert J. van Beelen and Aarnout J. van Delden of the Institute for Marine and Atmospheric Research Utrecht, Utrecht University, The Netherlands which shows that the hours of sunshine decreased somewhat from 1958-1983 and then increased sharply between 1985 and 2010 at a number of places. The authors postulate that the reduction of cloud cover since 1985 was possibly due to the cleaner air with reduced aerosols during this period.

It was not so long ago that the CERN CLOUD experiments showed that cosmic rays could indeed influence cloud formation providing support for Svensmark’s hypothesis that it is solar effects via cloud formation which dominates climate.

If we assume that the reduction in sunshine hours between 1958 and 1983 was due to man-made pollution and that this was reversed in the period after 1985, it still needs Svensmark’s solar effects or some other mechanism to explain the very sharp reduction in cloud cover and increase in sunshine hours  after 1985. It seems patently obvious from every day observations that cloud cover is far more important to weather and climate than any far-fetched notions of man-made carbon dioxide having any significant influence.

The Hockey Shtick: A paper recently published in the journal Weather finds that global summer average sunshine [solar short-wave radiation that reaches Earth’s surface] dimmed during the period 1958-1983 [prompting an ice age scare], but markedly increased from 1985-2010. The increase in summer average sunshine between those two periods is 6 Watts per square meter, which dwarfs the alleged effects of CO2 by more than 5 times. [Alleged CO2 effect from 1958-2010 was calculated using the IPCC formula 5.35*ln(389.78/315) = 1.14 Watts per square meter]. At one measurement site [De Bilt], summer sunshine increased from 1985-2010 by 15 Watts per square meter, more than 23 times the IPCC alleged forcing from CO2 during the same timeframe [5.35*ln(389.78/346.04) = 0.64 Watts per square meter].

The paper states the increase in sunshine reaching the Earth’s surface is due to a decrease in aerosols including clouds, which are influenced by both anthropogenic and natural factors, and possibly changes in solar activity.

from van Beelen and van Delden “Weather” Vol.67 No. 1, January 2012


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